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 EEDBB190493; Tue, 10 Sep 2024 10:17:56 +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=1725963477; cv=none; b=NvOVABN2S3VUn3VL9bnfh2FJTz+BSb3WtghNzIAAVpHNlH+PeWYARc2F3Amq//Wmv8S+MvRp2F+bixhLZfK1dmKSMglWh1FPC9emceTTXyKwc3IUjGEd4oCsmlVKQgiNqgBeBQO2onolRqZTVV3MdMgaq4zH43PiHStgwqnYXL4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725963477; c=relaxed/simple; bh=4CiWa8YH8DtcNg/vPE/WkpQjaOK5u2aYEugQ/mmXjVM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZqxLbwqZCGwlCmxoKwWrqs5aWfif5wz6TodHympOamvB9aabKalYIPj1AhpORo0T4NX/XGQ7RYwmDf3Lr/pBIuA3S6Ewd/FaG2N/+bEQsxXkvS7z3k+uJh9oC/ZnjO2bUc/V+oHkCrruOi/YNe88lqhOzMDtCnKKq8REzvgxgm4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ZG/+vLNV; 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="ZG/+vLNV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2E280C4CEC3; Tue, 10 Sep 2024 10:17:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1725963476; bh=4CiWa8YH8DtcNg/vPE/WkpQjaOK5u2aYEugQ/mmXjVM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZG/+vLNVo0K0qKlS1uZVXCuRRCjC7T6qOiWNm0AGrQrStXW98Taqm7eabBrilsULo 6vzAr47rDfP3okzpoQaaKEQUHxVXword6fF4CObWUCq7zeS237aTdrV1IcCauT2BSA E9sRXuVQjMdR8BwhDM7fVVBL4dg2XAVw+F+sWUQQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Roland Xu , Thomas Gleixner Subject: [PATCH 5.15 071/214] rtmutex: Drop rt_mutex::wait_lock before scheduling Date: Tue, 10 Sep 2024 11:31:33 +0200 Message-ID: <20240910092601.641902330@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240910092558.714365667@linuxfoundation.org> References: <20240910092558.714365667@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-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 | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -1613,6 +1613,7 @@ static int __sched rt_mutex_slowlock_blo } static void __sched rt_mutex_handle_deadlock(int res, int detect_deadlock, + struct rt_mutex_base *lock, struct rt_mutex_waiter *w) { /* @@ -1625,10 +1626,10 @@ static void __sched rt_mutex_handle_dead if (build_ww_mutex() && w->ww_ctx) return; - /* - * Yell loudly and stop the task right here. - */ + raw_spin_unlock_irq(&lock->wait_lock); + WARN(1, "rtmutex deadlock detected\n"); + while (1) { set_current_state(TASK_INTERRUPTIBLE); schedule(); @@ -1680,7 +1681,7 @@ static int __sched __rt_mutex_slowlock(s } else { __set_current_state(TASK_RUNNING); remove_waiter(lock, waiter); - rt_mutex_handle_deadlock(ret, chwalk, waiter); + rt_mutex_handle_deadlock(ret, chwalk, lock, waiter); } /*