linux-kernel - [PATCH 2/4] signal/x86: do_signal: syscall restart should be done only once.

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Message-Id: <20180320023857.1885-3-gniibe@fsij.org>
Date:   Tue, 20 Mar 2018 11:38:55 +0900
From:   NIIBE Yutaka <gniibe@...j.org>
To:     linux-kernel@...r.kernel.org
Cc:     gniibe@...j.org
Subject: [PATCH 2/4] signal/x86: do_signal: syscall restart should be done only once.

do_signal may be called multiple times from exit_to_usermode_loop.  In
those multiple calls, only the one should handle restarting the system
call.

When actually delivering a signal, make sure the register will not be
examined again as syscall errno by another call of do_signal.

Signed-off-by: NIIBE Yutaka <gniibe@...j.org>
---
 arch/x86/kernel/signal.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index cdfb82031243..e709b54a01b8 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -729,6 +729,7 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 			regs->ip -= 2;
 			break;
 		}
+		regs->orig_ax = -1;
 	}

 	/*
-- 
2.11.0