Re: [PATCH v6.6] erofs: fix NULL dereference of dif->bdev_handle in fscache mode

Re: [PATCH v6.6] erofs: fix NULL dereference of dif->bdev_handle in fscache mode

[Hongbo Li via Linux-erofs]

When I run nydus on linux 6.6.35, the erofs crashed with the following
messages:

```
[ 2120.070101] RIP: 0010:erofs_map_dev+0x147/0x1e0 [erofs]
[ 2120.070188] Code: e8 4e bd 6d dc 8b 43 28 4c 89 ef 8d 70 ff e8 f0 ee 
69 dc 48 85 c0 0f 84 83 00 00 00 41 80 7d 44 00 75 31 48 8b 50 10 4c 89 
e7 <48> 8b 12 48 89 53 08 48 8b 50 18 48 89 53 10 48 8b 50 20 48 89 53
[ 2120.070288] RSP: 0018:ffff982a48adb9d8 EFLAGS: 00010246
[ 2120.070357] RAX: ffff8c2607e2f040 RBX: ffff982a48adba38 RCX: 
0000000000000000
[ 2120.070431] RDX: 0000000000000000 RSI: ffff8c25d17c7dc8 RDI: 
ffff8c354725e198
[ 2120.070522] RBP: ffff8c35466cf800 R08: ffff8c2607e2f040 R09: 
ffff8c354725e188
[ 2120.070631] R10: 0000000000000000 R11: 0000000000000000 R12: 
ffff8c354725e198
[ 2120.070741] R13: ffff8c354725e180 R14: ffff8c25d14d01c0 R15: 
0000000000001000
[ 2120.070853] FS:  000000c000a00090(0000) GS:ffff8c34ffe00000(0000) 
knlGS:0000000000000000
[ 2120.070965] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2120.071054] CR2: 0000000000000000 CR3: 00000001067dc005 CR4: 
00000000001706f0
[ 2120.071163] Call Trace:
[ 2120.071245]  <TASK>
[ 2120.071325]  ? __die+0x24/0x70
[ 2120.071413]  ? page_fault_oops+0x82/0x150
[ 2120.071499]  ? fixup_exception+0x26/0x350
[ 2120.071585]  ? exc_page_fault+0x69/0x150
[ 2120.071671]  ? asm_exc_page_fault+0x26/0x30
[ 2120.071759]  ? erofs_map_dev+0x147/0x1e0 [erofs]
[ 2120.071853]  ? erofs_map_dev+0x130/0x1e0 [erofs]
[ 2120.071946]  erofs_fscache_data_read_slice+0xe7/0x390 [erofs]
[ 2120.072044]  ? xas_create+0x160/0x1b0
[ 2120.072130]  ? __kmem_cache_alloc_node+0x18c/0x2c0
[ 2120.072219]  ? erofs_fscache_readahead+0x49/0x110 [erofs]
[ 2120.072314]  ? xas_load+0xe/0x50
[ 2120.072397]  erofs_fscache_readahead+0xe0/0x110 [erofs]
[ 2120.072492]  read_pages+0x5a/0x220
[ 2120.072579]  page_cache_ra_order+0x1f0/0x2f0
[ 2120.072667]  filemap_get_pages+0xef/0x290
[ 2120.072755]  filemap_read+0xcb/0x310
[ 2120.072841]  ? ovl_open+0x9e/0xf0 [overlay]
[ 2120.072942]  ? ima_file_check+0x57/0x80
[ 2120.073028]  ? mntput_no_expire+0x4a/0x250
[ 2120.073116]  do_iter_readv_writev+0x12d/0x140
[ 2120.073204]  do_iter_read+0xfd/0x190
[ 2120.073288]  ovl_read_iter+0x1c3/0x210 [overlay]
[ 2120.073384]  vfs_read+0x1c7/0x300
[ 2120.073471]  ksys_read+0x63/0xe0
[ 2120.073555]  do_syscall_64+0x37/0x90
[ 2120.073640]  entry_SYSCALL_64_after_hwframe+0x78/0xe2
[ 2120.073729] RIP: 0033:0x403ace
```

The reason is the same with 8bd90b6ae7856("erofs: fix NULL dereference 
of dif->bdev_handle in fscache mode") in mainline. So we should backport 
this
patch into stable linux-6.6.y to avoid this bug.

On 2024/6/27 17:13, Hongbo Li wrote:
> From: Jingbo Xu <jefflexu@linux.alibaba.com>
> 
> Avoid NULL dereference of dif->bdev_handle, as dif->bdev_handle is NULL
> in fscache mode.
> 
>   BUG: kernel NULL pointer dereference, address: 0000000000000000
>   RIP: 0010:erofs_map_dev+0xbd/0x1c0
>   Call Trace:
>    <TASK>
>    erofs_fscache_data_read_slice+0xa7/0x340
>    erofs_fscache_data_read+0x11/0x30
>    erofs_fscache_readahead+0xd9/0x100
>    read_pages+0x47/0x1f0
>    page_cache_ra_order+0x1e5/0x270
>    filemap_get_pages+0xf2/0x5f0
>    filemap_read+0xb8/0x2e0
>    vfs_read+0x18d/0x2b0
>    ksys_read+0x53/0xd0
>    do_syscall_64+0x42/0xf0
>    entry_SYSCALL_64_after_hwframe+0x6e/0x76
> 
> Reported-by: Yiqun Leng <yqleng@linux.alibaba.com>
> Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=7245
> Fixes: 49845720080d ("erofs: Convert to use bdev_open_by_path()")
> Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
> Reviewed-by: Yue Hu <huyue2@coolpad.com>
> Reviewed-by: Chao Yu <chao@kernel.org>
> Link: https://lore.kernel.org/r/20231114070704.23398-1-jefflexu@linux.alibaba.com
> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
> Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
> ---
>   fs/erofs/data.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/erofs/data.c b/fs/erofs/data.c
> index 029c761670bf..c98aeda8abb2 100644
> --- a/fs/erofs/data.c
> +++ b/fs/erofs/data.c
> @@ -220,7 +220,7 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
>   			up_read(&devs->rwsem);
>   			return 0;
>   		}
> -		map->m_bdev = dif->bdev_handle->bdev;
> +		map->m_bdev = dif->bdev_handle ? dif->bdev_handle->bdev : NULL;
>   		map->m_daxdev = dif->dax_dev;
>   		map->m_dax_part_off = dif->dax_part_off;
>   		map->m_fscache = dif->fscache;
> @@ -238,7 +238,8 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
>   			if (map->m_pa >= startoff &&
>   			    map->m_pa < startoff + length) {
>   				map->m_pa -= startoff;
> -				map->m_bdev = dif->bdev_handle->bdev;
> +				map->m_bdev = dif->bdev_handle ?
> +					      dif->bdev_handle->bdev : NULL;
>   				map->m_daxdev = dif->dax_dev;
>   				map->m_dax_part_off = dif->dax_part_off;
>   				map->m_fscache = dif->fscache;

[PATCH v6.6] erofs: fix NULL dereference of dif->bdev_handle in fscache mode

[Hongbo Li via Linux-erofs]

From: Jingbo Xu <jefflexu@linux.alibaba.com>

Avoid NULL dereference of dif->bdev_handle, as dif->bdev_handle is NULL
in fscache mode.

 BUG: kernel NULL pointer dereference, address: 0000000000000000
 RIP: 0010:erofs_map_dev+0xbd/0x1c0
 Call Trace:
  <TASK>
  erofs_fscache_data_read_slice+0xa7/0x340
  erofs_fscache_data_read+0x11/0x30
  erofs_fscache_readahead+0xd9/0x100
  read_pages+0x47/0x1f0
  page_cache_ra_order+0x1e5/0x270
  filemap_get_pages+0xf2/0x5f0
  filemap_read+0xb8/0x2e0
  vfs_read+0x18d/0x2b0
  ksys_read+0x53/0xd0
  do_syscall_64+0x42/0xf0
  entry_SYSCALL_64_after_hwframe+0x6e/0x76

Reported-by: Yiqun Leng <yqleng@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=7245
Fixes: 49845720080d ("erofs: Convert to use bdev_open_by_path()")
Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20231114070704.23398-1-jefflexu@linux.alibaba.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
---
 fs/erofs/data.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 029c761670bf..c98aeda8abb2 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -220,7 +220,7 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
 			up_read(&devs->rwsem);
 			return 0;
 		}
-		map->m_bdev = dif->bdev_handle->bdev;
+		map->m_bdev = dif->bdev_handle ? dif->bdev_handle->bdev : NULL;
 		map->m_daxdev = dif->dax_dev;
 		map->m_dax_part_off = dif->dax_part_off;
 		map->m_fscache = dif->fscache;
@@ -238,7 +238,8 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
 			if (map->m_pa >= startoff &&
 			    map->m_pa < startoff + length) {
 				map->m_pa -= startoff;
-				map->m_bdev = dif->bdev_handle->bdev;
+				map->m_bdev = dif->bdev_handle ?
+					      dif->bdev_handle->bdev : NULL;
 				map->m_daxdev = dif->dax_dev;
 				map->m_dax_part_off = dif->dax_part_off;
 				map->m_fscache = dif->fscache;
-- 
2.34.1

Re: [PATCH v6.6] erofs: fix NULL dereference of dif->bdev_handle in fscache mode

[Gao Xiang]

On 2024/6/27 17:11, Hongbo Li wrote:
> When I run nydus on linux 6.6.35, the erofs crashed with the following
> messages:
> 
> ```
> [ 2120.070101] RIP: 0010:erofs_map_dev+0x147/0x1e0 [erofs]
> [ 2120.070188] Code: e8 4e bd 6d dc 8b 43 28 4c 89 ef 8d 70 ff e8 f0 ee 69 dc 48 85 c0 0f 84 83 00 00 00 41 80 7d 44 00 75 31 48 8b 50 10 4c 89 e7 <48> 8b 12 48 89 53 08 48 8b 50 18 48 89 53 10 48 8b 50 20 48 89 53
> [ 2120.070288] RSP: 0018:ffff982a48adb9d8 EFLAGS: 00010246
> [ 2120.070357] RAX: ffff8c2607e2f040 RBX: ffff982a48adba38 RCX: 0000000000000000
> [ 2120.070431] RDX: 0000000000000000 RSI: ffff8c25d17c7dc8 RDI: ffff8c354725e198
> [ 2120.070522] RBP: ffff8c35466cf800 R08: ffff8c2607e2f040 R09: ffff8c354725e188
> [ 2120.070631] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8c354725e198
> [ 2120.070741] R13: ffff8c354725e180 R14: ffff8c25d14d01c0 R15: 0000000000001000
> [ 2120.070853] FS:  000000c000a00090(0000) GS:ffff8c34ffe00000(0000) knlGS:0000000000000000
> [ 2120.070965] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 2120.071054] CR2: 0000000000000000 CR3: 00000001067dc005 CR4: 00000000001706f0
> [ 2120.071163] Call Trace:
> [ 2120.071245]  <TASK>
> [ 2120.071325]  ? __die+0x24/0x70
> [ 2120.071413]  ? page_fault_oops+0x82/0x150
> [ 2120.071499]  ? fixup_exception+0x26/0x350
> [ 2120.071585]  ? exc_page_fault+0x69/0x150
> [ 2120.071671]  ? asm_exc_page_fault+0x26/0x30
> [ 2120.071759]  ? erofs_map_dev+0x147/0x1e0 [erofs]
> [ 2120.071853]  ? erofs_map_dev+0x130/0x1e0 [erofs]
> [ 2120.071946]  erofs_fscache_data_read_slice+0xe7/0x390 [erofs]
> [ 2120.072044]  ? xas_create+0x160/0x1b0
> [ 2120.072130]  ? __kmem_cache_alloc_node+0x18c/0x2c0
> [ 2120.072219]  ? erofs_fscache_readahead+0x49/0x110 [erofs]
> [ 2120.072314]  ? xas_load+0xe/0x50
> [ 2120.072397]  erofs_fscache_readahead+0xe0/0x110 [erofs]
> [ 2120.072492]  read_pages+0x5a/0x220
> [ 2120.072579]  page_cache_ra_order+0x1f0/0x2f0
> [ 2120.072667]  filemap_get_pages+0xef/0x290
> [ 2120.072755]  filemap_read+0xcb/0x310
> [ 2120.072841]  ? ovl_open+0x9e/0xf0 [overlay]
> [ 2120.072942]  ? ima_file_check+0x57/0x80
> [ 2120.073028]  ? mntput_no_expire+0x4a/0x250
> [ 2120.073116]  do_iter_readv_writev+0x12d/0x140
> [ 2120.073204]  do_iter_read+0xfd/0x190
> [ 2120.073288]  ovl_read_iter+0x1c3/0x210 [overlay]
> [ 2120.073384]  vfs_read+0x1c7/0x300
> [ 2120.073471]  ksys_read+0x63/0xe0
> [ 2120.073555]  do_syscall_64+0x37/0x90
> [ 2120.073640]  entry_SYSCALL_64_after_hwframe+0x78/0xe2
> [ 2120.073729] RIP: 0033:0x403ace
> ```
> 
> The reason is the same with 8bd90b6ae7856("erofs: fix NULL dereference of dif->bdev_handle in fscache mode") in mainline. So we should backport this
> patch into stable linux-6.6.y to avoid this bug.

Yes, commit 8bd90b6ae785 should be backported to
Linux 6.6.y LTS immediately.

Thanks,
Gao Xiang

Re: [PATCH v6.6] erofs: fix NULL dereference of dif->bdev_handle in fscache mode

[Gao Xiang]

On 2024/6/27 17:35, Gao Xiang wrote:
> 
> 
> On 2024/6/27 17:11, Hongbo Li wrote:

..

>>
>> The reason is the same with 8bd90b6ae7856("erofs: fix NULL dereference of dif->bdev_handle in fscache mode") in mainline. So we should backport this
>> patch into stable linux-6.6.y to avoid this bug.
> 
> Yes, commit 8bd90b6ae785 should be backported to
> Linux 6.6.y LTS immediately.

BTW, It seems that

commit "erofs: Convert to use bdev_open_by_path()" was
backported as a dependency since v6.6.23 even I
explicitly commented that this patch is unnecessary
and I tend to manually backport instead as below:

https://lore.kernel.org/r/ZgDHG8Ucl3EkY4ZS@debian


However, my comment was eventually ignored and
some other related fix like
"erofs: fix NULL dereference of dif->bdev_handle in fscache mode"

wasn't backported along with
"erofs: Convert to use bdev_open_by_path()"

So the affected 6.6 LTS versions seem to be
v6.6.23 ~ v6.6.35 (current)

Thanks,
Gao Xiang

Re: [PATCH v6.6] erofs: fix NULL dereference of dif->bdev_handle in fscache mode

[Greg KH]

On Thu, Jun 27, 2024 at 05:50:26PM +0800, Gao Xiang wrote:
> 
> 
> On 2024/6/27 17:35, Gao Xiang wrote:
> > 
> > 
> > On 2024/6/27 17:11, Hongbo Li wrote:
> 
> ..
> 
> > > 
> > > The reason is the same with 8bd90b6ae7856("erofs: fix NULL dereference of dif->bdev_handle in fscache mode") in mainline. So we should backport this
> > > patch into stable linux-6.6.y to avoid this bug.
> > 
> > Yes, commit 8bd90b6ae785 should be backported to
> > Linux 6.6.y LTS immediately.
> 
> BTW, It seems that
> 
> commit "erofs: Convert to use bdev_open_by_path()" was
> backported as a dependency since v6.6.23 even I
> explicitly commented that this patch is unnecessary
> and I tend to manually backport instead as below:
> 
> https://lore.kernel.org/r/ZgDHG8Ucl3EkY4ZS@debian
> 
> 
> However, my comment was eventually ignored and
> some other related fix like
> "erofs: fix NULL dereference of dif->bdev_handle in fscache mode"
> 
> wasn't backported along with
> "erofs: Convert to use bdev_open_by_path()"

Sorry, I missed that somehow, my fault.

> So the affected 6.6 LTS versions seem to be
> v6.6.23 ~ v6.6.35 (current)

So what specifically should we do here?

thanks,

greg k-h

Re: [PATCH v6.6] erofs: fix NULL dereference of dif->bdev_handle in fscache mode

[Gao Xiang]

Hi Greg,

On 2024/6/27 19:16, Greg KH wrote:
> On Thu, Jun 27, 2024 at 05:50:26PM +0800, Gao Xiang wrote:
>>
>>
>> On 2024/6/27 17:35, Gao Xiang wrote:
>>>
>>>
>>> On 2024/6/27 17:11, Hongbo Li wrote:
>>
>> ..
>>
>>>>
>>>> The reason is the same with 8bd90b6ae7856("erofs: fix NULL dereference of dif->bdev_handle in fscache mode") in mainline. So we should backport this
>>>> patch into stable linux-6.6.y to avoid this bug.
>>>
>>> Yes, commit 8bd90b6ae785 should be backported to
>>> Linux 6.6.y LTS immediately.
>>
>> BTW, It seems that
>>
>> commit "erofs: Convert to use bdev_open_by_path()" was
>> backported as a dependency since v6.6.23 even I
>> explicitly commented that this patch is unnecessary
>> and I tend to manually backport instead as below:
>>
>> https://lore.kernel.org/r/ZgDHG8Ucl3EkY4ZS@debian
>>
>>
>> However, my comment was eventually ignored and
>> some other related fix like
>> "erofs: fix NULL dereference of dif->bdev_handle in fscache mode"
>>
>> wasn't backported along with
>> "erofs: Convert to use bdev_open_by_path()"
> 
> Sorry, I missed that somehow, my fault.
> 
>> So the affected 6.6 LTS versions seem to be
>> v6.6.23 ~ v6.6.35 (current)
> 
> So what specifically should we do here?

Thanks for the reply..  Honestly I'd like to revert

block: Provide bdev_open_* functions
erofs: Convert to use bdev_open_by_path()
erofs: fix handling kern_mount() failure

Not quite sure if they can be cleanly reverted, but
since the upstream doen't have 'bdev_handle' anymore,
I will resend a proper backport for
"erofs: fix handling kern_mount() failure".

Thanks,
Gao Xiang

> 
> thanks,
> 
> greg k-h

Re: [PATCH v6.6] erofs: fix NULL dereference of dif->bdev_handle in fscache mode

[Gao Xiang]

On 2024/6/27 20:36, Gao Xiang wrote:
> Hi Greg,
> 
> On 2024/6/27 19:16, Greg KH wrote:

...

>>
>> So what specifically should we do here?
> 
> Thanks for the reply..  Honestly I'd like to revert
> 
> block: Provide bdev_open_* functions
> erofs: Convert to use bdev_open_by_path()
> erofs: fix handling kern_mount() failure
> 
> Not quite sure if they can be cleanly reverted, but
> since the upstream doen't have 'bdev_handle' anymore,
> I will resend a proper backport for
> "erofs: fix handling kern_mount() failure".

Sigh, I just tried and it seems it causes more
conflicts due to my revert.  It seems another churn..

Anyway, on 6.6 LTS only the erofs one uses the
obsolete `struct bdev_handle`, but I think at least
it doesn't cause some serious issue.

Hi Greg,

Could you just pick up Hongbo's backport to resolve
the NULL dereference issue?

Thanks,
GaoXiang

> 
> Thanks,
> Gao Xiang
> 
>>
>> thanks,
>>
>> greg k-h

Re: [PATCH v6.6] erofs: fix NULL dereference of dif->bdev_handle in fscache mode

[Greg KH]

On Thu, Jun 27, 2024 at 08:51:37PM +0800, Gao Xiang wrote:
> 
> 
> On 2024/6/27 20:36, Gao Xiang wrote:
> > Hi Greg,
> > 
> > On 2024/6/27 19:16, Greg KH wrote:
> 
> ...
> 
> > > 
> > > So what specifically should we do here?
> > 
> > Thanks for the reply..  Honestly I'd like to revert
> > 
> > block: Provide bdev_open_* functions
> > erofs: Convert to use bdev_open_by_path()
> > erofs: fix handling kern_mount() failure
> > 
> > Not quite sure if they can be cleanly reverted, but
> > since the upstream doen't have 'bdev_handle' anymore,
> > I will resend a proper backport for
> > "erofs: fix handling kern_mount() failure".
> 
> Sigh, I just tried and it seems it causes more
> conflicts due to my revert.  It seems another churn..
> 
> Anyway, on 6.6 LTS only the erofs one uses the
> obsolete `struct bdev_handle`, but I think at least
> it doesn't cause some serious issue.
> 
> Hi Greg,
> 
> Could you just pick up Hongbo's backport to resolve
> the NULL dereference issue?

Sure, is that the one earlier in this thread?

And if so, what is the git commit id of it in Linus's tree?

thanks,

greg k-h

Re: [PATCH v6.6] erofs: fix NULL dereference of dif->bdev_handle in fscache mode

[Gao Xiang]

On 2024/6/27 21:22, Greg KH wrote:
> On Thu, Jun 27, 2024 at 08:51:37PM +0800, Gao Xiang wrote:
>>
>>
>> On 2024/6/27 20:36, Gao Xiang wrote:
>>> Hi Greg,
>>>
>>> On 2024/6/27 19:16, Greg KH wrote:
>>
>> ...
>>
>>>>
>>>> So what specifically should we do here?
>>>
>>> Thanks for the reply..  Honestly I'd like to revert
>>>
>>> block: Provide bdev_open_* functions
>>> erofs: Convert to use bdev_open_by_path()
>>> erofs: fix handling kern_mount() failure
>>>
>>> Not quite sure if they can be cleanly reverted, but
>>> since the upstream doen't have 'bdev_handle' anymore,
>>> I will resend a proper backport for
>>> "erofs: fix handling kern_mount() failure".
>>
>> Sigh, I just tried and it seems it causes more
>> conflicts due to my revert.  It seems another churn..
>>
>> Anyway, on 6.6 LTS only the erofs one uses the
>> obsolete `struct bdev_handle`, but I think at least
>> it doesn't cause some serious issue.
>>
>> Hi Greg,
>>
>> Could you just pick up Hongbo's backport to resolve
>> the NULL dereference issue?
> 
> Sure, is that the one earlier in this thread?

Yeah.

> 
> And if so, what is the git commit id of it in Linus's tree?

commit 8bd90b6ae7856dd5000b75691d905b39b9ea5d6b upstream.

Thanks,
Gao Xiang

> 
> thanks,
> 
> greg k-h

Re: [PATCH v6.6] erofs: fix NULL dereference of dif->bdev_handle in fscache mode

[Greg KH]

On Thu, Jun 27, 2024 at 10:03:38PM +0800, Gao Xiang wrote:
> 
> 
> On 2024/6/27 21:22, Greg KH wrote:
> > On Thu, Jun 27, 2024 at 08:51:37PM +0800, Gao Xiang wrote:
> > > 
> > > 
> > > On 2024/6/27 20:36, Gao Xiang wrote:
> > > > Hi Greg,
> > > > 
> > > > On 2024/6/27 19:16, Greg KH wrote:
> > > 
> > > ...
> > > 
> > > > > 
> > > > > So what specifically should we do here?
> > > > 
> > > > Thanks for the reply..  Honestly I'd like to revert
> > > > 
> > > > block: Provide bdev_open_* functions
> > > > erofs: Convert to use bdev_open_by_path()
> > > > erofs: fix handling kern_mount() failure
> > > > 
> > > > Not quite sure if they can be cleanly reverted, but
> > > > since the upstream doen't have 'bdev_handle' anymore,
> > > > I will resend a proper backport for
> > > > "erofs: fix handling kern_mount() failure".
> > > 
> > > Sigh, I just tried and it seems it causes more
> > > conflicts due to my revert.  It seems another churn..
> > > 
> > > Anyway, on 6.6 LTS only the erofs one uses the
> > > obsolete `struct bdev_handle`, but I think at least
> > > it doesn't cause some serious issue.
> > > 
> > > Hi Greg,
> > > 
> > > Could you just pick up Hongbo's backport to resolve
> > > the NULL dereference issue?
> > 
> > Sure, is that the one earlier in this thread?
> 
> Yeah.
> 
> > 
> > And if so, what is the git commit id of it in Linus's tree?
> 
> commit 8bd90b6ae7856dd5000b75691d905b39b9ea5d6b upstream.

Now queued up, thanks.

greg k-h

Re: [PATCH v6.6] erofs: fix NULL dereference of dif->bdev_handle in fscache mode

[Gao Xiang]

On 2024/7/2 16:46, Greg KH wrote:
> On Thu, Jun 27, 2024 at 10:03:38PM +0800, Gao Xiang wrote:
>>
>>

..

>>
>>>
>>> And if so, what is the git commit id of it in Linus's tree?
>>
>> commit 8bd90b6ae7856dd5000b75691d905b39b9ea5d6b upstream.
> 
> Now queued up, thanks.

Thanks Greg!

Thanks,
Gao Xiang

> 
> greg k-h