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From: =?UTF-8?B?5LqT5paH5p2w?= <qwjhust@gmail.com>
Date: Tue, 9 Jan 2024 15:08:41 +0800
Message-ID: <CAGFpFsQsRm0s3OG1zENHSgPB+TcbGG6NKXKhugCYnzX=shf00A@mail.gmail.com>
Subject: Re: [PATCH] f2fs: fix NULL pointer dereference in f2fs_submit_page_write()
To: jaegeuk@kernel.org, chao@kernel.org, guoweichao@oppo.com, 
	linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org
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This patch has been merged into the new patch.

[PATCH v2] f2fs: fix max open zone constraints
https://lore.kernel.org/linux-f2fs-devel/20240109035804.642-1-qwjhust@gmail=
com/


Wenjie <qwjhust@gmail.com> =E4=BA=8E2024=E5=B9=B41=E6=9C=887=E6=97=A5=E5=91=
=A8=E6=97=A5 21:12=E5=86=99=E9=81=93=EF=BC=9A
>
> From: Wenjie Qi <qwjhust@gmail.com>
>
> BUG: kernel NULL pointer dereference, address: 0000000000000014
> RIP: 0010:f2fs_submit_page_write+0x6cf/0x780 [f2fs]
> Call Trace:
> <TASK>
> ? show_regs+0x6e/0x80
> ? __die+0x29/0x70
> ? page_fault_oops+0x154/0x4a0
> ? prb_read_valid+0x20/0x30
> ? __irq_work_queue_local+0x39/0xd0
> ? irq_work_queue+0x36/0x70
> ? do_user_addr_fault+0x314/0x6c0
> ? exc_page_fault+0x7d/0x190
> ? asm_exc_page_fault+0x2b/0x30
> ? f2fs_submit_page_write+0x6cf/0x780 [f2fs]
> ? f2fs_submit_page_write+0x736/0x780 [f2fs]
> do_write_page+0x50/0x170 [f2fs]
> f2fs_outplace_write_data+0x61/0xb0 [f2fs]
> f2fs_do_write_data_page+0x3f8/0x660 [f2fs]
> f2fs_write_single_data_page+0x5bb/0x7a0 [f2fs]
> f2fs_write_cache_pages+0x3da/0xbe0 [f2fs]
> ...
>
> It is possible that other threads have added this fio to io->bio
> and submitted the io->bio before entering f2fs_submit_page_write().
> At this point io->bio =3D NULL.
> If is_end_zone_blkaddr(sbi, fio->new_blkaddr) of this fio is true,
> then an NULL pointer dereference error occurs at bio_get(io->bio).
> In this case, the code to determine the zone end can simply be skipped.
>
> Signed-off-by: Wenjie Qi <qwjhust@gmail.com>
> ---
>  fs/f2fs/data.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 1896928cae77..d08e92bb2621 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -1100,7 +1100,7 @@ void f2fs_submit_page_write(struct f2fs_io_info *fi=
o)
>                 goto next;
>  out:
>  #ifdef CONFIG_BLK_DEV_ZONED
> -       if (f2fs_sb_has_blkzoned(sbi) && btype < META &&
> +       if (io->bio && f2fs_sb_has_blkzoned(sbi) && btype < META &&
>                         is_end_zone_blkaddr(sbi, fio->new_blkaddr)) {
>                 spin_lock_bh(&sbi->available_active_zones_lock);
>                 if (sbi->available_active_zones > 0) {
> --
> 2.34.1
>