tree 778e82fdab4c9c430f76034d6214707e92b76ade
parent dfbc17de626ae31220e273b1131735a88b80e48f
author Nick Maniscalco <maniscalco@google.com> 1627336144 +0000
committer CQ Bot <commit-bot@chromium.org> 1627336144 +0000

[kernel] Don't panic when racing during secondary CPU shutdown

platform_halt_secondary_cpus's job is to shutdown any and all online
secondary CPUs.  It does this by querying the set of online CPUs,
applying a mask to mask off the primary (CPU-0) and then calling
mp_unplug_cpu_mask.

platform_halt_secondary_cpus could be called concurrently by multiple
threads.  If that happens, it's possible for the calls to race and
result in the "loser" calling mp_unplug_cpu_mask with a mask
containing CPUs that are already offline, which would result in
ZX_ERR_BAD_STATE.

This CL changes platform_halt_secondary_cpus to ignore a
ZX_ERR_BAD_STATE from mp_unplug_cpu_mask if it finds that the
secondary CPUs have already been offlined.

Tested by running several instances of dm_reboot_bootloader_test in a
loop for several hours.

Fixed: 81355
Change-Id: I599fc650e5541a5ac2c529acce46f0b2a5343f2e
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/559962
Reviewed-by: Rasha Eqbal <rashaeqbal@google.com>
Commit-Queue: Nick Maniscalco <maniscalco@google.com>