mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 02:39:48 +00:00
![Eric Biggers](/assets/img/avatar_default.png)
Kmemleak is falsely reporting a leak of the slab allocation in sctp_stream_init_ext(): BUG: memory leak unreferenced object 0xffff8881114f5d80 (size 96): comm "syz-executor934", pid 7160, jiffies 4294993058 (age 31.950s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000ce7a1326>] kmemleak_alloc_recursive include/linux/kmemleak.h:55 [inline] [<00000000ce7a1326>] slab_post_alloc_hook mm/slab.h:439 [inline] [<00000000ce7a1326>] slab_alloc mm/slab.c:3326 [inline] [<00000000ce7a1326>] kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553 [<000000007abb7ac9>] kmalloc include/linux/slab.h:547 [inline] [<000000007abb7ac9>] kzalloc include/linux/slab.h:742 [inline] [<000000007abb7ac9>] sctp_stream_init_ext+0x2b/0xa0 net/sctp/stream.c:157 [<0000000048ecb9c1>] sctp_sendmsg_to_asoc+0x946/0xa00 net/sctp/socket.c:1882 [<000000004483ca2b>] sctp_sendmsg+0x2a8/0x990 net/sctp/socket.c:2102 [...] But it's freed later. Kmemleak misses the allocation because its pointer is stored in the generic radix tree sctp_stream::out, and the generic radix tree uses raw pages which aren't tracked by kmemleak. Fix this by adding the kmemleak hooks to the generic radix tree code. Link: http://lkml.kernel.org/r/20191004065039.727564-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Reported-by: <syzbot+7f3b6b106be8dcdcdeec@syzkaller.appspotmail.com> Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Vlad Yasevich <vyasevich@gmail.com> Cc: Xin Long <lucien.xin@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
237 lines
5.3 KiB
C
237 lines
5.3 KiB
C
|
|
#include <linux/export.h>
|
|
#include <linux/generic-radix-tree.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/kmemleak.h>
|
|
|
|
#define GENRADIX_ARY (PAGE_SIZE / sizeof(struct genradix_node *))
|
|
#define GENRADIX_ARY_SHIFT ilog2(GENRADIX_ARY)
|
|
|
|
struct genradix_node {
|
|
union {
|
|
/* Interior node: */
|
|
struct genradix_node *children[GENRADIX_ARY];
|
|
|
|
/* Leaf: */
|
|
u8 data[PAGE_SIZE];
|
|
};
|
|
};
|
|
|
|
static inline int genradix_depth_shift(unsigned depth)
|
|
{
|
|
return PAGE_SHIFT + GENRADIX_ARY_SHIFT * depth;
|
|
}
|
|
|
|
/*
|
|
* Returns size (of data, in bytes) that a tree of a given depth holds:
|
|
*/
|
|
static inline size_t genradix_depth_size(unsigned depth)
|
|
{
|
|
return 1UL << genradix_depth_shift(depth);
|
|
}
|
|
|
|
/* depth that's needed for a genradix that can address up to ULONG_MAX: */
|
|
#define GENRADIX_MAX_DEPTH \
|
|
DIV_ROUND_UP(BITS_PER_LONG - PAGE_SHIFT, GENRADIX_ARY_SHIFT)
|
|
|
|
#define GENRADIX_DEPTH_MASK \
|
|
((unsigned long) (roundup_pow_of_two(GENRADIX_MAX_DEPTH + 1) - 1))
|
|
|
|
static inline unsigned genradix_root_to_depth(struct genradix_root *r)
|
|
{
|
|
return (unsigned long) r & GENRADIX_DEPTH_MASK;
|
|
}
|
|
|
|
static inline struct genradix_node *genradix_root_to_node(struct genradix_root *r)
|
|
{
|
|
return (void *) ((unsigned long) r & ~GENRADIX_DEPTH_MASK);
|
|
}
|
|
|
|
/*
|
|
* Returns pointer to the specified byte @offset within @radix, or NULL if not
|
|
* allocated
|
|
*/
|
|
void *__genradix_ptr(struct __genradix *radix, size_t offset)
|
|
{
|
|
struct genradix_root *r = READ_ONCE(radix->root);
|
|
struct genradix_node *n = genradix_root_to_node(r);
|
|
unsigned level = genradix_root_to_depth(r);
|
|
|
|
if (ilog2(offset) >= genradix_depth_shift(level))
|
|
return NULL;
|
|
|
|
while (1) {
|
|
if (!n)
|
|
return NULL;
|
|
if (!level)
|
|
break;
|
|
|
|
level--;
|
|
|
|
n = n->children[offset >> genradix_depth_shift(level)];
|
|
offset &= genradix_depth_size(level) - 1;
|
|
}
|
|
|
|
return &n->data[offset];
|
|
}
|
|
EXPORT_SYMBOL(__genradix_ptr);
|
|
|
|
static inline struct genradix_node *genradix_alloc_node(gfp_t gfp_mask)
|
|
{
|
|
struct genradix_node *node;
|
|
|
|
node = (struct genradix_node *)__get_free_page(gfp_mask|__GFP_ZERO);
|
|
|
|
/*
|
|
* We're using pages (not slab allocations) directly for kernel data
|
|
* structures, so we need to explicitly inform kmemleak of them in order
|
|
* to avoid false positive memory leak reports.
|
|
*/
|
|
kmemleak_alloc(node, PAGE_SIZE, 1, gfp_mask);
|
|
return node;
|
|
}
|
|
|
|
static inline void genradix_free_node(struct genradix_node *node)
|
|
{
|
|
kmemleak_free(node);
|
|
free_page((unsigned long)node);
|
|
}
|
|
|
|
/*
|
|
* Returns pointer to the specified byte @offset within @radix, allocating it if
|
|
* necessary - newly allocated slots are always zeroed out:
|
|
*/
|
|
void *__genradix_ptr_alloc(struct __genradix *radix, size_t offset,
|
|
gfp_t gfp_mask)
|
|
{
|
|
struct genradix_root *v = READ_ONCE(radix->root);
|
|
struct genradix_node *n, *new_node = NULL;
|
|
unsigned level;
|
|
|
|
/* Increase tree depth if necessary: */
|
|
while (1) {
|
|
struct genradix_root *r = v, *new_root;
|
|
|
|
n = genradix_root_to_node(r);
|
|
level = genradix_root_to_depth(r);
|
|
|
|
if (n && ilog2(offset) < genradix_depth_shift(level))
|
|
break;
|
|
|
|
if (!new_node) {
|
|
new_node = genradix_alloc_node(gfp_mask);
|
|
if (!new_node)
|
|
return NULL;
|
|
}
|
|
|
|
new_node->children[0] = n;
|
|
new_root = ((struct genradix_root *)
|
|
((unsigned long) new_node | (n ? level + 1 : 0)));
|
|
|
|
if ((v = cmpxchg_release(&radix->root, r, new_root)) == r) {
|
|
v = new_root;
|
|
new_node = NULL;
|
|
}
|
|
}
|
|
|
|
while (level--) {
|
|
struct genradix_node **p =
|
|
&n->children[offset >> genradix_depth_shift(level)];
|
|
offset &= genradix_depth_size(level) - 1;
|
|
|
|
n = READ_ONCE(*p);
|
|
if (!n) {
|
|
if (!new_node) {
|
|
new_node = genradix_alloc_node(gfp_mask);
|
|
if (!new_node)
|
|
return NULL;
|
|
}
|
|
|
|
if (!(n = cmpxchg_release(p, NULL, new_node)))
|
|
swap(n, new_node);
|
|
}
|
|
}
|
|
|
|
if (new_node)
|
|
genradix_free_node(new_node);
|
|
|
|
return &n->data[offset];
|
|
}
|
|
EXPORT_SYMBOL(__genradix_ptr_alloc);
|
|
|
|
void *__genradix_iter_peek(struct genradix_iter *iter,
|
|
struct __genradix *radix,
|
|
size_t objs_per_page)
|
|
{
|
|
struct genradix_root *r;
|
|
struct genradix_node *n;
|
|
unsigned level, i;
|
|
restart:
|
|
r = READ_ONCE(radix->root);
|
|
if (!r)
|
|
return NULL;
|
|
|
|
n = genradix_root_to_node(r);
|
|
level = genradix_root_to_depth(r);
|
|
|
|
if (ilog2(iter->offset) >= genradix_depth_shift(level))
|
|
return NULL;
|
|
|
|
while (level) {
|
|
level--;
|
|
|
|
i = (iter->offset >> genradix_depth_shift(level)) &
|
|
(GENRADIX_ARY - 1);
|
|
|
|
while (!n->children[i]) {
|
|
i++;
|
|
iter->offset = round_down(iter->offset +
|
|
genradix_depth_size(level),
|
|
genradix_depth_size(level));
|
|
iter->pos = (iter->offset >> PAGE_SHIFT) *
|
|
objs_per_page;
|
|
if (i == GENRADIX_ARY)
|
|
goto restart;
|
|
}
|
|
|
|
n = n->children[i];
|
|
}
|
|
|
|
return &n->data[iter->offset & (PAGE_SIZE - 1)];
|
|
}
|
|
EXPORT_SYMBOL(__genradix_iter_peek);
|
|
|
|
static void genradix_free_recurse(struct genradix_node *n, unsigned level)
|
|
{
|
|
if (level) {
|
|
unsigned i;
|
|
|
|
for (i = 0; i < GENRADIX_ARY; i++)
|
|
if (n->children[i])
|
|
genradix_free_recurse(n->children[i], level - 1);
|
|
}
|
|
|
|
genradix_free_node(n);
|
|
}
|
|
|
|
int __genradix_prealloc(struct __genradix *radix, size_t size,
|
|
gfp_t gfp_mask)
|
|
{
|
|
size_t offset;
|
|
|
|
for (offset = 0; offset < size; offset += PAGE_SIZE)
|
|
if (!__genradix_ptr_alloc(radix, offset, gfp_mask))
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(__genradix_prealloc);
|
|
|
|
void __genradix_free(struct __genradix *radix)
|
|
{
|
|
struct genradix_root *r = xchg(&radix->root, NULL);
|
|
|
|
genradix_free_recurse(genradix_root_to_node(r),
|
|
genradix_root_to_depth(r));
|
|
}
|
|
EXPORT_SYMBOL(__genradix_free);
|