From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Florian Weimer <fweimer@redhat.com>
Cc: Nicholas Piggin <npiggin@gmail.com>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
linuxppc-dev@lists.ozlabs.org, linux-mm <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@amacapital.net>,
Dave Hansen <dave.hansen@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
linux-arch@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: POWER: Unexpected fault when writing to brk-allocated memory
Date: Tue, 7 Nov 2017 14:44:22 +0300 [thread overview]
Message-ID: <20171107114422.bgnm5k6w2zqjoazc@node.shutemov.name> (raw)
In-Reply-To: <c5586546-1e7e-0f0f-a8b3-680fadb38dcf@redhat.com>
On Tue, Nov 07, 2017 at 12:26:12PM +0100, Florian Weimer wrote:
> On 11/07/2017 12:15 PM, Kirill A. Shutemov wrote:
>
> > > First of all, using addr and MAP_FIXED to develop our heuristic can
> > > never really give unchanged ABI. It's an in-band signal. brk() is a
> > > good example that steadily keeps incrementing address, so depending
> > > on malloc usage and address space randomization, you will get a brk()
> > > that ends exactly at 128T, then the next one will be >
> > > DEFAULT_MAP_WINDOW, and it will switch you to 56 bit address space.
> >
> > No, it won't. You will hit stack first.
>
> That's not actually true on POWER in some cases. See the process maps I
> posted here:
>
> <https://marc.info/?l=linuxppc-embedded&m=150988538106263&w=2>
Hm? I see that in all three cases the [stack] is the last mapping.
Do I miss something?
--
Kirill A. Shutemov
WARNING: multiple messages have this Message-ID (diff)
From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Florian Weimer <fweimer@redhat.com>
Cc: Nicholas Piggin <npiggin@gmail.com>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
linuxppc-dev@lists.ozlabs.org, linux-mm <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@amacapital.net>,
Dave Hansen <dave.hansen@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
linux-arch@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: POWER: Unexpected fault when writing to brk-allocated memory
Date: Tue, 7 Nov 2017 14:44:22 +0300 [thread overview]
Message-ID: <20171107114422.bgnm5k6w2zqjoazc@node.shutemov.name> (raw)
In-Reply-To: <c5586546-1e7e-0f0f-a8b3-680fadb38dcf@redhat.com>
On Tue, Nov 07, 2017 at 12:26:12PM +0100, Florian Weimer wrote:
> On 11/07/2017 12:15 PM, Kirill A. Shutemov wrote:
>
> > > First of all, using addr and MAP_FIXED to develop our heuristic can
> > > never really give unchanged ABI. It's an in-band signal. brk() is a
> > > good example that steadily keeps incrementing address, so depending
> > > on malloc usage and address space randomization, you will get a brk()
> > > that ends exactly at 128T, then the next one will be >
> > > DEFAULT_MAP_WINDOW, and it will switch you to 56 bit address space.
> >
> > No, it won't. You will hit stack first.
>
> That's not actually true on POWER in some cases. See the process maps I
> posted here:
>
> <https://marc.info/?l=linuxppc-embedded&m=150988538106263&w=2>
Hm? I see that in all three cases the [stack] is the last mapping.
Do I miss something?
--
Kirill A. Shutemov
--
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next prev parent reply other threads:[~2017-11-07 11:44 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-03 17:05 POWER: Unexpected fault when writing to brk-allocated memory Florian Weimer
2017-11-03 17:05 ` Florian Weimer
2017-11-05 12:18 ` Nicholas Piggin
2017-11-05 12:18 ` Nicholas Piggin
2017-11-05 12:35 ` Florian Weimer
2017-11-05 12:54 ` Nicholas Piggin
2017-11-05 12:54 ` Nicholas Piggin
2017-11-05 14:50 ` Florian Weimer
2017-11-05 14:50 ` Florian Weimer
2017-11-06 6:18 ` Aneesh Kumar K.V
2017-11-06 6:18 ` Aneesh Kumar K.V
2017-11-06 6:47 ` Nicholas Piggin
2017-11-06 6:47 ` Nicholas Piggin
2017-11-06 8:11 ` Florian Weimer
2017-11-06 8:11 ` Florian Weimer
2017-11-06 8:25 ` Nicholas Piggin
2017-11-06 8:25 ` Nicholas Piggin
2017-11-06 8:30 ` Aneesh Kumar K.V
2017-11-06 8:30 ` Aneesh Kumar K.V
2017-11-06 8:32 ` Florian Weimer
2017-11-06 8:32 ` Florian Weimer
2017-11-06 10:20 ` Nicholas Piggin
2017-11-06 10:20 ` Nicholas Piggin
2017-11-07 5:07 ` Nicholas Piggin
2017-11-07 5:07 ` Nicholas Piggin
2017-11-07 8:15 ` Florian Weimer
2017-11-07 8:15 ` Florian Weimer
2017-11-07 9:24 ` Nicholas Piggin
2017-11-07 9:24 ` Nicholas Piggin
2017-11-07 11:16 ` Kirill A. Shutemov
2017-11-07 11:16 ` Kirill A. Shutemov
2017-11-07 11:15 ` Kirill A. Shutemov
2017-11-07 11:15 ` Kirill A. Shutemov
2017-11-07 11:26 ` Florian Weimer
2017-11-07 11:26 ` Florian Weimer
2017-11-07 11:44 ` Kirill A. Shutemov [this message]
2017-11-07 11:44 ` Kirill A. Shutemov
2017-11-07 13:05 ` Florian Weimer
2017-11-07 13:16 ` Kirill A. Shutemov
2017-11-07 13:16 ` Kirill A. Shutemov
2017-11-08 6:08 ` Michael Ellerman
2017-11-08 6:08 ` Michael Ellerman
2017-11-08 6:08 ` Michael Ellerman
2017-11-08 6:18 ` Florian Weimer
2017-11-08 6:18 ` Florian Weimer
2017-11-07 11:56 ` Nicholas Piggin
2017-11-07 11:56 ` Nicholas Piggin
2017-11-07 12:28 ` Kirill A. Shutemov
2017-11-07 12:28 ` Kirill A. Shutemov
2017-11-07 13:33 ` Nicholas Piggin
2017-11-07 13:33 ` Nicholas Piggin
2017-11-07 13:45 ` Aneesh Kumar K.V
2017-11-07 13:45 ` Aneesh Kumar K.V
2017-11-07 14:01 ` Kirill A. Shutemov
2017-11-07 14:01 ` Kirill A. Shutemov
2017-11-09 17:15 ` Nicholas Piggin
2017-11-09 17:15 ` Nicholas Piggin
2017-11-09 19:44 ` Matthew Wilcox
2017-11-09 19:44 ` Matthew Wilcox
2017-11-10 1:26 ` Nicholas Piggin
2017-11-10 1:26 ` Nicholas Piggin
2017-11-10 12:08 ` David Laight
2017-11-10 12:08 ` David Laight
2017-11-11 10:30 ` Nicholas Piggin
2017-11-11 10:30 ` Nicholas Piggin
2017-11-08 4:56 ` Michael Ellerman
2017-11-08 4:56 ` Michael Ellerman
2017-11-08 8:30 ` Kirill A. Shutemov
2017-11-08 8:30 ` Kirill A. Shutemov
2017-11-06 8:10 ` Florian Weimer
2017-11-06 8:10 ` Florian Weimer
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