Crash reports show that sys_fallocate is called from the content process: https://crash-stats.mozilla.com/search/?product=Firefox&reason=~SIGSYS&address=0x11d&_sort=-date&_facets=signature&_columns=date&_columns=signature&_columns=product&_columns=version&_columns=build_id&_columns=platform#crash-reports
Just in case it helps, this happens consistently for me when printing to a file. Also, crash happens just after reaching a supposedly unreached code: [Child 8846] ###!!! ASSERTION: Deallocator for PPrintProgressDialogChild should not be called on nsPrintingProxy.: 'Not Reached' http://searchfox.org/mozilla-central/source/embedding/components/printingui/ipc/nsPrintingProxy.cpp#227
Created attachment 8773574 [details] stack trace, crashed due to printing to file Just crashed trying to print a boarding pass to PDF.
Looks like we need to whitelist this at least until we have proper e10s-enabled printing on Linux.
Created attachment 8774333 [details] [diff] [review] Add sys_fallocate to seccomp whitelist. r=gcp Try push: https://treeherder.mozilla.org/#/jobs?repo=try&revision=c020cee1bab7
Try in Comment 4
Pushed by email@example.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/7107f6c51542 Add sys_fallocate to seccomp whitelist. r=gcp