Re: [Valgrind-users] SfMayBlock with fuse-compatible

[Radoslaw K. <ku...@9l...>]

W dniu 08.12.2016 o 17:24, Ivo Raisr pisze:
>
>
> 2016-12-08 11:28 GMT+01:00 Radoslaw Kujawa <ku...@9l... 
> <mailto:ku...@9l...>>:
>
>
>     W dniu 08.12.2016 o 11:12, Ivo Raisr pisze:
>>
>>
>>     2016-12-07 13:54 GMT+01:00 Radoslaw Kujawa <ku...@9l...
>>     <mailto:ku...@9l...>>:
>>
>>         Hi Ivo,
>>
>>         here is the log that appeared when we switched on trace-syscalls:
>>
>>         SYSCALL[28094,1](89) sys_readlink (
>>         0x374581b667(/proc/self/exe), 0xffeffec10, 4096 ) -->
>>         [pre-success] Success(0x52)
>>         valgrind: m_syswrap/syswrap-main.c:1938
>>         (vgPlain_client_syscall): Assertion '0 == (sci->flags &
>>         ~(SfPollAfter | SfYieldAfter | SfNoWriteResult))' failed.
>>
>>
>>     Hi Radek,
>>
>>     Thanks to the log you provided, I was able to quickly analyse the
>>     situation and get to the root cause.
>>     Pre-syscall wrapper for sys_readlink in syswrap-generic.c sets
>>     SfMayBlock unconditionally (via FUSE_COMPATIBLE_MAY_BLOCK)
>>     in the anticipation that the subsequent real syscall may block.
>>     However in some cases, such as when operating on /proc/self/exe,
>>     the wrapper calls the real syscall
>>     itself and therefore SfMayBlock should not have been set.
>>
>>     If you are able to compile Valgrind from sources, I can prepare a
>>     small patch for you to test.
>>     Unfortunately I don't have an environment to test with FUSE for you.
>>     I.
>
>     Yes, we can recompile Valgrind. We will be grateful if you prepare
>     a patch for us.
>     If it occurs that this patch resolves the problem, do you think we
>     should report it as a bug via bugzilla?
>
>
>
> Please find attached a patch. File a bug anyway and report your findings.
> I.

Thanks for patch, it helped. I've reported this issue via bugzilla.
Radek