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 F2CD81F7910; Tue, 11 Feb 2025 01:31:48 +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=1739237509; cv=none; b=r4V8kLo4nS1cHBzdLLdYt0wOMTCouJjro9m3gc0c0dGDZtwrMkxoNd5eNK7u3cdMltXC8u0/E7S8J/nhc/JKbCLEhOKmr+MQlLQ4H/zZpUg31qOvotvwbXYOSBA/rbGaYCI0QD5rWTdMnDKH2E96b5un4dFoPa93nC4HYUcGPpg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739237509; c=relaxed/simple; bh=XmFhPgocvk5M8n3X6b6Z/pyIVE09pHfdrlXGz9mvK7g=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=hzBcq/AHgKYu2gmW2Gu8x8W8S8LfW06D1Z0O92hm4jZYwf1OykkhkQEa+VdDCQcBmJpzxmDZLvi59IV4BH/MriH5uUO+yPDC7KLAaRgj4dCoklqO9fAdET0QpB6EEbwZU5iiR7kYvPLltvJRIzTE/jhLT04C/O02MZD2Fcb80yw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aX/g1c7s; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="aX/g1c7s" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7B93BC4CEE5; Tue, 11 Feb 2025 01:31:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739237508; bh=XmFhPgocvk5M8n3X6b6Z/pyIVE09pHfdrlXGz9mvK7g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aX/g1c7ssEXIz3QaDAlWCksh8vGqZjDD5PvePX4eiYA0oDN/A3YH3bpS9UKNNioYb au5XxrLkGKAEDo8HQrRdEeRnwRg76K7C0kgEJwAorbeU3s3GIzkUzjbNNO5T5vYw4H AAbfdzHVYDm3adKmxGJ1bX79dAeF49X3jdoHhtgXtbA+6IT3T6OSTmQQaMvPvE526C Ybjr1CAravNExYrZxQAPjuH/KbId8dGsu1o3NR2YbMZQ/XawhrImsrW3tzDXlqogDh 3e3VpqZXJb1JMF1HFyHFUOZEdr5gjUGwB5WNV865zQQSOFaEzRG1gBnyWSbuUWTr6l VJT6pmJw6MLUw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Rik van Riel , =?UTF-8?q?Marc=20Aur=C3=A8le=20La=20France?= , Christoph Hellwig , "Martin K . Petersen" , Sasha Levin , James.Bottomley@HansenPartnership.com, linux-scsi@vger.kernel.org Subject: [PATCH AUTOSEL 6.6 08/15] scsi: core: Use GFP_NOIO to avoid circular locking dependency Date: Mon, 10 Feb 2025 20:31:28 -0500 Message-Id: <20250211013136.4098219-8-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250211013136.4098219-1-sashal@kernel.org> References: <20250211013136.4098219-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.6.76 Content-Transfer-Encoding: 8bit From: Rik van Riel [ Upstream commit 5363ee9d110e139584c2d92a0b640bc210588506 ] Filesystems can write to disk from page reclaim with __GFP_FS set. Marc found a case where scsi_realloc_sdev_budget_map() ends up in page reclaim with GFP_KERNEL, where it could try to take filesystem locks again, leading to a deadlock. WARNING: possible circular locking dependency detected 6.13.0 #1 Not tainted ------------------------------------------------------ kswapd0/70 is trying to acquire lock: ffff8881025d5d78 (&q->q_usage_counter(io)){++++}-{0:0}, at: blk_mq_submit_bio+0x461/0x6e0 but task is already holding lock: ffffffff81ef5f40 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x9f/0x760 The full lockdep splat can be found in Marc's report: https://lkml.org/lkml/2025/1/24/1101 Avoid the potential deadlock by doing the allocation with GFP_NOIO, which prevents both filesystem and block layer recursion. Reported-by: Marc Aurèle La France Signed-off-by: Rik van Riel Link: https://lore.kernel.org/r/20250129104525.0ae8421e@fangorn Reviewed-by: Christoph Hellwig Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/scsi/scsi_scan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c index ca99be7341d9b..cead0fbbe5dbd 100644 --- a/drivers/scsi/scsi_scan.c +++ b/drivers/scsi/scsi_scan.c @@ -245,7 +245,7 @@ static int scsi_realloc_sdev_budget_map(struct scsi_device *sdev, } ret = sbitmap_init_node(&sdev->budget_map, scsi_device_max_queue_depth(sdev), - new_shift, GFP_KERNEL, + new_shift, GFP_NOIO, sdev->request_queue->node, false, true); if (!ret) sbitmap_resize(&sdev->budget_map, depth); -- 2.39.5