Re: [EXT] [PATCH 09/15] qed: use new module_firmware_crashed()

On Sat, May 09, 2020 at 09:32:51AM +0300, Igor Russkikh wrote:

quoted

This makes use of the new module_firmware_crashed() to help
annotate when firmware for device drivers crash. When firmware
crashes devices can sometimes become unresponsive, and recovery
sometimes requires a driver unload / reload and in the worst cases
a reboot.

Using a taint flag allows us to annotate when this happens clearly.

Cc: Ariel Elior <redacted>
Cc: GR-everest-linux-l2@marvell.com
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 drivers/net/ethernet/qlogic/qed/qed_debug.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/qlogic/qed/qed_debug.c

b/drivers/net/ethernet/qlogic/qed/qed_debug.c
index f4eebaabb6d0..9cc6287b889b 100644

--- a/drivers/net/ethernet/qlogic/qed/qed_debug.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_debug.c

@@ -7854,6 +7854,7 @@ int qed_dbg_all_data(struct qed_dev *cdev, void

*buffer)
 						 REGDUMP_HEADER_SIZE,
 						 &feature_size);
 		if (!rc) {
+			module_firmware_crashed();
 			*(u32 *)((u8 *)buffer + offset) =
 			    qed_calc_regdump_header(cdev,
PROTECTION_OVERRIDE,
 						    cur_engine,

@@ -7869,6 +7870,7 @@ int qed_dbg_all_data(struct qed_dev *cdev, void

*buffer)
 		rc = qed_dbg_fw_asserts(cdev, (u8 *)buffer + offset +
 					REGDUMP_HEADER_SIZE,
&feature_size);
 		if (!rc) {
+			module_firmware_crashed();
 			*(u32 *)((u8 *)buffer + offset) =
 			    qed_calc_regdump_header(cdev, FW_ASSERTS,
 						    cur_engine,
feature_size,

@@ -7906,6 +7908,7 @@ int qed_dbg_all_data(struct qed_dev *cdev, void

*buffer)
 		rc = qed_dbg_grc(cdev, (u8 *)buffer + offset +
 				 REGDUMP_HEADER_SIZE, &feature_size);
 		if (!rc) {
+			module_firmware_crashed();
 			*(u32 *)((u8 *)buffer + offset) =
 			    qed_calc_regdump_header(cdev, GRC_DUMP,
 						    cur_engine,

Hi Luis,

qed_dbg_all_data is being used to gather debug dump from device. Failures
inside it may happen due to various reasons, but they normally do not indicate
FW failure.

So I think its not a good place to insert this call.
Its hard to find exact good place to insert it in qed.

Is there a way to check if what happened was indeed a fw crash?

One more thing is that AFAIU taint flag gets permanent on kernel, but for
example our device can recover itself from some FW crashes, thus it'd be
transparent for user.

Similar things are *supposed* to recoverable with other device, however
this can also sometimes lead to a situation where devices are not usable
anymore, and require a full driver unload / load.

Whats the logical purpose of module_firmware_crashed? Does it mean fatal
unrecoverable error on device?

Its just to annotate on the module and kernel that this has happened.

I take it you may agree that, firmware crashing *often* is not good design,
and these issues should be reported to / fixed by vendors. In cases
where driver bugs are reported it is good to see if a firmware crash has
happened before, so that during analysis this is ruled out.

  Luis