commit 79865f0eed7cf0e0ad687ee0a59d59a1d505b514

Author: mjw <mjw@a5019735-40e9-0310-863c-91ae7b9d1cf9>

Date:   Sat Jun 17 13:49:22 2017 +0000

    epoll_pwait can have a NULL sigmask.

    According to the epoll_pwait(2) man page:

           The  sigmask  argument  may  be  specified  as  NULL,  in  which  case

           epoll_pwait() is equivalent to epoll_wait().

    But doing that under valgrind gives:

    ==13887== Syscall param epoll_pwait(sigmask) points to unaddressable byte(s)

    ==13887==    at 0x4F2B940: epoll_pwait (epoll_pwait.c:43)

    ==13887==    by 0x400ADE: main (syscalls-2007.c:89)

    ==13887==  Address 0x0 is not stack'd, malloc'd or (recently) free'd

    This is because the sys_epoll_pwait wrapper has:

       if (ARG4)

          PRE_MEM_READ( "epoll_pwait(sigmask)", ARG5, sizeof(vki_sigset_t) );

    Which looks like a typo (ARG4 is timeout and ARG5 is sigmask).

    This shows up with newer glibc which translates an epoll_wait call into

    an epoll_pwait call with NULL sigmask.

    Fix typo and add a testcase.

    https://bugs.kde.org/show_bug.cgi?id=381289

    git-svn-id: svn://svn.valgrind.org/valgrind/trunk@16451 a5019735-40e9-0310-863c-91ae7b9d1cf9

diff --git a/coregrind/m_syswrap/syswrap-linux.c b/coregrind/m_syswrap/syswrap-linux.c

index 26e02fd..4120c1d 100644

--- a/coregrind/m_syswrap/syswrap-linux.c

+++ b/coregrind/m_syswrap/syswrap-linux.c

@@ -1901,7 +1901,7 @@ PRE(sys_epoll_pwait)

                  int, maxevents, int, timeout, vki_sigset_t *, sigmask,

                  vki_size_t, sigsetsize);

    PRE_MEM_WRITE( "epoll_pwait(events)", ARG2, sizeof(struct vki_epoll_event)*ARG3);

-   if (ARG4)

+   if (ARG5)

       PRE_MEM_READ( "epoll_pwait(sigmask)", ARG5, sizeof(vki_sigset_t) );

 }

 POST(sys_epoll_pwait)

diff --git a/memcheck/tests/linux/syscalls-2007.c b/memcheck/tests/linux/syscalls-2007.c

index b61c6d5..5494623 100644

--- a/memcheck/tests/linux/syscalls-2007.c

+++ b/memcheck/tests/linux/syscalls-2007.c

@@ -79,5 +79,16 @@ int main (void)

   }

 #endif

+#if defined(HAVE_EPOLL_CREATE) && defined(HAVE_EPOLL_PWAIT)

+  {

+    int fd3;

+    struct epoll_event evs[10];

+

+    fd3 = epoll_create (10);

+    /* epoll_pwait can take a NULL sigmask. */

+    epoll_pwait (fd3, evs, 10, 1, NULL);

+  }

+#endif

+

   return 0;

 }