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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Ye Bin <yebin10@huawei.com>, Bart Van Assche <bvanassche@acm.org>,
	"Martin K . Petersen" <martin.petersen@oracle.com>,
	Sasha Levin <sashal@kernel.org>,
	linux-scsi@vger.kernel.org
Subject: [PATCH AUTOSEL 4.19 06/11] scsi: scsi_dh_rdac: Avoid crash during rdac_bus_attach()
Date: Tue, 10 Aug 2021 10:16:19 -0400	[thread overview]
Message-ID: <20210810141625.3118097-6-sashal@kernel.org> (raw)
In-Reply-To: <20210810141625.3118097-1-sashal@kernel.org>

From: Ye Bin <yebin10@huawei.com>

[ Upstream commit bc546c0c9abb3bb2fb46866b3d1e6ade9695a5f6 ]

The following BUG_ON() was observed during RDAC scan:

[595952.944297] kernel BUG at drivers/scsi/device_handler/scsi_dh_rdac.c:427!
[595952.951143] Internal error: Oops - BUG: 0 [#1] SMP
......
[595953.251065] Call trace:
[595953.259054]  check_ownership+0xb0/0x118
[595953.269794]  rdac_bus_attach+0x1f0/0x4b0
[595953.273787]  scsi_dh_handler_attach+0x3c/0xe8
[595953.278211]  scsi_dh_add_device+0xc4/0xe8
[595953.282291]  scsi_sysfs_add_sdev+0x8c/0x2a8
[595953.286544]  scsi_probe_and_add_lun+0x9fc/0xd00
[595953.291142]  __scsi_scan_target+0x598/0x630
[595953.295395]  scsi_scan_target+0x120/0x130
[595953.299481]  fc_user_scan+0x1a0/0x1c0 [scsi_transport_fc]
[595953.304944]  store_scan+0xb0/0x108
[595953.308420]  dev_attr_store+0x44/0x60
[595953.312160]  sysfs_kf_write+0x58/0x80
[595953.315893]  kernfs_fop_write+0xe8/0x1f0
[595953.319888]  __vfs_write+0x60/0x190
[595953.323448]  vfs_write+0xac/0x1c0
[595953.326836]  ksys_write+0x74/0xf0
[595953.330221]  __arm64_sys_write+0x24/0x30

Code is in check_ownership:

	list_for_each_entry_rcu(tmp, &h->ctlr->dh_list, node) {
		/* h->sdev should always be valid */
		BUG_ON(!tmp->sdev);
		tmp->sdev->access_state = access_state;
	}

	rdac_bus_attach
		initialize_controller
			list_add_rcu(&h->node, &h->ctlr->dh_list);
			h->sdev = sdev;

	rdac_bus_detach
		list_del_rcu(&h->node);
		h->sdev = NULL;

Fix the race between rdac_bus_attach() and rdac_bus_detach() where h->sdev
is NULL when processing the RDAC attach.

Link: https://lore.kernel.org/r/20210113063103.2698953-1-yebin10@huawei.com
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Ye Bin <yebin10@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/scsi/device_handler/scsi_dh_rdac.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c
index 6c629ef1bc4e..b3c23edd4b6c 100644
--- a/drivers/scsi/device_handler/scsi_dh_rdac.c
+++ b/drivers/scsi/device_handler/scsi_dh_rdac.c
@@ -453,8 +453,8 @@ static int initialize_controller(struct scsi_device *sdev,
 		if (!h->ctlr)
 			err = SCSI_DH_RES_TEMP_UNAVAIL;
 		else {
-			list_add_rcu(&h->node, &h->ctlr->dh_list);
 			h->sdev = sdev;
+			list_add_rcu(&h->node, &h->ctlr->dh_list);
 		}
 		spin_unlock(&list_lock);
 		err = SCSI_DH_OK;
@@ -779,11 +779,11 @@ static void rdac_bus_detach( struct scsi_device *sdev )
 	spin_lock(&list_lock);
 	if (h->ctlr) {
 		list_del_rcu(&h->node);
-		h->sdev = NULL;
 		kref_put(&h->ctlr->kref, release_controller);
 	}
 	spin_unlock(&list_lock);
 	sdev->handler_data = NULL;
+	synchronize_rcu();
 	kfree(h);
 }
 
-- 
2.30.2


  parent reply	other threads:[~2021-08-10 14:21 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-10 14:16 [PATCH AUTOSEL 4.19 01/11] dmaengine: xilinx_dma: Fix read-after-free bug when terminating transfers Sasha Levin
2021-08-10 14:16 ` [PATCH AUTOSEL 4.19 02/11] dmaengine: usb-dmac: Fix PM reference leak in usb_dmac_probe() Sasha Levin
2021-08-10 14:16 ` [PATCH AUTOSEL 4.19 03/11] ARM: dts: am43x-epos-evm: Reduce i2c0 bus speed for tps65218 Sasha Levin
2021-08-10 14:16 ` [PATCH AUTOSEL 4.19 04/11] dmaengine: of-dma: router_xlate to return -EPROBE_DEFER if controller is not yet available Sasha Levin
2021-08-10 14:16 ` [PATCH AUTOSEL 4.19 05/11] scsi: megaraid_mm: Fix end of loop tests for list_for_each_entry() Sasha Levin
2021-08-10 14:16 ` Sasha Levin [this message]
2021-08-10 14:16 ` [PATCH AUTOSEL 4.19 07/11] scsi: core: Avoid printing an error if target_alloc() returns -ENXIO Sasha Levin
2021-08-10 14:16 ` [PATCH AUTOSEL 4.19 08/11] ARM: dts: nomadik: Fix up interrupt controller node names Sasha Levin
2021-08-10 14:16 ` [PATCH AUTOSEL 4.19 10/11] Revert "ACPICA: Fix memory leak caused by _CID repair function" Sasha Levin
2021-08-10 14:16 ` [PATCH AUTOSEL 4.19 11/11] net: usb: lan78xx: don't modify phy_device state concurrently Sasha Levin

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