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 A14C71DEFFC; Tue, 11 Feb 2025 01:31:13 +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=1739237473; cv=none; b=Bdp/R8EvyA0jpwlkA9k4rKAeNrPWtEO02Sd0pYy+IQ2f9COwZf3gzaYJ/dIgPkivtr4QD/vel8OSzah9HzaAAqiGGMvt1cj2qoVBxJ+dyWPRCNUjyBF8XCgXq55QpX+1D2bEIY6nscdA+FTH79/wOsRkICyvFoehotrK13wpiSc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739237473; c=relaxed/simple; bh=AvpDWiT8RYU89bwyqqgYdwBmnSzet2y0wzAleiu8oeA=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=f8cK7tMYwA2hWvxGFQED7o1GFat+DRbWYB01UTYGJv/jAJkYZkm+A2T2b19E5zoCD4MTpFVvySAmgbJwU8GOSeiwRilRYynheZv8SNTl7b3PNhdpJo+KeIsyFGbqt9qWnhgz0qmPa1+PS5e1cMPP/Qk0+ZzIQBOdoym1CQoBAWY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Y1Dk6b0Z; 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="Y1Dk6b0Z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 88906C4CED1; Tue, 11 Feb 2025 01:31:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739237473; bh=AvpDWiT8RYU89bwyqqgYdwBmnSzet2y0wzAleiu8oeA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Y1Dk6b0ZzXkBpcaYdu8B+tNrMzfYxLWnhjUx8U3YBHN64Vr1DSPu3LhINttzIhCIF fSD6hZ6juBCi8WzdxZsfhOS0XJZbTlUbDlIKo75z0nqG2G/LpIHjmOJSmWJfJ/PcVz 5R10ZAdnhzbFGj5od6oFvM1EK5IYnHEJgeCeme60qWftCVSGoEdrCBFgR4DsjKuGKe NINNvkJG47CXaCwOwmqO/Uwv1v/2Ju/j0T1A1DyJKXyVsov7NIDX3B3fw4/J+U8++C E1CVXTaQC5FbuouQQzV4ooIEG1dUClC6NchjI0TcuXvsiaLfISwLYUf3+GmxxGO15I 2aJTsq13tlx3w== 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 6.12 11/19] scsi: core: Use GFP_NOIO to avoid circular locking dependency Date: Mon, 10 Feb 2025 20:30:39 -0500 Message-Id: <20250211013047.4096767-11-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250211013047.4096767-1-sashal@kernel.org> References: <20250211013047.4096767-1-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 6.12.13 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 042329b74c6e6..fe08af4dcb67c 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