* [PATCH] block: fix memleak when __blk_rq_map_user_iov() is failed
@ 2019-12-18 8:44 Yang Yingliang
2019-12-19 8:27 ` Bob Liu
2019-12-19 12:45 ` Jens Axboe
0 siblings, 2 replies; 3+ messages in thread
From: Yang Yingliang @ 2019-12-18 8:44 UTC (permalink / raw)
To: axboe; +Cc: linux-block, linux-kernel, yangyingliang
When I doing fuzzy test, get the memleak report:
BUG: memory leak
unreferenced object 0xffff88837af80000 (size 4096):
comm "memleak", pid 3557, jiffies 4294817681 (age 112.499s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
20 00 00 00 10 01 00 00 00 00 00 00 01 00 00 00 ...............
backtrace:
[<000000001c894df8>] bio_alloc_bioset+0x393/0x590
[<000000008b139a3c>] bio_copy_user_iov+0x300/0xcd0
[<00000000a998bd8c>] blk_rq_map_user_iov+0x2f1/0x5f0
[<000000005ceb7f05>] blk_rq_map_user+0xf2/0x160
[<000000006454da92>] sg_common_write.isra.21+0x1094/0x1870
[<00000000064bb208>] sg_write.part.25+0x5d9/0x950
[<000000004fc670f6>] sg_write+0x5f/0x8c
[<00000000b0d05c7b>] __vfs_write+0x7c/0x100
[<000000008e177714>] vfs_write+0x1c3/0x500
[<0000000087d23f34>] ksys_write+0xf9/0x200
[<000000002c8dbc9d>] do_syscall_64+0x9f/0x4f0
[<00000000678d8e9a>] entry_SYSCALL_64_after_hwframe+0x49/0xbe
If __blk_rq_map_user_iov() is failed in blk_rq_map_user_iov(),
the bio(s) which is allocated before this failing will leak. The
refcount of the bio(s) is init to 1 and increased to 2 by calling
bio_get(), but __blk_rq_unmap_user() only decrease it to 1, so
the bio cannot be freed. Fix it by calling blk_rq_unmap_user().
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
block/blk-map.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/blk-map.c b/block/blk-map.c
index 3a62e471d81b..b0790268ed9d 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -151,7 +151,7 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
return 0;
unmap_rq:
- __blk_rq_unmap_user(bio);
+ blk_rq_unmap_user(bio);
fail:
rq->bio = NULL;
return ret;
--
2.17.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] block: fix memleak when __blk_rq_map_user_iov() is failed
2019-12-18 8:44 [PATCH] block: fix memleak when __blk_rq_map_user_iov() is failed Yang Yingliang
@ 2019-12-19 8:27 ` Bob Liu
2019-12-19 12:45 ` Jens Axboe
1 sibling, 0 replies; 3+ messages in thread
From: Bob Liu @ 2019-12-19 8:27 UTC (permalink / raw)
To: Yang Yingliang, axboe; +Cc: linux-block, linux-kernel
On 12/18/19 4:44 PM, Yang Yingliang wrote:
> When I doing fuzzy test, get the memleak report:
>
> BUG: memory leak
> unreferenced object 0xffff88837af80000 (size 4096):
> comm "memleak", pid 3557, jiffies 4294817681 (age 112.499s)
> hex dump (first 32 bytes):
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> 20 00 00 00 10 01 00 00 00 00 00 00 01 00 00 00 ...............
> backtrace:
> [<000000001c894df8>] bio_alloc_bioset+0x393/0x590
> [<000000008b139a3c>] bio_copy_user_iov+0x300/0xcd0
> [<00000000a998bd8c>] blk_rq_map_user_iov+0x2f1/0x5f0
> [<000000005ceb7f05>] blk_rq_map_user+0xf2/0x160
> [<000000006454da92>] sg_common_write.isra.21+0x1094/0x1870
> [<00000000064bb208>] sg_write.part.25+0x5d9/0x950
> [<000000004fc670f6>] sg_write+0x5f/0x8c
> [<00000000b0d05c7b>] __vfs_write+0x7c/0x100
> [<000000008e177714>] vfs_write+0x1c3/0x500
> [<0000000087d23f34>] ksys_write+0xf9/0x200
> [<000000002c8dbc9d>] do_syscall_64+0x9f/0x4f0
> [<00000000678d8e9a>] entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> If __blk_rq_map_user_iov() is failed in blk_rq_map_user_iov(),
> the bio(s) which is allocated before this failing will leak. The
> refcount of the bio(s) is init to 1 and increased to 2 by calling
> bio_get(), but __blk_rq_unmap_user() only decrease it to 1, so
> the bio cannot be freed. Fix it by calling blk_rq_unmap_user().
>
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Good catch! Looks fine to me.
Reviewed-by: Bob Liu <bob.liu@oracle.com>
> ---
> block/blk-map.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/block/blk-map.c b/block/blk-map.c
> index 3a62e471d81b..b0790268ed9d 100644
> --- a/block/blk-map.c
> +++ b/block/blk-map.c
> @@ -151,7 +151,7 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
> return 0;
>
> unmap_rq:
> - __blk_rq_unmap_user(bio);
> + blk_rq_unmap_user(bio);
> fail:
> rq->bio = NULL;
> return ret;
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] block: fix memleak when __blk_rq_map_user_iov() is failed
2019-12-18 8:44 [PATCH] block: fix memleak when __blk_rq_map_user_iov() is failed Yang Yingliang
2019-12-19 8:27 ` Bob Liu
@ 2019-12-19 12:45 ` Jens Axboe
1 sibling, 0 replies; 3+ messages in thread
From: Jens Axboe @ 2019-12-19 12:45 UTC (permalink / raw)
To: Yang Yingliang; +Cc: linux-block, linux-kernel
On 12/18/19 1:44 AM, Yang Yingliang wrote:
> When I doing fuzzy test, get the memleak report:
>
> BUG: memory leak
> unreferenced object 0xffff88837af80000 (size 4096):
> comm "memleak", pid 3557, jiffies 4294817681 (age 112.499s)
> hex dump (first 32 bytes):
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> 20 00 00 00 10 01 00 00 00 00 00 00 01 00 00 00 ...............
> backtrace:
> [<000000001c894df8>] bio_alloc_bioset+0x393/0x590
> [<000000008b139a3c>] bio_copy_user_iov+0x300/0xcd0
> [<00000000a998bd8c>] blk_rq_map_user_iov+0x2f1/0x5f0
> [<000000005ceb7f05>] blk_rq_map_user+0xf2/0x160
> [<000000006454da92>] sg_common_write.isra.21+0x1094/0x1870
> [<00000000064bb208>] sg_write.part.25+0x5d9/0x950
> [<000000004fc670f6>] sg_write+0x5f/0x8c
> [<00000000b0d05c7b>] __vfs_write+0x7c/0x100
> [<000000008e177714>] vfs_write+0x1c3/0x500
> [<0000000087d23f34>] ksys_write+0xf9/0x200
> [<000000002c8dbc9d>] do_syscall_64+0x9f/0x4f0
> [<00000000678d8e9a>] entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> If __blk_rq_map_user_iov() is failed in blk_rq_map_user_iov(),
> the bio(s) which is allocated before this failing will leak. The
> refcount of the bio(s) is init to 1 and increased to 2 by calling
> bio_get(), but __blk_rq_unmap_user() only decrease it to 1, so
> the bio cannot be freed. Fix it by calling blk_rq_unmap_user().
Applied, thanks.
--
Jens Axboe
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-12-18 8:44 [PATCH] block: fix memleak when __blk_rq_map_user_iov() is failed Yang Yingliang
2019-12-19 8:27 ` Bob Liu
2019-12-19 12:45 ` Jens Axboe
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