From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794060915; b=G4XkVxfmHSsS94Y21KeqrsAYmB4SdWgQ8+hOAbTh5OjZk9iDFR/dBfRwUSfPsrz3GSs5 m8qF/H6qrXTBOU5BlW6DpbWzuZsDAChdZJA5kt5MvdKDmdvpyjXTlO1OxcXITUGC+imlq hwv5qjsczwVg/WvWf8J2RgXQto3CRyedjSOEhtEyR+juCX2byB+bvw2XBKo74GcsT+H6w yzaBoPBOSHRRYKyvSE9oCVBYr5Z7QTLvVudOGI/yx7RseYa0YkUOZ6wfpxLDQuD5cyx/y wsOmatyur0kRxf2t+SC3nnRFFt7Uo6bHw3T0XZIwL616Ct8VJcVW2P6R1/7znIBz8fg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794060915; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=x9o6ybrOTMPzmNTEnQG9mHVRt4EV5AWgpeKRuUlCvLw=; b=aAeHQ1QGrba4+MaIhuZHAhFiUHDLbnaA0HjRYxrBf0zP6QBSjXySUuE6uI+x60hpJPih AEXIyffeQ7G6PBinol9k7cEFZRsS/5F2eZVdwlFPJGyOfJB4k3kxn+owxZh5kK2I5+NKj 8F7MR1eTC40uIXvaB2ulKtFOpZ1kRHScY9V8tV4b/uhK59OC2HOQKrRYGqKsK8lBZ6P66 AFZ8utzOUL10hzdKEp6Dk6DBAl7LPEZoRQ0f+yF5IeayfJ92dwPvRN4D7gw7tG41YvP39 cWfBYZ5CGeQDRuka/xnWAUDEHQ79fy1iLh0bF8X2czJ8GW9H2ccKBY0m+hJttLwLssQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b="SZJ/aKND"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 000CF606D809; Sat, 7 Nov 2026 14:15:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=SZJ/aKND Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9E9881F0089F; Sat, 7 Nov 2026 14:15:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794060914; bh=x9o6ybrOTMPzmNTEnQG9mHVRt4EV5AWgpeKRuUlCvLw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=SZJ/aKNDT2TAfdtbMzT6DFd8J3Bc601OR7so7PfsRWou+58yKvVgwhLTU9eOPJVw6 Txjx9/36AmgUwKdI3D9hGQllW2DFBoxYibS14exqlIhOO/caHSLICqNFyPW6WlK+XY 6Gdgvc4jMf4NDo9wa2Az/O85IKunLzSFlhDX4jJU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yunye Zhao , Yu Kuai , Sasha Levin Subject: [PATCH 6.12 0283/1536] md: add cond_resched() to md_do_sync()s skip path Date: Sat, 7 Nov 2026 08:38:19 -0500 Message-ID: <20261107135005.612042604@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134957.653319350@linuxfoundation.org> References: <20261107134957.653319350@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yunye Zhao [ Upstream commit 162eb5ba791f6260fdaabae75fa2df20134f67d8 ] When sync_request() reports a skipped region (*skipped == 1), md_do_sync()'s main loop advances the cursor and takes an early continue: j += sectors; ... if (last_check + window > io_sectors || j == max_sectors) continue; If the personality returns a small span per call (raid10 recovery returns only 128 sectors), syncing a large, mostly clean array iterates this branch an enormous number of times without ever yielding the CPU. On a non-preemptive kernel the resync thread then trips the soft-lockup watchdog: watchdog: BUG: soft lockup - CPU#149 stuck for 313s! [mdX_resync] md_bitmap_start_sync+0x6f/0xe0 raid10_sync_request+0x2c9/0x1530 [raid10] md_do_sync+0x810/0x1030 md_thread+0xa7/0x150 Add a cond_resched(). This does not reduce the wasted iterations; the excessive iteration count is a raid10 problem addressed separately. Signed-off-by: Yunye Zhao Link: https://patch.msgid.link/20260723135535.101995-3-yunye.zhao@linux.alibaba.com Signed-off-by: Yu Kuai Signed-off-by: Sasha Levin --- drivers/md/md.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index db8df74fcf67a..634b68b6632ea 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -9293,8 +9293,10 @@ void md_do_sync(struct md_thread *thread) */ md_new_event(); - if (last_check + window > io_sectors || j == max_sectors) + if (last_check + window > io_sectors || j == max_sectors) { + cond_resched(); continue; + } last_check = io_sectors; repeat: -- 2.53.0