When the driver notices fw_status == 0xff it tries to perform a PCI
reset on itself via pci_reset_function() in the context of the driver's
health thread. However, pdsc_reset_prepare calls
pdsc_stop_health_thread(), which attempts to stop/flush the health
thread. This results in a deadlock because the stop/flush will never
complete since the driver called pci_reset_function() from the health
thread context. Fix by changing the pdsc_check_pci_health_function()
to queue a newly introduced pdsc_pci_reset_thread() on the pdsc's
work queue.
Unloading the driver in the fw_down/dead state uncovered another issue,
which can be seen in the following trace:
WARNING: CPU: 51 PID: 6914 at kernel/workqueue.c:1450 __queue_work+0x358/0x440
[...]
RIP: 0010:__queue_work+0x358/0x440
[...]
Call Trace:
<TASK>
? __warn+0x85/0x140
? __queue_work+0x358/0x440
? report_bug+0xfc/0x1e0
? handle_bug+0x3f/0x70
? exc_invalid_op+0x17/0x70
? asm_exc_invalid_op+0x1a/0x20
? __queue_work+0x358/0x440
queue_work_on+0x28/0x30
pdsc_devcmd_locked+0x96/0xe0 [pds_core]
pdsc_devcmd_reset+0x71/0xb0 [pds_core]
pdsc_teardown+0x51/0xe0 [pds_core]
pdsc_remove+0x106/0x200 [pds_core]
pci_device_remove+0x37/0xc0
device_release_driver_internal+0xae/0x140
driver_detach+0x48/0x90
bus_remove_driver+0x6d/0xf0
pci_unregister_driver+0x2e/0xa0
pdsc_cleanup_module+0x10/0x780 [pds_core]
__x64_sys_delete_module+0x142/0x2b0
? syscall_trace_enter.isra.18+0x126/0x1a0
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x72/0xdc
RIP: 0033:0x7fbd9d03a14b
[...]
Fix this by preventing the devcmd reset if the FW is not running.
Fixes: d9407ff118 ("pds_core: Prevent health thread from running during reset/remove")
Reviewed-by: Shannon Nelson <shannon.nelson@amd.com>
Signed-off-by: Brett Creeley <brett.creeley@amd.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
81665adf25