* [PATCH] fs: f2fs: fix kernel discard_thread NULL dereference
@ 2022-10-17 10:04 Hoi Pok Wu
2022-10-17 12:23 ` Chao Yu
0 siblings, 1 reply; 2+ messages in thread
From: Hoi Pok Wu @ 2022-10-17 10:04 UTC (permalink / raw)
To: jaegeuk, chao
Cc: Hoi Pok Wu, linux-f2fs-devel, linux-kernel,
syzbot+035a381ea1afb63f098d, syzkaller-bugs
Pointer discard_thread is pointing to nowhere, using IS_ERR prevents the
situation. IS_ERR also seen being used throughout the file.
Link: https://syzkaller.appspot.com/bug?id=9499bc6574cea5940e48199c2fd0732d9b11e5e1
Reported-by: syzbot+035a381ea1afb63f098d@syzkaller.appspotmail.com
Signed-off-by: Hoi Pok Wu <wuhoipok@gmail.com>
---
fs/f2fs/segment.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index acf3d3fa4363..79978b7206b5 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1634,7 +1634,8 @@ void f2fs_stop_discard_thread(struct f2fs_sb_info *sbi)
struct task_struct *discard_thread = dcc->f2fs_issue_discard;
dcc->f2fs_issue_discard = NULL;
- kthread_stop(discard_thread);
+ if (!IS_ERR(discard_thread))
+ kthread_stop(discard_thread);
}
}
--
2.38.0
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] fs: f2fs: fix kernel discard_thread NULL dereference
2022-10-17 10:04 [PATCH] fs: f2fs: fix kernel discard_thread NULL dereference Hoi Pok Wu
@ 2022-10-17 12:23 ` Chao Yu
0 siblings, 0 replies; 2+ messages in thread
From: Chao Yu @ 2022-10-17 12:23 UTC (permalink / raw)
To: Hoi Pok Wu, jaegeuk
Cc: linux-f2fs-devel, linux-kernel, syzbot+035a381ea1afb63f098d,
syzkaller-bugs
On 2022/10/17 18:04, Hoi Pok Wu wrote:
> Pointer discard_thread is pointing to nowhere, using IS_ERR prevents the
> situation. IS_ERR also seen being used throughout the file.
I guess below patch can fix this issue from root cause?
https://lore.kernel.org/linux-f2fs-devel/20221013155628.434671-1-chao@kernel.org/T/#u
Thanks,
>
> Link: https://syzkaller.appspot.com/bug?id=9499bc6574cea5940e48199c2fd0732d9b11e5e1
> Reported-by: syzbot+035a381ea1afb63f098d@syzkaller.appspotmail.com
> Signed-off-by: Hoi Pok Wu <wuhoipok@gmail.com>
> ---
> fs/f2fs/segment.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index acf3d3fa4363..79978b7206b5 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1634,7 +1634,8 @@ void f2fs_stop_discard_thread(struct f2fs_sb_info *sbi)
> struct task_struct *discard_thread = dcc->f2fs_issue_discard;
>
> dcc->f2fs_issue_discard = NULL;
> - kthread_stop(discard_thread);
> + if (!IS_ERR(discard_thread))
> + kthread_stop(discard_thread);
> }
> }
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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