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mirror of https://github.com/golang/go synced 2024-07-08 12:18:55 +00:00

runtime: keep //go:cgo_unsafe_args arguments alive to prevent GC

When syscall's DLL.FindProc calls into syscall_getprocaddress with a
byte slice pointer, we need to keep those bytes alive. Otherwise the GC
will collect the allocation, and we wind up calling `GetProcAddress` on
garbage, which showed up as various flakes in the builders. It turns out
that this problem extends to many uses of //go:cgo_unsafe_args
throughout, on all platforms. So this patch fixes the issue by keeping
non-integer pointer arguments alive through their invocation in
//go:cgo_unsafe_args functions.

Fixes #49731.

Change-Id: I93e4fbc2e8e210cb3fc53149708758bb33f2f9c7
Reviewed-on: https://go-review.googlesource.com/c/go/+/367654
Trust: Jason A. Donenfeld <Jason@zx2c4.com>
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Patrik Nyblom <pnyb@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
This commit is contained in:
Jason A. Donenfeld 2021-11-29 15:07:04 -05:00
parent f90a42b410
commit f463b20789
7 changed files with 138 additions and 29 deletions

View File

@ -105,28 +105,38 @@ func syscallNoErr()
//go:nosplit
//go:cgo_unsafe_args
func pthread_attr_init(attr *pthreadattr) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_attr_init_trampoline)), unsafe.Pointer(&attr))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_attr_init_trampoline)), unsafe.Pointer(&attr))
KeepAlive(attr)
return ret
}
func pthread_attr_init_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func pthread_attr_getstacksize(attr *pthreadattr, size *uintptr) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_attr_getstacksize_trampoline)), unsafe.Pointer(&attr))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_attr_getstacksize_trampoline)), unsafe.Pointer(&attr))
KeepAlive(attr)
KeepAlive(size)
return ret
}
func pthread_attr_getstacksize_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func pthread_attr_setdetachstate(attr *pthreadattr, state int) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_attr_setdetachstate_trampoline)), unsafe.Pointer(&attr))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_attr_setdetachstate_trampoline)), unsafe.Pointer(&attr))
KeepAlive(attr)
return ret
}
func pthread_attr_setdetachstate_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func pthread_create(attr *pthreadattr, start uintptr, arg unsafe.Pointer) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_create_trampoline)), unsafe.Pointer(&attr))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_create_trampoline)), unsafe.Pointer(&attr))
KeepAlive(attr)
KeepAlive(arg) // Just for consistency. Arg of course needs to be kept alive for the start function.
return ret
}
func pthread_create_trampoline()
@ -175,6 +185,7 @@ func mmap_trampoline()
//go:cgo_unsafe_args
func munmap(addr unsafe.Pointer, n uintptr) {
libcCall(unsafe.Pointer(abi.FuncPCABI0(munmap_trampoline)), unsafe.Pointer(&addr))
KeepAlive(addr) // Just for consistency. Hopefully addr is not a Go address.
}
func munmap_trampoline()
@ -182,6 +193,7 @@ func munmap_trampoline()
//go:cgo_unsafe_args
func madvise(addr unsafe.Pointer, n uintptr, flags int32) {
libcCall(unsafe.Pointer(abi.FuncPCABI0(madvise_trampoline)), unsafe.Pointer(&addr))
KeepAlive(addr) // Just for consistency. Hopefully addr is not a Go address.
}
func madvise_trampoline()
@ -189,13 +201,16 @@ func madvise_trampoline()
//go:cgo_unsafe_args
func mlock(addr unsafe.Pointer, n uintptr) {
libcCall(unsafe.Pointer(abi.FuncPCABI0(mlock_trampoline)), unsafe.Pointer(&addr))
KeepAlive(addr) // Just for consistency. Hopefully addr is not a Go address.
}
func mlock_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func read(fd int32, p unsafe.Pointer, n int32) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(read_trampoline)), unsafe.Pointer(&fd))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(read_trampoline)), unsafe.Pointer(&fd))
KeepAlive(p)
return ret
}
func read_trampoline()
@ -239,14 +254,18 @@ func usleep_no_g(usec uint32) {
//go:nosplit
//go:cgo_unsafe_args
func write1(fd uintptr, p unsafe.Pointer, n int32) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(write_trampoline)), unsafe.Pointer(&fd))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(write_trampoline)), unsafe.Pointer(&fd))
KeepAlive(p)
return ret
}
func write_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func open(name *byte, mode, perm int32) (ret int32) {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(open_trampoline)), unsafe.Pointer(&name))
ret = libcCall(unsafe.Pointer(abi.FuncPCABI0(open_trampoline)), unsafe.Pointer(&name))
KeepAlive(name)
return
}
func open_trampoline()
@ -285,6 +304,8 @@ func walltime_trampoline()
//go:cgo_unsafe_args
func sigaction(sig uint32, new *usigactiont, old *usigactiont) {
libcCall(unsafe.Pointer(abi.FuncPCABI0(sigaction_trampoline)), unsafe.Pointer(&sig))
KeepAlive(new)
KeepAlive(old)
}
func sigaction_trampoline()
@ -292,6 +313,8 @@ func sigaction_trampoline()
//go:cgo_unsafe_args
func sigprocmask(how uint32, new *sigset, old *sigset) {
libcCall(unsafe.Pointer(abi.FuncPCABI0(sigprocmask_trampoline)), unsafe.Pointer(&how))
KeepAlive(new)
KeepAlive(old)
}
func sigprocmask_trampoline()
@ -306,6 +329,8 @@ func sigaltstack(new *stackt, old *stackt) {
new.ss_size = 32768
}
libcCall(unsafe.Pointer(abi.FuncPCABI0(sigaltstack_trampoline)), unsafe.Pointer(&new))
KeepAlive(new)
KeepAlive(old)
}
func sigaltstack_trampoline()
@ -320,20 +345,32 @@ func raiseproc_trampoline()
//go:cgo_unsafe_args
func setitimer(mode int32, new, old *itimerval) {
libcCall(unsafe.Pointer(abi.FuncPCABI0(setitimer_trampoline)), unsafe.Pointer(&mode))
KeepAlive(new)
KeepAlive(old)
}
func setitimer_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func sysctl(mib *uint32, miblen uint32, oldp *byte, oldlenp *uintptr, newp *byte, newlen uintptr) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(sysctl_trampoline)), unsafe.Pointer(&mib))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(sysctl_trampoline)), unsafe.Pointer(&mib))
KeepAlive(mib)
KeepAlive(oldp)
KeepAlive(oldlenp)
KeepAlive(newp)
return ret
}
func sysctl_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func sysctlbyname(name *byte, oldp *byte, oldlenp *uintptr, newp *byte, newlen uintptr) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(sysctlbyname_trampoline)), unsafe.Pointer(&name))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(sysctlbyname_trampoline)), unsafe.Pointer(&name))
KeepAlive(name)
KeepAlive(oldp)
KeepAlive(oldlenp)
KeepAlive(newp)
return ret
}
func sysctlbyname_trampoline()
@ -355,56 +392,79 @@ func kqueue_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func kevent(kq int32, ch *keventt, nch int32, ev *keventt, nev int32, ts *timespec) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(kevent_trampoline)), unsafe.Pointer(&kq))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(kevent_trampoline)), unsafe.Pointer(&kq))
KeepAlive(ch)
KeepAlive(ev)
KeepAlive(ts)
return ret
}
func kevent_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func pthread_mutex_init(m *pthreadmutex, attr *pthreadmutexattr) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_mutex_init_trampoline)), unsafe.Pointer(&m))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_mutex_init_trampoline)), unsafe.Pointer(&m))
KeepAlive(m)
KeepAlive(attr)
return ret
}
func pthread_mutex_init_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func pthread_mutex_lock(m *pthreadmutex) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_mutex_lock_trampoline)), unsafe.Pointer(&m))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_mutex_lock_trampoline)), unsafe.Pointer(&m))
KeepAlive(m)
return ret
}
func pthread_mutex_lock_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func pthread_mutex_unlock(m *pthreadmutex) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_mutex_unlock_trampoline)), unsafe.Pointer(&m))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_mutex_unlock_trampoline)), unsafe.Pointer(&m))
KeepAlive(m)
return ret
}
func pthread_mutex_unlock_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func pthread_cond_init(c *pthreadcond, attr *pthreadcondattr) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_cond_init_trampoline)), unsafe.Pointer(&c))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_cond_init_trampoline)), unsafe.Pointer(&c))
KeepAlive(c)
KeepAlive(attr)
return ret
}
func pthread_cond_init_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func pthread_cond_wait(c *pthreadcond, m *pthreadmutex) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_cond_wait_trampoline)), unsafe.Pointer(&c))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_cond_wait_trampoline)), unsafe.Pointer(&c))
KeepAlive(c)
KeepAlive(m)
return ret
}
func pthread_cond_wait_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func pthread_cond_timedwait_relative_np(c *pthreadcond, m *pthreadmutex, t *timespec) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_cond_timedwait_relative_np_trampoline)), unsafe.Pointer(&c))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_cond_timedwait_relative_np_trampoline)), unsafe.Pointer(&c))
KeepAlive(c)
KeepAlive(m)
KeepAlive(t)
return ret
}
func pthread_cond_timedwait_relative_np_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func pthread_cond_signal(c *pthreadcond) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_cond_signal_trampoline)), unsafe.Pointer(&c))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_cond_signal_trampoline)), unsafe.Pointer(&c))
KeepAlive(c)
return ret
}
func pthread_cond_signal_trampoline()

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@ -15,7 +15,9 @@ import (
//go:nosplit
//go:cgo_unsafe_args
func g0_pthread_key_create(k *pthreadkey, destructor uintptr) int32 {
return asmcgocall(unsafe.Pointer(abi.FuncPCABI0(pthread_key_create_trampoline)), unsafe.Pointer(&k))
ret := asmcgocall(unsafe.Pointer(abi.FuncPCABI0(pthread_key_create_trampoline)), unsafe.Pointer(&k))
KeepAlive(k)
return ret
}
func pthread_key_create_trampoline()

View File

@ -17,35 +17,47 @@ import (
//go:nosplit
//go:cgo_unsafe_args
func pthread_attr_init(attr *pthreadattr) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_attr_init_trampoline)), unsafe.Pointer(&attr))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_attr_init_trampoline)), unsafe.Pointer(&attr))
KeepAlive(attr)
return ret
}
func pthread_attr_init_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func pthread_attr_destroy(attr *pthreadattr) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_attr_destroy_trampoline)), unsafe.Pointer(&attr))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_attr_destroy_trampoline)), unsafe.Pointer(&attr))
KeepAlive(attr)
return ret
}
func pthread_attr_destroy_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func pthread_attr_getstacksize(attr *pthreadattr, size *uintptr) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_attr_getstacksize_trampoline)), unsafe.Pointer(&attr))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_attr_getstacksize_trampoline)), unsafe.Pointer(&attr))
KeepAlive(attr)
KeepAlive(size)
return ret
}
func pthread_attr_getstacksize_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func pthread_attr_setdetachstate(attr *pthreadattr, state int) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_attr_setdetachstate_trampoline)), unsafe.Pointer(&attr))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_attr_setdetachstate_trampoline)), unsafe.Pointer(&attr))
KeepAlive(attr)
return ret
}
func pthread_attr_setdetachstate_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func pthread_create(attr *pthreadattr, start uintptr, arg unsafe.Pointer) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_create_trampoline)), unsafe.Pointer(&attr))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(pthread_create_trampoline)), unsafe.Pointer(&attr))
KeepAlive(attr)
KeepAlive(arg) // Just for consistency. Arg of course needs to be kept alive for the start function.
return ret
}
func pthread_create_trampoline()

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@ -14,7 +14,10 @@ import (
//go:nosplit
//go:cgo_unsafe_args
func thrsleep(ident uintptr, clock_id int32, tsp *timespec, lock uintptr, abort *uint32) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(thrsleep_trampoline)), unsafe.Pointer(&ident))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(thrsleep_trampoline)), unsafe.Pointer(&ident))
KeepAlive(tsp)
KeepAlive(abort)
return ret
}
func thrsleep_trampoline()

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@ -56,6 +56,7 @@ func mmap(addr unsafe.Pointer, n uintptr, prot, flags, fd int32, off uint32) (un
ret2 int
}{addr, n, prot, flags, fd, off, nil, 0}
libcCall(unsafe.Pointer(abi.FuncPCABI0(mmap_trampoline)), unsafe.Pointer(&args))
KeepAlive(addr) // Just for consistency. Hopefully addr is not a Go address.
return args.ret1, args.ret2
}
func mmap_trampoline()
@ -64,6 +65,7 @@ func mmap_trampoline()
//go:cgo_unsafe_args
func munmap(addr unsafe.Pointer, n uintptr) {
libcCall(unsafe.Pointer(abi.FuncPCABI0(munmap_trampoline)), unsafe.Pointer(&addr))
KeepAlive(addr) // Just for consistency. Hopefully addr is not a Go address.
}
func munmap_trampoline()
@ -71,13 +73,16 @@ func munmap_trampoline()
//go:cgo_unsafe_args
func madvise(addr unsafe.Pointer, n uintptr, flags int32) {
libcCall(unsafe.Pointer(abi.FuncPCABI0(madvise_trampoline)), unsafe.Pointer(&addr))
KeepAlive(addr) // Just for consistency. Hopefully addr is not a Go address.
}
func madvise_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func open(name *byte, mode, perm int32) (ret int32) {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(open_trampoline)), unsafe.Pointer(&name))
ret = libcCall(unsafe.Pointer(abi.FuncPCABI0(open_trampoline)), unsafe.Pointer(&name))
KeepAlive(name)
return
}
func open_trampoline()
@ -91,14 +96,18 @@ func close_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func read(fd int32, p unsafe.Pointer, n int32) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(read_trampoline)), unsafe.Pointer(&fd))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(read_trampoline)), unsafe.Pointer(&fd))
KeepAlive(p)
return ret
}
func read_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func write1(fd uintptr, p unsafe.Pointer, n int32) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(write_trampoline)), unsafe.Pointer(&fd))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(write_trampoline)), unsafe.Pointer(&fd))
KeepAlive(p)
return ret
}
func write_trampoline()
@ -121,6 +130,8 @@ func pipe2_trampoline()
//go:cgo_unsafe_args
func setitimer(mode int32, new, old *itimerval) {
libcCall(unsafe.Pointer(abi.FuncPCABI0(setitimer_trampoline)), unsafe.Pointer(&mode))
KeepAlive(new)
KeepAlive(old)
}
func setitimer_trampoline()
@ -140,7 +151,12 @@ func usleep_no_g(usec uint32) {
//go:nosplit
//go:cgo_unsafe_args
func sysctl(mib *uint32, miblen uint32, out *byte, size *uintptr, dst *byte, ndst uintptr) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(sysctl_trampoline)), unsafe.Pointer(&mib))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(sysctl_trampoline)), unsafe.Pointer(&mib))
KeepAlive(mib)
KeepAlive(out)
KeepAlive(size)
KeepAlive(dst)
return ret
}
func sysctl_trampoline()
@ -184,7 +200,11 @@ func kqueue_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func kevent(kq int32, ch *keventt, nch int32, ev *keventt, nev int32, ts *timespec) int32 {
return libcCall(unsafe.Pointer(abi.FuncPCABI0(kevent_trampoline)), unsafe.Pointer(&kq))
ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(kevent_trampoline)), unsafe.Pointer(&kq))
KeepAlive(ch)
KeepAlive(ev)
KeepAlive(ts)
return ret
}
func kevent_trampoline()
@ -192,6 +212,8 @@ func kevent_trampoline()
//go:cgo_unsafe_args
func sigaction(sig uint32, new *sigactiont, old *sigactiont) {
libcCall(unsafe.Pointer(abi.FuncPCABI0(sigaction_trampoline)), unsafe.Pointer(&sig))
KeepAlive(new)
KeepAlive(old)
}
func sigaction_trampoline()
@ -201,6 +223,8 @@ func sigprocmask(how uint32, new *sigset, old *sigset) {
// sigprocmask is called from sigsave, which is called from needm.
// As such, we have to be able to run with no g here.
asmcgocall_no_g(unsafe.Pointer(abi.FuncPCABI0(sigprocmask_trampoline)), unsafe.Pointer(&how))
KeepAlive(new)
KeepAlive(old)
}
func sigprocmask_trampoline()
@ -208,6 +232,8 @@ func sigprocmask_trampoline()
//go:cgo_unsafe_args
func sigaltstack(new *stackt, old *stackt) {
libcCall(unsafe.Pointer(abi.FuncPCABI0(sigaltstack_trampoline)), unsafe.Pointer(&new))
KeepAlive(new)
KeepAlive(old)
}
func sigaltstack_trampoline()

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@ -312,6 +312,8 @@ func syscall_wait4(pid uintptr, wstatus *uint32, options uintptr, rusage unsafe.
entersyscallblock()
asmcgocall(unsafe.Pointer(&asmsysvicall6x), unsafe.Pointer(&call))
exitsyscall()
KeepAlive(wstatus)
KeepAlive(rusage)
return int(call.r1), call.err
}

View File

@ -422,6 +422,8 @@ func syscall_loadsystemlibrary(filename *uint16, absoluteFilepath *uint16) (hand
}
cgocall(asmstdcallAddr, unsafe.Pointer(c))
KeepAlive(filename)
KeepAlive(absoluteFilepath)
handle = c.r1
if handle == 0 {
err = c.err
@ -441,6 +443,7 @@ func syscall_loadlibrary(filename *uint16) (handle, err uintptr) {
c.n = 1
c.args = uintptr(noescape(unsafe.Pointer(&filename)))
cgocall(asmstdcallAddr, unsafe.Pointer(c))
KeepAlive(filename)
handle = c.r1
if handle == 0 {
err = c.err
@ -459,6 +462,7 @@ func syscall_getprocaddress(handle uintptr, procname *byte) (outhandle, err uint
c.n = 2
c.args = uintptr(noescape(unsafe.Pointer(&handle)))
cgocall(asmstdcallAddr, unsafe.Pointer(c))
KeepAlive(procname)
outhandle = c.r1
if outhandle == 0 {
err = c.err