linux-kernel - [PATCH 11/11] x86/fault: Don't look for extable entries for SMEP violations

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Message-Id: <45fd30a3ef59733d8618fcd3736217b5edda3971.1612113550.git.luto@kernel.org>
Date:   Sun, 31 Jan 2021 09:24:42 -0800
From:   Andy Lutomirski <luto@...nel.org>
To:     x86@...nel.org
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Yonghong Song <yhs@...com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>
Subject: [PATCH 11/11] x86/fault: Don't look for extable entries for SMEP violations

If we get a SMEP violation or a fault that would have been a SMEP
violation if we had SMEP, we shouldn't run fixups.  Just OOPS.

Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Signed-off-by: Andy Lutomirski <luto@...nel.org>
---
 arch/x86/mm/fault.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index d39946ad8a91..08f5f74cf989 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1211,12 +1211,13 @@ void do_user_addr_fault(struct pt_regs *regs,
 		/*
 		 * Whoops, this is kernel mode code trying to execute from
 		 * user memory.  Unless this is AMD erratum #93, we are toast.
-		 * Don't even try to look up the VMA.
+		 * Don't even try to look up the VMA or look for extable
+		 * entries.
 		 */
 		if (is_errata93(regs, address))
 			return;
 
-		bad_area_nosemaphore(regs, error_code, address);
+		page_fault_oops(regs, error_code, address);
 		return;
 	}
 
-- 
2.29.2