[PATCH 4.14 072/125] scsi: mptfusion: Fix null pointer dereferences in mptscsih_remove()

Greg Kroah-Hartman
2020-11-03T21:16:26Z

From: Helge Deller <deller@gmx.de>

commit 2f4843b172c2c0360ee7792ad98025fae7baefde upstream.

The mptscsih_remove() function triggers a kernel oops if the Scsi_Host
pointer (ioc->sh) is NULL, as can be seen in this syslog:

ioc0: LSI53C1030 B2: Capabilities={Initiator,Target}
Begin: Waiting for root file system ...
scsi host2: error handler thread failed to spawn, error = -4
mptspi: ioc0: WARNING - Unable to register controller with SCSI subsystem
Backtrace:
[<000000001045b7cc>] mptspi_probe+0x248/0x3d0 [mptspi]
[<0000000040946470>] pci_device_probe+0x1ac/0x2d8
[<0000000040add668>] really_probe+0x1bc/0x988
[<0000000040ade704>] driver_probe_device+0x160/0x218
[<0000000040adee24>] device_driver_attach+0x160/0x188
[<0000000040adef90>] __driver_attach+0x144/0x320
[<0000000040ad7c78>] bus_for_each_dev+0xd4/0x158
[<0000000040adc138>] driver_attach+0x4c/0x80
[<0000000040adb3ec>] bus_add_driver+0x3e0/0x498
[<0000000040ae0130>] driver_register+0xf4/0x298
[<00000000409450c4>] __pci_register_driver+0x78/0xa8
[<000000000007d248>] mptspi_init+0x18c/0x1c4 [mptspi]

This patch adds the necessary NULL-pointer checks. Successfully tested on
a HP C8000 parisc workstation with buggy SCSI drives.

Link: https://lore.kernel.org/r/20201022090005.GA9000@ls3530.fritz.box
Cc: <stable@vger.kernel.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/message/fusion/mptscsih.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

--- a/drivers/message/fusion/mptscsih.c
+++ b/drivers/message/fusion/mptscsih.c
@@ -1174,8 +1174,10 @@ mptscsih_remove(struct pci_dev *pdev)
MPT_SCSI_HOST *hd;
int sz1;

- if((hd = shost_priv(host)) == NULL)
- return;
+ if (host == NULL)
+ hd = NULL;
+ else
+ hd = shost_priv(host);

mptscsih_shutdown(pdev);

@@ -1191,14 +1193,15 @@ mptscsih_remove(struct pci_dev *pdev)
"Free'd ScsiLookup (%d) memory\n",
ioc->name, sz1));

- kfree(hd->info_kbuf);
+ if (hd)
+ kfree(hd->info_kbuf);

/* NULL the Scsi_Host pointer
*/
ioc->sh = NULL;

- scsi_host_put(host);
-
+ if (host)
+ scsi_host_put(host);
mpt_detach(pdev);

}