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| author |   Linus Torvalds <torvalds@linux-foundation.org> | 2018-06-04 13:05:02 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-06-04 13:05:02 -0700 |
| commit | 9214407d1237a985894894f9be2b1a7416b69d14 (patch) | |
| tree | 394e3e94e5b0cae6ef5be922661008e478580de6 /fs | |
| parent | Merge tag 'docs-4.18' of git://git.lwn.net/linux (diff) | |
| parent | fasync: Fix deadlock between task-context and interrupt-context kill_fasync() (diff) | |
| download | linux-dev-9214407d1237a985894894f9be2b1a7416b69d14.tar.xz linux-dev-9214407d1237a985894894f9be2b1a7416b69d14.zip | |
Merge tag 'locks-v4.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux
Pull fasync fix from Jeff Layton:
"Just a single fix for a deadlock in the fasync handling code that
Kirill observed while testing.
The fix is to change the fa_lock to be rwlock_t, and use a read lock
in kill_fasync_rcu"
* tag 'locks-v4.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux:
fasync: Fix deadlock between task-context and interrupt-context kill_fasync()
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/fcntl.c | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/fs/fcntl.c b/fs/fcntl.c index d737ff082472..c42169459298 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -871,9 +871,9 @@ int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp) if (fa->fa_file != filp) continue; - spin_lock_irq(&fa->fa_lock); + write_lock_irq(&fa->fa_lock); fa->fa_file = NULL; - spin_unlock_irq(&fa->fa_lock); + write_unlock_irq(&fa->fa_lock); *fp = fa->fa_next; call_rcu(&fa->fa_rcu, fasync_free_rcu); @@ -918,13 +918,13 @@ struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasy if (fa->fa_file != filp) continue; - spin_lock_irq(&fa->fa_lock); + write_lock_irq(&fa->fa_lock); fa->fa_fd = fd; - spin_unlock_irq(&fa->fa_lock); + write_unlock_irq(&fa->fa_lock); goto out; } - spin_lock_init(&new->fa_lock); + rwlock_init(&new->fa_lock); new->magic = FASYNC_MAGIC; new->fa_file = filp; new->fa_fd = fd; @@ -987,14 +987,13 @@ static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band) { while (fa) { struct fown_struct *fown; - unsigned long flags; if (fa->magic != FASYNC_MAGIC) { printk(KERN_ERR "kill_fasync: bad magic number in " "fasync_struct!\n"); return; } - spin_lock_irqsave(&fa->fa_lock, flags); + read_lock(&fa->fa_lock); if (fa->fa_file) { fown = &fa->fa_file->f_owner; /* Don't send SIGURG to processes which have not set a @@ -1003,7 +1002,7 @@ static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band) if (!(sig == SIGURG && fown->signum == 0)) send_sigio(fown, fa->fa_fd, band); } - spin_unlock_irqrestore(&fa->fa_lock, flags); + read_unlock(&fa->fa_lock); fa = rcu_dereference(fa->fa_next); } } |