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| author | Tycho Nightingale <tychon@FreeBSD.org> | 2020-10-13 18:28:48 +0000 |
|---|---|---|
| committer | Tycho Nightingale <tychon@FreeBSD.org> | 2020-10-13 18:28:48 +0000 |
| commit | 42360f5c5b575b3f4098110fc8dfd2f4d11b6481 (patch) | |
| tree | d10770ec509e709c49ed220353ff1cf0a40c0042 | |
| parent | 47e2650ea4ff1d7d603b6b1c53b8cb6789532210 (diff) | |
| download | src-42360f5c5b575b3f4098110fc8dfd2f4d11b6481.tar.gz src-42360f5c5b575b3f4098110fc8dfd2f4d11b6481.zip | |
eliminate possible race in parallel TLB shootdown IPI
On the target side TLB shootdown IPI handler, prevent the compiler
from performing a forward store optimization which may mask a
subsequent update to the scoreboard by the initiator.
Reported by: Max Laier, Anton Rang
Discussed with: kib
Sponsored by: Dell EMC Isilon
Notes
Notes:
svn path=/head/; revision=366678
| -rw-r--r-- | sys/amd64/amd64/mp_machdep.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/sys/amd64/amd64/mp_machdep.c b/sys/amd64/amd64/mp_machdep.c index 308f2fc2a292..fb6a12278177 100644 --- a/sys/amd64/amd64/mp_machdep.c +++ b/sys/amd64/amd64/mp_machdep.c @@ -1094,7 +1094,7 @@ invlop_handler(void) for (;;) { for (initiator_cpu_id = 0; initiator_cpu_id <= mp_maxid; initiator_cpu_id++) { - if (scoreboard[initiator_cpu_id] == 0) + if (atomic_load_int(&scoreboard[initiator_cpu_id]) == 0) break; } if (initiator_cpu_id > mp_maxid) |