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authorAlan Cox <alan@linux.intel.com>2009-12-12 10:32:36 +0000
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-12 14:46:21 -0800
commit6698e34720660e18b45e2e3b115ee4584d0c3b5e (patch)
tree1e6e136d58a1f66928603f0e48cd8f163fef5196
parent09cea96caa59fabab3030c53bd698b9b568d959a (diff)
tty: Fix BKL taken under a spinlock bug introduced in the BKL split
The fasync path takes the BKL (it probably doesn't need to in fact) while holding the file_list spinlock. You can't do that with the kernel lock: it causes lock inversions and deadlocks. Leave the BKL over that bit for the moment. Identified by AKPM. Signed-off-by: Alan Cox <alan@linux.intel.com> Acked-and-Tested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/char/tty_io.c2
1 files changed, 0 insertions, 2 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 684f0e0b175..f15df40bc31 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -516,7 +516,6 @@ static void do_tty_hangup(struct work_struct *work)
/* inuse_filps is protected by the single kernel lock */
lock_kernel();
check_tty_count(tty, "do_tty_hangup");
- unlock_kernel();
file_list_lock();
/* This breaks for file handles being sent over AF_UNIX sockets ? */
@@ -531,7 +530,6 @@ static void do_tty_hangup(struct work_struct *work)
}
file_list_unlock();
- lock_kernel();
tty_ldisc_hangup(tty);
read_lock(&tasklist_lock);