linux-kernel - [PATCH AUTOSEL 5.3 53/89] riscv: avoid sending a SIGTRAP to a user thread trapped in WARN()

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Message-Id: <20191018220324.8165-53-sashal@kernel.org>
Date:   Fri, 18 Oct 2019 18:02:48 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Vincent Chen <vincent.chen@...ive.com>,
        Christoph Hellwig <hch@....de>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 5.3 53/89] riscv: avoid sending a SIGTRAP to a user thread trapped in WARN()

From: Vincent Chen <vincent.chen@...ive.com>

[ Upstream commit e0c0fc18f10d5080cddde0e81505fd3e952c20c4 ]

On RISC-V, when the kernel runs code on behalf of a user thread, and the
kernel executes a WARN() or WARN_ON(), the user thread will be sent
a bogus SIGTRAP.  Fix the RISC-V kernel code to not send a SIGTRAP when
a WARN()/WARN_ON() is executed.

Signed-off-by: Vincent Chen <vincent.chen@...ive.com>
Reviewed-by: Christoph Hellwig <hch@....de>
[paul.walmsley@...ive.com: fixed subject]
Signed-off-by: Paul Walmsley <paul.walmsley@...ive.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/riscv/kernel/traps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index 055a937aca70a..82f42a55451eb 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -134,7 +134,7 @@ asmlinkage void do_trap_break(struct pt_regs *regs)
 			break;
 		case BUG_TRAP_TYPE_WARN:
 			regs->sepc += get_break_insn_length(regs->sepc);
-			break;
+			return;
 		case BUG_TRAP_TYPE_BUG:
 #endif /* CONFIG_GENERIC_BUG */
 		default:
-- 
2.20.1