From: Michal Hocko <mhocko@kernel.org>
To: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
akpm@linux-foundation.org, mm-commits@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org, linux-next@vger.kernel.org,
sfr@canb.auug.org.au, broonie@kernel.org
Subject: Re: ppc elf_map breakage with MAP_FIXED_NOREPLACE
Date: Fri, 26 Jan 2018 15:04:15 +0100 [thread overview]
Message-ID: <20180126140415.GD5027@dhcp22.suse.cz> (raw)
In-Reply-To: <5acba3c2-754d-e449-24ff-a72a0ad0d895@linux.vnet.ibm.com>
On Fri 26-01-18 18:04:27, Anshuman Khandual wrote:
[...]
> I tried to instrument mmap_region() for a single instance of 'sed'
> binary and traced all it's VMA creation. But there is no trace when
> that 'anon' VMA got created which suddenly shows up during subsequent
> elf_map() call eventually failing it. Please note that the following
> VMA was never created through call into map_region() in the process
> which is strange.
Could you share your debugging patch?
> =================================================================
> [ 9.076867] Details for VMA[3] c000001fce42b7c0
> [ 9.076925] vma c000001fce42b7c0 start 0000000010030000 end 0000000010040000
> next c000001fce42b580 prev c000001fce42b880 mm c000001fce40fa00
> prot 8000000000000104 anon_vma (null) vm_ops (null)
> pgoff 1003 file (null) private_data (null)
> flags: 0x100073(read|write|mayread|maywrite|mayexec|account)
> =================================================================
Isn't this vdso or some other special mapping? It is not really an
anonymous vma. Please hook into __install_special_mapping
> VMA creation for 'sed' binary
> =============================
> [ 9.071902] XXX: mm c000001fce40fa00 registered
>
> [ 9.071971] Total VMAs 2 on MM c000001fce40fa00
> ----
> [ 9.072010] Details for VMA[1] c000001fce42bdc0
> [ 9.072064] vma c000001fce42bdc0 start 0000000010000000 end 0000000010020000
> next c000001fce42b580 prev (null) mm c000001fce40fa00
> prot 8000000000000105 anon_vma (null) vm_ops c008000011ddca18
> pgoff 0 file c000001fe2969a00 private_data (null)
> flags: 0x875(read|exec|mayread|maywrite|mayexec|denywrite)
This one doesn't have any stack trace either... Yet it is a file
mapping obviously. Special mappings shouldn't have any file associated.
Strange...
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2018-01-27 7:55 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-05 0:20 mmotm 2018-01-04-16-19 uploaded akpm
2018-01-05 6:43 ` Anshuman Khandual
2018-01-05 8:46 ` Michal Hocko
2018-01-07 6:49 ` Anshuman Khandual
2018-01-07 9:02 ` ppc elf_map breakage with MAP_FIXED_NOREPLACE (was: Re: mmotm 2018-01-04-16-19 uploaded) Michal Hocko
2018-01-07 11:26 ` Michael Ellerman
2018-01-08 3:02 ` ppc elf_map breakage with MAP_FIXED_NOREPLACE Anshuman Khandual
2018-01-08 22:12 ` Michael Ellerman
2018-01-09 11:48 ` Anshuman Khandual
2018-01-09 16:13 ` Michal Hocko
2018-01-11 10:08 ` Anshuman Khandual
2018-01-17 8:07 ` Michal Hocko
2018-01-23 11:25 ` Anshuman Khandual
2018-01-23 12:45 ` Michal Hocko
2018-01-23 15:58 ` Anshuman Khandual
2018-01-23 16:06 ` Michal Hocko
2018-01-24 5:09 ` Anshuman Khandual
2018-01-24 9:05 ` Michal Hocko
2018-01-26 12:34 ` Anshuman Khandual
2018-01-26 14:04 ` Michal Hocko [this message]
2018-01-29 2:47 ` Anshuman Khandual
2018-01-29 5:32 ` Anshuman Khandual
2018-01-29 13:22 ` Michal Hocko
[not found] ` <87k1w081e7.fsf@concordia.ellerman.id.au>
2018-01-30 9:42 ` Michal Hocko
2018-01-31 5:05 ` Anshuman Khandual
2018-01-31 13:19 ` Michal Hocko
2018-02-01 3:13 ` Anshuman Khandual
2018-02-01 13:10 ` Michal Hocko
2018-02-01 13:40 ` Michal Hocko
2018-02-01 20:55 ` Kees Cook
2018-02-13 10:04 ` [RFC PATCH] elf: enforce MAP_FIXED on overlaying elf segments (was: Re: ppc elf_map breakage with MAP_FIXED_NOREPLACE) Michal Hocko
2018-02-14 16:30 ` Khalid Aziz
2018-02-01 13:48 ` ppc elf_map breakage with MAP_FIXED_NOREPLACE Michal Hocko
2018-02-01 21:06 ` Kees Cook
2018-02-12 14:48 ` Michal Hocko
2018-02-13 1:02 ` Anshuman Khandual
2018-02-13 6:49 ` Anshuman Khandual
2018-02-13 10:00 ` Michal Hocko
2018-01-05 12:14 ` mmotm 2018-01-04-16-19 uploaded Michal Hocko
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