Commit f4985dc7 authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds

fs/fcntl.c:kill_fasync_rcu() fa_lock must be IRQ-safe

Fix a lockdep-splat-causing regression introduced by commit 989a2979
("fasync: RCU and fine grained locking").

kill_fasync() can be called from both process and hard-irq context, so
fa_lock must be taken with IRQs disabled.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=16230Reported-by: 's avatarSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: 's avatarDominik Brodowski <linux@dominikbrodowski.net>
Tested-by: 's avatarDominik Brodowski <linux@dominikbrodowski.net>
Cc: Maciej Rutecki <maciej.rutecki@gmail.com>
Acked-by: 's avatarEric Dumazet <eric.dumazet@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: "David S. Miller" <davem@davemloft.net>
Acked-by: 's avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
parent fb967ecc
......@@ -733,12 +733,14 @@ 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(&fa->fa_lock);
spin_lock_irqsave(&fa->fa_lock, flags);
if (fa->fa_file) {
fown = &fa->fa_file->f_owner;
/* Don't send SIGURG to processes which have not set a
......@@ -747,7 +749,7 @@ 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(&fa->fa_lock);
spin_unlock_irqrestore(&fa->fa_lock, flags);
fa = rcu_dereference(fa->fa_next);
}
}
......
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