From: Dave Hansen <dave.hansen@intel.com>
To: "Luck, Tony" <tony.luck@intel.com>, Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@alien8.de>,
Thomas Gleixner <tglx@linutronix.de>,
Rik van Riel <riel@surriel.com>
Subject: Re: [GIT PULL] x86/mm changes for v4.21
Date: Wed, 6 Feb 2019 16:33:54 -0800 [thread overview]
Message-ID: <8b0b85cb-c08e-3426-fe34-0b6dfc9c0cc4@intel.com> (raw)
In-Reply-To: <20190207001737.GA32096@agluck-desk>
On 2/6/19 4:17 PM, Luck, Tony wrote:
> [ 93.491692] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff99623f2c3f70
> [ 93.499658] RDX: 2e6b58da00000121 RSI: 0000000000000000 RDI: 7fff9981feeab000
...
> Potentially the problem might be a non-canonical address passed down
> by the machine check recovery code to switch the page with the error
> to uncacheable. Perhaps the refactored code is now using that in the
>
> invpcid (%rcx),%rax
>
> instruction that gets the #GP fault?
That looks probable. RDI even has the non-canonical address still in it
(RCX is pointing to the stack, btw).
I think there's an option to dump the trace buffers at panic time. You
might want to enable the TLB flush tracing:
/sys/kernel/debug/tracing/events/tlb/tlb_flush
and see if we get a suspect flush captured just before the #GP.
I wonder if the patches that you bisected to just changed the flushing
from being CR3-based (and not taking an address) to being INVPCID-based,
and taking an address that is sensitive to canonicality.
next prev parent reply other threads:[~2019-02-07 0:33 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-24 23:11 Ingo Molnar
2018-12-27 2:45 ` pr-tracker-bot
2019-02-07 0:17 ` Luck, Tony
2019-02-07 0:33 ` Dave Hansen [this message]
2019-02-07 9:50 ` Peter Zijlstra
2019-02-07 10:18 ` Peter Zijlstra
2019-02-07 11:50 ` Linus Torvalds
2019-02-07 14:01 ` Peter Zijlstra
2019-02-07 17:36 ` Luck, Tony
2019-02-07 17:57 ` Peter Zijlstra
2019-02-07 18:07 ` Andy Lutomirski
2019-02-07 18:46 ` Luck, Tony
2019-02-07 20:24 ` Andy Lutomirski
2019-02-07 22:53 ` Linus Torvalds
2019-02-07 23:05 ` Andy Lutomirski
2019-02-07 18:40 ` Luck, Tony
2019-02-08 12:08 ` [PATCH] x86/mm/cpa: Fix set_mce_nospec() Peter Zijlstra
2019-02-08 13:37 ` [tip:x86/urgent] " tip-bot for Peter Zijlstra
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