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 1ACC92236EC; Tue, 11 Feb 2025 01:32:15 +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=1739237535; cv=none; b=p+qr1/JzjI5db8flQEhhgyJQUdPsbzmDd53oMSxyYXBKXLUt/CX6HLmg/sBGJBYbKgYuo9zsuBFFl6o8BprPdxm91DLNDTTrNJAccMH6Pi7CE4T3nph15BuRCvkOHKbn4BZOKwx7UAY1yRbqJpI6AikMtdt9PImVuMYVg66S0OQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739237535; c=relaxed/simple; bh=1VHiijSQilmW7pa/YP6ujaK75Y61pSc1YVCPPtkBMyk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=PrZ1IEOkSw9Z7EBscsc5bLYu+3+fbQOnKEq1CCEiRuIghVbfCnmhN1w4ymaVVBPaEmWQ+hpKSYmBoxpRhg5LV9CVxSEpiVuJf2hDVVY45ay7b7kyH2yz9SYYQMN5SMsi8s4CmFKOFum+p0ItppaLYEJA0UkRuA/pusS4MYG+Ri0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IuxwG7O4; 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="IuxwG7O4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F03E0C4CEEA; Tue, 11 Feb 2025 01:32:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739237535; bh=1VHiijSQilmW7pa/YP6ujaK75Y61pSc1YVCPPtkBMyk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IuxwG7O4+7R9t7yXTqT/XAMkqipvFBTKXeLWbT0DVwbir8l2m6odJdU1agdbZy2Qq LY5NOVXgDNCqhdzqi+hFCsrgR0KVAXwJf7r8szn1wCOgvNnNpttZQj5MPK1xtOSE3V 9jV2I4O3Pj7a8mP5UCe4o0a/zzwTd90wbf1I1iXAsasHe6Um6R0aNDLhiAdWHzJNJ3 aoCzBwkz0aMTaZvDbRtiy69JkxSSw4ATDsKEGkxOKeLinSbQqcVDCIMzUvieQg9a7g FcSCUTrlC6fkzUn35w8V6W7RB8K4G9Lmw62u/jMkIR4XQZzB+31W3iV74cUpqV6r9o ezAHjPXIAyZrw== 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 6.1 05/11] scsi: core: Use GFP_NOIO to avoid circular locking dependency Date: Mon, 10 Feb 2025 20:32:00 -0500 Message-Id: <20250211013206.4098522-5-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250211013206.4098522-1-sashal@kernel.org> References: <20250211013206.4098522-1-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 6.1.128 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 852d509b19b2b..69288303e6004 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