2023-08-20 11:38:37

by Huacai Chen

Subject: Re: [PATCH v4 3/4] MIPS: Return earlier in die() if notify_die() returns NOTIFY_STOP

Hi, Tiezhu,

On Sun, Aug 20, 2023 at 7:21 AM Tiezhu Yang <[email protected]> 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 <[email protected]>
> Signed-off-by: Tiezhu Yang <[email protected]>
> ---
> 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.

Huacai
> }
>
> extern struct exception_table_entry __start___dbe_table[];
> --
> 2.1.0
>

2023-08-21 04:22:28

by Tiezhu Yang

Subject: Re: [PATCH v4 3/4] MIPS: Return earlier in die() if notify_die() returns NOTIFY_STOP

On 08/20/2023 04:53 PM, Huacai Chen wrote:
> Hi, Tiezhu,
>
> On Sun, Aug 20, 2023 at 7:21 AM Tiezhu Yang <[email protected]> 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 <[email protected]>
>> Signed-off-by: Tiezhu Yang <[email protected]>
>> ---
>> 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.

Thanks,
Tiezhu

2023-08-22 13:23:49

by Huacai Chen

Subject: Re: [PATCH v4 3/4] MIPS: Return earlier in die() if notify_die() returns NOTIFY_STOP

On Mon, Aug 21, 2023 at 10:29 AM Tiezhu Yang <[email protected]> wrote:
>
>
>
> On 08/20/2023 04:53 PM, Huacai Chen wrote:
> > Hi, Tiezhu,
> >
> > On Sun, Aug 20, 2023 at 7:21 AM Tiezhu Yang <[email protected]> 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 <[email protected]>
> >> Signed-off-by: Tiezhu Yang <[email protected]>
> >> ---
> >> 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?

Huacai
>
> Thanks,
> Tiezhu
>