From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 58FC91C08 for ; Wed, 28 Dec 2022 16:44:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF2F1C433EF; Wed, 28 Dec 2022 16:44:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1672245860; bh=FtAeghpOcG2WZJsrWRmoGbAgKj+g/KOYm0uLL2+J9z0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=APPPUzJNeOPDWo/uR3596bmlHQd34uzUGBUYJDFNPoWdEHPJwScB7KfagMBcJwpZq CCNcPCTt6I7/YAxE/koCCDIf1MydqkzZUD0mDnE0N7DwvIdRQ9RDpX1Z+sIzvLMrNY F2DFPkjFr0hSmDO1x963cwo8vXBaZ5d/fs2Lj670= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zqiang , "Joel Fernandes (Google)" , "Paul E. McKenney" , Sasha Levin Subject: [PATCH 6.1 0937/1146] rcu: Fix __this_cpu_read() lockdep warning in rcu_force_quiescent_state() Date: Wed, 28 Dec 2022 15:41:16 +0100 Message-Id: <20221228144355.754580940@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20221228144330.180012208@linuxfoundation.org> References: <20221228144330.180012208@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Zqiang [ Upstream commit ceb1c8c9b8aa9199da46a0f29d2d5f08d9b44c15 ] Running rcutorture with non-zero fqs_duration module parameter in a kernel built with CONFIG_PREEMPTION=y results in the following splat: BUG: using __this_cpu_read() in preemptible [00000000] code: rcu_torture_fqs/398 caller is __this_cpu_preempt_check+0x13/0x20 CPU: 3 PID: 398 Comm: rcu_torture_fqs Not tainted 6.0.0-rc1-yoctodev-standard+ Call Trace: dump_stack_lvl+0x5b/0x86 dump_stack+0x10/0x16 check_preemption_disabled+0xe5/0xf0 __this_cpu_preempt_check+0x13/0x20 rcu_force_quiescent_state.part.0+0x1c/0x170 rcu_force_quiescent_state+0x1e/0x30 rcu_torture_fqs+0xca/0x160 ? rcu_torture_boost+0x430/0x430 kthread+0x192/0x1d0 ? kthread_complete_and_exit+0x30/0x30 ret_from_fork+0x22/0x30 The problem is that rcu_force_quiescent_state() uses __this_cpu_read() in preemptible code instead of the proper raw_cpu_read(). This commit therefore changes __this_cpu_read() to raw_cpu_read(). Signed-off-by: Zqiang Reviewed-by: Joel Fernandes (Google) Signed-off-by: Paul E. McKenney Signed-off-by: Sasha Levin --- kernel/rcu/tree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 93416afebd59..14d9384fba05 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2418,7 +2418,7 @@ void rcu_force_quiescent_state(void) struct rcu_node *rnp_old = NULL; /* Funnel through hierarchy to reduce memory contention. */ - rnp = __this_cpu_read(rcu_data.mynode); + rnp = raw_cpu_read(rcu_data.mynode); for (; rnp != NULL; rnp = rnp->parent) { ret = (READ_ONCE(rcu_state.gp_flags) & RCU_GP_FLAG_FQS) || !raw_spin_trylock(&rnp->fqslock); -- 2.35.1