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 C454718B46D; Tue, 10 Sep 2024 10:05:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725962713; cv=none; b=KUuKIKWuyW6NYpKe2NvY75Nbnl9K7eJYhBuwUN/ikmBCuNiNqv7Dk4DEsVg3XJAPh0T3AqtgVcz+o8l+YPH5zFqKpFzdU817/RqsWC9RwzKRU+rP8htD/degq5mRqkCXWVCoP6A7KizAu2NGHE/18Ckadnb1/EDw5TslGBFps8g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725962713; c=relaxed/simple; bh=oEv3vMhlaCqgaRTIAgvgmNM63QnOipi81b/eFRC7lIw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cIL75SqMYwPFcvgNKwnvJIbaKO1RfrsGRfvzCpNVl1rrct0dTHae/fNeYsq5pRfDLs3xCS3vClVLkXbSRfzRxePVr396kR11e7HF6ehtsBeLi59IneW/9o0zFpKfDYRU+/vAtVG5Z6N5nIeEeain2slXBbxagixFLon0AbhOpi4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=p9k+VJZA; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="p9k+VJZA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4AF17C4CEC3; Tue, 10 Sep 2024 10:05:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1725962713; bh=oEv3vMhlaCqgaRTIAgvgmNM63QnOipi81b/eFRC7lIw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=p9k+VJZA3pJ6NyJ8++VFUOuGFhiftLy9ILIR/onyOMQ4JpfvWp/mNAUn3SMltG0jQ i3I7xig5jpMpQ04Vgnj+64HrgtxdYhV9PrnV1R4Cvv2J3qDbgZ8VFH19+wyGnIFx+q zxV4X/PO9ZJH/bGNIbQe6Mp9UihkOwMsIyGj315o= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Roland Xu , Thomas Gleixner Subject: [PATCH 5.4 119/121] rtmutex: Drop rt_mutex::wait_lock before scheduling Date: Tue, 10 Sep 2024 11:33:14 +0200 Message-ID: <20240910092551.450115510@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240910092545.737864202@linuxfoundation.org> References: <20240910092545.737864202@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Roland Xu commit d33d26036a0274b472299d7dcdaa5fb34329f91b upstream. rt_mutex_handle_deadlock() is called with rt_mutex::wait_lock held. In the good case it returns with the lock held and in the deadlock case it emits a warning and goes into an endless scheduling loop with the lock held, which triggers the 'scheduling in atomic' warning. Unlock rt_mutex::wait_lock in the dead lock case before issuing the warning and dropping into the schedule for ever loop. [ tglx: Moved unlock before the WARN(), removed the pointless comment, massaged changelog, added Fixes tag ] Fixes: 3d5c9340d194 ("rtmutex: Handle deadlock detection smarter") Signed-off-by: Roland Xu Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/ME0P300MB063599BEF0743B8FA339C2CECC802@ME0P300MB0635.AUSP300.PROD.OUTLOOK.COM Signed-off-by: Greg Kroah-Hartman --- kernel/locking/rtmutex.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -1204,6 +1204,7 @@ __rt_mutex_slowlock(struct rt_mutex *loc } static void rt_mutex_handle_deadlock(int res, int detect_deadlock, + struct rt_mutex *lock, struct rt_mutex_waiter *w) { /* @@ -1213,6 +1214,7 @@ static void rt_mutex_handle_deadlock(int if (res != -EDEADLOCK || detect_deadlock) return; + raw_spin_unlock_irq(&lock->wait_lock); /* * Yell lowdly and stop the task right here. */ @@ -1268,7 +1270,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, if (unlikely(ret)) { __set_current_state(TASK_RUNNING); remove_waiter(lock, &waiter); - rt_mutex_handle_deadlock(ret, chwalk, &waiter); + rt_mutex_handle_deadlock(ret, chwalk, lock, &waiter); } /*