From: Rong Chen <rong.a.chen@intel.com>
To: Song Liu <songliubraving@fb.com>, Xiao Ni <xni@redhat.com>
Cc: kernel test robot <lkp@intel.com>,
"kbuild-all@lists.01.org" <kbuild-all@lists.01.org>,
"linux-raid@vger.kernel.org" <linux-raid@vger.kernel.org>
Subject: Re: [kbuild-all] Re: [song-md:md-next 5/6] drivers/md/raid10.c:1526:8-27: atomic_dec_and_test variation before object free at line 1532.
Date: Tue, 16 Mar 2021 15:01:28 +0800 [thread overview]
Message-ID: <85f3998d-82a8-095a-951d-04c141e0beef@intel.com> (raw)
In-Reply-To: <3EE962E0-8054-4460-8EEB-0338EE5C1940@fb.com>
On 3/16/21 2:56 PM, Song Liu wrote:
>
>> On Mar 15, 2021, at 7:29 PM, Xiao Ni <xni@redhat.com> wrote:
>>
>> Hi all
>>
>> The atomic_t r10_bio->remaining starts at 1 in raid10_handle_discard. It means
>> raid10_handle_discard uses it and sets it to 1. So in fact it starts at 0 and sets to 1
>> when it's used at first time. Then r10_bio->remaining is added by atomic_inc per usage.
>>
>> It decrements the value when leaving raid10_handle_discard and in every callback function.
>> So the count of r10_bio->remaining in this patch is right.
>>
>> Regards
>> Xiao
> It does look like a false alarm, as we set r10bio to first_r10bio after
> the free.
>
> Thanks,
> Song
Hi all,
Thanks for the clarification, we have disabled such warning.
Best Regards,
Rong Chen
>
>> On 03/16/2021 08:29 AM, kernel test robot wrote:
>>> tree: git://git.kernel.org/pub/scm/linux/kernel/git/song/md.git md-next
>>> head: 49c4d345c81f149a29b3db6e521e5191e55f02b6
>>> commit: f3cf8c2b2caf6ae77b7c786218d3b060faef63a6 [5/6] md/raid10: improve discard request for far layout
>>> config: x86_64-allyesconfig (attached as .config)
>>> compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
>>>
>>> If you fix the issue, kindly add following tag as appropriate
>>> Reported-by: kernel test robot <lkp@intel.com>
>>>
>>>
>>> "coccinelle warnings: (new ones prefixed by >>)"
>>>>> drivers/md/raid10.c:1526:8-27: atomic_dec_and_test variation before object free at line 1532.
>>> drivers/md/raid10.c:1526:8-27: atomic_dec_and_test variation before object free at line 1537.
>>>
>>> vim +1526 drivers/md/raid10.c
>>>
>>> 1520
>>> 1521 static void raid_end_discard_bio(struct r10bio *r10bio)
>>> 1522 {
>>> 1523 struct r10conf *conf = r10bio->mddev->private;
>>> 1524 struct r10bio *first_r10bio;
>>> 1525
>>>> 1526 while (atomic_dec_and_test(&r10bio->remaining)) {
>>> 1527
>>> 1528 allow_barrier(conf);
>>> 1529
>>> 1530 if (!test_bit(R10BIO_Discard, &r10bio->state)) {
>>> 1531 first_r10bio = (struct r10bio *)r10bio->master_bio;
>>>> 1532 free_r10bio(r10bio);
>>> 1533 r10bio = first_r10bio;
>>> 1534 } else {
>>> 1535 md_write_end(r10bio->mddev);
>>> 1536 bio_endio(r10bio->master_bio);
>>> 1537 free_r10bio(r10bio);
>>> 1538 break;
>>> 1539 }
>>> 1540 }
>>> 1541 }
>>> 1542
>>>
>>> ---
>>> 0-DAY CI Kernel Test Service, Intel Corporation
>>> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
> _______________________________________________
> kbuild-all mailing list -- kbuild-all@lists.01.org
> To unsubscribe send an email to kbuild-all-leave@lists.01.org
WARNING: multiple messages have this Message-ID (diff)
From: Rong Chen <rong.a.chen@intel.com>
To: kbuild-all@lists.01.org
Subject: Re: [song-md:md-next 5/6] drivers/md/raid10.c:1526:8-27: atomic_dec_and_test variation before object free at line 1532.
Date: Tue, 16 Mar 2021 15:01:28 +0800 [thread overview]
Message-ID: <85f3998d-82a8-095a-951d-04c141e0beef@intel.com> (raw)
In-Reply-To: <3EE962E0-8054-4460-8EEB-0338EE5C1940@fb.com>
[-- Attachment #1: Type: text/plain, Size: 2728 bytes --]
On 3/16/21 2:56 PM, Song Liu wrote:
>
>> On Mar 15, 2021, at 7:29 PM, Xiao Ni <xni@redhat.com> wrote:
>>
>> Hi all
>>
>> The atomic_t r10_bio->remaining starts at 1 in raid10_handle_discard. It means
>> raid10_handle_discard uses it and sets it to 1. So in fact it starts at 0 and sets to 1
>> when it's used at first time. Then r10_bio->remaining is added by atomic_inc per usage.
>>
>> It decrements the value when leaving raid10_handle_discard and in every callback function.
>> So the count of r10_bio->remaining in this patch is right.
>>
>> Regards
>> Xiao
> It does look like a false alarm, as we set r10bio to first_r10bio after
> the free.
>
> Thanks,
> Song
Hi all,
Thanks for the clarification, we have disabled such warning.
Best Regards,
Rong Chen
>
>> On 03/16/2021 08:29 AM, kernel test robot wrote:
>>> tree: git://git.kernel.org/pub/scm/linux/kernel/git/song/md.git md-next
>>> head: 49c4d345c81f149a29b3db6e521e5191e55f02b6
>>> commit: f3cf8c2b2caf6ae77b7c786218d3b060faef63a6 [5/6] md/raid10: improve discard request for far layout
>>> config: x86_64-allyesconfig (attached as .config)
>>> compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
>>>
>>> If you fix the issue, kindly add following tag as appropriate
>>> Reported-by: kernel test robot <lkp@intel.com>
>>>
>>>
>>> "coccinelle warnings: (new ones prefixed by >>)"
>>>>> drivers/md/raid10.c:1526:8-27: atomic_dec_and_test variation before object free at line 1532.
>>> drivers/md/raid10.c:1526:8-27: atomic_dec_and_test variation before object free at line 1537.
>>>
>>> vim +1526 drivers/md/raid10.c
>>>
>>> 1520
>>> 1521 static void raid_end_discard_bio(struct r10bio *r10bio)
>>> 1522 {
>>> 1523 struct r10conf *conf = r10bio->mddev->private;
>>> 1524 struct r10bio *first_r10bio;
>>> 1525
>>>> 1526 while (atomic_dec_and_test(&r10bio->remaining)) {
>>> 1527
>>> 1528 allow_barrier(conf);
>>> 1529
>>> 1530 if (!test_bit(R10BIO_Discard, &r10bio->state)) {
>>> 1531 first_r10bio = (struct r10bio *)r10bio->master_bio;
>>>> 1532 free_r10bio(r10bio);
>>> 1533 r10bio = first_r10bio;
>>> 1534 } else {
>>> 1535 md_write_end(r10bio->mddev);
>>> 1536 bio_endio(r10bio->master_bio);
>>> 1537 free_r10bio(r10bio);
>>> 1538 break;
>>> 1539 }
>>> 1540 }
>>> 1541 }
>>> 1542
>>>
>>> ---
>>> 0-DAY CI Kernel Test Service, Intel Corporation
>>> https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org
> _______________________________________________
> kbuild-all mailing list -- kbuild-all(a)lists.01.org
> To unsubscribe send an email to kbuild-all-leave(a)lists.01.org
next prev parent reply other threads:[~2021-03-16 7:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-16 0:29 [song-md:md-next 5/6] drivers/md/raid10.c:1526:8-27: atomic_dec_and_test variation before object free at line 1532 kernel test robot
2021-03-16 0:29 ` kernel test robot
2021-03-16 2:29 ` Xiao Ni
2021-03-16 2:29 ` Xiao Ni
2021-03-16 6:56 ` Song Liu
2021-03-16 6:56 ` Song Liu
2021-03-16 7:01 ` Rong Chen [this message]
2021-03-16 7:01 ` Rong Chen
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