From: Segher Boessenkool <segher@kernel•crashing.org>
To: Michael Ellerman <mpe@ellerman•id.au>
Cc: Carl Jacobsen <cjacobsen@storix•com>, linuxppc-dev@lists•ozlabs.org
Subject: Re: Kernel panic from malloc() on SUSE 15.1?
Date: Thu, 5 Nov 2020 05:00:15 -0600 [thread overview]
Message-ID: <20201105110015.GY2672@gate.crashing.org> (raw)
In-Reply-To: <87lffgt8b9.fsf@mpe.ellerman.id.au>
On Thu, Nov 05, 2020 at 09:19:22PM +1100, Michael Ellerman wrote:
> Carl Jacobsen <cjacobsen@storix•com> writes:
> This doesn't make a lot of sense.
>
> > Bad kernel stack pointer 7fffffffeac0 at 700
>
> "at 700" is the regs->nip value, and suggests we're trying to handle a
> program check, which is either a trap or BUG or WARN, or illegal
> instruction or several other things.
> > REGS: c00000001ec2fd40 TRAP: 0300 Tainted: G (4.12.14-197.18-default)
>
> But then here it says TRAP = 0x300, which is != 0x700.
>
> The trap number is hardcoded in the bad stack handling code, and I don't
> see how we can end up with nip == 0x700 but the trap value == 0x300.
>
> > MSR: 8000000000001000 <SF,ME> CR: 44000844 XER: 20000000
>
> And here the MSR says you were in big endian mode, but you said before
> your machine was ppc64le.
It looks like you got a DSI (the 300), but for some reason that
interrupt was not taken in LE mode, so the instruction at 300 was read
as a lot of gobbledygook, not a valid insn, and the processor took a
program interrupt (the 700).
(MSR[RI]=0, but there can be other causes for that of course.)
Segher
next prev parent reply other threads:[~2020-11-05 11:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-02 20:14 Kernel panic from malloc() on SUSE 15.1? Carl Jacobsen
2020-11-03 2:26 ` Michael Ellerman
2020-11-03 22:09 ` Carl Jacobsen
2020-11-05 10:19 ` Michael Ellerman
2020-11-05 11:00 ` Segher Boessenkool [this message]
2020-11-05 19:44 ` Carl Jacobsen
2020-11-06 12:25 ` Michael Ellerman
2020-11-07 7:44 ` Carl Jacobsen
2020-11-06 12:51 ` Michal Suchánek
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