We saw crashes where slub percpu freelist was corrupted, this may catch the problem earlier where we first time see bad freelist, and suppress further corruption.
This is enabled with 'slub_debug=F'. https://virtuozzo.atlassian.net/browse/PSBM-155867 Signed-off-by: Pavel Tikhomirov <ptikhomi...@virtuozzo.com> --- v2: fixed compilation in case !CONFIG_SLUB_DEBUG --- mm/slub.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/mm/slub.c b/mm/slub.c index d4392708a0148..748a4a036ff35 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1085,6 +1085,20 @@ static void setup_object_debug(struct kmem_cache *s, struct page *page, init_tracking(s, object); } + +static inline int alloc_valid_pointer_check(struct kmem_cache *s, + struct page *page, void *object) +{ + if (s->flags & SLAB_CONSISTENCY_CHECKS && + !check_valid_pointer(s, page, object)) { + if (printk_ratelimit()) + object_err(s, page, object, "Freelist Pointer corrupted"); + return 0; + } + + return 1; +} + static inline int alloc_consistency_checks(struct kmem_cache *s, struct page *page, void *object) { @@ -1343,6 +1357,10 @@ static unsigned long kmem_cache_flags(unsigned long object_size, static inline void setup_object_debug(struct kmem_cache *s, struct page *page, void *object) {} +static inline int alloc_valid_pointer_check(struct kmem_cache *s, + struct page *page, + void *object) { return 0; } + static inline int alloc_debug_processing(struct kmem_cache *s, struct page *page, void *object, unsigned long addr) { return 0; } @@ -2517,6 +2535,10 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, * That page must be frozen for per cpu allocations to work. */ VM_BUG_ON(!c->page->frozen); + + if (kmem_cache_debug(s) && !alloc_valid_pointer_check(s, c->page, freelist)) + return NULL; + c->freelist = get_freepointer(s, freelist); c->tid = next_tid(c->tid); return freelist; -- 2.45.2 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel
