From: Chen Jun <chenjun102@huawei.com>
To: <linux-kernel@vger.kernel.org>, <rostedt@goodmis.org>,
<mingo@redhat.com>
Cc: <rui.xiang@huawei.com>
Subject: [PATCH] trace: Fix a kmemleak noise
Date: Wed, 24 Nov 2021 14:08:01 +0000 [thread overview]
Message-ID: <20211124140801.87121-1-chenjun102@huawei.com> (raw)
when run
echo 'hist:key=common_pid.execname,common_timestamp' >
/sys/kernel/debug/tracing/events/xxx/trigger
many kmemleak reported
unreferenced object 0xffff0000c7ea4980 (size 128):
comm "bash", pid 338, jiffies 4294912626 (age 9339.324s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<00000000f3469921>] kmem_cache_alloc_trace+0x4c0/0x6f0
[<0000000054ca40c3>] hist_trigger_elt_data_alloc+0x140/0x178
[<00000000633bd154>] tracing_map_init+0x1f8/0x268
[<000000007e814ab9>] event_hist_trigger_func+0xca0/0x1ad0
[<00000000bf8520ed>] trigger_process_regex+0xd4/0x128
[<00000000f549355a>] event_trigger_write+0x7c/0x120
[<00000000b80f898d>] vfs_write+0xc4/0x380
[<00000000823e1055>] ksys_write+0x74/0xf8
[<000000008a9374aa>] __arm64_sys_write+0x24/0x30
[<0000000087124017>] do_el0_svc+0x88/0x1c0
[<00000000efd0dcd1>] el0_svc+0x1c/0x28
[<00000000dbfba9b3>] el0_sync_handler+0x88/0xc0
[<00000000e7399680>] el0_sync+0x148/0x180
unreferenced object 0xffff0000c7ea4980 (size 128):
comm "bash", pid 338, jiffies 4294912626 (age 9339.324s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<00000000f3469921>] kmem_cache_alloc_trace+0x4c0/0x6f0
[<0000000054ca40c3>] hist_trigger_elt_data_alloc+0x140/0x178
[<00000000633bd154>] tracing_map_init+0x1f8/0x268
[<000000007e814ab9>] event_hist_trigger_func+0xca0/0x1ad0
[<00000000bf8520ed>] trigger_process_regex+0xd4/0x128
[<00000000f549355a>] event_trigger_write+0x7c/0x120
[<00000000b80f898d>] vfs_write+0xc4/0x380
[<00000000823e1055>] ksys_write+0x74/0xf8
[<000000008a9374aa>] __arm64_sys_write+0x24/0x30
[<0000000087124017>] do_el0_svc+0x88/0x1c0
[<00000000efd0dcd1>] el0_svc+0x1c/0x28
[<00000000dbfba9b3>] el0_sync_handler+0x88/0xc0
[<00000000e7399680>] el0_sync+0x148/0x180
The reason is elts->pages[i] is alloced by get_zeroed_page.
and kmemleak will not scan the area alloced by get_zeroed_page.
The address stored in elts->pages will be regarded as leaked.
To fix this, call kmemleak_alloc to tell kmemleak to scan elts->pages[i]
Signed-off-by: Chen Jun <chenjun102@huawei.com>
---
kernel/trace/tracing_map.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c
index 4b50fc0cb12c..66307675d2a5 100644
--- a/kernel/trace/tracing_map.c
+++ b/kernel/trace/tracing_map.c
@@ -15,6 +15,7 @@
#include <linux/jhash.h>
#include <linux/slab.h>
#include <linux/sort.h>
+#include <linux/kmemleak.h>
#include "tracing_map.h"
#include "trace.h"
@@ -307,6 +308,7 @@ static void tracing_map_array_free(struct tracing_map_array *a)
for (i = 0; i < a->n_pages; i++) {
if (!a->pages[i])
break;
+ kmemleak_free(a->pages[i]);
free_page((unsigned long)a->pages[i]);
}
@@ -342,6 +344,7 @@ static struct tracing_map_array *tracing_map_array_alloc(unsigned int n_elts,
a->pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
if (!a->pages[i])
goto free;
+ kmemleak_alloc(a->pages[i], PAGE_SIZE, 1, GFP_KERNEL);
}
out:
return a;
--
2.17.1
next reply other threads:[~2021-11-24 14:11 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-24 14:08 Chen Jun [this message]
2021-11-24 15:16 ` [PATCH] trace: Fix a kmemleak noise Steven Rostedt
2021-11-25 1:48 ` chenjun (AM)
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