openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity

slub: Make CONFIG_DEBUG_PAGE_ALLOC work with new fastpath 

Fastpath can do a speculative access to a page that CONFIG_DEBUG_PAGE_ALLOC may have
marked as invalid to retrieve the pointer to the next free object.

Use probe_kernel_read in that case in order not to cause a page fault.

Cc: <stable@kernel.org> # 38.x
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
This commit is contained in:
Christoph Lameter 2011-05-16 15:26:08 -05:00 committed by Pekka Enberg
parent 6332aa9d25
commit 1393d9a185
1 changed files with 13 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
mm/slub.c
View File

@ -261,6 +261,18 @@ static inline void *get_freepointer(struct kmem_cache *s, void *object)
return *(void **)(object + s->offset); return *(void **)(object + s->offset);
} }
static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
{
void *p;
#ifdef CONFIG_DEBUG_PAGEALLOC
probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
#else
p = get_freepointer(s, object);
#endif
return p;
}
static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp) static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
{ {
*(void **)(object + s->offset) = fp; *(void **)(object + s->offset) = fp;
@ -1933,7 +1945,7 @@ static __always_inline void *slab_alloc(struct kmem_cache *s,
if (unlikely(!this_cpu_cmpxchg_double( if (unlikely(!this_cpu_cmpxchg_double(
s->cpu_slab->freelist, s->cpu_slab->tid, s->cpu_slab->freelist, s->cpu_slab->tid,
object, tid, object, tid,
get_freepointer(s, object), next_tid(tid)))) { get_freepointer_safe(s, object), next_tid(tid)))) {
note_cmpxchg_failure("slab_alloc", s, tid); note_cmpxchg_failure("slab_alloc", s, tid);
goto redo; goto redo;