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Subject: Re: [PATCH 4.19 23/30] x86_64: increase stack size for KASAN_EXTRA
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org
Cc:     stable@vger.kernel.org, Qian Cai <cai@lca.pw>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
References: <20190221125250.543158526@linuxfoundation.org>
 <20190221125251.864751477@linuxfoundation.org>
From:   Andrey Ryabinin <aryabinin@virtuozzo.com>
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Date:   Thu, 21 Feb 2019 18:00:06 +0300
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On 2/21/19 5:36 PM, Greg Kroah-Hartman wrote:
> 4.19-stable review patch.  If anyone has any objections, please let me know.
> 

Drop it please. It increases kernel stack up to 4-order which is above PAGE_ALLOC_COSTLY_ORDER.
This changes behavior of the fork() by making it fail with -ENOMEM due of high memory fragmentation.

The patch that removes KASAN_EXTRA (not in Linus's tree yet) would be a better fix for the problem.