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 6F46918C030; Tue, 10 Sep 2024 09:41:46 +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=1725961306; cv=none; b=j/894iZQnkYSxE82vTjq/YEe3rS5S5h+ByezJVDc5sNBJGauVWR/IJxPXD4yc9y5Fu6sDYx4ofghtyepBd/hPsF8V1nYqx0C0zyVCWeINFFDae9yMi76/He+z4V9QDn0NY5j3/OwFVNAIsrfhj42FtYZDVV/4/HYykI6Q73gZNA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725961306; c=relaxed/simple; bh=YCe4fdAK1GsgfL/bNCLxtcat3jVrLCda3s0bdGo614c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dqRuyhI86npmRqmAdAr6/dkg7iGOX+m0DX15Sed9TONYSnWgP3M8z2Rhh42/PZG+WpPtDAGPvhD8AmjS3JtnPPeLXPy94OQdHXIOmYyTjAtQiwfNgQwQm4a3l2DpgfrGRj4SaKYIDkxLBQv4dRt1GKCVKUBtzh/YBMC+qtTIGpc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=h3V6+I8S; 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="h3V6+I8S" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A498DC4CEC3; Tue, 10 Sep 2024 09:41:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1725961306; bh=YCe4fdAK1GsgfL/bNCLxtcat3jVrLCda3s0bdGo614c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=h3V6+I8SmVUJZ1jpMoYore9pplaX4wNrRwiz5R3BgvueBNWMECaulKw3rVkSnilG6 tnSVsiutuSCP92Qqy8QcQLFhXrMtuPmR0wwEFg/XTmP3pDP345ZN4fYIBU7fpZFd0E JljNlXty65mfxqJBAYCa7+cPagJQYfTBGcj+74H4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Roland Xu , Thomas Gleixner Subject: [PATCH 6.10 026/375] rtmutex: Drop rt_mutex::wait_lock before scheduling Date: Tue, 10 Sep 2024 11:27:03 +0200 Message-ID: <20240910092623.139658372@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240910092622.245959861@linuxfoundation.org> References: <20240910092622.245959861@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 6.10-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 @@ -1644,6 +1644,7 @@ 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) { /* @@ -1656,10 +1657,10 @@ 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); rt_mutex_schedule(); @@ -1713,7 +1714,7 @@ 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); } /*