linux-kernel - Re: [PATCH v4 3/4] MIPS: Return earlier in die() if notify_die() returns NOTIFY

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Date:   Tue, 22 Aug 2023 16:55:26 +0800
From:   Tiezhu Yang <yangtiezhu@...ngson.cn>
To:     Huacai Chen <chenhuacai@...nel.org>
Cc:     Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        "Maciej W. Rozycki" <macro@...am.me.uk>,
        linux-mips@...r.kernel.org, linux-kernel@...r.kernel.org,
        loongson-kernel@...ts.loongnix.cn
Subject: Re: [PATCH v4 3/4] MIPS: Return earlier in die() if notify_die()
 returns NOTIFY_STOP



On 08/22/2023 03:38 PM, Huacai Chen wrote:
> On Mon, Aug 21, 2023 at 10:29 AM Tiezhu Yang <yangtiezhu@...ngson.cn> wrote:
>>
>>
>>
>> On 08/20/2023 04:53 PM, Huacai Chen wrote:
>>> Hi, Tiezhu,
>>>
>>> On Sun, Aug 20, 2023 at 7:21 AM Tiezhu Yang <yangtiezhu@...ngson.cn> wrote:
>>>>
>>>> After the call to oops_exit(), it should not panic or execute
>>>> the crash kernel if the oops is to be suppressed.
>>>>
>>>> Suggested-by: Maciej W. Rozycki <macro@...am.me.uk>
>>>> Signed-off-by: Tiezhu Yang <yangtiezhu@...ngson.cn>
>>>> ---
>>>>  arch/mips/kernel/traps.c | 6 ++++--
>>>>  1 file changed, 4 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
>>>> index 8e528a8..fd770dc 100644
>>>> --- a/arch/mips/kernel/traps.c
>>>> +++ b/arch/mips/kernel/traps.c
>>>> @@ -412,6 +412,9 @@ void die(const char *str, struct pt_regs *regs)
>>>>
>>>>         oops_exit();
>>>>
>>>> +       if (ret == NOTIFY_STOP)
>>>> +               return;
>>>> +
>>>>         if (in_interrupt())
>>>>                 panic("Fatal exception in interrupt");
>>>>
>>>> @@ -421,8 +424,7 @@ void die(const char *str, struct pt_regs *regs)
>>>>         if (regs && kexec_should_crash(current))
>>>>                 crash_kexec(regs);
>>>>
>>>> -       if (ret != NOTIFY_STOP)
>>>> -               make_task_dead(SIGSEGV);
>>>> +       make_task_dead(SIGSEGV);
>>> Then you call make_task_dead() at the end unconditionally, and die()
>>> becomes a noreturn function again.
>>
>> No, it can return if (ret == NOTIFY_STOP), so die() is a return
>> function now, please see objdump -d arch/mips/kernel/traps.o.
> Then should loongarch patches need to be updated, too?

Yes, I think so, will do it.

Thanks,
Tiezhu