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PSM/PSM2: Disable signal handler hijacking by default #1781

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Merged
merged 1 commit into from
Jun 14, 2016
Merged

PSM/PSM2: Disable signal handler hijacking by default #1781

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6 changes: 5 additions & 1 deletion ompi/mpi/java/c/mpi_MPI.c
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,7 @@
* All rights reserved.
* Copyright (c) 2015 Los Alamos National Security, LLC. All rights
* reserved.
* Copyright (c) 2015 Cisco Systems, Inc. All rights reserved.
* Copyright (c) 2015-2016 Cisco Systems, Inc. All rights reserved.
* Copyright (c) 2015 Intel, Inc. All rights reserved.
* Copyright (c) 2015 Research Organization for Information Science
* and Technology (RIST). All rights reserved.
Expand Down Expand Up @@ -131,6 +131,10 @@ OBJ_CLASS_INSTANCE(ompi_java_buffer_t,
*/
jint JNI_OnLoad(JavaVM *vm, void *reserved)
{
// Ensure that PSM signal hijacking is disabled *before* loading
// the library (see comment in the function for more detail).
opal_init_psm();

libmpi = dlopen("libmpi." OPAL_DYN_LIB_SUFFIX, RTLD_NOW | RTLD_GLOBAL);

#if defined(HAVE_DL_INFO) && defined(HAVE_LIBGEN_H)
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9 changes: 8 additions & 1 deletion opal/runtime/opal.h
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Expand Up @@ -10,7 +10,7 @@
* Copyright (c) 2004-2005 The Regents of the University of California.
* All rights reserved.
* Copyright (c) 2008 Sun Microsystems, Inc. All rights reserved.
* Copyright (c) 2010-2012 Cisco Systems, Inc. All rights reserved.
* Copyright (c) 2010-2016 Cisco Systems, Inc. All rights reserved.
* Copyright (c) 2014 Intel, Inc. All rights reserved.
* $COPYRIGHT$
*
Expand Down Expand Up @@ -76,6 +76,13 @@ OPAL_DECLSPEC int opal_finalize(void);
*/
OPAL_DECLSPEC int opal_init_util(int* pargc, char*** pargv);

/**
* Disable PSM/PSM2 signal hijacking.
*
* See comment in the function for more detail.
*/
OPAL_DECLSPEC int opal_init_psm(void);

/**
* Finalize the OPAL layer, excluding the MCA system.
*
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34 changes: 33 additions & 1 deletion opal/runtime/opal_init.c
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Expand Up @@ -10,7 +10,7 @@
* University of Stuttgart. All rights reserved.
* Copyright (c) 2004-2005 The Regents of the University of California.
* All rights reserved.
* Copyright (c) 2007-2012 Cisco Systems, Inc. All rights reserved.
* Copyright (c) 2007-2016 Cisco Systems, Inc. All rights reserved.
* Copyright (c) 2007 Sun Microsystems, Inc. All rights reserved.
* Copyright (c) 2009 Oak Ridge National Labs. All rights reserved.
* Copyright (c) 2010-2015 Los Alamos National Security, LLC.
Expand Down Expand Up @@ -265,6 +265,34 @@ opal_err2str(int errnum, const char **errmsg)
}


int opal_init_psm(void)
{
/* Very early in the init sequence -- before *ANY* MCA components
are opened -- we need to disable some behavior from the PSM and
PSM2 libraries (by default): at least some old versions of
these libraries hijack signal handlers during their library
constructors and then do not un-hijack them when the libraries
are unloaded.

It is a bit of an abstraction break that we have to put
vendor/transport-specific code in the OPAL core, but we're
out of options, unfortunately.

NOTE: We only disable this behavior if the corresponding
environment variables are not already set (i.e., if the
user/environment has indicated a preference for this behavior,
we won't override it). */
if (NULL == getenv("IPATH_NO_BACKTRACE")) {
opal_setenv("IPATH_NO_BACKTRACE", "1", true, &environ);
}
if (NULL == getenv("HFI_NO_BACKTRACE")) {
opal_setenv("HFI_NO_BACKTRACE", "1", true, &environ);
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This might be a bit late, however, I believe this is unnecessary. Even though PSM2 library calls into the fini() code and runs sigaction() the resulting calls use a static struct that is initialized to all ZEROs (I double checked all the structs are in the .bss section). The resulting calls into sigaction with this parameter set, results in a simple query of the signal handlers, but no modification. So this work around really doesn't fix anything, other than avoiding some CPU cycles during dlclose(). I only mention this as near the end of the month this will be patched and then the HFI_NO_BACKTRACE will not exist inside libpsm2, so it will be wasted code.

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We opted for the "extra" protection solely because we couldn't be certain of the behavior, and the old libraries are going to be around on systems for a very long time (or at least so history says). So even though it technically isn't required, it doesn't hurt and maybe saves us from a little user angst.

}

return OPAL_SUCCESS;
}


int
opal_init_util(int* pargc, char*** pargv)
{
Expand Down Expand Up @@ -328,6 +356,10 @@ opal_init_util(int* pargc, char*** pargv)
goto return_error;
}

// Disable PSM signal hijacking (see comment in function for more
// details)
opal_init_psm();

/* Setup the parameter system */
if (OPAL_SUCCESS != (ret = mca_base_var_init())) {
error = "mca_base_var_init";
Expand Down