From: "Luck, Tony" <tony.luck@intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>
Cc: "x86@kernel.org" <x86@kernel.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Linus Torvalds <torvalds@linux-foundation.org>,
Song Liu <songliubraving@fb.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Peter Ziljstra <peterz@infradead.org>
Subject: RE: [patch V2 00/20] x86/fpu: Clean up exception fixups and error handling in sigframe related code
Date: Wed, 8 Sep 2021 04:06:43 +0000 [thread overview]
Message-ID: <cf9a841219904c048983fe2aee578761@intel.com> (raw)
In-Reply-To: <87sfyg8118.ffs@tglx>
>> Huch? That tree is based on 0bcfe68b876 and it just has those 20 patches
>> on top which should not at all interfere with your root filesystem
>> device. Let me verify.
>
> I lost connection to my test machines. Will continue tomorrow morning.
To save you some time I ran a bisect. It says the wheels fall off the bus at
patch 13/20
$ git bisect bad
43bce826b58940bd3143f110d36f5901d009e527 is the first bad commit
commit 43bce826b58940bd3143f110d36f5901d009e527
Author: Thomas Gleixner <tglx@linutronix.de>
Date: Mon Aug 30 18:27:25 2021 +0200
x86/fpu/signal: Move xstate clearing out of copy_fpregs_to_sigframe()
When the direct saving of the FPU registers to the user space sigframe
fails, copy_fpregs_to_sigframe() attempts to clear the user buffer.
The most likely reason for such a fail is a page fault. As
copy_fpregs_to_sigframe() is invoked with pagefaults disabled the chance
that __clear_user() succeeds is minuscule.
Move the clearing out into the caller which replaces the
fault_in_pages_writeable() in that error handling path.
The return value confusion will be cleaned up separately.
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
:040000 040000 a7dce9444541186dcc30f21c9d0416d48f215507 71056cf4baa014ca33ab4861b0aca76b154979bf M arch
next prev parent reply other threads:[~2021-09-08 4:10 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-07 19:56 [patch V2 00/20] x86/fpu: Clean up exception fixups and error handling in sigframe related code Thomas Gleixner
2021-09-07 20:04 ` Thomas Gleixner
2021-09-07 20:07 ` Luck, Tony
2021-09-07 20:18 ` Thomas Gleixner
2021-09-07 21:13 ` Luck, Tony
2021-09-07 21:55 ` Thomas Gleixner
2021-09-07 22:37 ` Thomas Gleixner
2021-09-07 23:20 ` Linus Torvalds
2021-09-07 23:22 ` Linus Torvalds
2021-09-08 13:22 ` Thomas Gleixner
2021-09-08 4:06 ` Luck, Tony [this message]
2021-09-08 5:14 ` Thomas Gleixner
2021-09-08 13:21 ` Thomas Gleixner
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