diff options
Diffstat (limited to 'src/runtime')
| -rw-r--r-- | src/runtime/netpoll.go | 47 | ||||
| -rw-r--r-- | src/runtime/proc.go | 21 | ||||
| -rw-r--r-- | src/runtime/signal_unix.go | 22 |
3 files changed, 76 insertions, 14 deletions
diff --git a/src/runtime/netpoll.go b/src/runtime/netpoll.go index 34ea82a7fa..77eb3aa4c6 100644 --- a/src/runtime/netpoll.go +++ b/src/runtime/netpoll.go @@ -79,16 +79,17 @@ type pollDesc struct { lock mutex // protects the following fields fd uintptr closing bool - everr bool // marks event scanning error happened - user uint32 // user settable cookie - rseq uintptr // protects from stale read timers - rg uintptr // pdReady, pdWait, G waiting for read or nil - rt timer // read deadline timer (set if rt.f != nil) - rd int64 // read deadline - wseq uintptr // protects from stale write timers - wg uintptr // pdReady, pdWait, G waiting for write or nil - wt timer // write deadline timer - wd int64 // write deadline + everr bool // marks event scanning error happened + user uint32 // user settable cookie + rseq uintptr // protects from stale read timers + rg uintptr // pdReady, pdWait, G waiting for read or nil + rt timer // read deadline timer (set if rt.f != nil) + rd int64 // read deadline + wseq uintptr // protects from stale write timers + wg uintptr // pdReady, pdWait, G waiting for write or nil + wt timer // write deadline timer + wd int64 // write deadline + self *pollDesc // storage for indirect interface. See (*pollDesc).makeArg. } type pollCache struct { @@ -157,6 +158,7 @@ func poll_runtime_pollOpen(fd uintptr) (*pollDesc, int) { pd.wseq++ pd.wg = 0 pd.wd = 0 + pd.self = pd unlock(&pd.lock) var errno int32 @@ -271,14 +273,14 @@ func poll_runtime_pollSetDeadline(pd *pollDesc, d int64, mode int) { // Copy current seq into the timer arg. // Timer func will check the seq against current descriptor seq, // if they differ the descriptor was reused or timers were reset. - pd.rt.arg = pd + pd.rt.arg = pd.makeArg() pd.rt.seq = pd.rseq resettimer(&pd.rt, pd.rd) } } else if pd.rd != rd0 || combo != combo0 { pd.rseq++ // invalidate current timers if pd.rd > 0 { - modtimer(&pd.rt, pd.rd, 0, rtf, pd, pd.rseq) + modtimer(&pd.rt, pd.rd, 0, rtf, pd.makeArg(), pd.rseq) } else { deltimer(&pd.rt) pd.rt.f = nil @@ -287,14 +289,14 @@ func poll_runtime_pollSetDeadline(pd *pollDesc, d int64, mode int) { if pd.wt.f == nil { if pd.wd > 0 && !combo { pd.wt.f = netpollWriteDeadline - pd.wt.arg = pd + pd.wt.arg = pd.makeArg() pd.wt.seq = pd.wseq resettimer(&pd.wt, pd.wd) } } else if pd.wd != wd0 || combo != combo0 { pd.wseq++ // invalidate current timers if pd.wd > 0 && !combo { - modtimer(&pd.wt, pd.wd, 0, netpollWriteDeadline, pd, pd.wseq) + modtimer(&pd.wt, pd.wd, 0, netpollWriteDeadline, pd.makeArg(), pd.wseq) } else { deltimer(&pd.wt) pd.wt.f = nil @@ -547,3 +549,20 @@ func (c *pollCache) alloc() *pollDesc { unlock(&c.lock) return pd } + +// makeArg converts pd to an interface{}. +// makeArg does not do any allocation. Normally, such +// a conversion requires an allocation because pointers to +// go:notinheap types (which pollDesc is) must be stored +// in interfaces indirectly. See issue 42076. +func (pd *pollDesc) makeArg() (i interface{}) { + x := (*eface)(unsafe.Pointer(&i)) + x._type = pdType + x.data = unsafe.Pointer(&pd.self) + return +} + +var ( + pdEface interface{} = (*pollDesc)(nil) + pdType *_type = efaceOf(&pdEface)._type +) diff --git a/src/runtime/proc.go b/src/runtime/proc.go index 035822216d..2f1272d310 100644 --- a/src/runtime/proc.go +++ b/src/runtime/proc.go @@ -1281,6 +1281,14 @@ found: checkdead() unlock(&sched.lock) + if GOOS == "darwin" { + // Make sure pendingPreemptSignals is correct when an M exits. + // For #41702. + if atomic.Load(&m.signalPending) != 0 { + atomic.Xadd(&pendingPreemptSignals, -1) + } + } + if osStack { // Return from mstart and let the system thread // library free the g0 stack and terminate the thread. @@ -3475,11 +3483,24 @@ func syscall_runtime_AfterForkInChild() { inForkedChild = false } +// pendingPreemptSignals is the number of preemption signals +// that have been sent but not received. This is only used on Darwin. +// For #41702. +var pendingPreemptSignals uint32 + // Called from syscall package before Exec. //go:linkname syscall_runtime_BeforeExec syscall.runtime_BeforeExec func syscall_runtime_BeforeExec() { // Prevent thread creation during exec. execLock.lock() + + // On Darwin, wait for all pending preemption signals to + // be received. See issue #41702. + if GOOS == "darwin" { + for int32(atomic.Load(&pendingPreemptSignals)) > 0 { + osyield() + } + } } // Called from syscall package after Exec. diff --git a/src/runtime/signal_unix.go b/src/runtime/signal_unix.go index dd6d79f8ec..80fd2d6604 100644 --- a/src/runtime/signal_unix.go +++ b/src/runtime/signal_unix.go @@ -336,6 +336,10 @@ func doSigPreempt(gp *g, ctxt *sigctxt) { // Acknowledge the preemption. atomic.Xadd(&gp.m.preemptGen, 1) atomic.Store(&gp.m.signalPending, 0) + + if GOOS == "darwin" { + atomic.Xadd(&pendingPreemptSignals, -1) + } } const preemptMSupported = true @@ -357,7 +361,18 @@ func preemptM(mp *m) { // required). return } + + // On Darwin, don't try to preempt threads during exec. + // Issue #41702. + if GOOS == "darwin" { + execLock.rlock() + } + if atomic.Cas(&mp.signalPending, 0, 1) { + if GOOS == "darwin" { + atomic.Xadd(&pendingPreemptSignals, 1) + } + // If multiple threads are preempting the same M, it may send many // signals to the same M such that it hardly make progress, causing // live-lock problem. Apparently this could happen on darwin. See @@ -365,6 +380,10 @@ func preemptM(mp *m) { // Only send a signal if there isn't already one pending. signalM(mp, sigPreempt) } + + if GOOS == "darwin" { + execLock.runlock() + } } // sigFetchG fetches the value of G safely when running in a signal handler. @@ -425,6 +444,9 @@ func sigtrampgo(sig uint32, info *siginfo, ctx unsafe.Pointer) { // no non-Go signal handler for sigPreempt. // The default behavior for sigPreempt is to ignore // the signal, so badsignal will be a no-op anyway. + if GOOS == "darwin" { + atomic.Xadd(&pendingPreemptSignals, -1) + } return } c.fixsigcode(sig) |