[PATCH 4.14 v2 1/2] scsi: mpt3sas: fix oops in error handlers after shutdown/unload

* [PATCH 4.14 v2 1/2] scsi: mpt3sas: fix oops in error handlers after shutdown/unload
@ 2018-03-10 15:24 Mauricio Faria de Oliveira
  2018-03-10 15:24 ` [PATCH 4.14 v2 2/2] scsi: mpt3sas: wait for and flush running commands on shutdown/unload Mauricio Faria de Oliveira
  2018-03-12 14:50 ` [PATCH 4.14 v2 1/2] scsi: mpt3sas: fix oops in error handlers after shutdown/unload Greg KH
  0 siblings, 2 replies; 5+ messages in thread
From: Mauricio Faria de Oliveira @ 2018-03-10 15:24 UTC (permalink / raw)
  To: stable, martin.petersen, sreekanth.reddy; +Cc: dougmill

From: Mauricio Faria de Oliveira <mauricfo@xxxxxxxxxxxxxxxxxx>

commit 9ff549ffb4fb4cc9a4b24d1de9dc3e68287797c4 upstream.

This patch adds checks for 'ioc->remove_host' in the SCSI error handlers, so
not to access pointers/resources potentially freed in the PCI shutdown/module
unload path.  The error handlers may be invoked after shutdown/unload,
depending on other components.

This problem was observed with kexec on a system with a mpt3sas based adapter
and an infiniband adapter which takes long enough to shutdown:

The mpt3sas driver finished shutting down / disabled interrupt handling, thus
some commands have not finished and timed out.

Since the system was still running (waiting for the infiniband adapter to
shutdown), the scsi error handler for task abort of mpt3sas was invoked, and
hit an oops -- either in scsih_abort() because 'ioc->scsi_lookup' was NULL
without commit dbec4c9040ed ("scsi: mpt3sas: lockless command submission"), or
later up in scsih_host_reset() (with or without that commit), because it
eventually called mpt3sas_base_get_iocstate().

After the above commit, the oops in scsih_abort() does not occur anymore
(_scsih_scsi_lookup_find_by_scmd() is no longer called), but that commit is
too big and out of the scope of linux-stable, where this patch might help, so
still go for the changes.

Also, this might help to prevent similar errors in the future, in case code
changes and possibly tries to access freed stuff.

Note the fix in scsih_host_reset() is still important anyway.

Signed-off-by: Mauricio Faria de Oliveira <mauricfo@xxxxxxxxxxxxxxxxxx>
Acked-by: Sreekanth Reddy <Sreekanth.Reddy@xxxxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
---
v2: update first hunk's line number to apply on 4.14.25

 drivers/scsi/mpt3sas/mpt3sas_scsih.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/mpt3sas/mpt3sas_scsih.c b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
index 33ff691..61a780f 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
@@ -2471,7 +2471,8 @@ int mpt3sas_scsih_issue_locked_tm(struct MPT3SAS_ADAPTER *ioc, u16 handle,
 	_scsih_tm_display_info(ioc, scmd);
 
 	sas_device_priv_data = scmd->device->hostdata;
-	if (!sas_device_priv_data || !sas_device_priv_data->sas_target) {
+	if (!sas_device_priv_data || !sas_device_priv_data->sas_target ||
+	    ioc->remove_host) {
 		sdev_printk(KERN_INFO, scmd->device,
 			"device been deleted! scmd(%p)\n", scmd);
 		scmd->result = DID_NO_CONNECT << 16;
@@ -2533,7 +2534,8 @@ int mpt3sas_scsih_issue_locked_tm(struct MPT3SAS_ADAPTER *ioc, u16 handle,
 	_scsih_tm_display_info(ioc, scmd);
 
 	sas_device_priv_data = scmd->device->hostdata;
-	if (!sas_device_priv_data || !sas_device_priv_data->sas_target) {
+	if (!sas_device_priv_data || !sas_device_priv_data->sas_target ||
+	    ioc->remove_host) {
 		sdev_printk(KERN_INFO, scmd->device,
 			"device been deleted! scmd(%p)\n", scmd);
 		scmd->result = DID_NO_CONNECT << 16;
@@ -2595,7 +2597,8 @@ int mpt3sas_scsih_issue_locked_tm(struct MPT3SAS_ADAPTER *ioc, u16 handle,
 	_scsih_tm_display_info(ioc, scmd);
 
 	sas_device_priv_data = scmd->device->hostdata;
-	if (!sas_device_priv_data || !sas_device_priv_data->sas_target) {
+	if (!sas_device_priv_data || !sas_device_priv_data->sas_target ||
+	    ioc->remove_host) {
 		starget_printk(KERN_INFO, starget, "target been deleted! scmd(%p)\n",
 			scmd);
 		scmd->result = DID_NO_CONNECT << 16;
@@ -2652,7 +2655,7 @@ int mpt3sas_scsih_issue_locked_tm(struct MPT3SAS_ADAPTER *ioc, u16 handle,
 	    ioc->name, scmd);
 	scsi_print_command(scmd);
 
-	if (ioc->is_driver_loading) {
+	if (ioc->is_driver_loading || ioc->remove_host) {
 		pr_info(MPT3SAS_FMT "Blocking the host reset\n",
 		    ioc->name);
 		r = FAILED;
-- 
1.8.3.1

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