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 47DDF1D5140; Tue, 11 Feb 2025 01:30:22 +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=1739237423; cv=none; b=XQ7ZiLYncY5VixwlBIG4looz1SZ3dl+bTBPNi/9ZLG7QC5Qnv7jt4B3U8nQaCXKnqILtBDEBlRjUHqPSrq2GzXWORVysDEb5vIgvfDWvxhaZlxyRr4FNX0ieBLg9aDt6unafb4MetXLfGhy149Z2N3vaZ/frKQjkPciVJBfJphs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739237423; c=relaxed/simple; bh=AvpDWiT8RYU89bwyqqgYdwBmnSzet2y0wzAleiu8oeA=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=QH22LDzDXTFytrx3pQtZpDv2gKLH5xQtDFtV1xwnihAZm47CUGnmi/QbUG2qV8zp6BO3JyR99IluOIG0niBNFSQ0ltlgJeHpoI7+Eq6IvOEvqcB77tdRqX04Ad59BydX8WshGgYWRITbbVao5V/bq6oMRz2p6F3iXfgDyn8G1Lo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DbdBhYpQ; 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="DbdBhYpQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B3B72C4CEDF; Tue, 11 Feb 2025 01:30:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739237422; bh=AvpDWiT8RYU89bwyqqgYdwBmnSzet2y0wzAleiu8oeA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DbdBhYpQA3Gc9BoIjSvz2CC+yFjn3OYgkDVgVdiMoSLruWMDzs1DyxhOpxJSHBPEB BDsx9EbjA+psFJtH2omL3O+1kPIJR1CKgDaB6Rldt8mFJBnBbSg706Qad3rh/gsU+Y J1UETDT/oIzCLjRbPJIPxWbLb+Gh3frOstJO/3AjLXqNORa4tlY3nzEWhAHJHJwl3Y qHbhY6WYEN5fKZLCYLJgGN3lYLmAxJw8iltbMjQYOLT36O8DDPDYas4PUzoKoolAvX DwflIubeiAfzhiQxVvrX3V1f0BOHUp0xEWkrwePPgb4DJ459tdVp8BzCZfuGaHUKh1 ZJKn8Vzu1jFoA== 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 6.13 12/21] scsi: core: Use GFP_NOIO to avoid circular locking dependency Date: Mon, 10 Feb 2025 20:29:45 -0500 Message-Id: <20250211012954.4096433-12-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250211012954.4096433-1-sashal@kernel.org> References: <20250211012954.4096433-1-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 6.13.2 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