On Fri, 24 Apr 2020 23:37:06 +0530 "Naveen N. Rao" <naveen.n....@linux.vnet.ibm.com> wrote:
> >> Le 23/04/2020 à 17:09, Naveen N. Rao a écrit : > >> > With STRICT_KERNEL_RWX, we are currently ignoring return value from > >> > __patch_instruction() in do_patch_instruction(), resulting in the error > >> > not being propagated back. Fix the same. > >> > >> Good patch. > >> > >> Be aware that there is ongoing work which tend to wanting to replace > >> error reporting by BUG_ON() . See > >> https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=166003 > > > > Thanks for the reference. I still believe that WARN_ON() should be used in > > 99% of the cases, including here. And only do a BUG_ON() when you know > > there's no recovering from it. > > I'm not sure if you meant that we should have a WARN_ON() in > patch_instruction(), or if it was about the users of > patch_instruction(). As you're well aware, ftrace likes to do its own > WARN_ON() if any of its operations fail through ftrace_bug(). That was > the reason I didn't add anything here. I'm fine with that too, and better reason not to call BUG_ON(), because I'm guessing if we crash, we never make it to the ftrace_bug() which reports information that can be used to debug what went wrong. -- Steve
