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authorLinus Torvalds <torvalds@linux-foundation.org>2018-06-04 23:05:02 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-06-04 23:05:02 +0300
commit9214407d1237a985894894f9be2b1a7416b69d14 (patch)
tree394e3e94e5b0cae6ef5be922661008e478580de6 /fs
parenteeee3149aaa022145b2659e3b0601dc705d69402 (diff)
parent7a107c0f55a3b4c6f84a4323df5610360bde1684 (diff)
downloadlinux-9214407d1237a985894894f9be2b1a7416b69d14.tar.xz
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.c15
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);
}
}