On Tue, Oct 15, 2019 at 09:59:46PM -0500, Eric Blake wrote: > On 10/15/19 9:43 PM, Eric Blake wrote: > > On 10/15/19 9:25 PM, Wang Yechao wrote: > > > Libvirtd has set SIGPIPE to ignored, and virFork resets all signal > > > handlers to the defaults. But child process may write logs to > > > stderr/stdout, that may generate SIGPIPE if journald has stopped. > > > > > > So block SIGPIPE in virFork, and unblock it before execve. > > > > How does that help? If writing to stderr hits EOF, it will queue up a > > SIGPIPE to be delivered as soon as you unblock SIGPIPE. > > > > The correct fix is to not unblock SIGPIPE until after any point at which > > you would be performing I/O that must not fail due to SIGPIPE, rather > > than messing with signal masks to just delay when SIGPIPE is delivered. > > Let's word this better: > > The correct fix is to keep SIGPIPE ignored until after any point at which > you would be performing I/O that must not cause SIGPIPE, reverting SIGPIPE > back to SIG_DFL at the last possible moment. Messing with signal masks > merely delays when SIGPIPE is delivered, rather than avoiding it. The challenge here is that we're in between fork + execve and want signal handlers back to their defaults at time of execve. If we set SIGPIPE to SIG_IGN and then execve() will that get reset back to SIG_DFL automatically ? Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
