From: David Woodhouse Date: Fri, 31 Oct 2008 14:52:24 +0000 (+0000) Subject: [JFFS2] Fix lack of locking in thread_should_wake() X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=b27cf88e9592953ae292d05324887f2f44979433;p=linux-beck.git [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: David Woodhouse Cc: stable@kernel.org --- diff --git a/fs/jffs2/background.c b/fs/jffs2/background.c index 8adebd3e43c6..3cceef4ad2b7 100644 --- a/fs/jffs2/background.c +++ b/fs/jffs2/background.c @@ -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