parport: ieee1284: use del_timer_sync() in parport_wait_event()
authorMichael Buesch <mb@bu3sch.de>
Tue, 6 Jan 2009 22:43:14 +0000 (14:43 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 6 Jan 2009 23:59:31 +0000 (15:59 -0800)
commitf59abb161c955b68fd3d473368420c5919733e09
treeb316a7acdbc2e2eb819614e61644249937903f47
parent50682bb4de35544466c264c017030de826614367
parport: ieee1284: use del_timer_sync() in parport_wait_event()

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.

This is 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.

- eturn from parport_wait_even, which destroys the automatic variable
  "timer" while the callback is running on another CPU.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/parport/ieee1284.c