Relocation of code for the next commit. There should be no changes here.
Link: https://lkml.kernel.org/r/20220906194824.2110408-28-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
By using the maple tree and the maple tree state, the vmacache is no
longer beneficial and is complicating the VMA code. Remove the vmacache
to reduce the work in keeping it up to date and code complexity.
Link: https://lkml.kernel.org/r/20220906194824.2110408-26-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Changing mmap_region() to use the maple tree state and the advanced maple
tree interface allows for a lot less tree walking.
This change removes the last caller of munmap_vma_range(), so drop this
unused function.
Add vma_expand() to expand a VMA if possible by doing the necessary
hugepage check, uprobe_munmap of files, dcache flush, modifications then
undoing the detaches, etc.
Link: https://lkml.kernel.org/r/20220906194824.2110408-25-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Move find_vma_intersection() to mmap.c and change implementation to maple
tree.
When searching for a vma within a range, it is easier to use the maple
tree interface.
Exported find_vma_intersection() for kvm module.
Link: https://lkml.kernel.org/r/20220906194824.2110408-24-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Avoid allocating a new VMA when it a vma modification can occur. When a
brk() can expand or contract a VMA, then the single store operation will
only modify one index of the maple tree instead of causing a node to split
or coalesce. This avoids unnecessary allocations/frees of maple tree
nodes and VMAs.
Move some limit & flag verifications out of the do_brk_flags() function to
use only relevant checks in the code path of bkr() and vm_brk_flags().
Set the vma to check if it can expand in vm_brk_flags() if extra criteria
are met.
Drop userfaultfd from do_brk_flags() path and only use it in
vm_brk_flags() path since that is the only place a munmap will happen.
Add a wraper for munmap for the brk case called do_brk_munmap().
Link: https://lkml.kernel.org/r/20220906194824.2110408-23-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Only write to the maple tree if we are not inserting or the insert isn't
going to overwrite the area to clear. This avoids spanning writes and
node coealescing when unnecessary.
The change requires a custom search for the linked list addition to find
the correct VMA for the prev link.
Link: https://lkml.kernel.org/r/20220906194824.2110408-19-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Remove the RB tree and start using the maple tree for vm_area_struct
tracking.
Drop validate_mm() calls in expand_upwards() and expand_downwards() as the
lock is not held.
Link: https://lkml.kernel.org/r/20220906194824.2110408-18-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The maple tree code was added to find the unmapped area in a previous
commit and was checked against what the rbtree returned, but the actual
result was never used. Start using the maple tree implementation and
remove the rbtree code.
Add kernel documentation comment for these functions.
Link: https://lkml.kernel.org/r/20220906194824.2110408-14-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use the maple tree's advanced API and a maple state to walk the tree for
the entry at the address of the next vma, then use the maple state to walk
back one entry to find the previous entry.
Add kernel documentation comments for this API.
Link: https://lkml.kernel.org/r/20220906194824.2110408-13-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Using the maple tree interface mt_find() will handle the RCU locking and
will start searching at the address up to the limit, ULONG_MAX in this
case.
Add kernel documentation to this API.
Link: https://lkml.kernel.org/r/20220906194824.2110408-12-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This simplifies the implementation and is faster than using the linked
list.
Link: https://lkml.kernel.org/r/20220906194824.2110408-11-Liam.Howlett@oracle.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This thin layer of abstraction over the maple tree state is for iterating
over VMAs. You can go forwards, go backwards or ask where the iterator
is. Rename the existing vma_next() to __vma_next() -- it will be removed
by the end of this series.
Link: https://lkml.kernel.org/r/20220906194824.2110408-10-Liam.Howlett@oracle.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Start tracking the VMAs with the new maple tree structure in parallel with
the rb_tree. Add debug and trace events for maple tree operations and
duplicate the rb_tree that is created on forks into the maple tree.
The maple tree is added to the mm_struct including the mm_init struct,
added support in required mm/mmap functions, added tracking in kernel/fork
for process forking, and used to find the unmapped_area and checked
against what the rbtree finds.
This also moves the mmap_lock() in exit_mmap() since the oom reaper call
does walk the VMAs. Otherwise lockdep will be unhappy if oom happens.
When splitting a vma fails due to allocations of the maple tree nodes,
the error path in __split_vma() calls new->vm_ops->close(new). The page
accounting for hugetlb is actually in the close() operation, so it
accounts for the removal of 1/2 of the VMA which was not adjusted. This
results in a negative exit value. To avoid the negative charge, set
vm_start = vm_end and vm_pgoff = 0.
There is also a potential accounting issue in special mappings from
insert_vm_struct() failing to allocate, so reverse the charge there in
the failure scenario.
Link: https://lkml.kernel.org/r/20220906194824.2110408-9-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Align larger anonymous memory mappings on THP boundaries by going through
thp_get_unmapped_area if THPs are enabled for the current process.
With this patch, larger anonymous mappings are now THP aligned. When a
malloc library allocates a 2MB or larger arena, that arena can now be
mapped with THPs right from the start, which can result in better TLB hit
rates and execution time.
Link: https://lkml.kernel.org/r/20220809142457.4751229f@imladris.surriel.com
Signed-off-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/hugetlb: fix write-fault handling for shared mappings", v2.
I observed that hugetlb does not support/expect write-faults in shared
mappings that would have to map the R/O-mapped page writable -- and I
found two case where we could currently get such faults and would
erroneously map an anon page into a shared mapping.
Reproducers part of the patches.
I propose to backport both fixes to stable trees. The first fix needs a
small adjustment.
This patch (of 2):
Staring at hugetlb_wp(), one might wonder where all the logic for shared
mappings is when stumbling over a write-protected page in a shared
mapping. In fact, there is none, and so far we thought we could get away
with that because e.g., mprotect() should always do the right thing and
map all pages directly writable.
Looks like we were wrong:
--------------------------------------------------------------------------
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <sys/mman.h>
#define HUGETLB_SIZE (2 * 1024 * 1024u)
static void clear_softdirty(void)
{
int fd = open("/proc/self/clear_refs", O_WRONLY);
const char *ctrl = "4";
int ret;
if (fd < 0) {
fprintf(stderr, "open(clear_refs) failed\n");
exit(1);
}
ret = write(fd, ctrl, strlen(ctrl));
if (ret != strlen(ctrl)) {
fprintf(stderr, "write(clear_refs) failed\n");
exit(1);
}
close(fd);
}
int main(int argc, char **argv)
{
char *map;
int fd;
fd = open("/dev/hugepages/tmp", O_RDWR | O_CREAT);
if (!fd) {
fprintf(stderr, "open() failed\n");
return -errno;
}
if (ftruncate(fd, HUGETLB_SIZE)) {
fprintf(stderr, "ftruncate() failed\n");
return -errno;
}
map = mmap(NULL, HUGETLB_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
if (map == MAP_FAILED) {
fprintf(stderr, "mmap() failed\n");
return -errno;
}
*map = 0;
if (mprotect(map, HUGETLB_SIZE, PROT_READ)) {
fprintf(stderr, "mmprotect() failed\n");
return -errno;
}
clear_softdirty();
if (mprotect(map, HUGETLB_SIZE, PROT_READ|PROT_WRITE)) {
fprintf(stderr, "mmprotect() failed\n");
return -errno;
}
*map = 0;
return 0;
}
--------------------------------------------------------------------------
Above test fails with SIGBUS when there is only a single free hugetlb page.
# echo 1 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
# ./test
Bus error (core dumped)
And worse, with sufficient free hugetlb pages it will map an anonymous page
into a shared mapping, for example, messing up accounting during unmap
and breaking MAP_SHARED semantics:
# echo 2 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
# ./test
# cat /proc/meminfo | grep HugePages_
HugePages_Total: 2
HugePages_Free: 1
HugePages_Rsvd: 18446744073709551615
HugePages_Surp: 0
Reason in this particular case is that vma_wants_writenotify() will
return "true", removing VM_SHARED in vma_set_page_prot() to map pages
write-protected. Let's teach vma_wants_writenotify() that hugetlb does not
support softdirty tracking.
Link: https://lkml.kernel.org/r/20220811103435.188481-1-david@redhat.com
Link: https://lkml.kernel.org/r/20220811103435.188481-2-david@redhat.com
Fixes: 64e455079e ("mm: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY cleared")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Peter Feiner <pfeiner@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Jamie Liu <jamieliu@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org> [3.18+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/mprotect: Fix soft-dirty checks", v4.
This patch (of 3):
The check wanted to make sure when soft-dirty tracking is enabled we won't
grant write bit by accident, as a page fault is needed for dirty tracking.
The intention is correct but we didn't check it right because
VM_SOFTDIRTY set actually means soft-dirty tracking disabled. Fix it.
There's another thing tricky about soft-dirty is that, we can't check the
vma flag !(vma_flags & VM_SOFTDIRTY) directly but only check it after we
checked CONFIG_MEM_SOFT_DIRTY because otherwise VM_SOFTDIRTY will be
defined as zero, and !(vma_flags & VM_SOFTDIRTY) will constantly return
true. To avoid misuse, introduce a helper for checking whether vma has
soft-dirty tracking enabled.
We can easily verify this with any exclusive anonymous page, like program
below:
=======8<======
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <assert.h>
#include <inttypes.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdbool.h>
#define BIT_ULL(nr) (1ULL << (nr))
#define PM_SOFT_DIRTY BIT_ULL(55)
unsigned int psize;
char *page;
uint64_t pagemap_read_vaddr(int fd, void *vaddr)
{
uint64_t value;
int ret;
ret = pread(fd, &value, sizeof(uint64_t),
((uint64_t)vaddr >> 12) * sizeof(uint64_t));
assert(ret == sizeof(uint64_t));
return value;
}
void clear_refs_write(void)
{
int fd = open("/proc/self/clear_refs", O_RDWR);
assert(fd >= 0);
write(fd, "4", 2);
close(fd);
}
#define check_soft_dirty(str, expect) do { \
bool dirty = pagemap_read_vaddr(fd, page) & PM_SOFT_DIRTY; \
if (dirty != expect) { \
printf("ERROR: %s, soft-dirty=%d (expect: %d)
", str, dirty, expect); \
exit(-1); \
} \
} while (0)
int main(void)
{
int fd = open("/proc/self/pagemap", O_RDONLY);
assert(fd >= 0);
psize = getpagesize();
page = mmap(NULL, psize, PROT_READ|PROT_WRITE,
MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
assert(page != MAP_FAILED);
*page = 1;
check_soft_dirty("Just faulted in page", 1);
clear_refs_write();
check_soft_dirty("Clear_refs written", 0);
mprotect(page, psize, PROT_READ);
check_soft_dirty("Marked RO", 0);
mprotect(page, psize, PROT_READ|PROT_WRITE);
check_soft_dirty("Marked RW", 0);
*page = 2;
check_soft_dirty("Wrote page again", 1);
munmap(page, psize);
close(fd);
printf("Test passed.
");
return 0;
}
=======8<======
Here we attach a Fixes to commit 64fe24a3e0 only for easy tracking, as
this patch won't apply to a tree before that point. However the commit
wasn't the source of problem, but instead 64e455079e. It's just that
after 64fe24a3e0 anonymous memory will also suffer from this problem
with mprotect().
Link: https://lkml.kernel.org/r/20220725142048.30450-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20220725142048.30450-2-peterx@redhat.com
Fixes: 64e455079e ("mm: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY cleared")
Fixes: 64fe24a3e0 ("mm/mprotect: try avoiding write faults for exclusive anonymous pages when changing protection")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Since the beginning, charged is set to 0 to avoid calling vm_unacct_memory
twice because vm_unacct_memory will be called by above unmap_region. But
since commit 4f74d2c8e8 ("vm: remove 'nr_accounted' calculations from
the unmap_vmas() interfaces"), unmap_region doesn't call vm_unacct_memory
anymore. So charged shouldn't be set to 0 now otherwise the calling to
paired vm_unacct_memory will be missed and leads to imbalanced account.
Link: https://lkml.kernel.org/r/20220618082027.43391-1-linmiaohe@huawei.com
Fixes: 4f74d2c8e8 ("vm: remove 'nr_accounted' calculations from the unmap_vmas() interfaces")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mmget_still_valid() has already been removed via commit 4d45e75a99 ("mm:
remove the now-unnecessary mmget_still_valid() hack"). Update the
corresponding comment.
Link: https://lkml.kernel.org/r/20220709092527.47778-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Now all the platforms enable ARCH_HAS_GET_PAGE_PROT. They define and
export own vm_get_page_prot() whether custom or standard
DECLARE_VM_GET_PAGE_PROT. Hence there is no need for default generic
fallback for vm_get_page_prot(). Just drop this fallback and also
ARCH_HAS_GET_PAGE_PROT mechanism.
Link: https://lkml.kernel.org/r/20220711070600.2378316-27-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This just converts the generic vm_get_page_prot() implementation into a
new macro i.e DECLARE_VM_GET_PAGE_PROT which later can be used across
platforms when enabling them with ARCH_HAS_VM_GET_PAGE_PROT. This does
not create any functional change.
Link: https://lkml.kernel.org/r/20220711070600.2378316-3-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/mmap: Drop __SXXX/__PXXX macros from across platforms",
v7.
__SXXX/__PXXX macros are unnecessary abstraction layer in creating the
generic protection_map[] array which is used for vm_get_page_prot(). This
abstraction layer can be avoided, if the platforms just define the array
protection_map[] for all possible vm_flags access permission combinations
and also export vm_get_page_prot() implementation.
This series drops __SXXX/__PXXX macros from across platforms in the tree.
First it build protects generic protection_map[] array with '#ifdef
__P000' and moves it inside platforms which enable
ARCH_HAS_VM_GET_PAGE_PROT. Later this build protects same array with
'#ifdef ARCH_HAS_VM_GET_PAGE_PROT' and moves inside remaining platforms
while enabling ARCH_HAS_VM_GET_PAGE_PROT. This adds a new macro
DECLARE_VM_GET_PAGE_PROT defining the current generic vm_get_page_prot(),
in order for it to be reused on platforms that do not require custom
implementation. Finally, ARCH_HAS_VM_GET_PAGE_PROT can just be dropped,
as all platforms now define and export vm_get_page_prot(), via looking up
a private and static protection_map[] array. protection_map[] data type
has been changed as 'static const' on all platforms that do not change it
during boot.
This patch (of 26):
Build protect generic protection_map[] array with __P000, so that it can
be moved inside all the platforms one after the other. Otherwise there
will be build failures during this process.
CONFIG_ARCH_HAS_VM_GET_PAGE_PROT cannot be used for this purpose as only
certain platforms enable this config now.
Link: https://lkml.kernel.org/r/20220711070600.2378316-1-anshuman.khandual@arm.com
Link: https://lkml.kernel.org/r/20220711070600.2378316-2-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
so it will be consistent with code mm directory and with
Documentation/admin-guide/mm and won't be confused with virtual machines.
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Tested-by: Ira Weiny <ira.weiny@intel.com>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Acked-by: Wu XiangCheng <bobwxc@email.cn>
- Convert to the generic mmap support (ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT).
- Add support for outline-only KASAN with 64-bit Radix MMU (P9 or later).
- Increase SIGSTKSZ and MINSIGSTKSZ and add support for AT_MINSIGSTKSZ.
- Enable the DAWR (Data Address Watchpoint) on POWER9 DD2.3 or later.
- Drop support for system call instruction emulation.
- Many other small features and fixes.
Thanks to: Alexey Kardashevskiy, Alistair Popple, Andy Shevchenko, Bagas Sanjaya, Bjorn
Helgaas, Bo Liu, Chen Huang, Christophe Leroy, Colin Ian King, Daniel Axtens, Dwaipayan
Ray, Fabiano Rosas, Finn Thain, Frank Rowand, Fuqian Huang, Guilherme G. Piccoli, Hangyu
Hua, Haowen Bai, Haren Myneni, Hari Bathini, He Ying, Jason Wang, Jiapeng Chong, Jing
Yangyang, Joel Stanley, Julia Lawall, Kajol Jain, Kevin Hao, Krzysztof Kozlowski, Laurent
Dufour, Lv Ruyi, Madhavan Srinivasan, Magali Lemes, Miaoqian Lin, Minghao Chi, Nathan
Chancellor, Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran, Oscar Salvador, Pali Rohár,
Paul Mackerras, Peng Wu, Qing Wang, Randy Dunlap, Reza Arbab, Russell Currey, Sohaib
Mohamed, Vaibhav Jain, Vasant Hegde, Wang Qing, Wang Wensheng, Xiang wangx, Xiaomeng Tong,
Xu Wang, Yang Guang, Yang Li, Ye Bin, YueHaibing, Yu Kuai, Zheng Bin, Zou Wei, Zucheng
Zheng.
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Merge tag 'powerpc-5.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
- Convert to the generic mmap support (ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
- Add support for outline-only KASAN with 64-bit Radix MMU (P9 or later)
- Increase SIGSTKSZ and MINSIGSTKSZ and add support for AT_MINSIGSTKSZ
- Enable the DAWR (Data Address Watchpoint) on POWER9 DD2.3 or later
- Drop support for system call instruction emulation
- Many other small features and fixes
Thanks to Alexey Kardashevskiy, Alistair Popple, Andy Shevchenko, Bagas
Sanjaya, Bjorn Helgaas, Bo Liu, Chen Huang, Christophe Leroy, Colin Ian
King, Daniel Axtens, Dwaipayan Ray, Fabiano Rosas, Finn Thain, Frank
Rowand, Fuqian Huang, Guilherme G. Piccoli, Hangyu Hua, Haowen Bai,
Haren Myneni, Hari Bathini, He Ying, Jason Wang, Jiapeng Chong, Jing
Yangyang, Joel Stanley, Julia Lawall, Kajol Jain, Kevin Hao, Krzysztof
Kozlowski, Laurent Dufour, Lv Ruyi, Madhavan Srinivasan, Magali Lemes,
Miaoqian Lin, Minghao Chi, Nathan Chancellor, Naveen N. Rao, Nicholas
Piggin, Oliver O'Halloran, Oscar Salvador, Pali Rohár, Paul Mackerras,
Peng Wu, Qing Wang, Randy Dunlap, Reza Arbab, Russell Currey, Sohaib
Mohamed, Vaibhav Jain, Vasant Hegde, Wang Qing, Wang Wensheng, Xiang
wangx, Xiaomeng Tong, Xu Wang, Yang Guang, Yang Li, Ye Bin, YueHaibing,
Yu Kuai, Zheng Bin, Zou Wei, and Zucheng Zheng.
* tag 'powerpc-5.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (200 commits)
powerpc/64: Include cache.h directly in paca.h
powerpc/64s: Only set HAVE_ARCH_UNMAPPED_AREA when CONFIG_PPC_64S_HASH_MMU is set
powerpc/xics: Include missing header
powerpc/powernv/pci: Drop VF MPS fixup
powerpc/fsl_book3e: Don't set rodata RO too early
powerpc/microwatt: Add mmu bits to device tree
powerpc/powernv/flash: Check OPAL flash calls exist before using
powerpc/powermac: constify device_node in of_irq_parse_oldworld()
powerpc/powermac: add missing g5_phy_disable_cpu1() declaration
selftests/powerpc/pmu: fix spelling mistake "mis-match" -> "mismatch"
powerpc: Enable the DAWR on POWER9 DD2.3 and above
powerpc/64s: Add CPU_FTRS_POWER10 to ALWAYS mask
powerpc/64s: Add CPU_FTRS_POWER9_DD2_2 to CPU_FTRS_ALWAYS mask
powerpc: Fix all occurences of "the the"
selftests/powerpc/pmu/ebb: remove fixed_instruction.S
powerpc/platforms/83xx: Use of_device_get_match_data()
powerpc/eeh: Drop redundant spinlock initialization
powerpc/iommu: Add missing of_node_put in iommu_init_early_dart
powerpc/pseries/vas: Call misc_deregister if sysfs init fails
powerpc/papr_scm: Fix leaking nvdimm_events_map elements
...
The readonly FS THP relies on khugepaged to collapse THP for suitable
vmas. But the behavior is inconsistent for "always" mode
(https://lore.kernel.org/linux-mm/00f195d4-d039-3cf2-d3a1-a2c88de397a0@suse.cz/).
The "always" mode means THP allocation should be tried all the time and
khugepaged should try to collapse THP all the time. Of course the
allocation and collapse may fail due to other factors and conditions.
Currently file THP may not be collapsed by khugepaged even though all the
conditions are met. That does break the semantics of "always" mode.
So make sure readonly FS vmas are registered to khugepaged to fix the
break.
Register suitable vmas in common mmap path, that could cover both readonly
FS vmas and shmem vmas, so remove the khugepaged calls in shmem.c.
Still need to keep the khugepaged call in vma_merge() since vma_merge() is
called in a lot of places, for example, madvise, mprotect, etc.
Link: https://lkml.kernel.org/r/20220510203222.24246-9-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Vlastmil Babka <vbabka@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Song Liu <song@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The khugepaged_enter_vma_merge() actually does as the same thing as the
khugepaged_enter() section called by shmem_mmap(), so consolidate them
into one helper and rename it to khugepaged_enter_vma().
Link: https://lkml.kernel.org/r/20220510203222.24246-8-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Acked-by: Vlastmil Babka <vbabka@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Song Liu <song@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit c1e8d7c6a7 ("mmap locking API: convert mmap_sem comments") missed
replacing some references of mmap_sem by mmap_lock due to misspelling
(mm_sem instead of mmap_sem).
Link: https://lkml.kernel.org/r/20220503113333.214124-1-mail@florommel.de
Signed-off-by: Florian Rommel <mail@florommel.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Powerpc needs flags and len to make decision on arch_get_mmap_end().
So add them as parameters to arch_get_mmap_end().
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b556daabe7d2bdb2361c4d6130280da7c1ba2c14.1649523076.git.christophe.leroy@csgroup.eu
Unlike most architectures, powerpc can only define at runtime
if it is going to use the generic arch_get_unmapped_area() or not.
Today, powerpc has a copy of the generic arch_get_unmapped_area()
because when selection HAVE_ARCH_UNMAPPED_AREA the generic
arch_get_unmapped_area() is not available.
Rename it generic_get_unmapped_area() and make it independent of
HAVE_ARCH_UNMAPPED_AREA.
Do the same for arch_get_unmapped_area_topdown() versus
HAVE_ARCH_UNMAPPED_AREA_TOPDOWN.
Do the same for hugetlb_get_unmapped_area() versus
HAVE_ARCH_HUGETLB_UNMAPPED_AREA.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/77f9d3e592f1c8511df9381aa1c4e754651da4d1.1649523076.git.christophe.leroy@csgroup.eu
There are no platforms left which use arch_vm_get_page_prot(). Just drop
generic arch_vm_get_page_prot().
Link: https://lkml.kernel.org/r/20220414062125.609297-8-anshuman.khandual@arm.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There are no platforms left which subscribe ARCH_HAS_FILTER_PGPROT. Hence
drop generic arch_filter_pgprot() and also config ARCH_HAS_FILTER_PGPROT.
Link: https://lkml.kernel.org/r/20220414062125.609297-7-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/mmap: Drop arch_vm_get_page_prot() and arch_filter_pgprot()", v7.
protection_map[] is an array based construct that translates given
vm_flags combination. This array contains page protection map, which is
populated by the platform via [__S000 .. __S111] and [__P000 .. __P111]
exported macros. Primary usage for protection_map[] is for
vm_get_page_prot(), which is used to determine page protection value for a
given vm_flags. vm_get_page_prot() implementation, could again call
platform overrides arch_vm_get_page_prot() and arch_filter_pgprot(). Some
platforms override protection_map[] that was originally built with
__SXXX/__PXXX with different runtime values.
Currently there are multiple layers of abstraction i.e __SXXX/__PXXX
macros , protection_map[], arch_vm_get_page_prot() and
arch_filter_pgprot() built between the platform and generic MM, finally
defining vm_get_page_prot().
Hence this series proposes to drop later two abstraction levels and
instead just move the responsibility of defining vm_get_page_prot() to the
platform (still utilizing generic protection_map[] array) itself making it
clean and simple.
This first introduces ARCH_HAS_VM_GET_PAGE_PROT which enables the
platforms to define custom vm_get_page_prot(). This starts converting
platforms that define the overrides arch_filter_pgprot() or
arch_vm_get_page_prot() which enables for those constructs to be dropped
off completely.
The series has been inspired from an earlier discuss with Christoph Hellwig
https://lore.kernel.org/all/1632712920-8171-1-git-send-email-anshuman.khandual@arm.com/
This patch (of 7):
Add a new config ARCH_HAS_VM_GET_PAGE_PROT, which when subscribed enables
a given platform to define its own vm_get_page_prot() but still utilizing
the generic protection_map[] array.
Link: https://lkml.kernel.org/r/20220414062125.609297-1-anshuman.khandual@arm.com
Link: https://lkml.kernel.org/r/20220414062125.609297-2-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use helper mlock_future_check() to check whether it's safe to enlarge the
locked_vm to simplify the code. Minor readability improvement.
Link: https://lkml.kernel.org/r/20220402032231.64974-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
protection_map[] maps vm_flags access combinations into page protection
value as defined by the platform via __PXXX and __SXXX macros. The array
indices in protection_map[], represents vm_flags access combinations but
it's not very intuitive to derive. This makes it clear and explicit.
Link: https://lkml.kernel.org/r/20220404031840.588321-3-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In case the lock is actually not held at this point.
Link: https://lkml.kernel.org/r/5827758.TJ1SttVevJ@mobilepool36.emlix.com
Signed-off-by: Rolf Eike Beer <eb@emlix.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This is a fix for commit f6795053da ("mm: mmap: Allow for "high"
userspace addresses") for hugetlb.
This patch adds support for "high" userspace addresses that are
optionally supported on the system and have to be requested via a hint
mechanism ("high" addr parameter to mmap).
Architectures such as powerpc and x86 achieve this by making changes to
their architectural versions of hugetlb_get_unmapped_area() function.
However, arm64 uses the generic version of that function.
So take into account arch_get_mmap_base() and arch_get_mmap_end() in
hugetlb_get_unmapped_area(). To allow that, move those two macros out
of mm/mmap.c into include/linux/sched/mm.h
If these macros are not defined in architectural code then they default
to (TASK_SIZE) and (base) so should not introduce any behavioural
changes to architectures that do not define them.
For the time being, only ARM64 is affected by this change.
Catalin (ARM64) said
"We should have fixed hugetlb_get_unmapped_area() as well when we added
support for 52-bit VA. The reason for commit f6795053da was to
prevent normal mmap() from returning addresses above 48-bit by default
as some user-space had hard assumptions about this.
It's a slight ABI change if you do this for hugetlb_get_unmapped_area()
but I doubt anyone would notice. It's more likely that the current
behaviour would cause issues, so I'd rather have them consistent.
Basically when arm64 gained support for 52-bit addresses we did not
want user-space calling mmap() to suddenly get such high addresses,
otherwise we could have inadvertently broken some programs (similar
behaviour to x86 here). Hence we added commit f6795053da. But we
missed hugetlbfs which could still get such high mmap() addresses. So
in theory that's a potential regression that should have bee addressed
at the same time as commit f6795053da (and before arm64 enabled
52-bit addresses)"
Link: https://lkml.kernel.org/r/ab847b6edb197bffdfe189e70fb4ac76bfe79e0d.1650033747.git.christophe.leroy@csgroup.eu
Fixes: f6795053da ("mm: mmap: Allow for "high" userspace addresses")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Steve Capper <steve.capper@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: <stable@vger.kernel.org> [5.0.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Rewrite how munlock works to massively reduce the contention
on i_mmap_rwsem (Hugh Dickins):
https://lore.kernel.org/linux-mm/8e4356d-9622-a7f0-b2c-f116b5f2efea@google.com/
- Sort out the page refcount mess for ZONE_DEVICE pages (Christoph Hellwig):
https://lore.kernel.org/linux-mm/20220210072828.2930359-1-hch@lst.de/
- Convert GUP to use folios and make pincount available for order-1
pages. (Matthew Wilcox)
- Convert a few more truncation functions to use folios (Matthew Wilcox)
- Convert page_vma_mapped_walk to use PFNs instead of pages (Matthew Wilcox)
- Convert rmap_walk to use folios (Matthew Wilcox)
- Convert most of shrink_page_list() to use a folio (Matthew Wilcox)
- Add support for creating large folios in readahead (Matthew Wilcox)
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Merge tag 'folio-5.18c' of git://git.infradead.org/users/willy/pagecache
Pull folio updates from Matthew Wilcox:
- Rewrite how munlock works to massively reduce the contention on
i_mmap_rwsem (Hugh Dickins):
https://lore.kernel.org/linux-mm/8e4356d-9622-a7f0-b2c-f116b5f2efea@google.com/
- Sort out the page refcount mess for ZONE_DEVICE pages (Christoph
Hellwig):
https://lore.kernel.org/linux-mm/20220210072828.2930359-1-hch@lst.de/
- Convert GUP to use folios and make pincount available for order-1
pages. (Matthew Wilcox)
- Convert a few more truncation functions to use folios (Matthew
Wilcox)
- Convert page_vma_mapped_walk to use PFNs instead of pages (Matthew
Wilcox)
- Convert rmap_walk to use folios (Matthew Wilcox)
- Convert most of shrink_page_list() to use a folio (Matthew Wilcox)
- Add support for creating large folios in readahead (Matthew Wilcox)
* tag 'folio-5.18c' of git://git.infradead.org/users/willy/pagecache: (114 commits)
mm/damon: minor cleanup for damon_pa_young
selftests/vm/transhuge-stress: Support file-backed PMD folios
mm/filemap: Support VM_HUGEPAGE for file mappings
mm/readahead: Switch to page_cache_ra_order
mm/readahead: Align file mappings for non-DAX
mm/readahead: Add large folio readahead
mm: Support arbitrary THP sizes
mm: Make large folios depend on THP
mm: Fix READ_ONLY_THP warning
mm/filemap: Allow large folios to be added to the page cache
mm: Turn can_split_huge_page() into can_split_folio()
mm/vmscan: Convert pageout() to take a folio
mm/vmscan: Turn page_check_references() into folio_check_references()
mm/vmscan: Account large folios correctly
mm/vmscan: Optimise shrink_page_list for non-PMD-sized folios
mm/vmscan: Free non-shmem folios without splitting them
mm/rmap: Constify the rmap_walk_control argument
mm/rmap: Convert rmap_walk() to take a folio
mm: Turn page_anon_vma() into folio_anon_vma()
mm/rmap: Turn page_lock_anon_vma_read() into folio_lock_anon_vma_read()
...
RLIMIT_MEMLOCK is already reimplemented on top of ucounts now. And
since commit 83c1fd763b ("mm,hugetlb: remove mlock ulimit for
SHM_HUGETLB"), mlock ulimit for SHM_HUGETLB is further removed.
So we should remove this obsolete comment.
Link: https://lkml.kernel.org/r/20220309090623.13036-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
_install_special_mapping() adds the VM_SPECIAL bit VM_DONTEXPAND (and
never attempts to update locked_vm), so it ought to be consistent with
mmap_region() and mlock_fixup(), making sure not to add VM_LOCKED or
VM_LOCKONFAULT. I doubt that this fixes any problem in practice: just
do it for consistency.
Link: https://lkml.kernel.org/r/a85315a9-21d1-6133-c5fc-c89863dfb25b@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__setup() handlers should return 1 if the command line option is handled
and 0 if not (or maybe never return 0; it just pollutes init's
environment). This prevents:
Unknown kernel command line parameters \
"BOOT_IMAGE=/boot/bzImage-517rc5 stack_guard_gap=100", will be \
passed to user space.
Run /sbin/init as init process
with arguments:
/sbin/init
with environment:
HOME=/
TERM=linux
BOOT_IMAGE=/boot/bzImage-517rc5
stack_guard_gap=100
Return 1 to indicate that the boot option has been handled.
Note that there is no warning message if someone enters:
stack_guard_gap=anything_invalid
and 'val' and stack_guard_gap are both set to 0 due to the use of
simple_strtoul(). This could be improved by using kstrtoxxx() and
checking for an error.
It appears that having stack_guard_gap == 0 is valid (if unexpected) since
using "stack_guard_gap=0" on the kernel command line does that.
Link: https://lkml.kernel.org/r/20220222005817.11087-1-rdunlap@infradead.org
Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru
Fixes: 1be7107fbe ("mm: larger stack guard gap, between vmas")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: Igor Zhbanov <i.zhbanov@omprussia.ru>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
oom reaping (__oom_reap_task_mm) relies on a 2 way synchronization with
exit_mmap. First it relies on the mmap_lock to exclude from unlock
path[1], page tables tear down (free_pgtables) and vma destruction.
This alone is not sufficient because mm->mmap is never reset.
For historical reasons[2] the lock is taken there is also MMF_OOM_SKIP
set for oom victims before.
The oom reaper only ever looks at oom victims so the whole scheme works
properly but process_mrelease can opearate on any task (with fatal
signals pending) which doesn't really imply oom victims. That means
that the MMF_OOM_SKIP part of the synchronization doesn't work and it
can see a task after the whole address space has been demolished and
traverse an already released mm->mmap list. This leads to use after
free as properly caught up by KASAN report.
Fix the issue by reseting mm->mmap so that MMF_OOM_SKIP synchronization
is not needed anymore. The MMF_OOM_SKIP is not removed from exit_mmap
yet but it acts mostly as an optimization now.
[1] 27ae357fa8 ("mm, oom: fix concurrent munlock and oom reaper unmap, v3")
[2] 2129258024 ("mm: oom: let oom_reap_task and exit_mmap run concurrently")
[mhocko@suse.com: changelog rewrite]
Link: https://lore.kernel.org/all/00000000000072ef2c05d7f81950@google.com/
Link: https://lkml.kernel.org/r/20220215201922.1908156-1-surenb@google.com
Fixes: 64591e8605 ("mm: protect free_pgtables with mmap_lock write lock in exit_mmap")
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reported-by: syzbot+2ccf63a4bd07cf39cab0@syzkaller.appspotmail.com
Suggested-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Rik van Riel <riel@surriel.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Jan Engelhardt <jengelh@inai.de>
Cc: Tim Murray <timmurray@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
munlock_vma_pages_range() will still be required, when munlocking but
not munmapping a set of pages; but when unmapping a pte, the mlock count
will be maintained in much the same way as it will be maintained when
mapping in the pte. Which removes the need for munlock_vma_pages_all()
on mlocked vmas when munmapping or exiting: eliminating the catastrophic
contention on i_mmap_rwsem, and the need for page lock on the pages.
There is still a need to update locked_vm accounting according to the
munmapped vmas when munmapping: do that in detach_vmas_to_be_unmapped().
exit_mmap() does not need locked_vm updates, so delete unlock_range().
And wasn't I the one who forbade the OOM reaper to attack mlocked vmas,
because of the uncertainty in blocking on all those page locks?
No fear of that now, so permit the OOM reaper on mlocked vmas.
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Pull signal/exit/ptrace updates from Eric Biederman:
"This set of changes deletes some dead code, makes a lot of cleanups
which hopefully make the code easier to follow, and fixes bugs found
along the way.
The end-game which I have not yet reached yet is for fatal signals
that generate coredumps to be short-circuit deliverable from
complete_signal, for force_siginfo_to_task not to require changing
userspace configured signal delivery state, and for the ptrace stops
to always happen in locations where we can guarantee on all
architectures that the all of the registers are saved and available on
the stack.
Removal of profile_task_ext, profile_munmap, and profile_handoff_task
are the big successes for dead code removal this round.
A bunch of small bug fixes are included, as most of the issues
reported were small enough that they would not affect bisection so I
simply added the fixes and did not fold the fixes into the changes
they were fixing.
There was a bug that broke coredumps piped to systemd-coredump. I
dropped the change that caused that bug and replaced it entirely with
something much more restrained. Unfortunately that required some
rebasing.
Some successes after this set of changes: There are few enough calls
to do_exit to audit in a reasonable amount of time. The lifetime of
struct kthread now matches the lifetime of struct task, and the
pointer to struct kthread is no longer stored in set_child_tid. The
flag SIGNAL_GROUP_COREDUMP is removed. The field group_exit_task is
removed. Issues where task->exit_code was examined with
signal->group_exit_code should been examined were fixed.
There are several loosely related changes included because I am
cleaning up and if I don't include them they will probably get lost.
The original postings of these changes can be found at:
https://lkml.kernel.org/r/87a6ha4zsd.fsf@email.froward.int.ebiederm.orghttps://lkml.kernel.org/r/87bl1kunjj.fsf@email.froward.int.ebiederm.orghttps://lkml.kernel.org/r/87r19opkx1.fsf_-_@email.froward.int.ebiederm.org
I trimmed back the last set of changes to only the obviously correct
once. Simply because there was less time for review than I had hoped"
* 'signal-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (44 commits)
ptrace/m68k: Stop open coding ptrace_report_syscall
ptrace: Remove unused regs argument from ptrace_report_syscall
ptrace: Remove second setting of PT_SEIZED in ptrace_attach
taskstats: Cleanup the use of task->exit_code
exit: Use the correct exit_code in /proc/<pid>/stat
exit: Fix the exit_code for wait_task_zombie
exit: Coredumps reach do_group_exit
exit: Remove profile_handoff_task
exit: Remove profile_task_exit & profile_munmap
signal: clean up kernel-doc comments
signal: Remove the helper signal_group_exit
signal: Rename group_exit_task group_exec_task
coredump: Stop setting signal->group_exit_task
signal: Remove SIGNAL_GROUP_COREDUMP
signal: During coredumps set SIGNAL_GROUP_EXIT in zap_process
signal: Make coredump handling explicit in complete_signal
signal: Have prepare_signal detect coredumps using signal->core_state
signal: Have the oom killer detect coredumps using signal->core_state
exit: Move force_uaccess back into do_exit
exit: Guarantee make_task_dead leaks the tsk when calling do_task_exit
...
oom-reaper and process_mrelease system call should protect against races
with exit_mmap which can destroy page tables while they walk the VMA
tree. oom-reaper protects from that race by setting MMF_OOM_VICTIM and
by relying on exit_mmap to set MMF_OOM_SKIP before taking and releasing
mmap_write_lock. process_mrelease has to elevate mm->mm_users to
prevent such race.
Both oom-reaper and process_mrelease hold mmap_read_lock when walking
the VMA tree. The locking rules and mechanisms could be simpler if
exit_mmap takes mmap_write_lock while executing destructive operations
such as free_pgtables.
Change exit_mmap to hold the mmap_write_lock when calling unlock_range,
free_pgtables and remove_vma. Note also that because oom-reaper checks
VM_LOCKED flag, unlock_range() should not be allowed to race with it.
Before this patch, remove_vma used to be called with no locks held,
however with fput being executed asynchronously and vm_ops->close not
being allowed to hold mmap_lock (it is called from __split_vma with
mmap_sem held for write), changing that should be fine.
In most cases this lock should be uncontended. Previously, Kirill
reported ~4% regression caused by a similar change [1]. We reran the
same test and although the individual results are quite noisy, the
percentiles show lower regression with 1.6% being the worst case [2].
The change allows oom-reaper and process_mrelease to execute safely
under mmap_read_lock without worries that exit_mmap might destroy page
tables from under them.
[1] https://lore.kernel.org/all/20170725141723.ivukwhddk2voyhuc@node.shutemov.name/
[2] https://lore.kernel.org/all/CAJuCfpGC9-c9P40x7oy=jy5SphMcd0o0G_6U1-+JAziGKG6dGA@mail.gmail.com/
Link: https://lkml.kernel.org/r/20211209191325.3069345-1-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christian Brauner <christian@brauner.io>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Jan Engelhardt <jengelh@inai.de>
Cc: Tim Murray <timmurray@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The patch to add anonymous vma names causes a build failure in some
configurations:
include/linux/mm_types.h: In function 'is_same_vma_anon_name':
include/linux/mm_types.h:924:37: error: implicit declaration of function 'strcmp' [-Werror=implicit-function-declaration]
924 | return name && vma_name && !strcmp(name, vma_name);
| ^~~~~~
include/linux/mm_types.h:22:1: note: 'strcmp' is defined in header '<string.h>'; did you forget to '#include <string.h>'?
This should not really be part of linux/mm_types.h in the first place,
as that header is meant to only contain structure defintions and need a
minimum set of indirect includes itself.
While the header clearly includes more than it should at this point,
let's not make it worse by including string.h as well, which would pull
in the expensive (compile-speed wise) fortify-string logic.
Move the new functions into a separate header that only needs to be
included in a couple of locations.
Link: https://lkml.kernel.org/r/20211207125710.2503446-1-arnd@kernel.org
Fixes: "mm: add a field to store names for private anonymous memory"
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Colin Cross <ccross@google.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In many userspace applications, and especially in VM based applications
like Android uses heavily, there are multiple different allocators in
use. At a minimum there is libc malloc and the stack, and in many cases
there are libc malloc, the stack, direct syscalls to mmap anonymous
memory, and multiple VM heaps (one for small objects, one for big
objects, etc.). Each of these layers usually has its own tools to
inspect its usage; malloc by compiling a debug version, the VM through
heap inspection tools, and for direct syscalls there is usually no way
to track them.
On Android we heavily use a set of tools that use an extended version of
the logic covered in Documentation/vm/pagemap.txt to walk all pages
mapped in userspace and slice their usage by process, shared (COW) vs.
unique mappings, backing, etc. This can account for real physical
memory usage even in cases like fork without exec (which Android uses
heavily to share as many private COW pages as possible between
processes), Kernel SamePage Merging, and clean zero pages. It produces
a measurement of the pages that only exist in that process (USS, for
unique), and a measurement of the physical memory usage of that process
with the cost of shared pages being evenly split between processes that
share them (PSS).
If all anonymous memory is indistinguishable then figuring out the real
physical memory usage (PSS) of each heap requires either a pagemap
walking tool that can understand the heap debugging of every layer, or
for every layer's heap debugging tools to implement the pagemap walking
logic, in which case it is hard to get a consistent view of memory
across the whole system.
Tracking the information in userspace leads to all sorts of problems.
It either needs to be stored inside the process, which means every
process has to have an API to export its current heap information upon
request, or it has to be stored externally in a filesystem that somebody
needs to clean up on crashes. It needs to be readable while the process
is still running, so it has to have some sort of synchronization with
every layer of userspace. Efficiently tracking the ranges requires
reimplementing something like the kernel vma trees, and linking to it
from every layer of userspace. It requires more memory, more syscalls,
more runtime cost, and more complexity to separately track regions that
the kernel is already tracking.
This patch adds a field to /proc/pid/maps and /proc/pid/smaps to show a
userspace-provided name for anonymous vmas. The names of named
anonymous vmas are shown in /proc/pid/maps and /proc/pid/smaps as
[anon:<name>].
Userspace can set the name for a region of memory by calling
prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, start, len, (unsigned long)name)
Setting the name to NULL clears it. The name length limit is 80 bytes
including NUL-terminator and is checked to contain only printable ascii
characters (including space), except '[',']','\','$' and '`'.
Ascii strings are being used to have a descriptive identifiers for vmas,
which can be understood by the users reading /proc/pid/maps or
/proc/pid/smaps. Names can be standardized for a given system and they
can include some variable parts such as the name of the allocator or a
library, tid of the thread using it, etc.
The name is stored in a pointer in the shared union in vm_area_struct
that points to a null terminated string. Anonymous vmas with the same
name (equivalent strings) and are otherwise mergeable will be merged.
The name pointers are not shared between vmas even if they contain the
same name. The name pointer is stored in a union with fields that are
only used on file-backed mappings, so it does not increase memory usage.
CONFIG_ANON_VMA_NAME kernel configuration is introduced to enable this
feature. It keeps the feature disabled by default to prevent any
additional memory overhead and to avoid confusing procfs parsers on
systems which are not ready to support named anonymous vmas.
The patch is based on the original patch developed by Colin Cross, more
specifically on its latest version [1] posted upstream by Sumit Semwal.
It used a userspace pointer to store vma names. In that design, name
pointers could be shared between vmas. However during the last
upstreaming attempt, Kees Cook raised concerns [2] about this approach
and suggested to copy the name into kernel memory space, perform
validity checks [3] and store as a string referenced from
vm_area_struct.
One big concern is about fork() performance which would need to strdup
anonymous vma names. Dave Hansen suggested experimenting with
worst-case scenario of forking a process with 64k vmas having longest
possible names [4]. I ran this experiment on an ARM64 Android device
and recorded a worst-case regression of almost 40% when forking such a
process.
This regression is addressed in the followup patch which replaces the
pointer to a name with a refcounted structure that allows sharing the
name pointer between vmas of the same name. Instead of duplicating the
string during fork() or when splitting a vma it increments the refcount.
[1] https://lore.kernel.org/linux-mm/20200901161459.11772-4-sumit.semwal@linaro.org/
[2] https://lore.kernel.org/linux-mm/202009031031.D32EF57ED@keescook/
[3] https://lore.kernel.org/linux-mm/202009031022.3834F692@keescook/
[4] https://lore.kernel.org/linux-mm/5d0358ab-8c47-2f5f-8e43-23b89d6a8e95@intel.com/
Changes for prctl(2) manual page (in the options section):
PR_SET_VMA
Sets an attribute specified in arg2 for virtual memory areas
starting from the address specified in arg3 and spanning the
size specified in arg4. arg5 specifies the value of the attribute
to be set. Note that assigning an attribute to a virtual memory
area might prevent it from being merged with adjacent virtual
memory areas due to the difference in that attribute's value.
Currently, arg2 must be one of:
PR_SET_VMA_ANON_NAME
Set a name for anonymous virtual memory areas. arg5 should
be a pointer to a null-terminated string containing the
name. The name length including null byte cannot exceed
80 bytes. If arg5 is NULL, the name of the appropriate
anonymous virtual memory areas will be reset. The name
can contain only printable ascii characters (including
space), except '[',']','\','$' and '`'.
This feature is available only if the kernel is built with
the CONFIG_ANON_VMA_NAME option enabled.
[surenb@google.com: docs: proc.rst: /proc/PID/maps: fix malformed table]
Link: https://lkml.kernel.org/r/20211123185928.2513763-1-surenb@google.com
[surenb: rebased over v5.15-rc6, replaced userpointer with a kernel copy,
added input sanitization and CONFIG_ANON_VMA_NAME config. The bulk of the
work here was done by Colin Cross, therefore, with his permission, keeping
him as the author]
Link: https://lkml.kernel.org/r/20211019215511.3771969-2-surenb@google.com
Signed-off-by: Colin Cross <ccross@google.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Glauber <jan.glauber@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rob Landley <rob@landley.net>
Cc: "Serge E. Hallyn" <serge.hallyn@ubuntu.com>
Cc: Shaohua Li <shli@fusionio.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When I say remove I mean remove. All profile_task_exit and
profile_munmap do is call a blocking notifier chain. The helpers
profile_task_register and profile_task_unregister are not called
anywhere in the tree. Which means this is all dead code.
So remove the dead code and make it easier to read do_exit.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lkml.kernel.org/r/20220103213312.9144-1-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Commit 21a3c273f8 ("mm, hugetlb: add thread name and pid to
SHM_HUGETLB mlock rlimit warning") marked this as deprecated in 2012,
but it is not deleted yet.
Mike says he still sees that message in log files on occasion, so maybe we
should preserve this warning.
Also remove hugetlbfs related user_shm_unlock in ipc/shm.c and remove the
user_shm_unlock after out.
Link: https://lkml.kernel.org/r/20211103105857.25041-1-zhangyiru3@huawei.com
Signed-off-by: zhangyiru <zhangyiru3@huawei.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Liu Zixian <liuzixian4@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: wuxu.wu <wuxu.wu@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The variable mm->total_vm could be accessed concurrently during mmaping
and system accounting as noticed by KCSAN,
BUG: KCSAN: data-race in __acct_update_integrals / mmap_region
read-write to 0xffffa40267bd14c8 of 8 bytes by task 15609 on cpu 3:
mmap_region+0x6dc/0x1400
do_mmap+0x794/0xca0
vm_mmap_pgoff+0xdf/0x150
ksys_mmap_pgoff+0xe1/0x380
do_syscall_64+0x37/0x50
entry_SYSCALL_64_after_hwframe+0x44/0xa9
read to 0xffffa40267bd14c8 of 8 bytes by interrupt on cpu 2:
__acct_update_integrals+0x187/0x1d0
acct_account_cputime+0x3c/0x40
update_process_times+0x5c/0x150
tick_sched_timer+0x184/0x210
__run_hrtimer+0x119/0x3b0
hrtimer_interrupt+0x350/0xaa0
__sysvec_apic_timer_interrupt+0x7b/0x220
asm_call_irq_on_stack+0x12/0x20
sysvec_apic_timer_interrupt+0x4d/0x80
asm_sysvec_apic_timer_interrupt+0x12/0x20
smp_call_function_single+0x192/0x2b0
perf_install_in_context+0x29b/0x4a0
__se_sys_perf_event_open+0x1a98/0x2550
__x64_sys_perf_event_open+0x63/0x70
do_syscall_64+0x37/0x50
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Reported by Kernel Concurrency Sanitizer on:
CPU: 2 PID: 15610 Comm: syz-executor.3 Not tainted 5.10.0+ #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
Ubuntu-1.8.2-1ubuntu1 04/01/2014
In vm_stat_account which called by mmap_region, increase total_vm, and
__acct_update_integrals may read total_vm at the same time. This will
cause a data race which lead to undefined behaviour. To avoid potential
bad read/write, volatile property and barrier are both used to avoid
undefined behaviour.
Link: https://lkml.kernel.org/r/20210913105550.1569419-1-liupeng256@huawei.com
Signed-off-by: Peng Liu <liupeng256@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Liam R. Howlett