Hi, On Wed, May 22, 2019 at 08:14:23AM +0200, Christophe Leroy wrote: > Le 22/05/2019 à 00:18, Aaro Koskinen a écrit : > >I was trying to upgrade from v5.0 -> v5.1 on PowerBook G4, but when trying > >to kexec a kernel the system gets stuck (no errors seen on the console). > > Do you mean you are trying to kexec a v5.1 kernel from a v5.0 kernel, or do > you have a working v5.1 kernel, but kexec doesn't work with it ?
To summarize, my system's boot goes like this: Open Firmware -> kernel A (small due to OF limit) -> (kexec) -> kernel B (big) First both A & B were at v5.0 ==> boot works. Then I upgraded B to v5.1 ==> boot works. Then I upgraded A to v5.1 ==> boot fails. So the issue must be in A. So after bisecting I got the following result: Kernel A with commit 93c4a162b014 ==> fails Kernel A with commit 93c4a162b014^1 ==> works n >Bisected to: 93c4a162b014 ("powerpc/6xx: Store PGDIR physical address > >in a SPRG"). This commit doesn't revert cleanly anymore but I tested > >that the one before works OK. > > Not sure that's the problem. There was a problem with that commit, but it > was fixed by 4622a2d43101 ("powerpc/6xx: fix setup and use of > SPRN_SPRG_PGDIR for hash32"). > You probably hit some commit between those two during bisect, that's likely > the reason why you ended here. > > Can you restart your bisect from 4622a2d43101 ? This is not a good commit to start with, as it already gives "kernel tried to execute exec protected page..." after the "Bye!" message. > If you have CONFIG_SMP, maybe you should also consider taking 397d2300b08c > ("powerpc/32s: fix flush_hash_pages() on SMP"). Stable 5.1.4 includes it. This is UP computer and CONFIG_SMP is not set. > >With current Linus HEAD (9c7db5004280), it gets a bit further but still > >doesn't work: now I get an error on the console after kexec "Starting > >new kernel! ... Bye!": > > > > kernel tried to execute exec-protected page (...) - exploit attempt? > > Interesting. > > Do you have CONFIG_STRICT_KERNEL_RWX=y in your .config ? If so, can you > retry without it ? I don't set that option. A.