On Mon, Apr 15, 2024 at 10:35:21AM +0200, Greg KH wrote: > On Mon, Apr 15, 2024 at 01:07:41AM -0700, Christoph Hellwig wrote: > > No, this advice is wronger than wrong. If you set panic_on_warn you > > get to keep the pieces. > > > > But don't add new WARN() calls please, just properly clean up and handle > the error. And any WARN() that userspace can trigger ends up triggering > syzbot reports which also is a major pain, even if you don't have > panic_on_warn enabled. Here's what was more recently written on WARN: https://docs.kernel.org/process/deprecated.html#bug-and-bug-on Specifically: - never use BUG*() - WARN*() should only be used for "expected to be unreachable" situations This, then, maps correctly to panic_on_warn: System owners may have set the panic_on_warn sysctl, to make sure their systems do not continue running in the face of "unreachable" conditions. As in, userspace should _never_ be able to reach a WARN(). If it can, either the logic leading to it needs to be fixed, or the WARN() needs to be changed to a pr_warn(). -- Kees Cook
