diff options
author | Suren Baghdasaryan <surenb@google.com> | 2023-02-21 23:43:29 +0000 |
---|---|---|
committer | Kent Overstreet <kent.overstreet@linux.dev> | 2023-08-14 12:28:44 -0400 |
commit | f83c2849b7fc3f96e70c52cf8a11ea872f194828 (patch) | |
tree | dc9300f429fce711a466a9f3e9a2cec3cb6f2688 | |
parent | bb8d006d02ee8eebe3f1bdcbf55ed54eb93e0c68 (diff) |
codetag: debug: introduce OBJEXTS_ALLOC_FAIL to mark failed slab_ext allocations
If slabobj_ext vector allocation for a slab object fails and later on it
succeeds for another object in the same slab, the slabobj_ext for the
original object will be NULL and will be flagged in case when
CONFIG_MEM_ALLOC_PROFILING_DEBUG is enabled.
Mark failed slabobj_ext vector allocations using a new objext_flags flag
stored in the lower bits of slab->obj_exts. When new allocation succeeds
it marks all tag references in the same slabobj_ext vector as empty to
avoid warnings implemented by CONFIG_MEM_ALLOC_PROFILING_DEBUG checks.
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
-rw-r--r-- | include/linux/memcontrol.h | 4 | ||||
-rw-r--r-- | mm/slab.h | 25 | ||||
-rw-r--r-- | mm/slab_common.c | 22 |
3 files changed, 43 insertions, 8 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index c7f21b15b540..3eb8975c1462 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -356,8 +356,10 @@ enum page_memcg_data_flags { #endif /* CONFIG_MEMCG */ enum objext_flags { + /* slabobj_ext vector failed to allocate */ + OBJEXTS_ALLOC_FAIL = __FIRST_OBJEXT_FLAG, /* the next bit after the last actual flag */ - __NR_OBJEXTS_FLAGS = __FIRST_OBJEXT_FLAG, + __NR_OBJEXTS_FLAGS = (__FIRST_OBJEXT_FLAG << 1), }; #define OBJEXTS_FLAGS_MASK (__NR_OBJEXTS_FLAGS - 1) diff --git a/mm/slab.h b/mm/slab.h index d8d0d1a017ef..bc2d3429dfd6 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -435,9 +435,34 @@ static inline void mark_objexts_empty(struct slabobj_ext *obj_exts) } } +static inline void mark_failed_objexts_alloc(struct slab *slab) +{ + slab->obj_exts = OBJEXTS_ALLOC_FAIL; +} + +static inline void handle_failed_objexts_alloc(unsigned long obj_exts, + struct slabobj_ext *vec, unsigned int objects) +{ + /* + * If vector previously failed to allocate then we have live + * objects with no tag reference. Mark all references in this + * vector as empty to avoid warnings later on. + */ + if (obj_exts & OBJEXTS_ALLOC_FAIL) { + unsigned int i; + + for (i = 0; i < objects; i++) + set_codetag_empty(&vec[i].ref); + } +} + + #else /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */ static inline void mark_objexts_empty(struct slabobj_ext *obj_exts) {} +static inline void mark_failed_objexts_alloc(struct slab *slab) {} +static inline void handle_failed_objexts_alloc(unsigned long obj_exts, + struct slabobj_ext *vec, unsigned int objects) {} #endif /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */ diff --git a/mm/slab_common.c b/mm/slab_common.c index 5c079da71585..5b204e16fd6e 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -217,29 +217,37 @@ int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s, gfp_t gfp, bool new_slab) { unsigned int objects = objs_per_slab(s, slab); - unsigned long obj_exts; - void *vec; + unsigned long new_exts; + unsigned long old_exts; + struct slabobj_ext *vec; gfp &= ~OBJCGS_CLEAR_MASK; /* Prevent recursive extension vector allocation */ gfp |= __GFP_NO_OBJ_EXT; vec = kcalloc_node(objects, sizeof(struct slabobj_ext), gfp, slab_nid(slab)); - if (!vec) + if (!vec) { + /* Mark vectors which failed to allocate */ + if (new_slab) + mark_failed_objexts_alloc(slab); + return -ENOMEM; + } - obj_exts = (unsigned long)vec; + new_exts = (unsigned long)vec; #ifdef CONFIG_MEMCG - obj_exts |= MEMCG_DATA_OBJEXTS; + new_exts |= MEMCG_DATA_OBJEXTS; #endif + old_exts = slab->obj_exts; + handle_failed_objexts_alloc(old_exts, vec, objects); if (new_slab) { /* * If the slab is brand new and nobody can yet access its * obj_exts, no synchronization is required and obj_exts can * be simply assigned. */ - slab->obj_exts = obj_exts; - } else if (cmpxchg(&slab->obj_exts, 0, obj_exts)) { + slab->obj_exts = new_exts; + } else if (cmpxchg(&slab->obj_exts, old_exts, new_exts) != old_exts) { /* * If the slab is already in use, somebody can allocate and * assign slabobj_exts in parallel. In this case the existing |