linux-kernel - [PATCH v2] x86/mce: Always call memory_failure() when there is a valid address

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Date:   Tue, 18 Apr 2023 11:03:43 -0700
From:   Tony Luck <tony.luck@...el.com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     Yazen Ghannam <yazen.ghannam@....com>, x86@...nel.org,
        linux-edac@...r.kernel.org, linux-kernel@...r.kernel.org,
        patches@...ts.linux.dev, Tony Luck <tony.luck@...el.com>
Subject: [PATCH v2] x86/mce: Always call memory_failure() when there is a valid address

Linux should always take poisoned pages offline when there is an error
report with a valid physcal address.

Note1: that call_me_maybe() will correctly handle the case currently
covered by the test of "kill_current_task" that is deleted by this
change because it will set the MF_MUST_KILL flag when p->mce_ripv is
not set.

Note2: This also provides defense against the case where the logged
error doesn't provide a physical address.

Suggested-by: Yazen Ghannam <yazen.ghannam@....com>
Signed-off-by: Tony Luck <tony.luck@...el.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..f72c97860524 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 (mce_usable_address(&m))
 			queue_task_work(&m, msg, kill_me_now);
 		else
 			queue_task_work(&m, msg, kill_me_maybe);
-- 
2.39.2