cupsd crashes when spawning "/usr/lib/cups/notifier/dbus dbus:// ''" via cups-exec

[tillkamppeter]

The following bug got reported to Ubuntu:
Bug 1719004: cupsd assert failure: cupsd: ../sysdeps/unix/sysv/linux/spawni.c:368: __spawnix: Assertion 'ec >= 0' failed.
Looking into the stack trace attached to the report one can see that the command
/usr/lib/cups/notifier/dbus dbus:// ''
was called by CUPS through the cups-exec helper, via the cupsdStartProcess() function with infd=14, outfd=-1, errfd=13, backfd=-1, sidefd=-1, root=0, profile=0x0, job=0x0, and correctly looking argv and envp string arrays. This leads to an assertion failure in some posux_spawn function (see stack trace).

[michaelrsweet]

@tillkamppeter The bug link isn't working for me...

Nothing immediately looks wrong in the stack trace. Seeing if I can find the glibc sources...

[michaelrsweet]

OK, looking at the glibc code, the only way we hit this assert is if args.err is not getting set by the child process. But I can't see how that would happen since __spawni_child always sets a value 0 or errno.

Right now this doesn't look like us...

[fweimer]

I filed a glibc bug: https://sourceware.org/bugzilla/show_bug.cgi?id=22273

However, I do not know if this bug is the root cause of the issue reported here.

[michaelrsweet]

Well, unless you can find more information that points to a problem in cupsd, there isn't anything we can do here... Closing for now, but we can always re-open if new information is available...