mirror of
https://github.com/golang/go.git
synced 2025-12-08 06:10:04 +00:00
0a5fae2a0e
In issue 50113, we see that a thread blocked in a system call can result
in a hang of AllThreadsSyscall. To resolve this, we must send a signal
to these threads to knock them out of the system call long enough to run
the per-thread syscall.
Stepping back, if we need to send signals anyway, it should be possible
to implement this entire mechanism on top of signals. This CL does so,
vastly simplifying the mechanism, both as a direct result of
newly-unnecessary code as well as some ancillary simplifications to make
things simpler to follow.
Major changes:
* The rest of the mechanism is moved to os_linux.go, with fields in mOS
instead of m itself.
* 'Fixup' fields and functions are renamed to 'perThreadSyscall' so they
are more precise about their purpose.
* Rather than getting passed a closure, doAllThreadsSyscall takes the
syscall number and arguments. This avoids a lot of hairy behavior:
* The closure may potentially only be live in fields in the M,
hidden from the GC. Not necessary with no closure.
* The need to loan out the race context. A direct RawSyscall6 call
does not require any race context.
* The closure previously conditionally panicked in strange
locations, like a signal handler. Now we simply throw.
* All manual fixup synchronization with mPark, sysmon, templateThread,
sigqueue, etc is gone. The core approach is much simpler:
doAllThreadsSyscall sends a signal to every thread in allm, which
executes the system call from the signal handler. We use (SIGRTMIN +
1), aka SIGSETXID, the same signal used by glibc for this purpose. As
such, we are careful to only handle this signal on non-cgo binaries.
Synchronization with thread creation is a key part of this CL. The
comment near the top of doAllThreadsSyscall describes the required
synchronization semantics and how they are achieved.
Note that current use of allocmLock protects the state mutations of allm
that are also protected by sched.lock. allocmLock is used instead of
sched.lock simply to avoid holding sched.lock for so long.
Fixes #50113
Change-Id: Ic7ea856dc66cf711731540a54996e08fc986ce84
Reviewed-on: https://go-review.googlesource.com/c/go/+/383434
Reviewed-by: Austin Clements <austin@google.com>
Trust: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
140 lines
3.3 KiB
Go
140 lines
3.3 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
//go:build ignore
|
|
|
|
/*
|
|
Input to cgo -cdefs
|
|
|
|
GOARCH=amd64 go tool cgo -cdefs defs_linux.go defs1_linux.go >defs_linux_amd64.h
|
|
*/
|
|
|
|
package runtime
|
|
|
|
/*
|
|
// Linux glibc and Linux kernel define different and conflicting
|
|
// definitions for struct sigaction, struct timespec, etc.
|
|
// We want the kernel ones, which are in the asm/* headers.
|
|
// But then we'd get conflicts when we include the system
|
|
// headers for things like ucontext_t, so that happens in
|
|
// a separate file, defs1.go.
|
|
|
|
#define _SYS_TYPES_H // avoid inclusion of sys/types.h
|
|
#include <asm/posix_types.h>
|
|
#define size_t __kernel_size_t
|
|
#include <asm/signal.h>
|
|
#include <asm/siginfo.h>
|
|
#include <asm/mman.h>
|
|
#include <asm-generic/errno.h>
|
|
#include <asm-generic/poll.h>
|
|
#include <linux/eventpoll.h>
|
|
#include <linux/time.h>
|
|
*/
|
|
import "C"
|
|
|
|
const (
|
|
EINTR = C.EINTR
|
|
EAGAIN = C.EAGAIN
|
|
ENOMEM = C.ENOMEM
|
|
ENOSYS = C.ENOSYS
|
|
|
|
PROT_NONE = C.PROT_NONE
|
|
PROT_READ = C.PROT_READ
|
|
PROT_WRITE = C.PROT_WRITE
|
|
PROT_EXEC = C.PROT_EXEC
|
|
|
|
MAP_ANON = C.MAP_ANONYMOUS
|
|
MAP_PRIVATE = C.MAP_PRIVATE
|
|
MAP_FIXED = C.MAP_FIXED
|
|
|
|
MADV_DONTNEED = C.MADV_DONTNEED
|
|
MADV_FREE = C.MADV_FREE
|
|
MADV_HUGEPAGE = C.MADV_HUGEPAGE
|
|
MADV_NOHUGEPAGE = C.MADV_NOHUGEPAGE
|
|
|
|
SA_RESTART = C.SA_RESTART
|
|
SA_ONSTACK = C.SA_ONSTACK
|
|
SA_SIGINFO = C.SA_SIGINFO
|
|
|
|
SI_KERNEL = C.SI_KERNEL
|
|
SI_TIMER = C.SI_TIMER
|
|
|
|
SIGHUP = C.SIGHUP
|
|
SIGINT = C.SIGINT
|
|
SIGQUIT = C.SIGQUIT
|
|
SIGILL = C.SIGILL
|
|
SIGTRAP = C.SIGTRAP
|
|
SIGABRT = C.SIGABRT
|
|
SIGBUS = C.SIGBUS
|
|
SIGFPE = C.SIGFPE
|
|
SIGKILL = C.SIGKILL
|
|
SIGUSR1 = C.SIGUSR1
|
|
SIGSEGV = C.SIGSEGV
|
|
SIGUSR2 = C.SIGUSR2
|
|
SIGPIPE = C.SIGPIPE
|
|
SIGALRM = C.SIGALRM
|
|
SIGSTKFLT = C.SIGSTKFLT
|
|
SIGCHLD = C.SIGCHLD
|
|
SIGCONT = C.SIGCONT
|
|
SIGSTOP = C.SIGSTOP
|
|
SIGTSTP = C.SIGTSTP
|
|
SIGTTIN = C.SIGTTIN
|
|
SIGTTOU = C.SIGTTOU
|
|
SIGURG = C.SIGURG
|
|
SIGXCPU = C.SIGXCPU
|
|
SIGXFSZ = C.SIGXFSZ
|
|
SIGVTALRM = C.SIGVTALRM
|
|
SIGPROF = C.SIGPROF
|
|
SIGWINCH = C.SIGWINCH
|
|
SIGIO = C.SIGIO
|
|
SIGPWR = C.SIGPWR
|
|
SIGSYS = C.SIGSYS
|
|
|
|
SIGRTMIN = C.SIGRTMIN
|
|
|
|
FPE_INTDIV = C.FPE_INTDIV
|
|
FPE_INTOVF = C.FPE_INTOVF
|
|
FPE_FLTDIV = C.FPE_FLTDIV
|
|
FPE_FLTOVF = C.FPE_FLTOVF
|
|
FPE_FLTUND = C.FPE_FLTUND
|
|
FPE_FLTRES = C.FPE_FLTRES
|
|
FPE_FLTINV = C.FPE_FLTINV
|
|
FPE_FLTSUB = C.FPE_FLTSUB
|
|
|
|
BUS_ADRALN = C.BUS_ADRALN
|
|
BUS_ADRERR = C.BUS_ADRERR
|
|
BUS_OBJERR = C.BUS_OBJERR
|
|
|
|
SEGV_MAPERR = C.SEGV_MAPERR
|
|
SEGV_ACCERR = C.SEGV_ACCERR
|
|
|
|
ITIMER_REAL = C.ITIMER_REAL
|
|
ITIMER_VIRTUAL = C.ITIMER_VIRTUAL
|
|
ITIMER_PROF = C.ITIMER_PROF
|
|
|
|
CLOCK_THREAD_CPUTIME_ID = C.CLOCK_THREAD_CPUTIME_ID
|
|
|
|
SIGEV_THREAD_ID = C.SIGEV_THREAD_ID
|
|
|
|
EPOLLIN = C.POLLIN
|
|
EPOLLOUT = C.POLLOUT
|
|
EPOLLERR = C.POLLERR
|
|
EPOLLHUP = C.POLLHUP
|
|
EPOLLRDHUP = C.POLLRDHUP
|
|
EPOLLET = C.EPOLLET
|
|
EPOLL_CLOEXEC = C.EPOLL_CLOEXEC
|
|
EPOLL_CTL_ADD = C.EPOLL_CTL_ADD
|
|
EPOLL_CTL_DEL = C.EPOLL_CTL_DEL
|
|
EPOLL_CTL_MOD = C.EPOLL_CTL_MOD
|
|
)
|
|
|
|
type Sigset C.sigset_t
|
|
type Timespec C.struct_timespec
|
|
type Timeval C.struct_timeval
|
|
type Sigaction C.struct_sigaction
|
|
type Siginfo C.siginfo_t
|
|
type Itimerspec C.struct_itimerspec
|
|
type Itimerval C.struct_itimerval
|
|
type Sigevent C.struct_sigevent
|
|
type EpollEvent C.struct_epoll_event
|