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=1793830827; b=3/ta6IVI02+IxTHkPbFrSHe0PH8GCty3SyBhGi+nXBBb7pFfOVg91jxHdrcqrda89EfV kehxZR+RhtcMZAnkk2KDPE+Dc8jsBg60Vw3i0Gy9dNUZZlV9pthaWonkLMw4xIBGhr/L9 zAmYELsFSiaXxKMNOQZmHPClUWA90uyQ79/VCqIpmO9CeB8E8G/HM7WcKJjdmbHOAoUqD kHorwB9p+cXAutOBkpW4Fp+JOlHqv+GoiXJWYsIv8aeTnigOakUNqiiLOutPsfmJPc3Dy mpFdH+NMeMc2cLE80K0kptcogpr6YSGwojmJCBnNH6jkn/2GVWr12sjVTv6CU6RgyPQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793830827; 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=A3MBBRVG22YsVonQY3co9MKgHW9XjtVemYIaGUPbFTI=; b=crOoYd8GIDK3Zxm2C1q/kYp0qkoVukQvoWAIDhOIbyOLI7i0j3kBcziYyMF92kM5dxYh lM+/rxCpX0AOKl/VWgg+iJ1cOXEWBSD5lY3ge6fBboJmqY3EiUod2OkZ0+Kxyo0cDdLSt N9bOfFRmAWM4RzxZ/G7Tzz1OGKRHbClRnlu1Ck2ADLob0GzjpOF5+heKfmC8zGnZiiL0g C8lw0V+l778+sdHk8TLi1JgTXiTJa7gA0SnfT2hLZk8DniM0rjf9da/AHmWsjO7PeZME5 LAyT2m+ANjSFFhXS4X4ylmh7gyLCFZlWCBIWxzZS4SsEHDVVZl+9YlX+u3qMp4beX0Q== 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=vWa40NAX; 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 E3D0D606B2D5; Wed, 4 Nov 2026 22:20:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=vWa40NAX Received: by smtp.kernel.org (Postfix) with ESMTPSA id 80A511F00919; Wed, 4 Nov 2026 22:20:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793830826; bh=A3MBBRVG22YsVonQY3co9MKgHW9XjtVemYIaGUPbFTI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=vWa40NAXEmZlc3cl6H4SRpmksJj9QHD46OEF1r2ltiITXgDS4LEl6SX9Yqt3i9jkB XH4PM+C1obnwAceuEx05Iv1SiJtCgpveguaYGSZX4/mIzK8sdI4ArxYELbrrjpGPL4 0VE1LgHKIHRksek5kJ6ZjqH9EzAswDf/cU3UsYxg= 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 6.18 0342/1005] md: add cond_resched() to md_do_sync()s skip path Date: Wed, 4 Nov 2026 16:01:15 -0500 Message-ID: <20261104211053.541771243@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-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 ce3bd127e3bb3..44f44219ed7fe 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -9751,8 +9751,10 @@ 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