linux-kernel - [PATCH 1/2] x86/traps: Attempt UMIP fixup only on #GP(0)

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Message-ID: <20231206004654.2986026-2-mhal@rbox.co>
Date:   Wed,  6 Dec 2023 01:43:44 +0100
From:   Michal Luczaj <mhal@...x.co>
To:     x86@...nel.org
Cc:     tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
        dave.hansen@...ux.intel.com, shuah@...nel.org, luto@...nel.org,
        torvalds@...uxfoundation.org, linux-kernel@...r.kernel.org,
        Michal Luczaj <mhal@...x.co>
Subject: [PATCH 1/2] x86/traps: Attempt UMIP fixup only on #GP(0)

Do not allow for UMIP exception fixup if the exception did not come
directly from the user space. This excludes #GP due to a bad IRET.

Signed-off-by: Michal Luczaj <mhal@...x.co>
---
 arch/x86/kernel/traps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index c876f1d36a81..1daa7cd9a76c 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -651,7 +651,7 @@ DEFINE_IDTENTRY_ERRORCODE(exc_general_protection)
 	cond_local_irq_enable(regs);
 
 	if (static_cpu_has(X86_FEATURE_UMIP)) {
-		if (user_mode(regs) && fixup_umip_exception(regs))
+		if (user_mode(regs) && !error_code && fixup_umip_exception(regs))
 			goto exit;
 	}
 
-- 
2.43.0