mirror of
https://github.com/golang/go
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4210930a28
A typo in the previous revision ("act" instead of "oldact") caused us
to return the sa_flags from the new (or zeroed) sigaction rather than
the old one.
In the presence of a signal handler registered before
runtime.libpreinit, this caused setsigstack to erroneously zero out
important sa_flags (such as SA_SIGINFO) in its attempt to re-register
the existing handler with SA_ONSTACK.
Change-Id: I3cd5152a38ec0d44ae611f183bc1651d65b8a115
Reviewed-on: https://go-review.googlesource.com/37852
Run-TryBot: Bryan Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
64 lines
1.5 KiB
Go
64 lines
1.5 KiB
Go
// Copyright 2017 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package main
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// This program failed with SIGSEGV when run under the C/C++ ThreadSanitizer.
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// The Go runtime had re-registered the C handler with the wrong flags due to a
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// typo, resulting in null pointers being passed for the info and context
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// parameters to the handler.
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/*
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#cgo CFLAGS: -fsanitize=thread
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#cgo LDFLAGS: -fsanitize=thread
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <ucontext.h>
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void check_params(int signo, siginfo_t *info, void *context) {
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ucontext_t* uc = (ucontext_t*)(context);
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if (info->si_signo != signo) {
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fprintf(stderr, "info->si_signo does not match signo.\n");
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abort();
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}
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if (uc->uc_stack.ss_size == 0) {
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fprintf(stderr, "uc_stack has size 0.\n");
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abort();
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}
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}
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// Set up the signal handler in a high priority constructor, so
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// that it is installed before the Go code starts.
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static void register_handler(void) __attribute__ ((constructor (200)));
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static void register_handler() {
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struct sigaction sa;
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memset(&sa, 0, sizeof(sa));
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sigemptyset(&sa.sa_mask);
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sa.sa_flags = SA_SIGINFO;
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sa.sa_sigaction = check_params;
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if (sigaction(SIGUSR1, &sa, NULL) != 0) {
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perror("failed to register SIGUSR1 handler");
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exit(EXIT_FAILURE);
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}
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}
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*/
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import "C"
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import "syscall"
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func init() {
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C.raise(C.int(syscall.SIGUSR1))
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}
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func main() {}
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