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Commit b27cf88e authored by David Woodhouse's avatar David Woodhouse
Browse files

[JFFS2] Fix lack of locking in thread_should_wake() 



The thread_should_wake() function trawls through the list of 'very
dirty' eraseblocks, determining whether the background GC thread should
wake. Doing this without holding the appropriate locks is a bad idea.

OLPC Trac #8615

Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
Cc: stable@kernel.org
parent f04de505

fs/jffs2/background.c

+5 −5
Original line number Diff line number Diff line
@@ -85,15 +85,15 @@ static int jffs2_garbage_collect_thread(void *_c) 
	for (;;) {

		allow_signal(SIGHUP);

	again:

		spin_lock(&c->erase_completion_lock);

		if (!jffs2_thread_should_wake(c)) {

			set_current_state (TASK_INTERRUPTIBLE);

			spin_unlock(&c->erase_completion_lock);

			D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread sleeping...\n"));

			/* Yes, there's a race here; we checked jffs2_thread_should_wake()

			   before setting current->state to TASK_INTERRUPTIBLE. But it doesn't

			   matter - We don't care if we miss a wakeup, because the GC thread

			   is only an optimisation anyway. */

			schedule();

		}

		} else

			spin_unlock(&c->erase_completion_lock);

			



		/* This thread is purely an optimisation. But if it runs when

		   other things could be running, it actually makes things a