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 944E51BC9FC; Tue, 27 Aug 2024 15:15:13 +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=1724771713; cv=none; b=tKXViIIBRnFycBhHaP89n3fVjTIT8gnanPlw8VrPZdjmZBD1MKoN4jq83RlJl93pSlZzjcW2MOxwfTIs+6Hp5zV/nQPTLsNOzKeKd+CI5COciN2FT3RX2Ac34zWey0wOA55VWlKhIO2a5Wen55uPOI+X0jwGslr+1P4qdU2tl+c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724771713; c=relaxed/simple; bh=idSxrWsTuxWwjl/ombsewL/ef7W7d/Wxpio1T13Hjco=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=TDv5jihKHlaN4paGvOZAvS+B1lSNeV/cnzXAUl3Ft0XReqx1oyZGRwoKTprD/O+EgXlU/19aVYKEwOlCgpWZ0fMG5ieIqHmbuK9R6v0AjP8BU7j+Wxq4BQtFQClpMt9LRniImLwuiAwaA0r1YJxtvdnQfAKtH+ycr1ts17lFPAU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=C/3aELx0; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="C/3aELx0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED2F5C4AF50; Tue, 27 Aug 2024 15:15:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1724771713; bh=idSxrWsTuxWwjl/ombsewL/ef7W7d/Wxpio1T13Hjco=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=C/3aELx0255L+/4FRh5z/iInc5Vn98OljSMGsoXCOKoD9r0Pm6IoXX/brgEb6kk2y kUZBAKgJ10XF3buT3GzPsiP53xBjUbaDQCYKI46aseNxY3jq/a+5OnDoq0f6Ptd0uh iyMTo6/8TKsxjBiRyja20+ib8IZK/uUDf8JO05rI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Kolbj=C3=B8rn=20Barmen?= , =?UTF-8?q?Jon=C3=A1=C5=A1=20Vidra?= , Michael Ellerman , Damien Le Moal Subject: [PATCH 6.10 240/273] ata: pata_macio: Fix DMA table overflow Date: Tue, 27 Aug 2024 16:39:24 +0200 Message-ID: <20240827143842.535423957@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240827143833.371588371@linuxfoundation.org> References: <20240827143833.371588371@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michael Ellerman commit 822c8020aebcf5804a143b891e34f29873fee5e2 upstream. Kolbjørn and Jonáš reported that their 32-bit PowerMacs were crashing in pata-macio since commit 09fe2bfa6b83 ("ata: pata_macio: Fix max_segment_size with PAGE_SIZE == 64K"). For example: kernel BUG at drivers/ata/pata_macio.c:544! Oops: Exception in kernel mode, sig: 5 [#1] BE PAGE_SIZE=4K MMU=Hash SMP NR_CPUS=2 DEBUG_PAGEALLOC PowerMac ... NIP pata_macio_qc_prep+0xf4/0x190 LR pata_macio_qc_prep+0xfc/0x190 Call Trace: 0xc1421660 (unreliable) ata_qc_issue+0x14c/0x2d4 __ata_scsi_queuecmd+0x200/0x53c ata_scsi_queuecmd+0x50/0xe0 scsi_queue_rq+0x788/0xb1c __blk_mq_issue_directly+0x58/0xf4 blk_mq_plug_issue_direct+0x8c/0x1b4 blk_mq_flush_plug_list.part.0+0x584/0x5e0 __blk_flush_plug+0xf8/0x194 __submit_bio+0x1b8/0x2e0 submit_bio_noacct_nocheck+0x230/0x304 btrfs_work_helper+0x200/0x338 process_one_work+0x1a8/0x338 worker_thread+0x364/0x4c0 kthread+0x100/0x104 start_kernel_thread+0x10/0x14 That commit increased max_segment_size to 64KB, with the justification that the SCSI core was already using that size when PAGE_SIZE == 64KB, and that there was existing logic to split over-sized requests. However with a sufficiently large request, the splitting logic causes each sg to be split into two commands in the DMA table, leading to overflow of the DMA table, triggering the BUG_ON(). With default settings the bug doesn't trigger, because the request size is limited by max_sectors_kb == 1280, however max_sectors_kb can be increased, and apparently some distros do that by default using udev rules. Fix the bug for 4KB kernels by reverting to the old max_segment_size. For 64KB kernels the sg_tablesize needs to be halved, to allow for the possibility that each sg will be split into two. Fixes: 09fe2bfa6b83 ("ata: pata_macio: Fix max_segment_size with PAGE_SIZE == 64K") Cc: stable@vger.kernel.org # v6.10+ Reported-by: Kolbjørn Barmen Closes: https://lore.kernel.org/all/62d248bb-e97a-25d2-bcf2-9160c518cae5@kolla.no/ Reported-by: Jonáš Vidra Closes: https://lore.kernel.org/all/3b6441b8-06e6-45da-9e55-f92f2c86933e@ufal.mff.cuni.cz/ Tested-by: Kolbjørn Barmen Signed-off-by: Michael Ellerman Signed-off-by: Damien Le Moal Signed-off-by: Greg Kroah-Hartman --- drivers/ata/pata_macio.c | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) diff --git a/drivers/ata/pata_macio.c b/drivers/ata/pata_macio.c index 1b85e8bf4ef9..1cb8d24b088f 100644 --- a/drivers/ata/pata_macio.c +++ b/drivers/ata/pata_macio.c @@ -208,6 +208,19 @@ static const char* macio_ata_names[] = { /* Don't let a DMA segment go all the way to 64K */ #define MAX_DBDMA_SEG 0xff00 +#ifdef CONFIG_PAGE_SIZE_64KB +/* + * The SCSI core requires the segment size to cover at least a page, so + * for 64K page size kernels it must be at least 64K. However the + * hardware can't handle 64K, so pata_macio_qc_prep() will split large + * requests. To handle the split requests the tablesize must be halved. + */ +#define PATA_MACIO_MAX_SEGMENT_SIZE SZ_64K +#define PATA_MACIO_SG_TABLESIZE (MAX_DCMDS / 2) +#else +#define PATA_MACIO_MAX_SEGMENT_SIZE MAX_DBDMA_SEG +#define PATA_MACIO_SG_TABLESIZE MAX_DCMDS +#endif /* * Wait 1s for disk to answer on IDE bus after a hard reset @@ -912,16 +925,10 @@ static int pata_macio_do_resume(struct pata_macio_priv *priv) static const struct scsi_host_template pata_macio_sht = { __ATA_BASE_SHT(DRV_NAME), - .sg_tablesize = MAX_DCMDS, + .sg_tablesize = PATA_MACIO_SG_TABLESIZE, /* We may not need that strict one */ .dma_boundary = ATA_DMA_BOUNDARY, - /* - * The SCSI core requires the segment size to cover at least a page, so - * for 64K page size kernels this must be at least 64K. However the - * hardware can't handle 64K, so pata_macio_qc_prep() will split large - * requests. - */ - .max_segment_size = SZ_64K, + .max_segment_size = PATA_MACIO_MAX_SEGMENT_SIZE, .device_configure = pata_macio_device_configure, .sdev_groups = ata_common_sdev_groups, .can_queue = ATA_DEF_QUEUE, -- 2.46.0