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SubjectRe: [PATCH 3/4] LoongArch: Add stacktrace support
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On 2022/8/2 上午9:30, Huacai Chen wrote:
> Hi, Qing,
>
> On Tue, Aug 2, 2022 at 9:20 AM zhangqing <zhangqing@loongson.cn> wrote:
>>
>>
>>
>> On 2022/8/1 下午11:30, Huacai Chen wrote:
>>> Hi, Qing,
>>>
>>> On Mon, Aug 1, 2022 at 8:17 PM Qing Zhang <zhangqing@loongson.cn> wrote:
>>>>
>>>> Use common arch_stack_walk infrastructure to avoid duplicated code and
>>>> avoid taking care of the stack storage and filtering.
>>>> Add sra (means __schedule return address) and scfa (means __schedule call
>>>> frame address) to thread_info and store it in switch_to().
>>>>
>>>> Now we can print the process stack by cat /proc/*/stack and can better
>>>> support ftrace.
>>>>
>>>> Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
>>>> ---
>>>> arch/loongarch/Kconfig | 5 ++++
>>>> arch/loongarch/include/asm/processor.h | 9 +++++++
>>>> arch/loongarch/include/asm/switch_to.h | 14 ++++++----
>>>> arch/loongarch/include/asm/uaccess.h | 4 +--
>>>> arch/loongarch/kernel/Makefile | 1 +
>>>> arch/loongarch/kernel/asm-offsets.c | 2 ++
>>>> arch/loongarch/kernel/process.c | 3 +++
>>>> arch/loongarch/kernel/stacktrace.c | 37 ++++++++++++++++++++++++++
>>>> arch/loongarch/kernel/switch.S | 2 ++
>>>> 9 files changed, 70 insertions(+), 7 deletions(-)
>>>> create mode 100644 arch/loongarch/kernel/stacktrace.c
>>>>
>>>> diff --git a/arch/loongarch/include/asm/uaccess.h b/arch/loongarch/include/asm/uaccess.h
>>>> index 2b44edc604a2..a8ae2af4025a 100644
>>>> --- a/arch/loongarch/include/asm/uaccess.h
>>>> +++ b/arch/loongarch/include/asm/uaccess.h
>>>> @@ -229,13 +229,13 @@ extern unsigned long __copy_user(void *to, const void *from, __kernel_size_t n);
>>>> static inline unsigned long __must_check
>>>> raw_copy_from_user(void *to, const void __user *from, unsigned long n)
>>>> {
>>>> - return __copy_user(to, from, n);
>>>> + return __copy_user(to, (__force const void *)from, n);
>>>> }
>>>>
>>>> static inline unsigned long __must_check
>>>> raw_copy_to_user(void __user *to, const void *from, unsigned long n)
>>>> {
>>>> - return __copy_user(to, from, n);
>>>> + return __copy_user((__force void *)to, from, n);
>>> Why this? Does it have something to do with stacktrace?
>>>
>>> Huacai
>>
>> Hi, huacai
>>
>> This is kernel test robot report sparse warnings:
>> I reproduced locally and found that other architectures calling
>> __copy_user also use __force conversion, Is this modification appropriate?
>>
>> kernel/trace/trace_events_user.c: note: in included file (through
>> include/linux/uaccess.h, include/linux/sched/task.h,
>> include/linux/sched/signal.h, ...):
>> arch/loongarch/include/asm/uaccess.h:232:32: sparse: sparse:
>> incorrect type in argument 2 (different address spaces) @@ expected
>> void const *from @@ got void const [noderef] __user *from @@
>> arch/loongarch/include/asm/uaccess.h:232:32: sparse: expected
>> void const *from
>> arch/loongarch/include/asm/uaccess.h:232:32: sparse: got void
>> const [noderef] __user *from
> The modification might be correct, but should it be in this patch?
>
> Huacai
I will send this patch separately, it has nothing to do with the series
patch.

arch/loongarch/kernel/ptrace.c: note: in included file (through
include/linux/uaccess.h, include/linux/sched/task.h,
include/linux/sched/signal.h, include/linux/ptrace.h, include/linux/audit.h)

-Qing
>>
>> Thanks,
>> -Qing
>>
>>
>>

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