From: Sven Schnelle <svens@linux.ibm.com>
Date: Fri, 6 Mar 2020 12:19:34 +0000 (+0100)
Subject: s390/ptrace: pass invalid syscall numbers to tracing
X-Git-Tag: v5.10.7~2280^2~14
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=00332c16b1604242a56289ff2b26e283dbad0812;p=platform%2Fkernel%2Flinux-rpi.git

s390/ptrace: pass invalid syscall numbers to tracing

tracing expects to see invalid syscalls, so pass it through.
The syscall path in entry.S checks the syscall number before
looking up the handler, so it is still safe.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
---

diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 50ff6dd..496f74d 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -401,9 +401,9 @@ ENTRY(system_call)
 	jnz	.Lsysc_nr_ok
 	# svc 0: system call number in %r1
 	llgfr	%r1,%r1				# clear high word in r1
+	sth	%r1,__PT_INT_CODE+2(%r11)
 	cghi	%r1,NR_syscalls
 	jnl	.Lsysc_nr_ok
-	sth	%r1,__PT_INT_CODE+2(%r11)
 	slag	%r8,%r1,3
 .Lsysc_nr_ok:
 	xc	__SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index ceb8105..1fdbb2d 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -847,11 +847,9 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
 	 * call number to gprs[2].
 	 */
 	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
-	    (tracehook_report_syscall_entry(regs) ||
-	     regs->gprs[2] >= NR_syscalls)) {
+	    tracehook_report_syscall_entry(regs)) {
 		/*
-		 * Tracing decided this syscall should not happen or the
-		 * debugger stored an invalid system call number. Skip
+		 * Tracing decided this syscall should not happen. Skip
 		 * the system call and the system call restart handling.
 		 */
 		goto skip;