Re: [PATCH 2/2] arch: add pidfd and io_uring syscalls everywhere

Jens Axboe
2019-04-03T15:51:21Z

On 4/3/19 9:49 AM, Will Deacon wrote:
> On Wed, Apr 03, 2019 at 09:39:52AM -0600, Jens Axboe wrote:
>> On 4/3/19 9:19 AM, Will Deacon wrote:
>>> On Wed, Apr 03, 2019 at 07:49:26AM -0600, Jens Axboe wrote:
>>>> On 4/3/19 5:11 AM, Will Deacon wrote:
>>>>> will@autoplooker:~/liburing/test$ ./io_uring_register
>>>>> RELIMIT_MEMLOCK: 67108864 (67108864)
>>>>> [ 35.477875] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000070
>>>>> [ 35.478969] Mem abort info:
>>>>> [ 35.479296] ESR = 0x96000004
>>>>> [ 35.479785] Exception class = DABT (current EL), IL = 32 bits
>>>>> [ 35.480528] SET = 0, FnV = 0
>>>>> [ 35.480980] EA = 0, S1PTW = 0
>>>>> [ 35.481345] Data abort info:
>>>>> [ 35.481680] ISV = 0, ISS = 0x00000004
>>>>> [ 35.482267] CM = 0, WnR = 0
>>>>> [ 35.482618] user pgtable: 4k pages, 48-bit VAs, pgdp = (____ptrval____)
>>>>> [ 35.483486] [0000000000000070] pgd=0000000000000000
>>>>> [ 35.484041] Internal error: Oops: 96000004 [#1] PREEMPT SMP
>>>>> [ 35.484788] Modules linked in:
>>>>> [ 35.485311] CPU: 113 PID: 3973 Comm: io_uring_regist Not tainted 5.1.0-rc3-00012-g40b114779944 #1
>>>>> [ 35.486712] Hardware name: linux,dummy-virt (DT)
>>>>> [ 35.487450] pstate: 20400005 (nzCv daif +PAN -UAO)
>>>>> [ 35.488228] pc : link_pwq+0x10/0x60
>>>>> [ 35.488794] lr : apply_wqattrs_commit+0xe0/0x118
>>>>> [ 35.489550] sp : ffff000017e2bbc0
>>>>
>>>> Huh, this looks odd, it's crashing inside the wq setup.
>>>
>>> Enabling KASAN seems to indicate a double-free, which may well be related.
>>
>> Does this help?
>
> Yes, thanks for the quick patch. Feel free to add:
>
> Reported-by: Will Deacon <will.deacon@arm.com>
> Tested-by: Will Deacon <will.deacon@arm.com>
>
> if you spin a proper patch.

Great, thanks for reporting/testing.

--
Jens Axboe