On Wed, 2020-03-11 at 06:36 -0400, Sreekanth Reddy wrote:
Generic protection fault type kernel panic is observed when user performs soft(ordered) HBA unplug operation while IOs are running on drives connected to HBA.
When user performs ordered HBA removal operation then kernel calls PCI device's .remove() call back function where driver is flushing out all the outstanding SCSI IO commands with DID_NO_CONNECT host byte and also un-maps sg buffers allocated for these IO commands. But in the ordered HBA removal case (unlike of real HBA hot unplug) HBA device is still alive and hence HBA hardware is performing the DMA operations to those buffers on the system memory which are already unmapped while flushing out the outstanding SCSI IO commands and this leads to Kernel panic.
Fix: Don't flush out the outstanding IOs from .remove() path in case of ordered HBA removal since HBA will be still alive in this case and it can complete the outstanding IOs. Flush out the outstanding IOs only in case physical HBA hot unplug where their won't be any communication with the HBA.
Can you please point to the commit that introduces the bug?
Cc: stable@vger.kernel.org Signed-off-by: Sreekanth Reddy sreekanth.reddy@broadcom.com
drivers/scsi/mpt3sas/mpt3sas_scsih.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/scsi/mpt3sas/mpt3sas_scsih.c b/drivers/scsi/mpt3sas/mpt3sas_scsih.c index 778d5e6..04a40af 100644 --- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c +++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c @@ -9908,8 +9908,8 @@ static void scsih_remove(struct pci_dev *pdev) ioc->remove_host = 1;
- mpt3sas_wait_for_commands_to_complete(ioc);
- _scsih_flush_running_cmds(ioc);
- if (!pci_device_is_present(pdev))
_scsih_flush_running_cmds(ioc);_scsih_fw_event_cleanup_queue(ioc); @@ -9992,8 +9992,8 @@ static void scsih_remove(struct pci_dev *pdev)
Just a note: this function is scsih_shutdown(). Doesn't block application of the patch, though. Just wondering how the patch was created.
ioc->remove_host = 1;
- mpt3sas_wait_for_commands_to_complete(ioc);
- _scsih_flush_running_cmds(ioc);
- if (!pci_device_is_present(pdev))
_scsih_flush_running_cmds(ioc);_scsih_fw_event_cleanup_queue(ioc);