From: Vlastimil Babka <vbabka@suse.cz>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>,
Dmitry Vyukov <dvyukov@google.com>,
syzbot
<bot+6a5269ce759a7bb12754ed9622076dc93f65a1f6@syzkaller.appspotmail.com>,
Jan Beulich <JBeulich@suse.com>, "H. Peter Anvin" <hpa@zytor.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
ldufour@linux.vnet.ibm.com, LKML <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@redhat.com>,
syzkaller-bugs@googlegroups.com,
Thomas Gleixner <tglx@linutronix.de>,
the arch/x86 maintainers <x86@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.com>, Hugh Dickins <hughd@google.com>,
David Rientjes <rientjes@google.com>,
linux-mm@kvack.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Thorsten Leemhuis <regressions@leemhuis.info>
Subject: Re: KASAN: use-after-free Read in __do_page_fault
Date: Wed, 1 Nov 2017 13:14:45 +0100 [thread overview]
Message-ID: <ec9d483c-3151-4bfe-2e5b-9396afd84bab@suse.cz> (raw)
In-Reply-To: <20171101101744.GA1846@redhat.com>
On 11/01/2017 11:17 AM, Andrea Arcangeli wrote:
> On Wed, Nov 01, 2017 at 08:42:57AM +0100, Vlastimil Babka wrote:
>> The vma should be pinned by mmap_sem, but handle_userfault() will in some
>> scenarios release it and then acquire again, so when we return to
>
> In the above message and especially in the below comment, I would
> suggest to take the opportunity to more accurately document the
> specific scenario instead of "some scenario" which is only "A return
> to userland to repeat the page fault later with a VM_FAULT_NOPAGE
> retval (potentially after handling any pending signal during the
> return to userland). The return to userland is identified whenever
> FAULT_FLAG_USER|FAULT_FLAG_KILLABLE are both set in vmf->flags".
OK, updated patch below
----8<----
next prev parent reply other threads:[~2017-11-01 12:14 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <94eb2c0433c8f42cac055cc86991@google.com>
2017-10-30 19:15 ` Dmitry Vyukov
2017-10-31 12:00 ` Vlastimil Babka
2017-10-31 12:42 ` Dmitry Vyukov
2017-10-31 13:20 ` Vlastimil Babka
2017-10-31 13:57 ` Vlastimil Babka
2017-10-31 14:11 ` Kirill A. Shutemov
2017-10-31 14:28 ` Vlastimil Babka
2017-10-31 19:15 ` Andrea Arcangeli
2017-11-01 7:42 ` Vlastimil Babka
2017-11-01 10:17 ` Andrea Arcangeli
2017-11-01 12:14 ` Vlastimil Babka [this message]
2017-10-31 15:37 ` Linus Torvalds
2017-10-31 19:13 ` Andrea Arcangeli
2017-11-01 15:26 ` Linus Torvalds
2017-11-02 19:36 ` Andrea Arcangeli
2017-11-02 10:00 ` Laurent Dufour
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