-----Original Message----- From: Mauricio Faria de Oliveira [mailto:mauricfo@xxxxxxxxxxxxxxxxxx] Sent: Saturday, February 17, 2018 4:10 AM To: linux-scsi@xxxxxxxxxxxxxxx; Bart.VanAssche@xxxxxxx; sreekanth.reddy@xxxxxxxxxxxx Cc: sathya.prakash@xxxxxxxxxxxx; chaitra.basappa@xxxxxxxxxxxx; suganath-prabu.subramani@xxxxxxxxxxxx; jejb@xxxxxxxxxxxxxxxxxx; martin.petersen@xxxxxxxxxx; dougmill@xxxxxxxxxxxxxxxxxx Subject: [PATCH v2 1/2] scsi: mpt3sas: fix oops in error handlers after shutdown/unload 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 dbec4c90 "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 commit dbec4c90, 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> --- 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 74fca18..5ab3caf 100644 --- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c +++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c @@ -2835,7 +2835,8 @@ 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; @@ -2898,7 +2899,8 @@ 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; @@ -2961,7 +2963,8 @@ 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; @@ -3019,7 +3022,7 @@ 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 Acked-by: Sreekanth Reddy <Sreekanth.Reddy@xxxxxxxxxxxx> Thanks, Sreekanth
