linux-kernel - Re: [PATCH] f2fs: fix bio memleak when committing super block

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Message-ID: <b5781bc9-ed04-4e3f-bbc1-126e18620ff3@kernel.org>
Date: Sat, 7 Jun 2025 19:24:29 +0800
From: Chao Yu <chao@...nel.org>
To: Sheng Yong <shengyong2021@...il.com>, jaegeuk@...nel.org
Cc: chao@...nel.org, linux-f2fs-devel@...ts.sourceforge.net,
 linux-kernel@...r.kernel.org, Sheng Yong <shengyong1@...omi.com>
Subject: Re: [PATCH] f2fs: fix bio memleak when committing super block

On 2025/6/7 14:41, Sheng Yong wrote:
> From: Sheng Yong <shengyong1@...omi.com>
> 
> When committing new super block, bio is allocated but not freed, and
> kmemleak complains:
> 
>    unreferenced object 0xffff88801d185600 (size 192):
>      comm "kworker/3:2", pid 128, jiffies 4298624992
>      hex dump (first 32 bytes):
>        00 00 00 00 00 00 00 00 80 67 c3 00 81 88 ff ff  .........g......
>        01 08 06 00 00 00 00 00 00 00 00 00 01 00 00 00  ................
>      backtrace (crc 650ecdb1):
>        kmem_cache_alloc_noprof+0x3a9/0x460
>        mempool_alloc_noprof+0x12f/0x310
>        bio_alloc_bioset+0x1e2/0x7e0
>        __f2fs_commit_super+0xe0/0x370
>        f2fs_commit_super+0x4ed/0x8c0
>        f2fs_record_error_work+0xc7/0x190
>        process_one_work+0x7db/0x1970
>        worker_thread+0x518/0xea0
>        kthread+0x359/0x690
>        ret_from_fork+0x34/0x70
>        ret_from_fork_asm+0x1a/0x30
> 
> The issue can be reproduced by:
> 
>    mount /dev/vda /mnt
>    i=0
>    while :; do
>        echo '[h]abc' > /sys/fs/f2fs/vda/extension_list
>        echo '[h]!abc' > /sys/fs/f2fs/vda/extension_list
>        echo scan > /sys/kernel/debug/kmemleak
>        dmesg | grep "new suspected memory leaks"
>        [ $? -eq 0 ] && break
>        i=$((i + 1))
>        echo "$i"
>    done
>    umount /mnt
> 
> Fixes: 5bcde4557862 ("f2fs: get rid of buffer_head use")
> Signed-off-by: Sheng Yong <shengyong1@...omi.com>

Reviewed-by: Chao Yu <chao@...nel.org>

Thanks,