Re: [PATCH RFC v3 1/6] exterr: Introduce extended syscall error reporting

[Alexander Shishkin]

Johannes Berg <johannes@xxxxxxxxxxxxxxxx> writes:

> On Tue, 2015-09-15 at 17:15 +0300, Alexander Shishkin wrote:
>> 
>> > It seems to me that current->ext_err_code needs to be cleared on 
>> > each system call entry (except for your special prctl() of 
>> > course!).
>> 
>> I'd say, it should be up to the program to decide for how long they 
>> want to keep the extended error code around.
>> 
>
> I'm not convinced that works - imagine a library wanting to use the
> prctl(), but the main application isn't doing that. Should the library
> clear it before every call, to be sure it's not getting stale data?
> etc.

In other words, a syscall that's capable of throwing an extended error
does clear the current::ext_err_code every time, but not other
syscalls. Otherwise it will indeed get very confusing.

Regards,
--
Alex
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