From: Jiri Kosina <jikos@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>, Joerg Roedel <jroedel@suse.de>,
Frederic Weisbecker <fweisbec@gmail.com>,
Nicolai Stange <nstange@suse.de>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86/mm: Remove in_nmi() warning from 64bit implementation of vmalloc_fault()
Date: Wed, 24 Apr 2019 09:31:34 +0200 (CEST) [thread overview]
Message-ID: <nycvar.YFH.7.76.1904240927550.9803@cbobk.fhfr.pm> (raw)
In-Reply-To: <20190424072610.GF4038@hirez.programming.kicks-ass.net>
On Wed, 24 Apr 2019, Peter Zijlstra wrote:
> > In-NMI warnings have been added to vmalloc_fault() via ebc8827f75 ("x86:
> > Barf when vmalloc and kmemcheck faults happen in NMI") back in the time
> > when our NMI entry code could not cope with nested NMIs.
> >
> > These days, it's perfectly fine to take a fault in NMI context and we
> > don't have to care about the fact that IRET from the fault handler might
> > cause NMI nesting.
> >
> > This warning has already been removed from 32bit implementation of
> > vmalloc_fault() in 6863ea0cda8 ("x86/mm: Remove in_nmi() warning from
> > vmalloc_fault()"), but 64bit version was omitted.
> >
> > Remove the bogus warning also from 64bit implementation of vmalloc_fault().
>
> Cute; did you actually trigger this?
Nope; Nicolai tripped over it while he was looking into interactions
between ftrace and pagefaults.
> > Fixes: 6863ea0cda8 ("x86/mm: Remove in_nmi() warning from vmalloc_fault()")
> > Reported-by: Nicolai Stange <nstange@suse.de>
> > Signed-off-by: Jiri Kosina <jkosina@suse.cz>
>
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Thanks,
--
Jiri Kosina
SUSE Labs
next prev parent reply other threads:[~2019-04-24 7:31 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-24 7:04 [PATCH] x86/mm: Remove in_nmi() warning from 64bit implementation of vmalloc_fault() Jiri Kosina
2019-04-24 7:26 ` Peter Zijlstra
2019-04-24 7:31 ` Jiri Kosina [this message]
2019-04-24 11:11 ` [tip:x86/mm] x86/mm: Remove in_nmi() warning from 64-bit " tip-bot for Jiri Kosina
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