From: Anshuman Khandual <khandual@linux.vnet.ibm.com>
To: Anshuman Khandual <khandual@linux.vnet.ibm.com>,
Michal Hocko <mhocko@kernel.org>
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: Mon, 29 Jan 2018 11:02:09 +0530 [thread overview]
Message-ID: <6db9b33d-fd46-c529-b357-3397926f0733@linux.vnet.ibm.com> (raw)
In-Reply-To: <15da8c87-e6db-13aa-01c8-a913656bfdb6@linux.vnet.ibm.com>
On 01/29/2018 08:17 AM, Anshuman Khandual wrote:
> On 01/26/2018 07:34 PM, Michal Hocko wrote:
>> 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?
>
> Please find the debug patch at the end.
>
>>
>>> =================================================================
>>> [ 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
>
> Yeah, will do. Its not an anon mapping as it does not have a anon_vma
> structure ?
Okay, this colliding VMA seems to be getting loaded from load_elf_binary()
function as well.
[ 9.422410] vma c000001fceedbc40 start 0000000010030000 end 0000000010040000
next c000001fceedbe80 prev c000001fceedb700 mm c000001fceea8200
prot 8000000000000104 anon_vma (null) vm_ops (null)
pgoff 1003 file (null) private_data (null)
flags: 0x100073(read|write|mayread|maywrite|mayexec|account)
[ 9.422576] CPU: 46 PID: 7457 Comm: sed Not tainted 4.14.0-dirty #158
[ 9.422610] Call Trace:
[ 9.422623] [c000001fdc4f79b0] [c000000000b17ac0] dump_stack+0xb0/0xf0 (unreliable)
[ 9.422670] [c000001fdc4f79f0] [c0000000002dafb8] do_brk_flags+0x2d8/0x440
[ 9.422708] [c000001fdc4f7ac0] [c0000000002db3d0] vm_brk_flags+0x80/0x130
[ 9.422747] [c000001fdc4f7b20] [c0000000003d23a4] set_brk+0x80/0xdc
[ 9.422785] [c000001fdc4f7b60] [c0000000003d1f24] load_elf_binary+0x1304/0x158c
[ 9.422830] [c000001fdc4f7c80] [c00000000035d3e0] search_binary_handler+0xd0/0x270
[ 9.422881] [c000001fdc4f7d10] [c00000000035f338] do_execveat_common.isra.31+0x658/0x890
[ 9.422926] [c000001fdc4f7df0] [c00000000035f980] SyS_execve+0x40/0x50
[ 9.423588] [c000001fdc4f7e30] [c00000000000b220] system_call+0x58/0x6c
which is getting hit after adding some more debug.
@@ -2949,6 +2997,13 @@ static int do_brk_flags(unsigned long addr, unsigned long request, unsigned long
if (flags & VM_LOCKED)
mm->locked_vm += (len >> PAGE_SHIFT);
vma->vm_flags |= VM_SOFTDIRTY;
+
+ if (!strcmp(current->comm, "sed")) {
+ if (just_init && (mm_ptr == vma->vm_mm)) {
+ dump_vma(vma);
+ dump_stack();
+ }
+ }
return 0;
}
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next prev parent reply other threads:[~2018-01-29 5:32 UTC|newest]
Thread overview: 40+ 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
2018-01-29 2:47 ` Anshuman Khandual
2018-01-29 5:32 ` Anshuman Khandual [this message]
2018-01-29 13:22 ` Michal Hocko
2018-01-30 3:35 ` Michael Ellerman
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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