2020-04-14 13:41:12

by Jules Irenge

Subject: [PATCH v2] fsnotify: Add missing annotation for fsnotify_finish_user_wait() and for fsnotify_prepare_user_wait()

Sparse reports warnings at fsnotify_prepare_user_wait()
and at fsnotify_finish_user_wait()

warning: context imbalance in fsnotify_finish_user_wait()
- wrong count at exit
warning: context imbalance in fsnotify_prepare_user_wait()
- unexpected unlock

The root cause is the missing annotation at fsnotify_finish_user_wait()
and at fsnotify_prepare_user_wait()
fsnotify_prepare_user_wait() has an extra annotation __release()
that only tell Sparse and not GCC to shutdown the warning

Add the missing __acquires(&fsnotify_mark_srcu) annotation
Add the missing __releases(&fsnotify_mark_srcu) annotation
Add the __release(&fsnotify_mark_srcu) annotation.

Signed-off-by: Jules Irenge <[email protected]>
---
changes since v2
-include annotations for fsnotify_prepare_user_wait()

fs/notify/mark.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index 1d96216dffd1..8387937b9d01 100644
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -325,13 +325,16 @@ static void fsnotify_put_mark_wake(struct fsnotify_mark *mark)
}

bool fsnotify_prepare_user_wait(struct fsnotify_iter_info *iter_info)
+ __releases(&fsnotify_mark_srcu)
{
int type;

fsnotify_foreach_obj_type(type) {
/* This can fail if mark is being removed */
- if (!fsnotify_get_mark_safe(iter_info->marks[type]))
+ if (!fsnotify_get_mark_safe(iter_info->marks[type])) {
+ __release(&fsnotify_mark_srcu);
goto fail;
+ }
}

/*
@@ -350,6 +353,7 @@ bool fsnotify_prepare_user_wait(struct fsnotify_iter_info *iter_info)
}

void fsnotify_finish_user_wait(struct fsnotify_iter_info *iter_info)
+ __acquires(&fsnotify_mark_srcu)
{
int type;

--
2.24.1

2020-04-15 22:52:43

by Jan Kara

Subject: Re: [PATCH v2] fsnotify: Add missing annotation for fsnotify_finish_user_wait() and for fsnotify_prepare_user_wait()

On Mon 13-04-20 22:42:40, Jules Irenge wrote:
> Sparse reports warnings at fsnotify_prepare_user_wait()
> and at fsnotify_finish_user_wait()
>
> warning: context imbalance in fsnotify_finish_user_wait()
> - wrong count at exit
> warning: context imbalance in fsnotify_prepare_user_wait()
> - unexpected unlock
>
> The root cause is the missing annotation at fsnotify_finish_user_wait()
> and at fsnotify_prepare_user_wait()
> fsnotify_prepare_user_wait() has an extra annotation __release()
> that only tell Sparse and not GCC to shutdown the warning
>
> Add the missing __acquires(&fsnotify_mark_srcu) annotation
> Add the missing __releases(&fsnotify_mark_srcu) annotation
> Add the __release(&fsnotify_mark_srcu) annotation.

Thanks for the patch. I've added it to my tree.

Honza

>
> Signed-off-by: Jules Irenge <[email protected]>
> ---
> changes since v2
> -include annotations for fsnotify_prepare_user_wait()
>
> fs/notify/mark.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/fs/notify/mark.c b/fs/notify/mark.c
> index 1d96216dffd1..8387937b9d01 100644
> --- a/fs/notify/mark.c
> +++ b/fs/notify/mark.c
> @@ -325,13 +325,16 @@ static void fsnotify_put_mark_wake(struct fsnotify_mark *mark)
> }
>
> bool fsnotify_prepare_user_wait(struct fsnotify_iter_info *iter_info)
> + __releases(&fsnotify_mark_srcu)
> {
> int type;
>
> fsnotify_foreach_obj_type(type) {
> /* This can fail if mark is being removed */
> - if (!fsnotify_get_mark_safe(iter_info->marks[type]))
> + if (!fsnotify_get_mark_safe(iter_info->marks[type])) {
> + __release(&fsnotify_mark_srcu);
> goto fail;
> + }
> }
>
> /*
> @@ -350,6 +353,7 @@ bool fsnotify_prepare_user_wait(struct fsnotify_iter_info *iter_info)
> }
>
> void fsnotify_finish_user_wait(struct fsnotify_iter_info *iter_info)
> + __acquires(&fsnotify_mark_srcu)
> {
> int type;
>
> --
> 2.24.1
>
--
Jan Kara <[email protected]>
SUSE Labs, CR