Messages in this thread Patch in this message | | | From | Michael Buesch <> | Subject | [PATCH] IEEE1284: Use del_timer_sync in parport_wait_event | Date | Sun, 30 Nov 2008 21:20:49 +0100 |
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Use del_timer_sync() instead of del_timer() to make sure the timer won't be running when we return from parport_wait_event(), because this would crash due to destruction of timer_list.
Signed-off-by: Michael Buesch <mb@bu3sch.de>
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This is completely untested and just based on a code review. Just think about the following sequence of events: add_timer. down_interruptible is interrupted by a signal. We enter the timer callback handler on another CPU. del_timer, but the timer callback is still running. Return from parport_wait_even, which destroys the automatic variable "timer" while the callback is running on another CPU.
Index: linux-2.6/drivers/parport/ieee1284.c =================================================================== --- linux-2.6.orig/drivers/parport/ieee1284.c 2008-10-24 21:08:12.000000000 +0200 +++ linux-2.6/drivers/parport/ieee1284.c 2008-11-30 21:09:25.000000000 +0100 @@ -84,7 +84,7 @@ int parport_wait_event (struct parport * add_timer (&timer); ret = down_interruptible (&port->physport->ieee1284.irq); - if (!del_timer (&timer) && !ret) + if (!del_timer_sync (&timer) && !ret) /* Timed out. */ ret = 1; -- Greetings Michael.
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