Messages in this thread Patch in this message |  | | | Date | Tue, 11 Nov 2008 16:23:27 -0800 | | From | Greg KH <> | | Subject | [patch 16/49] JFFS2: Fix lack of locking in thread_should_wake() |
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2.6.27-stable review patch. If anyone has any objections, please let us know.
------------------ From: David Woodhouse <David.Woodhouse@intel.com>
commit b27cf88e9592953ae292d05324887f2f44979433 upstream
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 <David.Woodhouse@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/jffs2/background.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- a/fs/jffs2/background.c +++ b/fs/jffs2/background.c @@ -85,15 +85,15 @@ static int jffs2_garbage_collect_thread( 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 --
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