linux-kernel - [PATCH 4.9 081/101] nios2: fix syscall restart checks

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Date:   Tue, 23 Aug 2022 10:03:54 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Al Viro <viro@...iv.linux.org.uk>,
        Dinh Nguyen <dinguyen@...nel.org>
Subject: [PATCH 4.9 081/101] nios2: fix syscall restart checks

From: Al Viro <viro@...iv.linux.org.uk>

commit 2d631bd58fe0ea3e3350212e23c9aba1fb606514 upstream.

sys_foo() returns -512 (aka -ERESTARTSYS) => do_signal() sees
512 in r2 and 1 in r1.

sys_foo() returns 512 => do_signal() sees 512 in r2 and 0 in r1.

The former is restart-worthy; the latter obviously isn't.

Fixes: b53e906d255d ("nios2: Signal handling support")
Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
Signed-off-by: Dinh Nguyen <dinguyen@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/nios2/kernel/signal.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/nios2/kernel/signal.c
+++ b/arch/nios2/kernel/signal.c
@@ -240,7 +240,7 @@ static int do_signal(struct pt_regs *reg
 	/*
 	 * If we were from a system call, check for system call restarting...
 	 */
-	if (regs->orig_r2 >= 0) {
+	if (regs->orig_r2 >= 0 && regs->r1) {
 		continue_addr = regs->ea;
 		restart_addr = continue_addr - 4;
 		retval = regs->r2;