From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guenter Roeck Subject: Re: [RFC][PATCH v3 00/33] timers: Use timer_shutdown*() before freeing timers Date: Fri, 4 Nov 2022 12:22:32 -0700 Message-ID: <20221104192232.GA2520396@roeck-us.net> References: <20221104054053.431922658@goodmis.org> Mime-Version: 1.0 Return-path: 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== Sender: Guenter Roeck Content-Disposition: inline In-Reply-To: <20221104054053.431922658@goodmis.org> List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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 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