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brettcreeleydavem330
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pds_core: Fix pdsc_check_pci_health function to use work thread
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: d9407ff ("pds_core: Prevent health thread from running during reset/remove") Reviewed-by: Shannon Nelson <[email protected]> Signed-off-by: Brett Creeley <[email protected]> Reviewed-by: Jacob Keller <[email protected]> Signed-off-by: David S. Miller <[email protected]>
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drivers/net/ethernet/amd/pds_core/core.c

Lines changed: 12 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -593,6 +593,16 @@ void pdsc_fw_up(struct pdsc *pdsc)
593593
pdsc_teardown(pdsc, PDSC_TEARDOWN_RECOVERY);
594594
}
595595

596+
void pdsc_pci_reset_thread(struct work_struct *work)
597+
{
598+
struct pdsc *pdsc = container_of(work, struct pdsc, pci_reset_work);
599+
struct pci_dev *pdev = pdsc->pdev;
600+
601+
pci_dev_get(pdev);
602+
pci_reset_function(pdev);
603+
pci_dev_put(pdev);
604+
}
605+
596606
static void pdsc_check_pci_health(struct pdsc *pdsc)
597607
{
598608
u8 fw_status;
@@ -607,7 +617,8 @@ static void pdsc_check_pci_health(struct pdsc *pdsc)
607617
if (fw_status != PDS_RC_BAD_PCI)
608618
return;
609619

610-
pci_reset_function(pdsc->pdev);
620+
/* prevent deadlock between pdsc_reset_prepare and pdsc_health_thread */
621+
queue_work(pdsc->wq, &pdsc->pci_reset_work);
611622
}
612623

613624
void pdsc_health_thread(struct work_struct *work)

drivers/net/ethernet/amd/pds_core/core.h

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -197,6 +197,7 @@ struct pdsc {
197197
struct pdsc_qcq notifyqcq;
198198
u64 last_eid;
199199
struct pdsc_viftype *viftype_status;
200+
struct work_struct pci_reset_work;
200201
};
201202

202203
/** enum pds_core_dbell_bits - bitwise composition of dbell values.
@@ -313,5 +314,6 @@ int pdsc_firmware_update(struct pdsc *pdsc, const struct firmware *fw,
313314

314315
void pdsc_fw_down(struct pdsc *pdsc);
315316
void pdsc_fw_up(struct pdsc *pdsc);
317+
void pdsc_pci_reset_thread(struct work_struct *work);
316318

317319
#endif /* _PDSC_H_ */

drivers/net/ethernet/amd/pds_core/dev.c

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -229,6 +229,9 @@ int pdsc_devcmd_reset(struct pdsc *pdsc)
229229
.reset.opcode = PDS_CORE_CMD_RESET,
230230
};
231231

232+
if (!pdsc_is_fw_running(pdsc))
233+
return 0;
234+
232235
return pdsc_devcmd(pdsc, &cmd, &comp, pdsc->devcmd_timeout);
233236
}
234237

drivers/net/ethernet/amd/pds_core/main.c

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -239,6 +239,7 @@ static int pdsc_init_pf(struct pdsc *pdsc)
239239
snprintf(wq_name, sizeof(wq_name), "%s.%d", PDS_CORE_DRV_NAME, pdsc->uid);
240240
pdsc->wq = create_singlethread_workqueue(wq_name);
241241
INIT_WORK(&pdsc->health_work, pdsc_health_thread);
242+
INIT_WORK(&pdsc->pci_reset_work, pdsc_pci_reset_thread);
242243
timer_setup(&pdsc->wdtimer, pdsc_wdtimer_cb, 0);
243244
pdsc->wdtimer_period = PDSC_WATCHDOG_SECS * HZ;
244245

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