[compiler-rt] r196385 - [sanitizer] Fix log_path behavior with StopTheWorld.
Sergey Matveev
earthdok at google.com
Wed Dec 4 06:37:01 PST 2013
Author: smatveev
Date: Wed Dec 4 08:37:01 2013
New Revision: 196385
URL: http://llvm.org/viewvc/llvm-project?rev=196385&view=rev
Log:
[sanitizer] Fix log_path behavior with StopTheWorld.
Summary:
Fix race on report_fd/report_fd_pid between the parent process and the
tracer task.
Reviewers: samsonov
Reviewed By: samsonov
CC: llvm-commits, kcc, dvyukov
Differential Revision: http://llvm-reviews.chandlerc.com/D2306
Modified:
compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.cc
compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h
compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc
compiler-rt/trunk/lib/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc
Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.cc?rev=196385&r1=196384&r2=196385&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.cc Wed Dec 4 08:37:01 2013
@@ -42,6 +42,13 @@ char report_path_prefix[sizeof(report_pa
// child thread will be different from |report_fd_pid|.
uptr report_fd_pid = 0;
+// PID of the tracer task in StopTheWorld. It shares the address space with the
+// main process, but has a different PID and thus requires special handling.
+uptr stoptheworld_tracer_pid = 0;
+// Cached pid of parent process - if the parent process dies, we want to keep
+// writing to the same log file.
+uptr stoptheworld_tracer_ppid = 0;
+
static DieCallbackType DieCallback;
void SetDieCallback(DieCallbackType callback) {
DieCallback = callback;
Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h?rev=196385&r1=196384&r2=196385&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h Wed Dec 4 08:37:01 2013
@@ -136,6 +136,8 @@ extern fd_t report_fd;
extern bool log_to_file;
extern char report_path_prefix[4096];
extern uptr report_fd_pid;
+extern uptr stoptheworld_tracer_pid;
+extern uptr stoptheworld_tracer_ppid;
uptr OpenFile(const char *filename, bool write);
// Opens the file 'file_name" and reads up to 'max_len' bytes.
Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc?rev=196385&r1=196384&r2=196385&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc Wed Dec 4 08:37:01 2013
@@ -198,10 +198,15 @@ char *FindPathToBinary(const char *name)
}
void MaybeOpenReportFile() {
- if (!log_to_file || (report_fd_pid == internal_getpid())) return;
+ if (!log_to_file) return;
+ uptr pid = internal_getpid();
+ // If in tracer, use the parent's file.
+ if (pid == stoptheworld_tracer_pid)
+ pid = stoptheworld_tracer_ppid;
+ if (report_fd_pid == pid) return;
InternalScopedBuffer<char> report_path_full(4096);
internal_snprintf(report_path_full.data(), report_path_full.size(),
- "%s.%d", report_path_prefix, internal_getpid());
+ "%s.%d", report_path_prefix, pid);
uptr openrv = OpenFile(report_path_full.data(), true);
if (internal_iserror(openrv)) {
report_fd = kStderrFd;
@@ -214,7 +219,7 @@ void MaybeOpenReportFile() {
internal_close(report_fd);
}
report_fd = openrv;
- report_fd_pid = internal_getpid();
+ report_fd_pid = pid;
}
void RawWrite(const char *buffer) {
Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc?rev=196385&r1=196384&r2=196385&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc Wed Dec 4 08:37:01 2013
@@ -356,6 +356,20 @@ class StopTheWorldScope {
int process_was_dumpable_;
};
+// When sanitizer output is being redirected to file (i.e. by using log_path),
+// the tracer should write to the parent's log instead of trying to open a new
+// file. Alert the logging code to the fact that we have a tracer.
+struct ScopedSetTracerPID {
+ explicit ScopedSetTracerPID(uptr tracer_pid) {
+ stoptheworld_tracer_pid = tracer_pid;
+ stoptheworld_tracer_ppid = internal_getpid();
+ }
+ ~ScopedSetTracerPID() {
+ stoptheworld_tracer_pid = 0;
+ stoptheworld_tracer_ppid = 0;
+ }
+};
+
void StopTheWorld(StopTheWorldCallback callback, void *argument) {
StopTheWorldScope in_stoptheworld;
// Prepare the arguments for TracerThread.
@@ -379,6 +393,7 @@ void StopTheWorld(StopTheWorldCallback c
Report("Failed spawning a tracer thread (errno %d).\n", local_errno);
tracer_thread_argument.mutex.Unlock();
} else {
+ ScopedSetTracerPID scoped_set_tracer_pid(tracer_pid);
// On some systems we have to explicitly declare that we want to be traced
// by the tracer thread.
#ifdef PR_SET_PTRACER
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