2023-09-06 20:29:49

by Chao Yu

[permalink] [raw]
Subject: [PATCH] f2fs: fix to drop meta_inode's page cache in f2fs_put_super()

syzbot reports a kernel bug as below:

F2FS-fs (loop1): detect filesystem reference count leak during umount, type: 10, count: 1
kernel BUG at fs/f2fs/super.c:1639!
CPU: 0 PID: 15451 Comm: syz-executor.1 Not tainted 6.5.0-syzkaller-09338-ge0152e7481c6 #0
RIP: 0010:f2fs_put_super+0xce1/0xed0 fs/f2fs/super.c:1639
Call Trace:
generic_shutdown_super+0x161/0x3c0 fs/super.c:693
kill_block_super+0x3b/0x70 fs/super.c:1646
kill_f2fs_super+0x2b7/0x3d0 fs/f2fs/super.c:4879
deactivate_locked_super+0x9a/0x170 fs/super.c:481
deactivate_super+0xde/0x100 fs/super.c:514
cleanup_mnt+0x222/0x3d0 fs/namespace.c:1254
task_work_run+0x14d/0x240 kernel/task_work.c:179
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
exit_to_user_mode_prepare+0x210/0x240 kernel/entry/common.c:204
__syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
syscall_exit_to_user_mode+0x1d/0x60 kernel/entry/common.c:296
do_syscall_64+0x44/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x63/0xcd

In f2fs_put_super(), it tries to do sanity check on dirty and IO
reference count of f2fs, once there is any reference count leak,
it will trigger panic.

The root case is, during f2fs_put_super(), if there is any IO error
in f2fs_wait_on_all_pages(), we missed to truncate meta_inode's page
cache later, result in panic, fix this case.

Fixes: 20872584b8c0 ("f2fs: fix to drop all dirty meta/node pages during umount()")
Reported-by: [email protected]
Closes: https://lore.kernel.org/linux-f2fs-devel/[email protected]
Signed-off-by: Chao Yu <[email protected]>
---
fs/f2fs/super.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 9ef9d5baece0..973184f267cb 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1675,7 +1675,7 @@ static void f2fs_put_super(struct super_block *sb)

f2fs_wait_on_all_pages(sbi, F2FS_WB_CP_DATA);

- if (err) {
+ if (err || f2fs_cp_error(sbi)) {
truncate_inode_pages_final(NODE_MAPPING(sbi));
truncate_inode_pages_final(META_MAPPING(sbi));
}
--
2.40.1


2023-09-20 16:02:34

by patchwork-bot+f2fs

[permalink] [raw]
Subject: Re: [f2fs-dev] [PATCH] f2fs: fix to drop meta_inode's page cache in f2fs_put_super()

Hello:

This patch was applied to jaegeuk/f2fs.git (dev)
by Jaegeuk Kim <[email protected]>:

On Tue, 5 Sep 2023 12:57:53 +0800 you wrote:
> syzbot reports a kernel bug as below:
>
> F2FS-fs (loop1): detect filesystem reference count leak during umount, type: 10, count: 1
> kernel BUG at fs/f2fs/super.c:1639!
> CPU: 0 PID: 15451 Comm: syz-executor.1 Not tainted 6.5.0-syzkaller-09338-ge0152e7481c6 #0
> RIP: 0010:f2fs_put_super+0xce1/0xed0 fs/f2fs/super.c:1639
> Call Trace:
> generic_shutdown_super+0x161/0x3c0 fs/super.c:693
> kill_block_super+0x3b/0x70 fs/super.c:1646
> kill_f2fs_super+0x2b7/0x3d0 fs/f2fs/super.c:4879
> deactivate_locked_super+0x9a/0x170 fs/super.c:481
> deactivate_super+0xde/0x100 fs/super.c:514
> cleanup_mnt+0x222/0x3d0 fs/namespace.c:1254
> task_work_run+0x14d/0x240 kernel/task_work.c:179
> resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
> exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
> exit_to_user_mode_prepare+0x210/0x240 kernel/entry/common.c:204
> __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
> syscall_exit_to_user_mode+0x1d/0x60 kernel/entry/common.c:296
> do_syscall_64+0x44/0xb0 arch/x86/entry/common.c:86
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> [...]

Here is the summary with links:
- [f2fs-dev] f2fs: fix to drop meta_inode's page cache in f2fs_put_super()
https://git.kernel.org/jaegeuk/f2fs/c/a4639380bbe6

You are awesome, thank you!
--
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