Patch "selftests/x86/ptrace_syscall: Fix for yet more glibc interference" has been added to the 4.14-stable tree

Patch "selftests/x86/ptrace_syscall: Fix for yet more glibc interference" has been added to the 4.14-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    selftests/x86/ptrace_syscall: Fix for yet more glibc interference

to the 4.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     selftests-x86-ptrace_syscall-fix-for-yet-more-glibc-interference.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 4b0b37d4cc54b21a6ecad7271cbc850555869c62 Mon Sep 17 00:00:00 2001
From: Andy Lutomirski <luto@kernel.org>
Date: Sat, 17 Mar 2018 08:25:07 -0700
Subject: selftests/x86/ptrace_syscall: Fix for yet more glibc interference

From: Andy Lutomirski <luto@kernel.org>

commit 4b0b37d4cc54b21a6ecad7271cbc850555869c62 upstream.

glibc keeps getting cleverer, and my version now turns raise() into
more than one syscall.  Since the test relies on ptrace seeing an
exact set of syscalls, this breaks the test.  Replace raise(SIGSTOP)
with syscall(SYS_tgkill, ...) to force glibc to get out of our way.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kselftest@vger.kernel.org
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/bc80338b453afa187bc5f895bd8e2c8d6e264da2.1521300271.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 tools/testing/selftests/x86/ptrace_syscall.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/tools/testing/selftests/x86/ptrace_syscall.c
+++ b/tools/testing/selftests/x86/ptrace_syscall.c
@@ -183,8 +183,10 @@ static void test_ptrace_syscall_restart(
 		if (ptrace(PTRACE_TRACEME, 0, 0, 0) != 0)
 			err(1, "PTRACE_TRACEME");
 
+		pid_t pid = getpid(), tid = syscall(SYS_gettid);
+
 		printf("\tChild will make one syscall\n");
-		raise(SIGSTOP);
+		syscall(SYS_tgkill, pid, tid, SIGSTOP);
 
 		syscall(SYS_gettid, 10, 11, 12, 13, 14, 15);
 		_exit(0);
@@ -301,9 +303,11 @@ static void test_restart_under_ptrace(vo
 		if (ptrace(PTRACE_TRACEME, 0, 0, 0) != 0)
 			err(1, "PTRACE_TRACEME");
 
+		pid_t pid = getpid(), tid = syscall(SYS_gettid);
+
 		printf("\tChild will take a nap until signaled\n");
 		setsigign(SIGUSR1, SA_RESTART);
-		raise(SIGSTOP);
+		syscall(SYS_tgkill, pid, tid, SIGSTOP);
 
 		syscall(SYS_pause, 0, 0, 0, 0, 0, 0);
 		_exit(0);


Patches currently in stable-queue which might be from luto@kernel.org are

queue-4.14/x86-entry-64-don-t-use-ist-entry-for-bp-stack.patch
queue-4.14/selftests-x86-ptrace_syscall-fix-for-yet-more-glibc-interference.patch
queue-4.14/x86-vsyscall-64-use-proper-accessor-to-update-p4d-entry.patch
queue-4.14/kvm-x86-fix-icebp-instruction-handling.patch