Unloading/reloading an atheroswifi device ends in vm_page_fault KDL

[v.vill]

Due to some problems with the updated wifi stack (see #14282 and #14349), sometimes wpa_supplicant or net_server crashes and then the network list becomes empty. Reopening the Network preferences window, selecting the wifi adapter and clicking on "Disable" then "Enable", sometimes makes the card available again. But nearly one time out of two or three attemps, it triggers a vm_page_fault KDL instead (see attached).

I'm running hrev 52205 x86_64 with an AR9565 wifi chip.

[v.vill]

KDL photo

[miqlas]

Empty network list is not new, happend frequently with the old wlan drivers too. I think it is the wlan-supplicant. But it never KDL'd for me.

[waddlesplash]

Please try again after hrev52288 (and your other WiFi-related tickets also.)

If it still occurs, please run threads 1 at the KDL prompt and include the output of that here.

[v.vill]

KDL threads

[v.vill]

No problem; see attached KDL screenshot. Reproduced with hrev52291.

[v.vill]

Darn. It appears this problem is now even more easily triggered than I thought. I opened a new ticket just in case (sorry for the noise if it wasn’t relevant); see #14411.

[waddlesplash]

OK, so, ​ath_reset_grablock just calls "pause", which is defined as a macro ​here. ​_pause then calls ​tsleep, also a macro, which calls msleep but with a NULL mutex. ​msleep apparently tries to unconditionally lock or unlock the mutex, which seems pretty strange. I need to look at what FreeBSD does here.

[waddlesplash]

This (and #14411) should be fixed with hrev52297. Please test.

[v.vill]

OK, we seem to be getting somewhere. I couldn't trigger the KDL anymore, no matter how hard I tried! This appears to be fixed (unfortunately it still leaves me with #14349, see my update there). Let me now if there's any additional steps I can take to verify further.

Kudos!

[waddlesplash]

Nice!