From: Lee Jones <lee.jones@linaro.org>
To: Sasha Levin <sashal@kernel.org>
Cc: gregkh@google.com, stable@vger.kernel.org
Subject: Re: [PATCH 4.9 3/8] arm64: fix for bad_mode() handler to always result in panic
Date: Mon, 25 Nov 2019 14:44:29 +0000 [thread overview]
Message-ID: <20191125144429.GF3296@dell> (raw)
In-Reply-To: <20191125134700.GA5861@sasha-vm>
On Mon, 25 Nov 2019, Sasha Levin wrote:
> On Fri, Nov 22, 2019 at 10:52:48AM +0000, Lee Jones wrote:
> > From: Hari Vyas <hari.vyas@broadcom.com>
> >
> > [ Upstream commit e4ba15debcfd27f60d43da940a58108783bff2a6 ]
> >
> > The bad_mode() handler is called if we encounter an uunknown exception,
> > with the expectation that the subsequent call to panic() will halt the
> > system. Unfortunately, if the exception calling bad_mode() is taken from
> > EL0, then the call to die() can end up killing the current user task and
> > calling schedule() instead of falling through to panic().
> >
> > Remove the die() call altogether, since we really want to bring down the
> > machine in this "impossible" case.
>
> Should this be in newer LTS kernels too? I don't see it in 4.14. We
> can't take anything into older kernels if it's not in newer ones - we
> don't want to break users who update their kernels.
Only; 3.18, 4.4, 4.9 and 5.3 were studied.
I can look at others if it helps.
--
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
next prev parent reply other threads:[~2019-11-25 14:44 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-22 10:52 [PATCH 4.9 1/8] ARM: 8904/1: skip nomap memblocks while finding the lowmem/highmem boundary Lee Jones
2019-11-22 10:52 ` [PATCH 4.9 2/8] can: dev: can_dellink(): remove return at end of void function Lee Jones
2019-11-22 10:52 ` [PATCH 4.9 3/8] arm64: fix for bad_mode() handler to always result in panic Lee Jones
2019-11-25 13:47 ` Sasha Levin
2019-11-25 14:44 ` Lee Jones [this message]
2019-11-25 17:41 ` Greg KH
2019-11-25 18:25 ` Lee Jones
2019-11-26 13:49 ` Lee Jones
2019-11-22 10:52 ` [PATCH 4.9 4/8] cpufreq: Skip cpufreq resume if it's not suspended Lee Jones
2019-11-22 10:52 ` [PATCH 4.9 5/8] bcache: silence static checker warning Lee Jones
2019-11-25 13:47 ` Sasha Levin
2019-11-22 10:52 ` [PATCH 4.9 6/8] dm: use blk_set_queue_dying() in __dm_destroy() Lee Jones
2019-11-22 10:52 ` [PATCH 4.9 7/8] ocfs2: remove ocfs2_is_o2cb_active() Lee Jones
2019-11-22 10:52 ` [PATCH 4.9 8/8] ext4: avoid unnecessary stalls in ext4_evict_inode() Lee Jones
2019-11-25 13:48 ` Sasha Levin
2019-11-25 14:46 ` Lee Jones
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