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v4.1.x: odls/default: cap the max number of child FDs to close #10360

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Merged
merged 1 commit into from
May 16, 2022
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v4.1.x: odls/default: cap the max number of child FDs to close #10360

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7 changes: 7 additions & 0 deletions orte/mca/odls/default/odls_default.h
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@
* University of Stuttgart. All rights reserved.
* Copyright (c) 2004-2005 The Regents of the University of California.
* All rights reserved.
* Copyright (c) 2022 Cisco Systems, Inc. All rights reserved
* $COPYRIGHT$
*
* Additional copyrights may follow
Expand All @@ -35,6 +36,7 @@ BEGIN_C_DECLS
*/
int orte_odls_default_component_open(void);
int orte_odls_default_component_close(void);
int orte_odls_default_component_register(void);
int orte_odls_default_component_query(mca_base_module_t **module, int *priority);

/*
Expand All @@ -43,6 +45,11 @@ int orte_odls_default_component_query(mca_base_module_t **module, int *priority)
extern orte_odls_base_module_t orte_odls_default_module;
ORTE_MODULE_DECLSPEC extern orte_odls_base_component_t mca_odls_default_component;

/* In non-Linux environments where we can't just see which fd's are
open (e.g., MacOS), use this value as the maximum number of FDs
to close when forking a new child process. */
extern int orte_odls_default_maxfd;

END_C_DECLS

#endif /* ORTE_ODLS_H */
17 changes: 17 additions & 0 deletions orte/mca/odls/default/odls_default_component.c
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Expand Up @@ -13,6 +13,7 @@
* Copyright (c) 2015 Los Alamos National Security, LLC. All rights
* reserved.
* Copyright (c) 2017 Intel, Inc. All rights reserved.
* Copyright (c) 2022 Cisco Systems, Inc. All rights reserved
* $COPYRIGHT$
*
* Additional copyrights may follow
Expand Down Expand Up @@ -60,6 +61,7 @@ orte_odls_base_component_t mca_odls_default_component = {
/* Component open and close functions */
.mca_open_component = orte_odls_default_component_open,
.mca_close_component = orte_odls_default_component_close,
.mca_register_component_params = orte_odls_default_component_register,
.mca_query_component = orte_odls_default_component_query,
},
.base_data = {
Expand All @@ -68,13 +70,28 @@ orte_odls_base_component_t mca_odls_default_component = {
},
};

int orte_odls_default_maxfd = 1024;


int orte_odls_default_component_open(void)
{
return ORTE_SUCCESS;
}

int orte_odls_default_component_register(void)
{
mca_base_component_var_register(&mca_odls_default_component.version, "maxfd",
"In non-Linux environments, use this value as a maximum number of file descriptors to close when forking a new child process",
MCA_BASE_VAR_TYPE_INT,
NULL,
0,
0,
OPAL_INFO_LVL_6,
MCA_BASE_VAR_SCOPE_READONLY,
&orte_odls_default_maxfd);
return ORTE_SUCCESS;
}

int orte_odls_default_component_query(mca_base_module_t **module, int *priority)
{
/* the base open/select logic protects us against operation when
Expand Down
24 changes: 21 additions & 3 deletions orte/mca/odls/default/odls_default_module.c
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Expand Up @@ -11,7 +11,7 @@
* All rights reserved.
* Copyright (c) 2007-2010 Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2007 Evergrid, Inc. All rights reserved.
* Copyright (c) 2008-2017 Cisco Systems, Inc. All rights reserved
* Copyright (c) 2008-2022 Cisco Systems, Inc. All rights reserved
* Copyright (c) 2010 IBM Corporation. All rights reserved.
* Copyright (c) 2011-2013 Los Alamos National Security, LLC. All rights
* reserved.
Expand Down Expand Up @@ -337,7 +337,6 @@ static int do_child(orte_odls_spawn_caddy_t *cd, int write_fd)
{
int i;
sigset_t sigs;
long fd, fdmax = sysconf(_SC_OPEN_MAX);
char dir[MAXPATHLEN];

#if HAVE_SETPGID
Expand Down Expand Up @@ -400,8 +399,27 @@ static int do_child(orte_odls_spawn_caddy_t *cd, int write_fd)
the pipe used for the IOF INTERNAL messages, and the pipe up to
the parent. */
if (ORTE_SUCCESS != close_open_file_descriptors(write_fd, cd->opts)) {
/* On some versions of MacOS (e.g., 12.3.1), we have seen
sysconf(_SC_OPEN_MAX) -- and "ulimit -n" -- return very
large numbers, and sometime return -1 (which means
"unlimited"). This can result in an unreasonably large
loop over closing all FDs (especially if -1 gets
interpreted as LONG_MAX).
https://github.com/open-mpi/ompi/issues/10358 has some
links to others who have seen this kind of behavior.

Protect against -1 and arbitrarily large values being
returned from sysconf(_SC_OPEN_MAX): use an MCA param to
cap the max value that we'll use, just in case there's an
actual reason for a user to change the built-in default
value that we're (somewhat arbitrarily) picking. */
long fd, fdmax = sysconf(_SC_OPEN_MAX);
if (-1 == fdmax || orte_odls_default_maxfd < fdmax) {
fdmax = orte_odls_default_maxfd;
}

// close *all* file descriptors -- slow
for(fd=3; fd<fdmax; fd++) {
for (fd = 3; fd < fdmax; fd++) {
if (
#if OPAL_PMIX_V1
fd != cd->opts.p_internal[1] &&
Expand Down