[compiler-rt] r271046 - [sanitizers] introduce __sanitizer_set_report_fd so that we can re-route the sanitizer logging to another fd from inside the process

[Mehdi Amini via llvm-commits]

Hi Kostya,

We see a bot failure with the test case you added below: http://lab.llvm.org:8080/green/job/clang-stage1-cmake-RA-globalisel_check/2068/console

After investigating, it seems that they trigger an ASAN failure, which is returning a negative error code. The `not` command tool interprets it as a crash, and you need to pass the --crash option to it.

Don't you observe this on your setup? I wonder why they are passing?

-- 
Mehdi




> On May 27, 2016, at 2:23 PM, Kostya Serebryany via llvm-commits <llvm-commits at lists.llvm.org> wrote:
> 
> Author: kcc
> Date: Fri May 27 16:23:05 2016
> New Revision: 271046
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=271046&view=rev
> Log:
> [sanitizers] introduce __sanitizer_set_report_fd so that we can re-route the sanitizer logging to another fd from inside the process
> 
> Added:
>    compiler-rt/trunk/test/sanitizer_common/TestCases/Posix/sanitizer_set_report_fd_test.cc
> Modified:
>    compiler-rt/trunk/include/sanitizer/common_interface_defs.h
>    compiler-rt/trunk/lib/asan/asan_posix.cc
>    compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.cc
> 
> Modified: compiler-rt/trunk/include/sanitizer/common_interface_defs.h
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/include/sanitizer/common_interface_defs.h?rev=271046&r1=271045&r2=271046&view=diff
> ==============================================================================
> --- compiler-rt/trunk/include/sanitizer/common_interface_defs.h (original)
> +++ compiler-rt/trunk/include/sanitizer/common_interface_defs.h Fri May 27 16:23:05 2016
> @@ -41,6 +41,9 @@ extern "C" {
> 
>   // Tell the tools to write their reports to "path.<pid>" instead of stderr.
>   void __sanitizer_set_report_path(const char *path);
> +  // Tell the tools to write their reports to the provided file descriptor
> +  // (casted to void *).
> +  void __sanitizer_set_report_fd(void *fd);
> 
>   // Notify the tools that the sandbox is going to be turned on. The reserved
>   // parameter will be used in the future to hold a structure with functions
> 
> Modified: compiler-rt/trunk/lib/asan/asan_posix.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_posix.cc?rev=271046&r1=271045&r2=271046&view=diff
> ==============================================================================
> --- compiler-rt/trunk/lib/asan/asan_posix.cc (original)
> +++ compiler-rt/trunk/lib/asan/asan_posix.cc Fri May 27 16:23:05 2016
> @@ -36,8 +36,9 @@ namespace __asan {
> void AsanOnDeadlySignal(int signo, void *siginfo, void *context) {
>   ScopedDeadlySignal signal_scope(GetCurrentThread());
>   int code = (int)((siginfo_t*)siginfo)->si_code;
> -  // Write the first message using the bullet-proof write.
> -  if (18 != internal_write(2, "ASAN:DEADLYSIGNAL\n", 18)) Die();
> +  // Write the first message using fd=2, just in case.
> +  // It may actually fail to write in case stderr is closed.
> +  internal_write(2, "ASAN:DEADLYSIGNAL\n", 18);
>   SignalContext sig = SignalContext::Create(siginfo, context);
> 
>   // Access at a reasonable offset above SP, or slightly below it (to account
> 
> 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=271046&r1=271045&r2=271046&view=diff
> ==============================================================================
> --- compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.cc (original)
> +++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.cc Fri May 27 16:23:05 2016
> @@ -496,6 +496,11 @@ void __sanitizer_set_report_path(const c
>   report_file.SetReportPath(path);
> }
> 
> +void __sanitizer_set_report_fd(void *fd) {
> +  report_file.fd = reinterpret_cast<uptr>(fd);
> +  report_file.fd_pid = internal_getpid();
> +}
> +
> void __sanitizer_report_error_summary(const char *error_summary) {
>   Printf("%s\n", error_summary);
> }
> 
> Added: compiler-rt/trunk/test/sanitizer_common/TestCases/Posix/sanitizer_set_report_fd_test.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/sanitizer_common/TestCases/Posix/sanitizer_set_report_fd_test.cc?rev=271046&view=auto
> ==============================================================================
> --- compiler-rt/trunk/test/sanitizer_common/TestCases/Posix/sanitizer_set_report_fd_test.cc (added)
> +++ compiler-rt/trunk/test/sanitizer_common/TestCases/Posix/sanitizer_set_report_fd_test.cc Fri May 27 16:23:05 2016
> @@ -0,0 +1,37 @@
> +// Test __sanitizer_set_report_fd:
> +// RUN: %clangxx -O2 %s -o %t
> +// RUN: not %run %t 2>&1   | FileCheck %s
> +// RUN: not %run %t stdout | FileCheck %s
> +// RUN: not %run %t %t-out && FileCheck < %t-out %s
> +
> +// REQUIRES: stable-runtime
> +// FIXME: implement SEGV handler in other sanitizers, not just asan.
> +// XFAIL: msan
> +// XFAIL: lsan
> +// XFAIL: tsan
> +
> +#include <sanitizer/common_interface_defs.h>
> +#include <stdio.h>
> +#include <string.h>
> +#include <stdlib.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <fcntl.h>
> +#include <assert.h>
> +
> +volatile int *null = 0;
> +
> +int main(int argc, char **argv) {
> +  if (argc == 2) {
> +    if (!strcmp(argv[1], "stdout")) {
> +      __sanitizer_set_report_fd(reinterpret_cast<void*>(1));
> +    } else {
> +      int fd = open(argv[1], O_CREAT | O_WRONLY | O_TRUNC, S_IRWXU);
> +      assert(fd > 0);
> +      __sanitizer_set_report_fd(reinterpret_cast<void*>(fd));
> +    }
> +  }
> +  *null = 0;
> +}
> +
> +// CHECK: ERROR: {{.*}} SEGV on unknown address
> 
> 
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