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| author | Alex Richardson <arichardson@FreeBSD.org> | 2021-02-18 10:25:10 +0000 |
|---|---|---|
| committer | Alex Richardson <arichardson@FreeBSD.org> | 2021-02-18 14:02:48 +0000 |
| commit | fa2528ac643519072c498b483d0dcc1fa5d99bc1 (patch) | |
| tree | 255d2d54811e94f63b72fe40c4a88b4f11978e9f /sys/kern/kern_synch.c | |
| parent | df093aa9463b2121d8307fb91c4ba7cf17f4ea64 (diff) | |
| download | src-fa2528ac643519072c498b483d0dcc1fa5d99bc1.tar.gz src-fa2528ac643519072c498b483d0dcc1fa5d99bc1.zip | |
Use atomic loads/stores when updating td->td_state
KCSAN complains about racy accesses in the locking code. Those races are
fine since they are inside a TD_SET_RUNNING() loop that expects the value
to be changed by another CPU.
Use relaxed atomic stores/loads to indicate that this variable can be
written/read by multiple CPUs at the same time. This will also prevent
the compiler from doing unexpected re-ordering.
Reported by: GENERIC-KCSAN
Test Plan: KCSAN no longer complains, kernel still runs fine.
Reviewed By: markj, mjg (earlier version)
Differential Revision: https://reviews.freebsd.org/D28569
Diffstat (limited to 'sys/kern/kern_synch.c')
| -rw-r--r-- | sys/kern/kern_synch.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/sys/kern/kern_synch.c b/sys/kern/kern_synch.c index 4c0491ab6e85..dcca67326264 100644 --- a/sys/kern/kern_synch.c +++ b/sys/kern/kern_synch.c @@ -570,7 +570,7 @@ setrunnable(struct thread *td, int srqflags) ("setrunnable: pid %d is a zombie", td->td_proc->p_pid)); swapin = 0; - switch (td->td_state) { + switch (TD_GET_STATE(td)) { case TDS_RUNNING: case TDS_RUNQ: break; @@ -593,7 +593,7 @@ setrunnable(struct thread *td, int srqflags) } break; default: - panic("setrunnable: state 0x%x", td->td_state); + panic("setrunnable: state 0x%x", TD_GET_STATE(td)); } if ((srqflags & (SRQ_HOLD | SRQ_HOLDTD)) == 0) thread_unlock(td); |