From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 3DA224195A0; Fri, 4 Sep 2026 05:20:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788499257; cv=none; b=cTkdoM6TaK1YMvTgs7n+8jpNoWWFs2xuQeUOMrPSGmnRs46U0kc5Xdk81GAZAe7KdOZ/banAdAJg6SK4FDE346+PMq6Ow/GsbN3UeVWaKGTt9MjLRIFE7zx9UWp0SHJKblnzNRMxhofi/GSBy0n/OTbJWxEEXiavkEzd3hIMb2k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788499257; c=relaxed/simple; bh=f7LY1Ipn1RcwsoP/xTVVfGyODh4zcGFANlkntSLtB68=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OHKuytTOJH+6EsT5ffwdFp6K1moFIe6ZrQzhaAaih3Riq7pGupRoC5np3LkuRpc+x/2uWvuIWs+alvxOXx0MMu89QdTfv5tKWlqNnwiIR9DNjd+5+SnwNG9Xi5wfUPTZibz9zfTfbLywFe3h/LEj8T5/aDETdQNZQm4U3MGkN1o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=FYrSsAU2; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="FYrSsAU2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 97B3E1F00A3D; Fri, 4 Sep 2026 05:20:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788499256; bh=lgkojPLYxcWEsqPMEpQRFI9of0n5XyRqe5P/ourYm8c=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=FYrSsAU2scRSqWNTBiLCfI5ZM13m6WgSSW+w78wS+eeoAUe7Le52BB71Rocu2l/hS 5MmOfeCEqyCW0onBpIj3yfshhcej7FyYU0ai/VEpjBMey3u3sr9rTLvx9wJsb7eBr8 tzFd8p3P0iveQHDns55XQcDIsYEo7rMQngBqDKCc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Max Kellermann , Zhang Yi , Jan Kara , Theodore Tso Subject: [PATCH 7.2 351/713] jbd2: check need_resched() when skipping busy checkpoint buffers Date: Fri, 4 Sep 2026 06:55:19 +0200 Message-ID: <20260904045811.699933207@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045803.810145556@linuxfoundation.org> References: <20260904045803.810145556@linuxfoundation.org> User-Agent: quilt/0.69 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 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Max Kellermann commit f213e12ff5c9590b1034ae8da0e6d09665c772d0 upstream. journal_shrink_one_cp_list() skips busy checkpoint buffers when called with JBD2_SHRINK_BUSY_SKIP. The continue statement on this path also skips the need_resched() check at the end of the loop body. Consequently, when a checkpoint list contains mostly busy buffers, the shrinker can walk the entire list while holding journal->j_list_lock, even when a reschedule has been requested. Large checkpoint lists under memory pressure can therefore cause long lock hold times and leave other CPUs spinning on j_list_lock, resulting in soft lockups or RCU stalls. Route the busy-buffer path through the need_resched() check so that the shrinker can release j_list_lock and reschedule promptly, restoring parity with the clean-buffer path, which already checks need_resched(). This does not change which checkpoint buffers are eligible for removal. Fixes: b98dba273a0e ("jbd2: remove journal_clean_one_cp_list()") Cc: stable@vger.kernel.org Signed-off-by: Max Kellermann Reviewed-by: Zhang Yi Reviewed-by: Jan Kara Link: https://patch.msgid.link/20260713102229.1598812-2-max.kellermann@ionos.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/jbd2/checkpoint.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/fs/jbd2/checkpoint.c +++ b/fs/jbd2/checkpoint.c @@ -392,7 +392,7 @@ static unsigned long journal_shrink_one_ ret = jbd2_journal_try_remove_checkpoint(jh); if (ret < 0) { if (type == JBD2_SHRINK_BUSY_SKIP) - continue; + goto next; break; } } @@ -403,6 +403,7 @@ static unsigned long journal_shrink_one_ break; } +next: if (need_resched()) break; } while (jh != last_jh && (!nr_to_scan || *nr_to_scan));