From: Michael Ellerman <mpe@ellerman.id.au>
To: Jens Axboe <axboe@kernel.dk>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH] powerpc: don't try to copy ppc for task with NULL pt_regs
Date: Tue, 28 Mar 2023 22:32:34 +1100 [thread overview]
Message-ID: <87lejhcdrh.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <d9f63344-fe7c-56ae-b420-4a1a04a2ae4c@kernel.dk>
Jens Axboe <axboe@kernel.dk> writes:
> Powerpc sets up PF_KTHREAD and PF_IO_WORKER with a NULL pt_regs, which
> from my (arguably very short) checking is not commonly done for other
> archs. This is fine, except when PF_IO_WORKER's have been created and
> the task does something that causes a coredump to be generated.
Do kthread's ever core dump? I didn't think they did, but I can't find
any logic to prevent it.
Maybe it's always been possible but just never happened due to luck.
As Nick said we should probably have a non-NULL regs for PF_IO_WORKERS,
but I'll still take this as a nice backportable fix for the immediate
crash.
I tagged it as Fixes: pointing back at the commit that added ppr_get(),
even though I don't know for sure the bug was triggerable back then
(v4.8).
cheers
next prev parent reply other threads:[~2023-03-28 11:33 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-26 22:15 [PATCH] powerpc: don't try to copy ppc for task with NULL pt_regs Jens Axboe
2023-03-27 6:36 ` Nicholas Piggin
2023-03-27 10:26 ` Christophe Leroy
2023-03-28 6:16 ` Nicholas Piggin
2023-03-28 11:47 ` Michael Ellerman
2023-03-30 8:44 ` Christophe Leroy
2023-03-27 12:42 ` Jens Axboe
2023-03-27 13:54 ` Michael Ellerman
2023-03-27 16:10 ` Jens Axboe
2023-03-28 11:32 ` Michael Ellerman [this message]
2023-03-28 12:39 ` Jens Axboe
2023-04-06 0:26 ` Michael Ellerman
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