From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752035AbeAWTFR (ORCPT ); Tue, 23 Jan 2018 14:05:17 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:43766 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751964AbeAWTFP (ORCPT ); Tue, 23 Jan 2018 14:05:15 -0500 Message-ID: <1516734237.31954.17.camel@fb.com> Subject: Re: [PATCH] lockdep: Avoid triggering hardlockup from debug_show_all_locks() From: Rik van Riel To: Tejun Heo , Peter Zijlstra , "Ingo Molnar" CC: , Date: Tue, 23 Jan 2018 14:03:57 -0500 In-Reply-To: <20180122220055.GB1771050@devbig577.frc2.facebook.com> References: <20180122220055.GB1771050@devbig577.frc2.facebook.com> Organization: Facebook, Inc. 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This can take a while on a slow console > device > and may end up triggering NMI hardlockup detector if someone else > ends > up waiting for tasklist_lock. > > Touch the NMI watchdog while printing the held locks to avoid > spuriously triggering the hardlockup detector. > > Signed-off-by: Tejun Heo On this patch: Acked-by: Rik van Riel However, it seems like we run into things like this on a fairly regular (though not very frequent) basis. Would it make sense to go through the code and add sprinkle around a few more touch_nmi_watchdog() calls? After all, there are maybe a few dozen places where we print out a lot of debugging information.