* [f2fs-dev] [PATCH v2] f2fs: fix to skip f2fs_balance_fs() if checkpoint is disabled
@ 2025-05-21 11:56 Chao Yu via Linux-f2fs-devel
2025-05-23 1:39 ` Zhiguo Niu
0 siblings, 1 reply; 3+ messages in thread
From: Chao Yu via Linux-f2fs-devel @ 2025-05-21 11:56 UTC (permalink / raw)
To: jaegeuk; +Cc: syzbot+aa5bb5f6860e08a60450, Qi Han, linux-kernel,
linux-f2fs-devel
INFO: task syz-executor328:5856 blocked for more than 144 seconds.
Not tainted 6.15.0-rc6-syzkaller-00208-g3c21441eeffc #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor328 state:D stack:24392 pid:5856 tgid:5832 ppid:5826 task_flags:0x400040 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x168f/0x4c70 kernel/sched/core.c:6767
__schedule_loop kernel/sched/core.c:6845 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6860
io_schedule+0x81/0xe0 kernel/sched/core.c:7742
f2fs_balance_fs+0x4b4/0x780 fs/f2fs/segment.c:444
f2fs_map_blocks+0x3af1/0x43b0 fs/f2fs/data.c:1791
f2fs_expand_inode_data+0x653/0xaf0 fs/f2fs/file.c:1872
f2fs_fallocate+0x4f5/0x990 fs/f2fs/file.c:1975
vfs_fallocate+0x6a0/0x830 fs/open.c:338
ioctl_preallocate fs/ioctl.c:290 [inline]
file_ioctl fs/ioctl.c:-1 [inline]
do_vfs_ioctl+0x1b8f/0x1eb0 fs/ioctl.c:885
__do_sys_ioctl fs/ioctl.c:904 [inline]
__se_sys_ioctl+0x82/0x170 fs/ioctl.c:892
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The root cause is after commit 84b5bb8bf0f6 ("f2fs: modify
f2fs_is_checkpoint_ready logic to allow more data to be written with the
CP disable"), we will get chance to allow f2fs_is_checkpoint_ready() to
return true once below conditions are all true:
1. checkpoint is disabled
2. there are not enough free segments
3. there are enough free blocks
Then it will cause f2fs_balance_fs() to trigger foreground GC.
void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need)
...
if (!f2fs_is_checkpoint_ready(sbi))
return;
And it mounts f2fs image w/ gc_merge,checkpoint=disable, so below deadloop
will happen:
- f2fs_do_shutdown - vfs_fallocate - gc_thread_func
- file_start_write
- __sb_start_write(SB_FREEZE_WRITE)
- f2fs_fallocate
- f2fs_expand_inode_data
- f2fs_map_blocks
- f2fs_balance_fs
- prepare_to_wait
- wake_up(gc_wait_queue_head)
- io_schedule
- bdev_freeze
- freeze_super
- sb->s_writers.frozen = SB_FREEZE_WRITE;
- sb_wait_write(sb, SB_FREEZE_WRITE);
- if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) continue;
: cause deadloop
This patch fix to add check condition in f2fs_balance_fs(), so that if
checkpoint is disabled, we will just skip trigger foreground GC to
avoid above deadloop issue.
Reported-by: syzbot+aa5bb5f6860e08a60450@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-f2fs-devel/682d743a.a00a0220.29bc26.0289.GAE@google.com
Fixes: 84b5bb8bf0f6 ("f2fs: modify f2fs_is_checkpoint_ready logic to allow more data to be written with the CP disable")
Cc: Qi Han <hanqi@vivo.com>
Signed-off-by: Chao Yu <chao@kernel.org>
---
v2:
- add missing Closes line
- fix to use git commit description style
fs/f2fs/segment.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 5ff0111ed974..19b716fda72a 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -433,6 +433,8 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need)
if (need && excess_cached_nats(sbi))
f2fs_balance_fs_bg(sbi, false);
+ if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED)))
+ return;
if (!f2fs_is_checkpoint_ready(sbi))
return;
--
2.49.0
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [f2fs-dev] [PATCH v2] f2fs: fix to skip f2fs_balance_fs() if checkpoint is disabled
2025-05-21 11:56 [f2fs-dev] [PATCH v2] f2fs: fix to skip f2fs_balance_fs() if checkpoint is disabled Chao Yu via Linux-f2fs-devel
@ 2025-05-23 1:39 ` Zhiguo Niu
2025-05-23 2:32 ` Chao Yu via Linux-f2fs-devel
0 siblings, 1 reply; 3+ messages in thread
From: Zhiguo Niu @ 2025-05-23 1:39 UTC (permalink / raw)
To: Chao Yu
Cc: syzbot+aa5bb5f6860e08a60450, jaegeuk, Qi Han, linux-kernel,
linux-f2fs-devel
Chao Yu via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>
于2025年5月21日周三 20:02写道：
>
> INFO: task syz-executor328:5856 blocked for more than 144 seconds.
> Not tainted 6.15.0-rc6-syzkaller-00208-g3c21441eeffc #0
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> task:syz-executor328 state:D stack:24392 pid:5856 tgid:5832 ppid:5826 task_flags:0x400040 flags:0x00004006
> Call Trace:
> <TASK>
> context_switch kernel/sched/core.c:5382 [inline]
> __schedule+0x168f/0x4c70 kernel/sched/core.c:6767
> __schedule_loop kernel/sched/core.c:6845 [inline]
> schedule+0x165/0x360 kernel/sched/core.c:6860
> io_schedule+0x81/0xe0 kernel/sched/core.c:7742
> f2fs_balance_fs+0x4b4/0x780 fs/f2fs/segment.c:444
> f2fs_map_blocks+0x3af1/0x43b0 fs/f2fs/data.c:1791
> f2fs_expand_inode_data+0x653/0xaf0 fs/f2fs/file.c:1872
> f2fs_fallocate+0x4f5/0x990 fs/f2fs/file.c:1975
> vfs_fallocate+0x6a0/0x830 fs/open.c:338
> ioctl_preallocate fs/ioctl.c:290 [inline]
> file_ioctl fs/ioctl.c:-1 [inline]
> do_vfs_ioctl+0x1b8f/0x1eb0 fs/ioctl.c:885
> __do_sys_ioctl fs/ioctl.c:904 [inline]
> __se_sys_ioctl+0x82/0x170 fs/ioctl.c:892
> do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
> do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> The root cause is after commit 84b5bb8bf0f6 ("f2fs: modify
> f2fs_is_checkpoint_ready logic to allow more data to be written with the
> CP disable"), we will get chance to allow f2fs_is_checkpoint_ready() to
> return true once below conditions are all true:
> 1. checkpoint is disabled
> 2. there are not enough free segments
> 3. there are enough free blocks
>
> Then it will cause f2fs_balance_fs() to trigger foreground GC.
>
> void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need)
> ...
> if (!f2fs_is_checkpoint_ready(sbi))
> return;
>
> And it mounts f2fs image w/ gc_merge,checkpoint=disable, so below deadloop
> will happen:
>
> - f2fs_do_shutdown - vfs_fallocate - gc_thread_func
> - file_start_write
> - __sb_start_write(SB_FREEZE_WRITE)
> - f2fs_fallocate
> - f2fs_expand_inode_data
> - f2fs_map_blocks
> - f2fs_balance_fs
> - prepare_to_wait
> - wake_up(gc_wait_queue_head)
> - io_schedule
> - bdev_freeze
> - freeze_super
> - sb->s_writers.frozen = SB_FREEZE_WRITE;
> - sb_wait_write(sb, SB_FREEZE_WRITE);
> - if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) continue;
> : cause deadloop
>
> This patch fix to add check condition in f2fs_balance_fs(), so that if
> checkpoint is disabled, we will just skip trigger foreground GC to
> avoid above deadloop issue.
>
> Reported-by: syzbot+aa5bb5f6860e08a60450@syzkaller.appspotmail.com
> Closes: https://lore.kernel.org/linux-f2fs-devel/682d743a.a00a0220.29bc26.0289.GAE@google.com
> Fixes: 84b5bb8bf0f6 ("f2fs: modify f2fs_is_checkpoint_ready logic to allow more data to be written with the CP disable")
> Cc: Qi Han <hanqi@vivo.com>
> Signed-off-by: Chao Yu <chao@kernel.org>
> ---
> v2:
> - add missing Closes line
> - fix to use git commit description style
>
> fs/f2fs/segment.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 5ff0111ed974..19b716fda72a 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -433,6 +433,8 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need)
> if (need && excess_cached_nats(sbi))
> f2fs_balance_fs_bg(sbi, false);
>
> + if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED)))
> + return;
> if (!f2fs_is_checkpoint_ready(sbi))
> return;
Hi Chao,
When I read this patch, I feel that it is somewhat redundant with the
following checking about SBI_CP_DISABLED in f2fs_is_checkpoint_ready.
Can we reorganize these checks for the f2fs_balance_fs case?
This will make the code easier to read and understand.
thanks!
>
> --
> 2.49.0
>
>
>
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [f2fs-dev] [PATCH v2] f2fs: fix to skip f2fs_balance_fs() if checkpoint is disabled
2025-05-23 1:39 ` Zhiguo Niu
@ 2025-05-23 2:32 ` Chao Yu via Linux-f2fs-devel
0 siblings, 0 replies; 3+ messages in thread
From: Chao Yu via Linux-f2fs-devel @ 2025-05-23 2:32 UTC (permalink / raw)
To: Zhiguo Niu
Cc: syzbot+aa5bb5f6860e08a60450, Qi Han, linux-kernel,
linux-f2fs-devel, jaegeuk
On 5/23/25 09:39, Zhiguo Niu wrote:
> Chao Yu via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>
> 于2025年5月21日周三 20:02写道：
>>
>> INFO: task syz-executor328:5856 blocked for more than 144 seconds.
>> Not tainted 6.15.0-rc6-syzkaller-00208-g3c21441eeffc #0
>> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>> task:syz-executor328 state:D stack:24392 pid:5856 tgid:5832 ppid:5826 task_flags:0x400040 flags:0x00004006
>> Call Trace:
>> <TASK>
>> context_switch kernel/sched/core.c:5382 [inline]
>> __schedule+0x168f/0x4c70 kernel/sched/core.c:6767
>> __schedule_loop kernel/sched/core.c:6845 [inline]
>> schedule+0x165/0x360 kernel/sched/core.c:6860
>> io_schedule+0x81/0xe0 kernel/sched/core.c:7742
>> f2fs_balance_fs+0x4b4/0x780 fs/f2fs/segment.c:444
>> f2fs_map_blocks+0x3af1/0x43b0 fs/f2fs/data.c:1791
>> f2fs_expand_inode_data+0x653/0xaf0 fs/f2fs/file.c:1872
>> f2fs_fallocate+0x4f5/0x990 fs/f2fs/file.c:1975
>> vfs_fallocate+0x6a0/0x830 fs/open.c:338
>> ioctl_preallocate fs/ioctl.c:290 [inline]
>> file_ioctl fs/ioctl.c:-1 [inline]
>> do_vfs_ioctl+0x1b8f/0x1eb0 fs/ioctl.c:885
>> __do_sys_ioctl fs/ioctl.c:904 [inline]
>> __se_sys_ioctl+0x82/0x170 fs/ioctl.c:892
>> do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>> do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
>> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>>
>> The root cause is after commit 84b5bb8bf0f6 ("f2fs: modify
>> f2fs_is_checkpoint_ready logic to allow more data to be written with the
>> CP disable"), we will get chance to allow f2fs_is_checkpoint_ready() to
>> return true once below conditions are all true:
>> 1. checkpoint is disabled
>> 2. there are not enough free segments
>> 3. there are enough free blocks
>>
>> Then it will cause f2fs_balance_fs() to trigger foreground GC.
>>
>> void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need)
>> ...
>> if (!f2fs_is_checkpoint_ready(sbi))
>> return;
>>
>> And it mounts f2fs image w/ gc_merge,checkpoint=disable, so below deadloop
>> will happen:
>>
>> - f2fs_do_shutdown - vfs_fallocate - gc_thread_func
>> - file_start_write
>> - __sb_start_write(SB_FREEZE_WRITE)
>> - f2fs_fallocate
>> - f2fs_expand_inode_data
>> - f2fs_map_blocks
>> - f2fs_balance_fs
>> - prepare_to_wait
>> - wake_up(gc_wait_queue_head)
>> - io_schedule
>> - bdev_freeze
>> - freeze_super
>> - sb->s_writers.frozen = SB_FREEZE_WRITE;
>> - sb_wait_write(sb, SB_FREEZE_WRITE);
>> - if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) continue;
>> : cause deadloop
>>
>> This patch fix to add check condition in f2fs_balance_fs(), so that if
>> checkpoint is disabled, we will just skip trigger foreground GC to
>> avoid above deadloop issue.
>>
>> Reported-by: syzbot+aa5bb5f6860e08a60450@syzkaller.appspotmail.com
>> Closes: https://lore.kernel.org/linux-f2fs-devel/682d743a.a00a0220.29bc26.0289.GAE@google.com
>> Fixes: 84b5bb8bf0f6 ("f2fs: modify f2fs_is_checkpoint_ready logic to allow more data to be written with the CP disable")
>> Cc: Qi Han <hanqi@vivo.com>
>> Signed-off-by: Chao Yu <chao@kernel.org>
>> ---
>> v2:
>> - add missing Closes line
>> - fix to use git commit description style
>>
>> fs/f2fs/segment.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>> index 5ff0111ed974..19b716fda72a 100644
>> --- a/fs/f2fs/segment.c
>> +++ b/fs/f2fs/segment.c
>> @@ -433,6 +433,8 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need)
>> if (need && excess_cached_nats(sbi))
>> f2fs_balance_fs_bg(sbi, false);
>>
>> + if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED)))
>> + return;
>> if (!f2fs_is_checkpoint_ready(sbi))
>> return;
> Hi Chao,
> When I read this patch, I feel that it is somewhat redundant with the
> following checking about SBI_CP_DISABLED in f2fs_is_checkpoint_ready.
> Can we reorganize these checks for the f2fs_balance_fs case?
Zhiguo,
Oh, I agreed. I think we can just use is_sbi_flag_set(sbi, SBI_CP_DISABLED)
instead of f2fs_is_checkpoint_ready() here, let me revise it in v3.
- if (!f2fs_is_checkpoint_ready(sbi))
+ if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED)))
Thanks,
> This will make the code easier to read and understand.
> thanks!
>>
>> --
>> 2.49.0
>>
>>
>>
>> _______________________________________________
>> Linux-f2fs-devel mailing list
>> Linux-f2fs-devel@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2025-05-23 2:33 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-05-21 11:56 [f2fs-dev] [PATCH v2] f2fs: fix to skip f2fs_balance_fs() if checkpoint is disabled Chao Yu via Linux-f2fs-devel
2025-05-23 1:39 ` Zhiguo Niu
2025-05-23 2:32 ` Chao Yu via Linux-f2fs-devel
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