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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Rich Felker <dalias@libc.org>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.4 158/268] sh: fix debug trap failure to process signals before return to user
Date:   Mon, 28 May 2018 12:02:12 +0200
Message-Id: <20180528100220.362000978@linuxfoundation.org>
In-Reply-To: <20180528100202.045206534@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Rich Felker <dalias@libc.org>

[ Upstream commit 96a598996f6ac518ac79839ecbb17c91af91f4f7 ]

When responding to a debug trap (breakpoint) in userspace, the
kernel's trap handler raised SIGTRAP but returned from the trap via a
code path that ignored pending signals, resulting in an infinite loop
re-executing the trapping instruction.

Signed-off-by: Rich Felker <dalias@libc.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/sh/kernel/entry-common.S |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/sh/kernel/entry-common.S
+++ b/arch/sh/kernel/entry-common.S
@@ -255,7 +255,7 @@ debug_trap:
 	mov.l	@r8, r8
 	jsr	@r8
 	 nop
-	bra	__restore_all
+	bra	ret_from_exception
 	 nop
 	CFI_ENDPROC