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tools/testing/selftests/proc/proc-pid-vm.c: hide "segfault at ffffffffff600000" dmesg spam 

Test tries to access vsyscall page and if it doesn't exist gets SIGSEGV
which can spam into dmesg.  However the segfault happens by design.
Handle it and carry information via exit code to parent.

Link: http://lkml.kernel.org/r/20190524181256.GA2260@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alexey Dobriyan 2019-07-16 16:26:36 -07:00 committed by Linus Torvalds
parent 9b98fa2294
commit bca1eac55a
1 changed files with 15 additions and 2 deletions
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17
tools/testing/selftests/proc/proc-pid-vm.c
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@ -215,6 +215,11 @@ static const char str_vsyscall[] =
"ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall]\n";
#ifdef __x86_64__
static void sigaction_SIGSEGV(int _, siginfo_t *__, void *___)
{
_exit(1);
}
/*
* vsyscall page can't be unmapped, probe it with memory load.
*/
@ -231,11 +236,19 @@ static void vsyscall(void)
if (pid == 0) {
struct rlimit rlim = {0, 0};
(void)setrlimit(RLIMIT_CORE, &rlim);
/* Hide "segfault at ffffffffff600000" messages. */
struct sigaction act;
memset(&act, 0, sizeof(struct sigaction));
act.sa_flags = SA_SIGINFO;
act.sa_sigaction = sigaction_SIGSEGV;
(void)sigaction(SIGSEGV, &act, NULL);
*(volatile int *)0xffffffffff600000UL;
exit(0);
}
wait(&wstatus);
if (WIFEXITED(wstatus)) {
waitpid(pid, &wstatus, 0);
if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus) == 0) {
g_vsyscall = true;
}
}