From mboxrd@z Thu Jan 1 00:00:00 1970 From: catalin.marinas@arm.com (Catalin Marinas) Date: Thu, 25 Jun 2015 14:24:54 +0100 Subject: [PATCH] ARM64: smp: Silence suspicious RCU usage with ipi tracepoints In-Reply-To: <558B2842.2030007@codeaurora.org> References: <1435176858-9568-1-git-send-email-sboyd@codeaurora.org> <20150624212930.GC12596@twins.programming.kicks-ass.net> <558B2842.2030007@codeaurora.org> Message-ID: <20150625132453.GA13892@localhost> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Jun 24, 2015 at 02:59:30PM -0700, Stephen Boyd wrote: > On 06/24/2015 02:29 PM, Peter Zijlstra wrote: > > On Wed, Jun 24, 2015 at 01:14:18PM -0700, Stephen Boyd wrote: > >> John Stultz reported an RCU splat on ARM with ipi trace events > >> enabled. It looks like the same problem exists on ARM64. > >> > >> At this point in the IPI handling path we haven't called > >> irq_enter() yet, so RCU doesn't know that we're about to exit > >> idle and properly warns that we're using RCU from an idle CPU. > >> Use trace_ipi_entry_rcuidle() instead of trace_ipi_entry() so > >> that RCU is informed about our exit from idle. > > I have a problem with $subject. It says 'silence', whereas afaict this > > fixes an actual bug, so it should be 'fixes'. > > Fair enough. I can resend or whoever applies this patch can > s/Silence/Fix/ on the $subject. I'll apply the patch and change the subject as well. Thanks. -- Catalin