From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f179.google.com (mail-oi1-f179.google.com [209.85.167.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F1FB7AD22 for ; Fri, 4 Nov 2022 19:22:35 +0000 (UTC) Received: by mail-oi1-f179.google.com with SMTP id n83so6151111oif.11 for ; Fri, 04 Nov 2022 12:22:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:from:to:cc:subject:date:message-id :reply-to; bh=+CrrtBZaWaBIBfDEz9a9BacRZtXiPhURWnCTyiBknKU=; b=f7SabvhELt4tvu58wD/HGUQtx2q3c42bp4689l/poRMwjHONs2y+uJybLQ6btnBic8 iSYK/T680hWQ8YubanyiQ/jk4TxtOOSgyzZyzTjBStaumbjkRAc3PTfrEP9z1ET4ppjL os0cjm+F8kyIi27l3gX1TCu+EYDnb6I6sC6rEheSVAEJvEJuF1rkSUHHVYhQ9PjtWNZC /KoHUhscmHo/jN1PCMTUxC8NT4KR3QukfsWt+gbIkumzBVh1p3Sny9bKzJeet5110tpk HzVFo5k5iKj3j88DvNf1ucVPdH/av+bU0vEDu76g9bGVlHfWhJDUhqHlYTifQBH3QuBi oWFg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=+CrrtBZaWaBIBfDEz9a9BacRZtXiPhURWnCTyiBknKU=; b=uCDe5pbBGN88AsW/v5JHbNpOKb1wfUeb5o+HHITPS3oSNhXqhpYiceH/ub/oifLVMG eXcJ/WqTJE76YHXxXc1s0QJDI3BA3SAfXBeoR36rujtlqTbSa3ROmHhpdx1sMW1oAGWt weplFCZnv+S6kH14EmtusMfcqFfSUDZ1aaOqST6kuxBTKcJYuQxdsP8JtD8exzcmbYkx Sd7tvpbmypSTHjwClEhvDzyhpAWmpuJ8qkBUsijSctrtwNfdB7NNGqdlmpZCMpJoxgCX gTC6eo/yG2PXs7jTC6zfdl5zbtA+oXGxqQrKNP4pcD9JvP8goN+8QUYHt2vTbft/uK+p IYRg== X-Gm-Message-State: ACrzQf2PAWpRLJ/0sv5DCb0mJVQc5yx7XQYwOh683Y862w11g1f58Cbf NwEpyt3VJDd2VW5idyUmpjc= X-Google-Smtp-Source: AMsMyM5j57nGJ6ihP9Jnolnn5vAnBZp3njFzbqkVuO45h5Gs91zBtM7qMBV3ZTA/jEfxwCmFGOBzYQ== X-Received: by 2002:aca:2819:0:b0:359:f8a7:c88 with SMTP id 25-20020aca2819000000b00359f8a70c88mr260428oix.278.1667589755023; Fri, 04 Nov 2022 12:22:35 -0700 (PDT) Received: from server.roeck-us.net ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id n132-20020acabd8a000000b003547a3401e6sm1729901oif.43.2022.11.04.12.22.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Nov 2022 12:22:34 -0700 (PDT) Sender: Guenter Roeck Date: Fri, 4 Nov 2022 12:22:32 -0700 From: Guenter Roeck To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Linus Torvalds , Thomas Gleixner , Stephen Boyd , Anna-Maria Gleixner , Andrew Morton , rcu@vger.kernel.org, linux-doc@vger.kernel.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-edac@vger.kernel.org, cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-acpi@vger.kernel.org, linux-atm-general@lists.sourceforge.net, netdev@vger.kernel.org, linux-pm@vger.kernel.org, drbd-dev@lists.linbit.com, linux-bluetooth@vger.kernel.org, openipmi-developer@lists.sourceforge.net, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, intel-gfx@lists.freedesktop.org, linux-input@vger.kernel.org, linux-parisc@vger.kernel.org, linux-leds@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-usb@vger.kernel.org, linux-wireless@vger.kernel.org, linux-scsi@vger.kernel.org, linux-staging@lists.linux.dev, linux-ext4@vger.kernel.org, linux-nilfs@vger.kernel.org, bridge@lists.linux-foundation.org, netfilter-devel@vger.kernel.org, coreteam@netfilter.org, lvs-devel@vger.kernel.org, linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org, tipc-discussion@lists.sourceforge.net, alsa-devel@alsa-project.org Subject: Re: [RFC][PATCH v3 00/33] timers: Use timer_shutdown*() before freeing timers Message-ID: <20221104192232.GA2520396@roeck-us.net> References: <20221104054053.431922658@goodmis.org> Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221104054053.431922658@goodmis.org> On Fri, Nov 04, 2022 at 01:40:53AM -0400, Steven Rostedt wrote: > > Back in April, I posted an RFC patch set to help mitigate a common issue > where a timer gets armed just before it is freed, and when the timer > goes off, it crashes in the timer code without any evidence of who the > culprit was. I got side tracked and never finished up on that patch set. > Since this type of crash is still our #1 crash we are seeing in the field, > it has become a priority again to finish it. > > This is v3 of that patch set. Thomas Gleixner posted an untested version > that makes timer->function NULL as the flag that it is shutdown. I took that > code, tested it (fixed it up), added more comments, and changed the > name to timer_shutdown_sync(). I also converted it to use WARN_ON_ONCE() > instead of just WARN_ON() as Linus asked for. > Unfortunately the renaming caused some symbol conflicts. Global definition: timer_shutdown File Line 0 time.c 93 static inline void timer_shutdown(struct clock_event_device *evt) 1 arm_arch_timer.c 690 static __always_inline int timer_shutdown(const int access, 2 timer-fttmr010.c 105 int (*timer_shutdown)(struct clock_event_device *evt); 3 timer-sp804.c 158 static inline void timer_shutdown(struct clock_event_device *evt) 4 timer.h 239 static inline int timer_shutdown(struct timer_list *timer) Guenter