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| author |   Christian Brauner <brauner@kernel.org> | 2024-09-25 11:05:16 +0200 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2024-10-22 11:16:56 +0200 |
| commit | 6474353a5e3d0b2cf610153cea0c61f576a36d0a (patch) | |
| tree | 1395d4b47fa1aaf0b08141610ec97a7c2c3f0d57 /include/linux/eventpoll.h | |
| parent | fs: support relative paths with FSCONFIG_SET_STRING (diff) | |
| download | wireguard-linux-6474353a5e3d0b2cf610153cea0c61f576a36d0a.tar.xz wireguard-linux-6474353a5e3d0b2cf610153cea0c61f576a36d0a.zip | |
epoll: annotate racy check
Epoll relies on a racy fastpath check during __fput() in
eventpoll_release() to avoid the hit of pointlessly acquiring a
semaphore. Annotate that race by using WRITE_ONCE() and READ_ONCE().
Link: https://lore.kernel.org/r/66edfb3c.050a0220.3195df.001a.GAE@google.com
Link: https://lore.kernel.org/r/20240925-fungieren-anbauen-79b334b00542@brauner
Reviewed-by: Jan Kara <jack@suse.cz>
Reported-by: syzbot+3b6b32dc50537a49bb4a@syzkaller.appspotmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to '')
| -rw-r--r-- | include/linux/eventpoll.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/eventpoll.h b/include/linux/eventpoll.h index 3337745d81bd..0c0d00fcd131 100644 --- a/include/linux/eventpoll.h +++ b/include/linux/eventpoll.h @@ -42,7 +42,7 @@ static inline void eventpoll_release(struct file *file) * because the file in on the way to be removed and nobody ( but * eventpoll ) has still a reference to this file. */ - if (likely(!file->f_ep)) + if (likely(!READ_ONCE(file->f_ep))) return; /* |