x86: Test and fix a minor compat entry regression

PATCH New Andy Lutomirski 2 participants 5 messages Feb 10, 2016 – Feb 17, 2016

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Andy Lutomirski

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2016-02-10 22:15 UTC #0 lore raw

cover x86: Test and fix a minor compat entry regression

I broke certain cases of compat syscall restart under ptrace. Here's a test and a fix.

Andy Lutomirski (3):
selftests/x86: Fix some error messages in ptrace_syscall selftests/x86: Add a test for syscall restart under ptrace x86/entry/compat: Keep TS_COMPAT set during signal delivery

 arch/x86/entry/common.c                      |  23 +++--
 tools/testing/selftests/x86/ptrace_syscall.c | 132 ++++++++++++++++++++++++++-
 2 files changed, 142 insertions(+), 13 deletions(-)

Signature · 1 line

2.5.0

Andy Lutomirski

author

2016-02-10 22:15 UTC #1 lore raw

PATCH 1/3 selftests/x86: Fix some error messages in ptrace_syscall

I had some obvious typos.

Signed-off-by Andy Lutomirski <[email protected]>

---
 tools/testing/selftests/x86/ptrace_syscall.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

tools/testing/selftests/x86/ptrace_syscall.c +3 -3

index 5105b49cd8aa..c6a0acc0a632 100644
@@ -187,7 +187,7 @@ static void test_ptrace_syscall_restart(void)
 
 	printf("[RUN]\tSYSEMU\n");
 	if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0)
-		err(1, "PTRACE_SYSCALL");
+		err(1, "PTRACE_SYSEMU");
 	wait_trap(chld);
 
 	if (ptrace(PTRACE_GETREGS, chld, 0, &regs) != 0)

@@ -218,7 +218,7 @@ static void test_ptrace_syscall_restart(void)
 		err(1, "PTRACE_SETREGS");
 
 	if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0)
-		err(1, "PTRACE_SYSCALL");
+		err(1, "PTRACE_SYSEMU");
 	wait_trap(chld);
 
 	if (ptrace(PTRACE_GETREGS, chld, 0, &regs) != 0)

@@ -250,7 +250,7 @@ static void test_ptrace_syscall_restart(void)
 		err(1, "PTRACE_SETREGS");
 
 	if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0)
-		err(1, "PTRACE_SYSCALL");
+		err(1, "PTRACE_SYSEMU");
 	wait_trap(chld);
 
 	if (ptrace(PTRACE_GETREGS, chld, 0, &regs) != 0)

Signature · 1 line

2.5.0

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merge bot

2016-02-17 12:16 UTC #2 lore raw

[tip:x86/asm] selftests/x86: Fix some error messages in ptrace_syscall

selftests/x86: Fix some error messages in ptrace_syscall

Commit-ID:  adcfd23ead69965e3ac3e69f56451dab5e39157a
Gitweb:     http://git.kernel.org/tip/adcfd23ead69965e3ac3e69f56451dab5e39157a
Author:     Andy Lutomirski <[email protected]>
AuthorDate: Wed, 10 Feb 2016 14:15:25 -0800
Committer:  Ingo Molnar <[email protected]>
CommitDate: Wed, 17 Feb 2016 09:51:06 +0100

selftests/x86: Fix some error messages in ptrace_syscall

I had some obvious typos.

Signed-off-by Andy Lutomirski <[email protected]>

Cc Al Viro <[email protected]>

Cc Andy Lutomirski <[email protected]>

Cc Borislav Petkov <[email protected]>

Cc Brian Gerst <[email protected]>

Cc Denys Vlasenko <[email protected]>

Cc H. Peter Anvin <[email protected]>

Cc Linus Torvalds <[email protected]>

Cc Peter Zijlstra <[email protected]>

Cc Robert O'Callahan <[email protected]>

Cc Shuah Khan <[email protected]>

Cc Thomas Gleixner <[email protected]>

Link http://lkml.kernel.org/r/e5e6772d4802986cf7df702e646fa24ac14f2204.1455142412.git.luto@kernel.org open here

Signed-off-by Ingo Molnar <[email protected]>

---
 tools/testing/selftests/x86/ptrace_syscall.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

tools/testing/selftests/x86/ptrace_syscall.c +3 -3

index 5105b49..c6a0acc 100644
@@ -187,7 +187,7 @@ static void test_ptrace_syscall_restart(void)
 
 	printf("[RUN]\tSYSEMU\n");
 	if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0)
-		err(1, "PTRACE_SYSCALL");
+		err(1, "PTRACE_SYSEMU");
 	wait_trap(chld);
 
 	if (ptrace(PTRACE_GETREGS, chld, 0, &regs) != 0)

@@ -218,7 +218,7 @@ static void test_ptrace_syscall_restart(void)
 		err(1, "PTRACE_SETREGS");
 
 	if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0)
-		err(1, "PTRACE_SYSCALL");
+		err(1, "PTRACE_SYSEMU");
 	wait_trap(chld);
 
 	if (ptrace(PTRACE_GETREGS, chld, 0, &regs) != 0)

@@ -250,7 +250,7 @@ static void test_ptrace_syscall_restart(void)
 		err(1, "PTRACE_SETREGS");
 
 	if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0)
-		err(1, "PTRACE_SYSCALL");
+		err(1, "PTRACE_SYSEMU");
 	wait_trap(chld);
 
 	if (ptrace(PTRACE_GETREGS, chld, 0, &regs) != 0)

Andy Lutomirski

author

2016-02-10 22:15 UTC #3 lore raw

PATCH 2/3 selftests/x86: Add a test for syscall restart under ptrace

In reply to Andy Lutomirski

This catches a regression from the compat syscall rework. The 32-bit variant of this test currently fails. The issue is that, for a 32-bit tracer and a 32-bit tracee, GETREGS+SETREGS with no changes should be a no-op. It currently isn't a no-op if RAX indicates signal restart, because the high bits get cleared and the kernel loses track of the restart state.

Reported-by Robert O'Callahan <[email protected]>

Signed-off-by Andy Lutomirski <[email protected]>

---
 tools/testing/selftests/x86/ptrace_syscall.c | 126 +++++++++++++++++++++++++++
 1 file changed, 126 insertions(+)

tools/testing/selftests/x86/ptrace_syscall.c +126 -0

index c6a0acc0a632..421456784bc6 100644
@@ -103,6 +103,17 @@ static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
 		err(1, "sigaction");
 }
 
+static void setsigign(int sig, int flags)
+{
+	struct sigaction sa;
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_sigaction = (void *)SIG_IGN;
+	sa.sa_flags = flags;
+	sigemptyset(&sa.sa_mask);
+	if (sigaction(sig, &sa, 0))
+		err(1, "sigaction");
+}
+
 static void clearhandler(int sig)
 {
 	struct sigaction sa;

@@ -277,6 +288,119 @@ static void test_ptrace_syscall_restart(void)
 	}
 }
 
+static void test_restart_under_ptrace(void)
+{
+	printf("[RUN]\tkernel syscall restart under ptrace\n");
+	pid_t chld = fork();
+	if (chld < 0)
+		err(1, "fork");
+
+	if (chld == 0) {
+		if (ptrace(PTRACE_TRACEME, 0, 0, 0) != 0)
+			err(1, "PTRACE_TRACEME");
+
+		printf("\tChild will take a nap until signaled\n");
+		setsigign(SIGUSR1, SA_RESTART);
+		raise(SIGSTOP);
+
+		syscall(SYS_pause, 0, 0, 0, 0, 0, 0);
+		_exit(0);
+	}
+
+	int status;
+
+	/* Wait for SIGSTOP. */
+	if (waitpid(chld, &status, 0) != chld || !WIFSTOPPED(status))
+		err(1, "waitpid");
+
+	struct user_regs_struct regs;
+
+	printf("[RUN]\tSYSCALL\n");
+	if (ptrace(PTRACE_SYSCALL, chld, 0, 0) != 0)
+		err(1, "PTRACE_SYSCALL");
+	wait_trap(chld);
+
+	/* We should be stopped at pause(2) entry. */
+
+	if (ptrace(PTRACE_GETREGS, chld, 0, &regs) != 0)
+		err(1, "PTRACE_GETREGS");
+
+	if (regs.user_syscall_nr != SYS_pause ||
+	    regs.user_arg0 != 0 || regs.user_arg1 != 0 ||
+	    regs.user_arg2 != 0 || regs.user_arg3 != 0 ||
+	    regs.user_arg4 != 0 || regs.user_arg5 != 0) {
+		printf("[FAIL]\tInitial args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5);
+		nerrs++;
+	} else {
+		printf("[OK]\tInitial nr and args are correct\n");
+	}
+
+	/* Interrupt it. */
+	kill(chld, SIGUSR1);
+
+	/* Advance.  We should be stopped at exit. */
+	printf("[RUN]\tSYSCALL\n");
+	if (ptrace(PTRACE_SYSCALL, chld, 0, 0) != 0)
+		err(1, "PTRACE_SYSCALL");
+	wait_trap(chld);
+
+	if (ptrace(PTRACE_GETREGS, chld, 0, &regs) != 0)
+		err(1, "PTRACE_GETREGS");
+
+	if (regs.user_syscall_nr != SYS_pause ||
+	    regs.user_arg0 != 0 || regs.user_arg1 != 0 ||
+	    regs.user_arg2 != 0 || regs.user_arg3 != 0 ||
+	    regs.user_arg4 != 0 || regs.user_arg5 != 0) {
+		printf("[FAIL]\tArgs after SIGUSR1 are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5);
+		nerrs++;
+	} else {
+		printf("[OK]\tArgs after SIGUSR1 are correct (ax = %ld)\n",
+		       (long)regs.user_ax);
+	}
+
+	/* Poke the regs back in.  This must not break anything. */
+	if (ptrace(PTRACE_SETREGS, chld, 0, &regs) != 0)
+		err(1, "PTRACE_SETREGS");
+
+	/* Catch the (ignored) SIGUSR1. */
+	if (ptrace(PTRACE_CONT, chld, 0, 0) != 0)
+		err(1, "PTRACE_CONT");
+	if (waitpid(chld, &status, 0) != chld)
+		err(1, "waitpid");
+	if (!WIFSTOPPED(status)) {
+		printf("[FAIL]\tChild was stopped for SIGUSR1 (status = 0x%x)\n", status);
+		nerrs++;
+	} else {
+		printf("[OK]\tChild got SIGUSR1\n");
+	}
+
+	/* The next event should be pause(2) again. */
+	printf("[RUN]\tStep again\n");
+	if (ptrace(PTRACE_SYSCALL, chld, 0, 0) != 0)
+		err(1, "PTRACE_SYSCALL");
+	wait_trap(chld);
+
+	/* We should be stopped at pause(2) entry. */
+
+	if (ptrace(PTRACE_GETREGS, chld, 0, &regs) != 0)
+		err(1, "PTRACE_GETREGS");
+
+	if (regs.user_syscall_nr != SYS_pause ||
+	    regs.user_arg0 != 0 || regs.user_arg1 != 0 ||
+	    regs.user_arg2 != 0 || regs.user_arg3 != 0 ||
+	    regs.user_arg4 != 0 || regs.user_arg5 != 0) {
+		printf("[FAIL]\tpause did not restart (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5);
+		nerrs++;
+	} else {
+		printf("[OK]\tpause(2) restarted correctly\n");
+	}
+
+	/* Kill it. */
+	kill(chld, SIGKILL);
+	if (waitpid(chld, &status, 0) != chld)
+		err(1, "waitpid");
+}
+
 int main()
 {
 	printf("[RUN]\tCheck int80 return regs\n");

@@ -290,5 +414,7 @@ int main()
 
 	test_ptrace_syscall_restart();
 
+	test_restart_under_ptrace();
+
 	return 0;
 }

Signature · 1 line

2.5.0

tip-bot for Andy Lutomirski

merge bot

2016-02-17 12:16 UTC #4 lore raw

[tip:x86/asm] selftests/x86: Add a test for syscall restart under ptrace

selftests/x86: Add a test for syscall restart under ptrace

Commit-ID:  403613432222549727e5d70cf44da8987653202a
Gitweb:     http://git.kernel.org/tip/403613432222549727e5d70cf44da8987653202a
Author:     Andy Lutomirski <[email protected]>
AuthorDate: Wed, 10 Feb 2016 14:15:26 -0800
Committer:  Ingo Molnar <[email protected]>
CommitDate: Wed, 17 Feb 2016 09:51:06 +0100

selftests/x86: Add a test for syscall restart under ptrace

Reported-by Robert O'Callahan <[email protected]>

Signed-off-by Andy Lutomirski <[email protected]>

Cc Al Viro <[email protected]>

Cc Andy Lutomirski <[email protected]>

Cc Borislav Petkov <[email protected]>

Cc Brian Gerst <[email protected]>

Cc Denys Vlasenko <[email protected]>

Cc H. Peter Anvin <[email protected]>

Cc Linus Torvalds <[email protected]>

Cc Peter Zijlstra <[email protected]>

Cc Shuah Khan <[email protected]>

Cc Thomas Gleixner <[email protected]>

Link http://lkml.kernel.org/r/c4040b40b5b4a37ed31375a69b683f753ec6788a.1455142412.git.luto@kernel.org open here

Signed-off-by Ingo Molnar <[email protected]>

---
 tools/testing/selftests/x86/ptrace_syscall.c | 126 +++++++++++++++++++++++++++
 1 file changed, 126 insertions(+)

tools/testing/selftests/x86/ptrace_syscall.c +126 -0

index c6a0acc..4214567 100644
@@ -103,6 +103,17 @@ static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
 		err(1, "sigaction");
 }
 
+static void setsigign(int sig, int flags)
+{
+	struct sigaction sa;
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_sigaction = (void *)SIG_IGN;
+	sa.sa_flags = flags;
+	sigemptyset(&sa.sa_mask);
+	if (sigaction(sig, &sa, 0))
+		err(1, "sigaction");
+}
+
 static void clearhandler(int sig)
 {
 	struct sigaction sa;

@@ -277,6 +288,119 @@ static void test_ptrace_syscall_restart(void)
 	}
 }
 
+static void test_restart_under_ptrace(void)
+{
+	printf("[RUN]\tkernel syscall restart under ptrace\n");
+	pid_t chld = fork();
+	if (chld < 0)
+		err(1, "fork");
+
+	if (chld == 0) {
+		if (ptrace(PTRACE_TRACEME, 0, 0, 0) != 0)
+			err(1, "PTRACE_TRACEME");
+
+		printf("\tChild will take a nap until signaled\n");
+		setsigign(SIGUSR1, SA_RESTART);
+		raise(SIGSTOP);
+
+		syscall(SYS_pause, 0, 0, 0, 0, 0, 0);
+		_exit(0);
+	}
+
+	int status;
+
+	/* Wait for SIGSTOP. */
+	if (waitpid(chld, &status, 0) != chld || !WIFSTOPPED(status))
+		err(1, "waitpid");
+
+	struct user_regs_struct regs;
+
+	printf("[RUN]\tSYSCALL\n");
+	if (ptrace(PTRACE_SYSCALL, chld, 0, 0) != 0)
+		err(1, "PTRACE_SYSCALL");
+	wait_trap(chld);
+
+	/* We should be stopped at pause(2) entry. */
+
+	if (ptrace(PTRACE_GETREGS, chld, 0, &regs) != 0)
+		err(1, "PTRACE_GETREGS");
+
+	if (regs.user_syscall_nr != SYS_pause ||
+	    regs.user_arg0 != 0 || regs.user_arg1 != 0 ||
+	    regs.user_arg2 != 0 || regs.user_arg3 != 0 ||
+	    regs.user_arg4 != 0 || regs.user_arg5 != 0) {
+		printf("[FAIL]\tInitial args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5);
+		nerrs++;
+	} else {
+		printf("[OK]\tInitial nr and args are correct\n");
+	}
+
+	/* Interrupt it. */
+	kill(chld, SIGUSR1);
+
+	/* Advance.  We should be stopped at exit. */
+	printf("[RUN]\tSYSCALL\n");
+	if (ptrace(PTRACE_SYSCALL, chld, 0, 0) != 0)
+		err(1, "PTRACE_SYSCALL");
+	wait_trap(chld);
+
+	if (ptrace(PTRACE_GETREGS, chld, 0, &regs) != 0)
+		err(1, "PTRACE_GETREGS");
+
+	if (regs.user_syscall_nr != SYS_pause ||
+	    regs.user_arg0 != 0 || regs.user_arg1 != 0 ||
+	    regs.user_arg2 != 0 || regs.user_arg3 != 0 ||
+	    regs.user_arg4 != 0 || regs.user_arg5 != 0) {
+		printf("[FAIL]\tArgs after SIGUSR1 are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5);
+		nerrs++;
+	} else {
+		printf("[OK]\tArgs after SIGUSR1 are correct (ax = %ld)\n",
+		       (long)regs.user_ax);
+	}
+
+	/* Poke the regs back in.  This must not break anything. */
+	if (ptrace(PTRACE_SETREGS, chld, 0, &regs) != 0)
+		err(1, "PTRACE_SETREGS");
+
+	/* Catch the (ignored) SIGUSR1. */
+	if (ptrace(PTRACE_CONT, chld, 0, 0) != 0)
+		err(1, "PTRACE_CONT");
+	if (waitpid(chld, &status, 0) != chld)
+		err(1, "waitpid");
+	if (!WIFSTOPPED(status)) {
+		printf("[FAIL]\tChild was stopped for SIGUSR1 (status = 0x%x)\n", status);
+		nerrs++;
+	} else {
+		printf("[OK]\tChild got SIGUSR1\n");
+	}
+
+	/* The next event should be pause(2) again. */
+	printf("[RUN]\tStep again\n");
+	if (ptrace(PTRACE_SYSCALL, chld, 0, 0) != 0)
+		err(1, "PTRACE_SYSCALL");
+	wait_trap(chld);
+
+	/* We should be stopped at pause(2) entry. */
+
+	if (ptrace(PTRACE_GETREGS, chld, 0, &regs) != 0)
+		err(1, "PTRACE_GETREGS");
+
+	if (regs.user_syscall_nr != SYS_pause ||
+	    regs.user_arg0 != 0 || regs.user_arg1 != 0 ||
+	    regs.user_arg2 != 0 || regs.user_arg3 != 0 ||
+	    regs.user_arg4 != 0 || regs.user_arg5 != 0) {
+		printf("[FAIL]\tpause did not restart (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5);
+		nerrs++;
+	} else {
+		printf("[OK]\tpause(2) restarted correctly\n");
+	}
+
+	/* Kill it. */
+	kill(chld, SIGKILL);
+	if (waitpid(chld, &status, 0) != chld)
+		err(1, "waitpid");
+}
+
 int main()
 {
 	printf("[RUN]\tCheck int80 return regs\n");

@@ -290,5 +414,7 @@ int main()
 
 	test_ptrace_syscall_restart();
 
+	test_restart_under_ptrace();
+
 	return 0;
 }