On Fri, 27 Oct 2023 at 12:57, Naresh Kamboju <naresh.kamboju@xxxxxxxxxx> wrote:
>
> On Thu, 26 Oct 2023 at 21:09, Ard Biesheuvel <ardb@xxxxxxxxxx> 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 ...
> > > 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 :-)
>
> I am happy to test any proposed fix patch.
>
Thanks Naresh. Patch attached.
From 0d3c9d39a4541f7c5dea5175adea2af63ec1b92d Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ardb@xxxxxxxxxx>
Date: Sat, 28 Oct 2023 09:40:29 +0200
Subject: [PATCH] Add missing ESR decoding for level -1 translation faults
Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
---
arch/arm64/mm/fault.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 460d799e1296..22318d56087d 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -791,7 +791,7 @@ static const struct fault_info fault_info[] = {
{ do_sea, SIGBUS, BUS_OBJERR, "synchronous external abort" },
{ do_tag_check_fault, SIGSEGV, SEGV_MTESERR, "synchronous tag check fault" },
{ do_bad, SIGKILL, SI_KERNEL, "unknown 18" },
- { do_bad, SIGKILL, SI_KERNEL, "unknown 19" },
+ { do_sea, SIGKILL, SI_KERNEL, "level -1 (translation table walk)" },
{ do_sea, SIGKILL, SI_KERNEL, "level 0 (translation table walk)" },
{ do_sea, SIGKILL, SI_KERNEL, "level 1 (translation table walk)" },
{ do_sea, SIGKILL, SI_KERNEL, "level 2 (translation table walk)" },
@@ -799,7 +799,7 @@ static const struct fault_info fault_info[] = {
{ do_sea, SIGBUS, BUS_OBJERR, "synchronous parity or ECC error" }, // Reserved when RAS is implemented
{ do_bad, SIGKILL, SI_KERNEL, "unknown 25" },
{ do_bad, SIGKILL, SI_KERNEL, "unknown 26" },
- { do_bad, SIGKILL, SI_KERNEL, "unknown 27" },
+ { do_sea, SIGKILL, SI_KERNEL, "level -1 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
{ do_sea, SIGKILL, SI_KERNEL, "level 0 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
{ do_sea, SIGKILL, SI_KERNEL, "level 1 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
{ do_sea, SIGKILL, SI_KERNEL, "level 2 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
@@ -811,9 +811,9 @@ static const struct fault_info fault_info[] = {
{ do_bad, SIGKILL, SI_KERNEL, "unknown 36" },
{ do_bad, SIGKILL, SI_KERNEL, "unknown 37" },
{ do_bad, SIGKILL, SI_KERNEL, "unknown 38" },
- { do_bad, SIGKILL, SI_KERNEL, "unknown 39" },
+ { do_bad, SIGKILL, SI_KERNEL, "level -1 address size fault" },
{ do_bad, SIGKILL, SI_KERNEL, "unknown 40" },
- { do_bad, SIGKILL, SI_KERNEL, "unknown 41" },
+ { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level -1 translation fault" },
{ do_bad, SIGKILL, SI_KERNEL, "unknown 42" },
{ do_bad, SIGKILL, SI_KERNEL, "unknown 43" },
{ do_bad, SIGKILL, SI_KERNEL, "unknown 44" },
--
2.39.2
