Re: [PATCH v2 12/12] linux-user: fix clock_nanosleep()

[Laurent Vivier]

Le 22/07/2020 à 10:55, Alex Bennée a écrit :
> 
> Laurent Vivier <laurent@vivier.eu> writes:
> 
>> Le 22/07/2020 à 08:29, Alex Bennée a écrit :
>>> From: Laurent Vivier <laurent@vivier.eu>
>>>
>>> If clock_nanosleep() encounters an error, it returns one of the positive
>>> error number.
>>>
>>> If the call is interrupted by a signal handler, it fails with error EINTR
>>> and if "remain" is not NULL and "flags" is not TIMER_ABSTIME, it returns
>>> the remaining unslept time in "remain".
>>>
>>> Update linux-user to not overwrite the "remain" structure if there is no
>>> error.
>>>
>>> Found with "make check-tcg", linux-test fails on nanosleep test:
>>>
>>>   TEST    linux-test on x86_64
>>> .../tests/tcg/multiarch/linux-test.c:242: nanosleep
>>> make[2]: *** [../Makefile.target:153: run-linux-test] Error 1
>>> make[1]: *** [.../tests/tcg/Makefile.qemu:76: run-guest-tests] Error 2
>>> make: *** [.../tests/Makefile.include:857: run-tcg-tests-x86_64-linux-user] 
>>> Error 2
>>>
>>> Reported-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
>>> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
>>> Message-Id: <20200721201754.2731479-1-laurent@vivier.eu>
>>> ---
>>>  linux-user/syscall.c | 15 ++++++++++++---
>>>  1 file changed, 12 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
>>> index 1211e759c26..caa7cd3cab9 100644
>>> --- a/linux-user/syscall.c
>>> +++ b/linux-user/syscall.c
>>> @@ -11829,10 +11829,19 @@ static abi_long do_syscall1(void *cpu_env, int 
>>> num, abi_long arg1,
>>>      {
>>>          struct timespec ts;
>>>          target_to_host_timespec(&ts, arg3);
>>> -        ret = get_errno(safe_clock_nanosleep(arg1, arg2,
>>> -                                             &ts, arg4 ? &ts : NULL));
>>> -        if (arg4)
>>> +        /*
>>> +         * clock_nanosleep() returns 0 or one of the *positive* error 
>>> number.
>>> +         */
>>> +        ret = host_to_target_errno(safe_clock_nanosleep(arg1, arg2, &ts,
>>> +                                                        arg4 ? &ts : 
>>> NULL));
>>> +        /*
>>> +         * if the call is interrupted by a signal handler, it fails
>>> +         * with error TARGET_EINTR and if arg4 is not NULL and arg2 is not
>>> +         * TIMER_ABSTIME, it returns the remaining unslept time in arg4.
>>> +         */
>>> +        if (ret == TARGET_EINTR && arg4 && arg2 != TIMER_ABSTIME) {
>>>              host_to_target_timespec(arg4, &ts);
>>> +        }
>>>  
>>>  #if defined(TARGET_PPC)
>>>          /* clock_nanosleep is odd in that it returns positive errno values.
>>>
>>
>> Wait a little before pushing that: I've made more tests and it seems to
>> break something in LTP. I have to analyze.
> 
> OK - which LTP test does it break?

clock_nanosleep01

> 
> I can drop from the PR if we don't have a clean-up by then (Fri?).

I have a fix. I'm testing it. I will send the v2 today.

https://github.com/vivier/qemu/commit/25060f425e71c57112a334d9930f234011d079a1

Thanks,
Laurent