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mcexec: workaround for overlayed /sys FS directory lseek() bug

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lseek() on directories under /sys filesystem that are part of an
overlayed filesystem behave differently than in the original /sys.
This causes segfault in libnuma when discovering topology
information. The patch fakes return value as it is supposed to be,
which also fixes the Intel MPI 2017 MPI_Init() crash.
This commit is contained in:
Balazs Gerofi
2016-11-03 13:41:25 +09:00
parent be4f6741f9
commit 24d8697cef
1 changed files with 34 additions and 0 deletions
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34
executer/user/mcexec.c
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@ -1686,6 +1686,40 @@ do_generic_syscall(
ret = -errno;
}
/* Overlayfs /sys/X directory lseek() problem work around */
if (w->sr.number == __NR_lseek && ret == -EINVAL) {
char proc_path[512];
char path[512];
struct stat sb;
sprintf(proc_path, "/proc/self/fd/%d", (int)w->sr.args[0]);
/* Get filename */
if (readlink(proc_path, path, sizeof(path)) < 0) {
fprintf(stderr, "%s: error: readlink() failed for %s\n",
__FUNCTION__, proc_path);
goto out;
}
/* Not in /sys? */
if (strncmp(path, "/sys/", 5))
goto out;
/* Stat */
if (stat(path, &sb) < 0) {
fprintf(stderr, "%s: error stat() failed for %s\n",
__FUNCTION__, path);
goto out;
}
/* Not dir? */
if ((sb.st_mode & S_IFMT) != S_IFDIR)
goto out;
ret = 0;
}
out:
__dprintf("do_generic_syscall(%ld):%ld (%#lx)\n", w->sr.number, ret, ret);
return ret;
}