On Fri, Apr 15, 2022, 4:31 PM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > > On Fri, Apr 15, 2022 at 04:24:14PM -0700, Jesse Barnes wrote: > > On Fri, Apr 15, 2022 at 4:04 PM Linus Torvalds > > <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > > > And for ordinary users, a WARN_ON_ONCE() is about a million times > > > better, becasue: > > > > > > - the machine will hopefully continue working, so they can report the warning > > > > > > - even when they don't notice them, distros tend to have automated > > > reporting infrastructure > > > > > > That's why I absolutely *DETEST* those stupid BUG_ON() cases - they > > > will often kill the machine with nasty locks held, resulting in a > > > completely undebuggable thing that never gets reported. > > > > > > Yes, you can be careful and only put BUG_ON() in places where recovery > > > is possible. But even then, they have no actual _advantages_ over just > > > a WARN_ON_ONCE. > > > > Generally agreed, and not to belabor this relatively small issue, but in some > > environments like cloud or managed client deployments, a crash can actually > > be preferable so we can get a dump, reboot the machine, and get things going > > again for the application or user, then debug offline. So having the > > flexibility to > > do that in those situations is helpful. And there, a full crash dump is better > > than just a log report with the WARN info, since debugging may be easier with > > all the kernel memory. > > But for those situations, don't you set panic_on_warn anyway? Yes ignore me. Jesse "returning to his cave of ignorace" Barnes
