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In-Reply-To: References: <20201215144531.GZ2657@paulmck-ThinkPad-P72> <20201215102246.4bdca3d8@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> Date: Wed, 16 Dec 2020 16:21:12 +0100 Message-ID: <87lfdxsro7.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201216_102115_422792_E6776EA8 X-CRM114-Status: GOOD ( 11.67 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sasha Levin , Matthew Wilcox , "Paul E. McKenney" , Peter Zijlstra , Netdev , open list , linux-stable , rcu@vger.kernel.org, lkft-triage@lists.linaro.org, Greg Kroah-Hartman , Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Dec 16 2020 at 15:55, Naresh Kamboju wrote: > On Tue, 15 Dec 2020 at 23:52, Jakub Kicinski wrote: >> > Or you could place checks for being in a BH-disable further up in >> > the code. Or build with CONFIG_DEBUG_INFO=y to allow more precise >> > interpretation of this stack trace. > > I will try to reproduce this warning with DEBUG_INFO=y enabled kernel and > get back to you with a better crash log. > >> >> My money would be on the option that whatever run on this workqueue >> before forgot to re-enable BH, but we already have a check for that... >> Naresh, do you have the full log? Is there nothing like "BUG: workqueue >> leaked lock" above the splat? No, because it's in the middle of the work. The workqueue bug triggers when the work has finished. So cleanup_up() net does .... synchronize_rcu(); <- might sleep. So up to here it should be fine. list_for_each_entry_continue_reverse(ops, &pernet_list, list) ops_exit_list(ops, &net_exit_list); ops_exit_list() is called for each ops which then either invokes ops->exit() or ops->exit_batch(). So one of those callbacks fails to reenable BH, so adding a check after each invocation of ops->exit() and ops->exit_batch() for !local_bh_disabled() should be able to identify the buggy callback. Thanks, tglx _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel