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
