Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
1
fork

Configure Feed

Select the types of activity you want to include in your feed.

alloc_tag: fix boot failure due to NULL pointer dereference

There is a boot failure when both CONFIG_DEBUG_KMEMLEAK and
CONFIG_MEM_ALLOC_PROFILING are enabled.

BUG: kernel NULL pointer dereference, address: 0000000000000000
RIP: 0010:__alloc_tagging_slab_alloc_hook+0x181/0x2f0
Call Trace:
kmem_cache_alloc_noprof+0x1c8/0x5c0
__alloc_object+0x2f/0x290
__create_object+0x22/0x80
kmemleak_init+0x122/0x190
mm_core_init+0xb6/0x160
start_kernel+0x39f/0x920
x86_64_start_reservations+0x18/0x30
x86_64_start_kernel+0x104/0x120
common_startup_64+0x12c/0x138

In kmemleak, mem_pool_alloc() directly calls kmem_cache_alloc_noprof(), as
a result, current->alloc_tag is NULL, leading to a null pointer
dereference.

Move the checks for SLAB_NO_OBJ_EXT, SLAB_NOLEAKTRACE, and
__GFP_NO_OBJ_EXT to the parent function __alloc_tagging_slab_alloc_hook()
to fix this.

Also this distinguishes the SLAB_NOLEAKTRACE case between the actual
memory allocation failures case, make CODETAG_FLAG_INACCURATE more
accurate.

Link: https://lkml.kernel.org/r/20250926080659.741991-1-ranxiaokai627@163.com
Fixes: b9e2f58ffb84 ("alloc_tag: mark inaccurate allocation counters in /proc/allocinfo output")
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Cc: Christoph Lameter (Ampere) <cl@gentwo.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

authored by

Ran Xiaokai and committed by
Andrew Morton
fb552b24 989c2f55

+9 -9
+9 -9
mm/slub.c
··· 2109 2109 { 2110 2110 struct slab *slab; 2111 2111 2112 - if (!p) 2113 - return NULL; 2114 - 2115 - if (s->flags & (SLAB_NO_OBJ_EXT | SLAB_NOLEAKTRACE)) 2116 - return NULL; 2117 - 2118 - if (flags & __GFP_NO_OBJ_EXT) 2119 - return NULL; 2120 - 2121 2112 slab = virt_to_slab(p); 2122 2113 if (!slab_obj_exts(slab) && 2123 2114 alloc_slab_obj_exts(slab, s, flags, false)) { ··· 2125 2134 __alloc_tagging_slab_alloc_hook(struct kmem_cache *s, void *object, gfp_t flags) 2126 2135 { 2127 2136 struct slabobj_ext *obj_exts; 2137 + 2138 + if (!object) 2139 + return; 2140 + 2141 + if (s->flags & (SLAB_NO_OBJ_EXT | SLAB_NOLEAKTRACE)) 2142 + return; 2143 + 2144 + if (flags & __GFP_NO_OBJ_EXT) 2145 + return; 2128 2146 2129 2147 obj_exts = prepare_slab_obj_exts_hook(s, flags, object); 2130 2148 /*