From: Li Nan <[email protected]>
need_replace will be set to 1 if no-Faulty mreplace exists, and mreplace
will be deref later. However, the latter check of mreplace might set
mreplace to NULL, null-ptr-deref occurs if need_replace is 1 at this time.
Fix it by merging two checks into one. And replace 'need_replace' with
'mreplace' because their values are always the same.
Fixes: ee37d7314a32 ("md/raid10: Fix raid10 replace hang when new added disk faulty")
Signed-off-by: Li Nan <[email protected]>
---
drivers/md/raid10.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 4fcfcb350d2b..e21502c03b45 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -3438,7 +3438,6 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
int must_sync;
int any_working;
int need_recover = 0;
- int need_replace = 0;
struct raid10_info *mirror = &conf->mirrors[i];
struct md_rdev *mrdev, *mreplace;
@@ -3451,10 +3450,10 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
!test_bit(In_sync, &mrdev->flags))
need_recover = 1;
if (mreplace != NULL &&
- !test_bit(Faulty, &mreplace->flags))
- need_replace = 1;
+ test_bit(Faulty, &mreplace->flags))
+ mreplace = NULL;
- if (!need_recover && !need_replace) {
+ if (!need_recover && !mreplace) {
rcu_read_unlock();
continue;
}
@@ -3470,8 +3469,6 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
rcu_read_unlock();
continue;
}
- if (mreplace && test_bit(Faulty, &mreplace->flags))
- mreplace = NULL;
/* Unless we are doing a full sync, or a replacement
* we only need to recover the block if it is set in
* the bitmap
@@ -3594,11 +3591,11 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
bio = r10_bio->devs[1].repl_bio;
if (bio)
bio->bi_end_io = NULL;
- /* Note: if need_replace, then bio
+ /* Note: if replace is not NULL, then bio
* cannot be NULL as r10buf_pool_alloc will
* have allocated it.
*/
- if (!need_replace)
+ if (!mreplace)
break;
bio->bi_next = biolist;
biolist = bio;
--
2.31.1
On Fri, May 26, 2023 at 12:47 AM <[email protected]> wrote:
>
> From: Li Nan <[email protected]>
>
> need_replace will be set to 1 if no-Faulty mreplace exists, and mreplace
> will be deref later. However, the latter check of mreplace might set
> mreplace to NULL, null-ptr-deref occurs if need_replace is 1 at this time.
>
> Fix it by merging two checks into one. And replace 'need_replace' with
> 'mreplace' because their values are always the same.
>
> Fixes: ee37d7314a32 ("md/raid10: Fix raid10 replace hang when new added disk faulty")
> Signed-off-by: Li Nan <[email protected]>
> ---
> drivers/md/raid10.c | 13 +++++--------
> 1 file changed, 5 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index 4fcfcb350d2b..e21502c03b45 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -3438,7 +3438,6 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
> int must_sync;
> int any_working;
> int need_recover = 0;
> - int need_replace = 0;
> struct raid10_info *mirror = &conf->mirrors[i];
> struct md_rdev *mrdev, *mreplace;
>
> @@ -3451,10 +3450,10 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
> !test_bit(In_sync, &mrdev->flags))
> need_recover = 1;
> if (mreplace != NULL &&
> - !test_bit(Faulty, &mreplace->flags))
> - need_replace = 1;
> + test_bit(Faulty, &mreplace->flags))
> + mreplace = NULL;
>
> - if (!need_recover && !need_replace) {
> + if (!need_recover && !mreplace) {
> rcu_read_unlock();
> continue;
> }
> @@ -3470,8 +3469,6 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
> rcu_read_unlock();
> continue;
> }
To make sure I understand the issue correctly:
The null-ptr-deref only happens when the Faulty bit was set after the
last check and before this check below, right?
> - if (mreplace && test_bit(Faulty, &mreplace->flags))
> - mreplace = NULL;
> /* Unless we are doing a full sync, or a replacement
> * we only need to recover the block if it is set in
> * the bitmap
Thanks,
Song
> @@ -3594,11 +3591,11 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
> bio = r10_bio->devs[1].repl_bio;
> if (bio)
> bio->bi_end_io = NULL;
> - /* Note: if need_replace, then bio
> + /* Note: if replace is not NULL, then bio
> * cannot be NULL as r10buf_pool_alloc will
> * have allocated it.
> */
> - if (!need_replace)
> + if (!mreplace)
> break;
> bio->bi_next = biolist;
> biolist = bio;
> --
> 2.31.1
>
Hi,
?? 2023/05/26 15:45, [email protected] д??:
> From: Li Nan <[email protected]>
>
> need_replace will be set to 1 if no-Faulty mreplace exists, and mreplace
> will be deref later. However, the latter check of mreplace might set
> mreplace to NULL, null-ptr-deref occurs if need_replace is 1 at this time.
>
> Fix it by merging two checks into one. And replace 'need_replace' with
> 'mreplace' because their values are always the same.
>
> Fixes: ee37d7314a32 ("md/raid10: Fix raid10 replace hang when new added disk faulty")
> Signed-off-by: Li Nan <[email protected]>
Other than some nits below, this patch looks good to me, feel free too
add:
Reviewed-by: Yu Kuai <[email protected]>
> ---
> drivers/md/raid10.c | 13 +++++--------
> 1 file changed, 5 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index 4fcfcb350d2b..e21502c03b45 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -3438,7 +3438,6 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
> int must_sync;
> int any_working;
> int need_recover = 0;
> - int need_replace = 0;
> struct raid10_info *mirror = &conf->mirrors[i];
> struct md_rdev *mrdev, *mreplace;
>
> @@ -3451,10 +3450,10 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
> !test_bit(In_sync, &mrdev->flags))
> need_recover = 1;
> if (mreplace != NULL &&
> - !test_bit(Faulty, &mreplace->flags))
> - need_replace = 1;
> + test_bit(Faulty, &mreplace->flags))
This can be keeped in one line.
> + mreplace = NULL;
>
> - if (!need_recover && !need_replace) {
> + if (!need_recover && !mreplace) {
> rcu_read_unlock();
> continue;
> }
> @@ -3470,8 +3469,6 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
> rcu_read_unlock();
> continue;
> }
> - if (mreplace && test_bit(Faulty, &mreplace->flags))
> - mreplace = NULL;
> /* Unless we are doing a full sync, or a replacement
> * we only need to recover the block if it is set in
> * the bitmap
> @@ -3594,11 +3591,11 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
> bio = r10_bio->devs[1].repl_bio;
> if (bio)
> bio->bi_end_io = NULL;
> - /* Note: if need_replace, then bio
> + /* Note: if replace is not NULL, then bio
> * cannot be NULL as r10buf_pool_alloc will
> * have allocated it.
> */
> - if (!need_replace)
> + if (!mreplace)
> break;
> bio->bi_next = biolist;
> biolist = bio;
>
Hi,
在 2023/05/27 5:38, Song Liu 写道:
> On Fri, May 26, 2023 at 12:47 AM <[email protected]> wrote: }
>
> To make sure I understand the issue correctly:
>
> The null-ptr-deref only happens when the Faulty bit was set after the
> last check and before this check below, right?
Yes, you're right.
Thanks,
Kuai
>
>> - if (mreplace && test_bit(Faulty, &mreplace->flags))
>> - mreplace = NULL;
>> /* Unless we are doing a full sync, or a replacement
>> * we only need to recover the block if it is set in
>> * the bitmap
>
> Thanks,
> Song
>
在 2023/5/27 5:38, Song Liu 写道:
> On Fri, May 26, 2023 at 12:47 AM <[email protected]> wrote:
>>
>> From: Li Nan <[email protected]>
>>
>> need_replace will be set to 1 if no-Faulty mreplace exists, and mreplace
>> will be deref later. However, the latter check of mreplace might set
>> mreplace to NULL, null-ptr-deref occurs if need_replace is 1 at this time.
>>
>> Fix it by merging two checks into one. And replace 'need_replace' with
>> 'mreplace' because their values are always the same.
>>
>> Fixes: ee37d7314a32 ("md/raid10: Fix raid10 replace hang when new added disk faulty")
>> Signed-off-by: Li Nan <[email protected]>
>> ---
>> drivers/md/raid10.c | 13 +++++--------
>> 1 file changed, 5 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
>> index 4fcfcb350d2b..e21502c03b45 100644
>> --- a/drivers/md/raid10.c
>> +++ b/drivers/md/raid10.c
>> @@ -3438,7 +3438,6 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
>> int must_sync;
>> int any_working;
>> int need_recover = 0;
>> - int need_replace = 0;
>> struct raid10_info *mirror = &conf->mirrors[i];
>> struct md_rdev *mrdev, *mreplace;
>>
>> @@ -3451,10 +3450,10 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
>> !test_bit(In_sync, &mrdev->flags))
>> need_recover = 1;
>> if (mreplace != NULL &&
>> - !test_bit(Faulty, &mreplace->flags))
>> - need_replace = 1;
>> + test_bit(Faulty, &mreplace->flags))
>> + mreplace = NULL;
>>
>> - if (!need_recover && !need_replace) {
>> + if (!need_recover && !mreplace) {
>> rcu_read_unlock();
>> continue;
>> }
>> @@ -3470,8 +3469,6 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
>> rcu_read_unlock();
>> continue;
>> }
>
> To make sure I understand the issue correctly:
>
> The null-ptr-deref only happens when the Faulty bit was set after the
> last check and before this check below, right?
>
Yes. I will improve log in next version.
--
Thanks,
Nan
在 2023/5/27 9:21, Yu Kuai 写道:
> Hi,
>
> 在 2023/05/26 15:45, [email protected] 写道:
>> From: Li Nan <[email protected]>
>>
>> need_replace will be set to 1 if no-Faulty mreplace exists, and mreplace
>> will be deref later. However, the latter check of mreplace might set
>> mreplace to NULL, null-ptr-deref occurs if need_replace is 1 at this
>> time.
>>
>> Fix it by merging two checks into one. And replace 'need_replace' with
>> 'mreplace' because their values are always the same.
>>
>> Fixes: ee37d7314a32 ("md/raid10: Fix raid10 replace hang when new
>> added disk faulty")
>> Signed-off-by: Li Nan <[email protected]>
>
> Other than some nits below, this patch looks good to me, feel free too
> add:
>
> Reviewed-by: Yu Kuai <[email protected]>
>> ---
>> drivers/md/raid10.c | 13 +++++--------
>> 1 file changed, 5 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
>> index 4fcfcb350d2b..e21502c03b45 100644
>> --- a/drivers/md/raid10.c
>> +++ b/drivers/md/raid10.c
>> @@ -3438,7 +3438,6 @@ static sector_t raid10_sync_request(struct mddev
>> *mddev, sector_t sector_nr,
>> int must_sync;
>> int any_working;
>> int need_recover = 0;
>> - int need_replace = 0;
>> struct raid10_info *mirror = &conf->mirrors[i];
>> struct md_rdev *mrdev, *mreplace;
>> @@ -3451,10 +3450,10 @@ static sector_t raid10_sync_request(struct
>> mddev *mddev, sector_t sector_nr,
>> !test_bit(In_sync, &mrdev->flags))
>> need_recover = 1;
>> if (mreplace != NULL &&
>> - !test_bit(Faulty, &mreplace->flags))
>> - need_replace = 1;
>> + test_bit(Faulty, &mreplace->flags))
> This can be keeped in one line.
>
OK, I will change it.
Thanks for your review.
--
Thanks,
Nan