From cd8084f91c02c1afd256a39aa833bff737631304 Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Mon, 7 Aug 2017 16:12:56 +0900 Subject: locking/lockdep: Apply crossrelease to completions Although wait_for_completion() and its family can cause deadlock, the lock correctness validator could not be applied to them until now, because things like complete() are usually called in a different context from the waiting context, which violates lockdep's assumption. Thanks to CONFIG_LOCKDEP_CROSSRELEASE, we can now apply the lockdep detector to those completion operations. Applied it. Signed-off-by: Byungchul Park Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akpm@linux-foundation.org Cc: boqun.feng@gmail.com Cc: kernel-team@lge.com Cc: kirill@shutemov.name Cc: npiggin@gmail.com Cc: walken@google.com Cc: willy@infradead.org Link: http://lkml.kernel.org/r/1502089981-21272-10-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar --- lib/Kconfig.debug | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'lib') diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index c6038f23bb1a..ebd40d3b0b28 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1162,6 +1162,15 @@ config LOCKDEP_CROSSRELEASE such as page locks or completions can use the lock correctness detector, lockdep. +config LOCKDEP_COMPLETE + bool "Lock debugging: allow completions to use deadlock detector" + depends on PROVE_LOCKING + select LOCKDEP_CROSSRELEASE + default n + help + A deadlock caused by wait_for_completion() and complete() can be + detected by lockdep using crossrelease feature. + config DEBUG_LOCKDEP bool "Lock dependency engine debugging" depends on DEBUG_KERNEL && LOCKDEP -- cgit