From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiko Carstens Date: Thu, 03 Dec 2020 14:54:42 +0000 Subject: Re: [PATCH AUTOSEL 5.9 27/39] sched/idle: Fix arch_cpu_idle() vs tracing Message-Id: <20201203145442.GC9994@osiris> List-Id: References: <20201203132834.930999-1-sashal@kernel.org> <20201203132834.930999-27-sashal@kernel.org> In-Reply-To: <20201203132834.930999-27-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Sasha Levin Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Peter Zijlstra , Sven Schnelle , Mark Rutland , linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, uclinux-h8-devel@lists.sourceforge.jp, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org, openrisc@lists.librecores.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org On Thu, Dec 03, 2020 at 08:28:21AM -0500, Sasha Levin wrote: > From: Peter Zijlstra > > [ Upstream commit 58c644ba512cfbc2e39b758dd979edd1d6d00e27 ] > > We call arch_cpu_idle() with RCU disabled, but then use > local_irq_{en,dis}able(), which invokes tracing, which relies on RCU. > > Switch all arch_cpu_idle() implementations to use > raw_local_irq_{en,dis}able() and carefully manage the > lockdep,rcu,tracing state like we do in entry. > > (XXX: we really should change arch_cpu_idle() to not return with > interrupts enabled) > > Reported-by: Sven Schnelle > Signed-off-by: Peter Zijlstra (Intel) > Reviewed-by: Mark Rutland > Tested-by: Mark Rutland > Link: https://lkml.kernel.org/r/20201120114925.594122626@infradead.org > Signed-off-by: Sasha Levin This patch broke s390 irq state tracing. A patch to fix this is scheduled to be merged upstream today (hopefully). Therefore I think this patch should not yet go into 5.9 stable.