From f4985dc714d7ab1920c5aa502b7f4073fa1b4177 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Tue, 29 Jun 2010 15:05:42 -0700 Subject: [PATCH] fs/fcntl.c:kill_fasync_rcu() fa_lock must be IRQ-safe Fix a lockdep-splat-causing regression introduced by commit 989a2979205d ("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=16230 Reported-by: Sergey Senozhatsky Reported-by: Dominik Brodowski Tested-by: Dominik Brodowski Cc: Maciej Rutecki Acked-by: Eric Dumazet Cc: Paul E. McKenney Cc: Lai Jiangshan Cc: "David S. Miller" Acked-by: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/fcntl.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/fcntl.c b/fs/fcntl.c index 51e11bf5708f..9d175d623aab 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -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); } } -- 2.20.1