Re: CVS commit: src/tests/lib/libc/sys

[Joerg Sonnenberger <joerg%bec.de@localhost>]

On Thu, May 14, 2020 at 11:36:28PM +0200, Kamil Rytarowski wrote:
> On 14.05.2020 23:02, Joerg Sonnenberger wrote:
> > On Thu, May 14, 2020 at 07:21:35PM +0000, Kamil Rytarowski wrote:
> >> Module Name:	src
> >> Committed By:	kamil
> >> Date:		Thu May 14 19:21:35 UTC 2020
> >>
> >> Modified Files:
> >> 	src/tests/lib/libc/sys: t_ptrace_fork_wait.h
> >>
> >> Log Message:
> >> Ignore interception of the SIGCHLD signals.
> >>
> >> SIGCHLD once blocked is discarded by the kernel as it has the
> >> SA_IGNORE property. During the fork(2) operation all signals can be
> >> shortly blocked and missed (unless there is a registered signal
> >> handler in the traced child). This leads to a race in this test if
> >> there would be an intention to catch SIGCHLD.
> > 
> > This doesn't sound right. sigprocmask and pthread_sigmask shouldn't
> > affect whether the signal handler is called, only when. Temporarily
> > masking a signal is different from setting it to SIG_IGN.
> > 
> > Joerg
> > 
> 
> I was looking into it and as there is no signal handler for SIGCHLD, the
> signal is discarded.

Sure, but that doesn't really have anything to do with signal blocking.
That's the part that is confusing.

Joerg