2024-02-02 07:44:02

by alexs

Subject: [PATCH v2] x86/dumpstack: uniform die messages prompt

From: Alex Shi <[email protected]>

panic() has a uniform prompt, like "Kernel panic - not syncing:". That's
easy to indicate a panic there. But die() message doesn't have.

We died thousands machine with very different reasons weekly. w/o a prompt
in dmesg, it's hard to write scripts to collect and anaylis the die reasons.
That makes admins' life pretty hard.

A uniform die() prompt could make the life of system administrators far more
easier.

Signed-off-by: Alex Shi <[email protected]>
To: [email protected]
To: "H. Peter Anvin" <[email protected]>
To: [email protected]
To: Dave Hansen <[email protected]>
To: Borislav Petkov <[email protected]>
To: Ingo Molnar <[email protected]>
To: Thomas Gleixner <[email protected]>
To: Peter Zijlstra <[email protected]>
To: Josh Poimboeuf <[email protected]>
---
arch/x86/kernel/dumpstack.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index f18ca44c904b..e9ad413d21f8 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -393,6 +393,8 @@ void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
}
NOKPROBE_SYMBOL(oops_end);

+#define DIE_PROMPT "DIE:\n"
+
static void __die_header(const char *str, struct pt_regs *regs, long err)
{
const char *pr = "";
@@ -405,8 +407,8 @@ static void __die_header(const char *str, struct pt_regs *regs, long err)
pr = IS_ENABLED(CONFIG_PREEMPT_RT) ? " PREEMPT_RT" : " PREEMPT";

printk(KERN_DEFAULT
- "%s: %04lx [#%d]%s%s%s%s%s\n", str, err & 0xffff, ++die_counter,
- pr,
+ DIE_PROMPT "%s: %04lx [#%d]%s%s%s%s%s\n", str, err & 0xffff,
+ ++die_counter, pr,
IS_ENABLED(CONFIG_SMP) ? " SMP" : "",
debug_pagealloc_enabled() ? " DEBUG_PAGEALLOC" : "",
IS_ENABLED(CONFIG_KASAN) ? " KASAN" : "",
--
2.43.0

2024-03-26 10:43:37

by Borislav Petkov

Subject: Re: [PATCH v2] x86/dumpstack: uniform die messages prompt

On Fri, Feb 02, 2024 at 03:45:12PM +0800, [email protected] wrote:
> @@ -405,8 +407,8 @@ static void __die_header(const char *str, struct pt_regs *regs, long err)
> pr = IS_ENABLED(CONFIG_PREEMPT_RT) ? " PREEMPT_RT" : " PREEMPT";
>
> printk(KERN_DEFAULT
> - "%s: %04lx [#%d]%s%s%s%s%s\n", str, err & 0xffff, ++die_counter,
> - pr,
> + DIE_PROMPT "%s: %04lx [#%d]%s%s%s%s%s\n", str, err & 0xffff,

Why do you need this DIE_PROMPT if you can simply do:

"Oops: %s: %04lx... "

?

And yes, I think I'd prefer having an "oops" in there as it is a lot
more prominent. It is called a "kernel oops" everywhere.

Thx.

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette

2024-03-27 02:33:40

by Alex Shi

Subject: Re: [PATCH v2] x86/dumpstack: uniform die messages prompt

On 3/26/24 6:43 PM, Borislav Petkov wrote:
> On Fri, Feb 02, 2024 at 03:45:12PM +0800, [email protected] wrote:
>> @@ -405,8 +407,8 @@ static void __die_header(const char *str, struct pt_regs *regs, long err)
>> pr = IS_ENABLED(CONFIG_PREEMPT_RT) ? " PREEMPT_RT" : " PREEMPT";
>>
>> printk(KERN_DEFAULT
>> - "%s: %04lx [#%d]%s%s%s%s%s\n", str, err & 0xffff, ++die_counter,
>> - pr,
>> + DIE_PROMPT "%s: %04lx [#%d]%s%s%s%s%s\n", str, err & 0xffff,
>
> Why do you need this DIE_PROMPT if you can simply do:
>
> "Oops: %s: %04lx... "
>
> ?
>
> And yes, I think I'd prefer having an "oops" in there as it is a lot
> more prominent. It is called a "kernel oops" everywhere.

Uh, 'Oops' is also a good preempt. If no other objection, I'd like to change this. :)

Thank a lot!

>
> Thx.
>