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From:   Tony Luck <tony.luck@intel.com>
To:     Borislav Petkov <bp@alien8.de>
Cc:     x86@kernel.org, linux-kernel@vger.kernel.org,
        linux-edac@vger.kernel.org, patches@lists.linux.dev,
        Tony Luck <tony.luck@intel.com>
Subject: [PATCH] x86/mce: Check that memory address is usable for recovery
Date:   Tue, 21 Mar 2023 17:51:31 -0700
Message-Id: <20230322005131.174499-1-tony.luck@intel.com>
MIME-Version: 1.0
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Precedence: bulk

uc_decode_notifier() includes a check that "struct mce"
contains a valid address for recovery. But the machine
check recovery code does not include a similar check.

Use mce_usable_address() to check that there is a valid
address.

Signed-off-by: Tony Luck <tony.luck@intel.com>
---
 arch/x86/kernel/cpu/mce/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 2eec60f50057..fa28b3f7d945 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -1533,7 +1533,7 @@ noinstr void do_machine_check(struct pt_regs *regs)
 		/* If this triggers there is no way to recover. Die hard. */
 		BUG_ON(!on_thread_stack() || !user_mode(regs));
 
-		if (kill_current_task)
+		if (kill_current_task || !mce_usable_address(&m))
 			queue_task_work(&m, msg, kill_me_now);
 		else
 			queue_task_work(&m, msg, kill_me_maybe);
-- 
2.39.2