[PATCH][libsanitizer] Cherry-pick r211008 [Was: Re: libsanitizer merge from upstream r208536]

[Paolo Carlini]

Hi,

On 06/16/2014 10:42 AM, Konstantin Serebryany wrote:

On Wed, Jun 11, 2014 at 2:28 PM, Paolo Carlini <paolo.carl...@oracle.com> wrote:

Hi,

On 05/22/2014 09:02 PM, Jakub Jelinek wrote:

In file included from
../../../../trunk/libsanitizer/asan/asan_interceptors.cc:147:0:

../../../../trunk/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:
In function ‘int __interceptor_accept4(int, void*, unsigned int*,
int)’:

../../../../trunk/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:1821:12:
warning: ‘addrlen0’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
unsigned addrlen0;
^

../../../../trunk/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:
In function ‘int __interceptor_accept(int, void*, unsigned int*)’:

../../../../trunk/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:1799:12:
warning: ‘addrlen0’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
unsigned addrlen0;
^
That sounds like a false positive warning:
    unsigned addrlen0;
    if (addrlen) {
      COMMON_INTERCEPTOR_READ_RANGE(ctx, addrlen, sizeof(*addrlen));
      addrlen0 = *addrlen;
    }
    int fd2 = REAL(accept4)(fd, addr, addrlen, f);
    if (fd2 >= 0) {
      if (fd >= 0) COMMON_INTERCEPTOR_FD_SOCKET_ACCEPT(ctx, fd, fd2);
      if (addr && addrlen)
        COMMON_INTERCEPTOR_WRITE_RANGE(ctx, addr, Min(*addrlen, addrlen0));
    }
(unless the COMMON_INTERCEPTOR* macros do too weird stuff), wonder why the
predicate aware uninit doesn't handle this.

By the way, I'm still seeing the above. Maybe a maintainer can have a look,
double check it's just a false positive a shut it up somehow?

I've "fixed" this in upstream trunk:
http://llvm.org/viewvc/llvm-project?view=revision&revision=211008
This will get into GCC with the next merge; or feel free to cherry pick.

Thus, can I apply the below?

Thanks!
Paolo.

/////////////////////

2014-06-23  Paolo Carlini  <paolo.carl...@oracle.com>

        * sanitizer_common/sanitizer_common_interceptors.inc:
        Cherry pick upstream r211008.

Index: sanitizer_common/sanitizer_common_interceptors.inc
===================================================================
--- sanitizer_common/sanitizer_common_interceptors.inc  (revision 211905)
+++ sanitizer_common/sanitizer_common_interceptors.inc  (working copy)
@@ -1796,7 +1796,7 @@ INTERCEPTOR(int, getsockopt, int sockfd, int level
 INTERCEPTOR(int, accept, int fd, void *addr, unsigned *addrlen) {
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, accept, fd, addr, addrlen);
-  unsigned addrlen0;
+  unsigned addrlen0 = 0;
   if (addrlen) {
     COMMON_INTERCEPTOR_READ_RANGE(ctx, addrlen, sizeof(*addrlen));
     addrlen0 = *addrlen;
@@ -1818,7 +1818,7 @@ INTERCEPTOR(int, accept, int fd, void *addr, unsig
 INTERCEPTOR(int, accept4, int fd, void *addr, unsigned *addrlen, int f) {
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, accept4, fd, addr, addrlen, f);
-  unsigned addrlen0;
+  unsigned addrlen0 = 0;
   if (addrlen) {
     COMMON_INTERCEPTOR_READ_RANGE(ctx, addrlen, sizeof(*addrlen));
     addrlen0 = *addrlen;