[compiler-rt] 0999975 - tsan: fix epoll_pwait2 interceptor

[Dmitry Vyukov via llvm-commits]

Author: Dmitry Vyukov
Date: 2022-11-30T10:37:11+01:00
New Revision: 099997540f45a50f1bfb1da85cd222e3509b87cb

URL: https://github.com/llvm/llvm-project/commit/099997540f45a50f1bfb1da85cd222e3509b87cb
DIFF: https://github.com/llvm/llvm-project/commit/099997540f45a50f1bfb1da85cd222e3509b87cb.diff

LOG: tsan: fix epoll_pwait2 interceptor

epoll_pwait2 is new and may not be present in libc and/or kernel.
Since we effectively add it to libc (as will be probed by the program
using dlsym or a weak function pointer) we need to handle the case
when it's not present in the actual libc.

Reviewed By: melver

Differential Revision: https://reviews.llvm.org/D138929

Added: 
    

Modified: 
    compiler-rt/lib/sanitizer_common/sanitizer_errno_codes.h
    compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/sanitizer_common/sanitizer_errno_codes.h b/compiler-rt/lib/sanitizer_common/sanitizer_errno_codes.h
index 192e9392d494a..3917b2817f2e9 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_errno_codes.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_errno_codes.h
@@ -25,6 +25,7 @@ namespace __sanitizer {
 #define errno_EBUSY 16
 #define errno_EINVAL 22
 #define errno_ENAMETOOLONG 36
+#define errno_ENOSYS 38
 
 // Those might not present or their value 
diff er on 
diff erent platforms.
 extern const int errno_EOWNERDEAD;

diff  --git a/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp b/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
index 72a771d762da6..bab725c2b07ac 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
@@ -1945,7 +1945,17 @@ TSAN_INTERCEPTOR(int, epoll_pwait, int epfd, void *ev, int cnt, int timeout,
 
 TSAN_INTERCEPTOR(int, epoll_pwait2, int epfd, void *ev, int cnt, void *timeout,
                  void *sigmask) {
-  SCOPED_TSAN_INTERCEPTOR(epoll_pwait2, epfd, ev, cnt, timeout, sigmask);
+  SCOPED_INTERCEPTOR_RAW(epoll_pwait2, epfd, ev, cnt, timeout, sigmask);
+  // This function is new and may not be present in libc and/or kernel.
+  // Since we effectively add it to libc (as will be probed by the program
+  // using dlsym or a weak function pointer) we need to handle the case
+  // when it's not present in the actual libc.
+  if (!REAL(epoll_pwait2)) {
+    errno = errno_ENOSYS;
+    return -1;
+  }
+  if (MustIgnoreInterceptor(thr))
+    REAL(epoll_pwait2)(epfd, ev, cnt, timeout, sigmask);
   if (epfd >= 0)
     FdAccess(thr, pc, epfd);
   int res = BLOCK_REAL(epoll_pwait2)(epfd, ev, cnt, timeout, sigmask);