On Thu, Oct 26, 2023 at 05:39:11PM +0200, Ard Biesheuvel wrote: > On Thu, 26 Oct 2023 at 17:30, Mark Rutland <mark.rutland@xxxxxxx> wrote: > > > > On Thu, Oct 26, 2023 at 08:11:26PM +0530, Naresh Kamboju wrote: > > > Following kernel crash noticed on qemu-arm64 while running LTP syscalls > > > set_robust_list test case running Linux next 6.6.0-rc7-next-20231026 and > > > 6.6.0-rc7-next-20231025. > > > > > > BAD: next-20231025 > > > Good: next-20231024 > > > > > > Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx> > > > Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx> > > > > > > Log: > > > ---- > > > <1>[ 203.119139] Unable to handle kernel unknown 43 at virtual > > > address 0001ffff9e2e7d78 > > > <1>[ 203.119838] Mem abort info: > > > <1>[ 203.120064] ESR = 0x000000009793002b > > > <1>[ 203.121040] EC = 0x25: DABT (current EL), IL = 32 bits > > > set_robust_list01 1 TPASS : set_robust_list: retval = -1 > > > (expected -1), errno = 22 (expected 22) > > > set_robust_list01 2 TPASS : set_robust_list: retval = 0 > > > (expected 0), errno = 0 (expected 0) > > > <1>[ 203.124496] SET = 0, FnV = 0 > > > <1>[ 203.124778] EA = 0, S1PTW = 0 > > > <1>[ 203.125029] FSC = 0x2b: unknown 43 > > > > It looks like this is fallout from the LPA2 enablement. > > > > According to the latest ARM ARM (ARM DDI 0487J.a), page D19-6475, that "unknown > > 43" (0x2b / 0b101011) is the DFSC for a level -1 translation fault: > > > > 0b101011 When FEAT_LPA2 is implemented: > > Translation fault, level -1. > > > > It's triggered here by an LDTR in a get_user() on a bogus userspace address. > > The exception is expected, and it's supposed to be handled via the exception > > fixups, but the LPA2 patches didn't update the fault_info table entries for all > > the level -1 faults, and so those all get handled by do_bad() and don't call > > fixup_exception(), causing them to be fatal. > > > > It should be relatively simple to update the fault_info table for the level -1 > > faults, but given the other issues we're seeing I think it's probably worth > > dropping the LPA2 patches for the moment. > > > > Thanks for the analysis Mark. > > I agree that this should not be difficult to fix, but given the other > CI problems and identified loose ends, I am not going to object to > dropping this partially or entirely at this point. I'm sure everybody > will be thrilled to go over those 60 patches again after I rebase them > onto v6.7-rc1 :-) FWIW, I'm more than happy to try; the issue has lagely been finding the time. Hopefully that'll be a bit easier after LPC! Mark.
