Don't enable interrupts in init_secondary().
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Authored by markj on Jan 3 2019, 9:37 PM.

Details

Reviewers

jhb
br
mhorne063_gmail.com

Commits

rS342766: Don't enable interrupts in init_secondary().

Summary

sched_throw() expects the caller to hold a spinlock section; see the
td_md initialization in cpu_fork(). This bug can cause a deadlock when
APs are started: statclock() fires before the thread lock acquired in
sched_throw() is released, and recurses on the thread lock.

Diff Detail

Repository

rS FreeBSD src repository - subversion

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Event Timeline

markj created this revision.Jan 3 2019, 9:37 PM

Harbormaster completed remote builds in B21823: Diff 52531.Jan 3 2019, 9:37 PM

markj added reviewers: jhb, br, mhorne063_gmail.com.Jan 3 2019, 9:48 PM

jhb accepted this revision.Jan 3 2019, 10:38 PM

jhb added inline comments.

sys/riscv/riscv/mp_machdep.c
231 ↗	(On Diff #52531)	Are interrupts enabled here at all? We really depend on them not being enabled on APs until after the first context switch.

This revision is now accepted and ready to land.Jan 3 2019, 10:38 PM

markj marked an inline comment as done.Jan 3 2019, 10:52 PM

markj added inline comments.

sys/riscv/riscv/mp_machdep.c
231 ↗	(On Diff #52531)	Hmm, it was added here: https://svnweb.freebsd.org/changeset/base/335005 We boot in QEMU without the intr_disable(), though. I added code to read and print sstatus here, and SIE is disabled. So it seems safe to remove the intr_disable().