tools/testing/selftests/proc/proc-pid-vm.c: hide "segfault at ffffffffff600000" dmesg spam (bca1eac5) · Commits · 戴 / test

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>

tools/testing/selftests/proc/proc-pid-vm.c

+15 −2

Original line number	Diff line number	Diff line
		@@ -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;
		}
		}

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