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Message-Id: <20221123111001.34855-1-jiasheng@iscas.ac.cn>
Date: Wed, 23 Nov 2022 19:10:01 +0800
From: Jiasheng Jiang <jiasheng@...as.ac.cn>
To: rostedt@...dmis.org, mhiramat@...nel.org, vbabka@...e.cz,
42.hyeyoo@...il.com, vasily.averin@...ux.dev,
akpm@...ux-foundation.org, shakeelb@...gle.com,
vvghjk1234@...il.com
Cc: linux-kernel@...r.kernel.org, Jiasheng Jiang <jiasheng@...as.ac.cn>
Subject: [PATCH] mm/tracing: Add check for kmem_cache
In __kmem_cache_alloc_lru() of mm/slab.c, cachep may be NULL when error
occurs in slab_alloc().
However, trace_kmem_cache_alloc() will still use it as the parameter,
which may cause NULL poineter dereference.
Therefore, it should be better to add the check and handle the error
in the trace_kmem_cache_alloc().
Fixes: 36555751c675 ("kmemtrace: SLAB hooks.")
Signed-off-by: Jiasheng Jiang <jiasheng@...as.ac.cn>
---
include/trace/events/kmem.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h
index 243073cfc29d..d99507d32ef5 100644
--- a/include/trace/events/kmem.h
+++ b/include/trace/events/kmem.h
@@ -32,8 +32,8 @@ TRACE_EVENT(kmem_cache_alloc,
TP_fast_assign(
__entry->call_site = call_site;
__entry->ptr = ptr;
- __entry->bytes_req = s->object_size;
- __entry->bytes_alloc = s->size;
+ __entry->bytes_req = s ? s->object_size : 0;
+ __entry->bytes_alloc = s ? s->size : 0;
__entry->gfp_flags = (__force unsigned long)gfp_flags;
__entry->node = node;
__entry->accounted = IS_ENABLED(CONFIG_MEMCG_KMEM) ?
--
2.25.1
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