[Bug 852760] Re: valgrind false positives on gcc-generated string routines

[Bug Watch Updater]

** Changed in: valgrind (ALT Linux)
       Status: Unknown => New

** Changed in: valgrind (ALT Linux)
   Importance: Unknown => Medium

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Title:
  valgrind false positives on gcc-generated string routines

Status in “valgrind” package in Ubuntu:
  New
Status in “valgrind” package in ALT Linux:
  New
Status in “valgrind” package in Fedora:
  Unknown

Bug description:
  #include <string.h>
  #include <stdio.h>
  #include <stdlib.h>

  main()
  {
      char *a = malloc(1);
      a[0] = '\0';
      printf("%lu\n", (unsigned long)strlen(a));
  }

  Compile with "gcc -O2" and run valgrind.

  ==5977== Invalid read of size 4
  ==5977==    at 0x400494: main (x.c:9)
  ==5977==  Address 0x51ce040 is 0 bytes inside a block of size 1 alloc'd
  ==5977==    at 0x4C28F9F: malloc (vg_replace_malloc.c:236)
  ==5977==    by 0x40048D: main (x.c:7)

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