Re: kern/57870 (umount hang (ld/sdmmc/rtsx))

[riastradh%NetBSD.org@localhost]

Synopsis: umount hang (ld/sdmmc/rtsx)

Responsible-Changed-From-To: kern-bug-people->riastradh
Responsible-Changed-By: riastradh%NetBSD.org@localhost
Responsible-Changed-When: Mon, 22 Jan 2024 01:28:46 +0000
Responsible-Changed-Why:
I'll take care of it


State-Changed-From-To: open->analyzed
State-Changed-By: riastradh%NetBSD.org@localhost
State-Changed-When: Mon, 22 Jan 2024 01:28:46 +0000
State-Changed-Why:
deadlock in sdmmc task queue
happens because DIOCCACHESYNC starts task and waits for it,
and detach triggers DIOCCACHESYNC,
and discovery triggering detach runs through task queue,
so finishing discovery task requires waiting for cache sync task,
but cache sync task can't start until prior tasks finish.
Fix: separate threads for discovery and tasks.
(plus a host of other issues in attach/detach sequence)