From: Huang Shijie <shijie@os.amperecomputing.com>
To: catalin.marinas@arm.com
Cc: will@kernel.org, tabba@google.com, ardb@kernel.org,
mark.rutland@arm.com, pasha.tatashin@soleen.com,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, patches@amperecomputing.com,
zwang@amperecomputing.com,
Huang Shijie <shijie@os.amperecomputing.com>
Subject: [PATCH] arm64: kexec: flush log to console in nmi_panic()
Date: Thu, 17 Jun 2021 12:50:23 +0000 [thread overview]
Message-ID: <20210617125023.7288-1-shijie@os.amperecomputing.com> (raw)
If kdump is configured, nmi_panic() may run to machine_kexec().
But in NMI context, the log is put in PER-CPU nmi_print_seq.
So we can not see any log on the console since we entered the NMI context,
such as the "Bye!" in previous line.
This patch fixes this issue by two steps:
1) Uses printk_safe_flush_on_panic() to flush the log from
nmi_print_seq to global printk ring buffer,
2) Then uses console_flush_on_panic() to flush to console.
After this patch, we can see the "Bye!" log in the panic console.
Signed-off-by: Huang Shijie <shijie@os.amperecomputing.com>
---
arch/arm64/kernel/machine_kexec.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 213d56c14f60..0ab841dab9db 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -6,6 +6,7 @@
* Copyright (C) Huawei Futurewei Technologies.
*/
+#include <linux/console.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>
@@ -189,6 +190,12 @@ void machine_kexec(struct kimage *kimage)
pr_info("Bye!\n");
+ if (in_nmi()) {
+ /* Flush the log to console if we are in NMI context */
+ printk_safe_flush_on_panic();
+ console_flush_on_panic(CONSOLE_FLUSH_PENDING);
+ }
+
local_daif_mask();
/*
--
2.30.2
next reply other threads:[~2021-06-17 4:51 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-17 12:50 Huang Shijie [this message]
2021-06-17 17:52 ` [PATCH] arm64: kexec: flush log to console in nmi_panic() Will Deacon
2021-06-17 17:55 ` Pavel Tatashin
2021-06-17 17:58 ` Will Deacon
2021-06-18 9:03 ` Huang Shijie
2021-06-21 10:08 ` Will Deacon
2021-06-22 10:14 ` Huang Shijie
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