Re: [PATCH v1 2/2] LoongArch: Return 0 for user tasks in arch_stack_walk_reliable()

[Tiezhu Yang <yangtiezhu@loongson.cn>]

On 2025/9/11 下午9:44, Miroslav Benes wrote:
> Hi,
> 
> On Tue, 9 Sep 2025, Tiezhu Yang wrote:
> 
>> When testing the kernel live patching with "modprobe livepatch-sample",
>> there is a timeout over 15 seconds from "starting patching transition"
>> to "patching complete", dmesg shows "unreliable stack" for user tasks
>> in debug mode. When executing "rmmod livepatch-sample", there exists
>> the similar issue.
>>
>> Like x86, arch_stack_walk_reliable() should return 0 for user tasks.
>> It is necessary to set regs->csr_prmd as task->thread.csr_prmd first,
>> then use user_mode() to check whether the task is in userspace.
> 
> it is a nice optimization for sure, but "unreliable stack" messages point
> to a fact that the unwinding of these tasks is probably suboptimal and
> could be improved, no?

Yes, makes sense, I will fix "unreliable stack" in the next version.

> It would also be nice to include these messages (not for all tasks) to the
> commit message.

OK, will do it.

Thanks,
Tiezhu