mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-12 21:57:43 +00:00
6904817607
most architectures are relying on mmap_sem for write in their arch_setup_additional_pages. If the waiting task gets killed by the oom killer it would block oom_reaper from asynchronous address space reclaim and reduce the chances of timely OOM resolving. Wait for the lock in the killable mode and return with EINTR if the task got killed while waiting. Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Andy Lutomirski <luto@amacapital.net> [x86 vdso] Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
96 lines
2.2 KiB
C
96 lines
2.2 KiB
C
/*
|
|
* arch/sh/kernel/vsyscall/vsyscall.c
|
|
*
|
|
* Copyright (C) 2006 Paul Mundt
|
|
*
|
|
* vDSO randomization
|
|
* Copyright(C) 2005-2006, Red Hat, Inc., Ingo Molnar
|
|
*
|
|
* This file is subject to the terms and conditions of the GNU General Public
|
|
* License. See the file "COPYING" in the main directory of this archive
|
|
* for more details.
|
|
*/
|
|
#include <linux/mm.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/init.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/module.h>
|
|
#include <linux/elf.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/err.h>
|
|
|
|
/*
|
|
* Should the kernel map a VDSO page into processes and pass its
|
|
* address down to glibc upon exec()?
|
|
*/
|
|
unsigned int __read_mostly vdso_enabled = 1;
|
|
EXPORT_SYMBOL_GPL(vdso_enabled);
|
|
|
|
static int __init vdso_setup(char *s)
|
|
{
|
|
vdso_enabled = simple_strtoul(s, NULL, 0);
|
|
return 1;
|
|
}
|
|
__setup("vdso=", vdso_setup);
|
|
|
|
/*
|
|
* These symbols are defined by vsyscall.o to mark the bounds
|
|
* of the ELF DSO images included therein.
|
|
*/
|
|
extern const char vsyscall_trapa_start, vsyscall_trapa_end;
|
|
static struct page *syscall_pages[1];
|
|
|
|
int __init vsyscall_init(void)
|
|
{
|
|
void *syscall_page = (void *)get_zeroed_page(GFP_ATOMIC);
|
|
syscall_pages[0] = virt_to_page(syscall_page);
|
|
|
|
/*
|
|
* XXX: Map this page to a fixmap entry if we get around
|
|
* to adding the page to ELF core dumps
|
|
*/
|
|
|
|
memcpy(syscall_page,
|
|
&vsyscall_trapa_start,
|
|
&vsyscall_trapa_end - &vsyscall_trapa_start);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Setup a VMA at program startup for the vsyscall page */
|
|
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
unsigned long addr;
|
|
int ret;
|
|
|
|
if (down_write_killable(&mm->mmap_sem))
|
|
return -EINTR;
|
|
|
|
addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0);
|
|
if (IS_ERR_VALUE(addr)) {
|
|
ret = addr;
|
|
goto up_fail;
|
|
}
|
|
|
|
ret = install_special_mapping(mm, addr, PAGE_SIZE,
|
|
VM_READ | VM_EXEC |
|
|
VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
|
|
syscall_pages);
|
|
if (unlikely(ret))
|
|
goto up_fail;
|
|
|
|
current->mm->context.vdso = (void *)addr;
|
|
|
|
up_fail:
|
|
up_write(&mm->mmap_sem);
|
|
return ret;
|
|
}
|
|
|
|
const char *arch_vma_name(struct vm_area_struct *vma)
|
|
{
|
|
if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)
|
|
return "[vdso]";
|
|
|
|
return NULL;
|
|
}
|