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Commit 6698e347 authored by Alan Cox's avatar Alan Cox Committed by Linus Torvalds
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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: default avatarAlan Cox <alan@linux.intel.com>
Acked-and-Tested-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 09cea96c

drivers/char/tty_io.c

+0 −2
Original line number Diff line number Diff line
@@ -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);