diff options
| author | cinap_lenrek <cinap_lenrek@felloff.net> | 2019-03-30 09:17:46 +0100 |
|---|---|---|
| committer | cinap_lenrek <cinap_lenrek@felloff.net> | 2019-03-30 09:17:46 +0100 |
| commit | 4f0bfe0fb8dc608a94fe429c5ddb12e58997e1ce (patch) | |
| tree | fc81407d959370278dfdb53da69c5ab8b3fef55c /sys/src/libdtracy | |
| parent | ac3147a9c58f339f9b978ab087464912c16bc8f8 (diff) | |
dtracy: avoid dmachlock() race
between being commited to a machno and having acquired the lock, the
scheduler could come in an schedule us on a different processor. the
solution is to have dtmachlock() take a special -1 argument to mean
"current mach" and return the actual mach number after the lock has
been acquired and interrupts being disabled.
Diffstat (limited to 'sys/src/libdtracy')
| -rw-r--r-- | sys/src/libdtracy/prog.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/sys/src/libdtracy/prog.c b/sys/src/libdtracy/prog.c index 402638f13..831a94b5e 100644 --- a/sys/src/libdtracy/prog.c +++ b/sys/src/libdtracy/prog.c @@ -336,13 +336,12 @@ dtgexec(DTActGr *g, DTTrigInfo *info) } void -dtptrigger(DTProbe *p, int machno, DTTrigInfo *info) +dtptrigger(DTProbe *p, DTTrigInfo *info) { DTEnab *e; info->ts = dttime(); - dtmachlock(machno); - info->machno = machno; + info->machno = dtmachlock(-1); for(e = p->enablist.probnext; e != &p->enablist; e = e->probnext) if(e->gr->chan->state == DTCGO){ info->ch = e->gr->chan; @@ -350,5 +349,5 @@ dtptrigger(DTProbe *p, int machno, DTTrigInfo *info) if(dtgexec(e->gr, info) < 0) e->gr->chan->state = DTCFAULT; } - dtmachunlock(machno); + dtmachunlock(info->machno); } |