commit 18b3ffc1a8dc951d8a8cdb076e7e30aafc216571

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

Date:   Sat Nov 19 14:54:44 2016 +0000

    Fix 372504  Hanging on exit_group

    Note that it is unclear if the PRE syscall for rt_sigsuspend

    is properly setting up a temporary mask in the thread state

    tmp_sig_mask:  if an handler is called while a thread is

    calling sigsuspend, the mask during the handler run must be

    the temporary mask set by sigsuspend.

    It is not clear if/where the valgrind sigframe builder/handler

    sets the tmp_sig_mask to the value as expected by the user

    (i.e. the value of the temporary mask which was given to

    the sigsuspend syscall)

    git-svn-id: svn://svn.valgrind.org/valgrind/trunk@16141 a5019735-40e9-0310-863c-91ae7b9d1cf9

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

index 1dcb95d..fda8dd1 100644

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

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

@@ -3558,6 +3558,12 @@ PRE(sys_rt_sigsuspend)

    PRE_REG_READ2(int, "rt_sigsuspend", vki_sigset_t *, mask, vki_size_t, size)

    if (ARG1 != (Addr)NULL) {

       PRE_MEM_READ( "rt_sigsuspend(mask)", ARG1, sizeof(vki_sigset_t) );

+      VG_(sigdelset)((vki_sigset_t*)ARG1, VG_SIGVGKILL); 

+      /* We cannot mask VG_SIGVGKILL, as otherwise this thread would not

+         be killable by VG_(nuke_all_threads_except).

+         We thus silently ignore the user request to mask this signal.

+         Note that this is similar to what is done for e.g.

+         sigprocmask (see m_signals.c calculate_SKSS_from_SCSS).  */

    }

 }

diff --git a/coregrind/pub_core_threadstate.h b/coregrind/pub_core_threadstate.h

index 861f233..f3d956c 100644

--- a/coregrind/pub_core_threadstate.h

+++ b/coregrind/pub_core_threadstate.h

@@ -354,7 +354,9 @@ typedef struct {

       different values is during the execution of a sigsuspend, where

       tmp_sig_mask is the temporary mask which sigsuspend installs.

       It is only consulted to compute the signal mask applied to a

-      signal handler. */

+      signal handler. 

+      PW Nov 2016 : it is not clear if and where this tmp_sig_mask

+      is set when an handler runs "inside" a sigsuspend. */

    vki_sigset_t tmp_sig_mask;

    /* A little signal queue for signals we can't get the kernel to