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* [PATCH] dm thin metadata: Fix use-after-free in dm_bm_set_read_only
@ 2021-09-18  2:26 Jeffle Xu
  2021-09-18  2:32 ` JeffleXu
  0 siblings, 1 reply; 4+ messages in thread
From: Jeffle Xu @ 2021-09-18  2:26 UTC (permalink / raw)
  To: gregkh, snitzer; +Cc: yebin10, stable, xiejingfeng, jefflexu, joseph.qi

From: Ye Bin <yebin10@huawei.com>

Hi Greg,

Ye Bin had ever fixed a use-after-free of dm-thin in v5.9, and the
complete patchset contains three patches:

[1/3] d16ff19e69ab  dm cache metadata: Avoid returning cmd->bm wild pointer on error
[2/3] 219403d7e56f dm thin metadata:  Avoid returning cmd->bm wild pointer on error
[3/3] 3a653b205f29 dm thin metadata: Fix use-after-free in dm_bm_set_read_only

However, 4.19.y stable only picks the former two patches [1]:
[1/3] 67f03c3d6829 dm cache metadata: Avoid returning cmd->bm wild pointer on error
[2/3] 2c00ee626ed4 dm thin metadata: Avoid returning cmd->bm wild pointer on error

We encountered a NULL crash and xiejingfeng found that the omitted patch 3 can
fix that. I'm not sure why patch 3 is not picked then, and we need this patch
to fix this issue.

[32402.449200] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
[32402.459553] Oops: 0002 [#1] SMP NOPTI
[32402.483982] RIP: 0010:dm_bm_set_read_only+0x5/0x10 [dm_persistent_data]
[32402.588073] Call Trace:
[32402.590522] dm_pool_metadata_read_only+0x22/0x30 [dm_thin_pool]
[32402.596526] set_pool_mode+0x209/0x2e0 [dm_thin_pool]
[32402.601579] metadata_operation_failed+0xd5/0xf0 [dm_thin_pool]
[32402.607499] commit+0x91/0xf0 [dm_thin_pool]
[32402.611771] pool_status+0x28a/0x700 [dm_thin_pool]
[32402.616652] retrieve_status+0xa1/0x1c0 [dm_mod]
[32402.627794] table_status+0x61/0xa0 [dm_mod]
[32402.632068] ctl_ioctl+0x1b3/0x480 [dm_mod]
[32402.636253] dm_ctl_ioctl+0xa/0x10 [dm_mod]
[32402.640440] do_vfs_ioctl+0x9f/0x610
[32402.653081] ksys_ioctl+0x70/0x80
[32402.656393] __x64_sys_ioctl+0x16/0x20
[32402.660145] do_syscall_64+0x7b/0x200
[32402.663813] entry_SYSCALL_64_after_hwframe+0x44/0xa9

[1] https://lore.kernel.org/lkml/20200908152225.086536876@linuxfoundation.org/

---
commit 3a653b205f29b3f9827a01a0c88bfbcb0d169494 upstream.

The following error ocurred when testing disk online/offline:

[  301.798344] device-mapper: thin: 253:5: aborting current metadata transaction
[  301.848441] device-mapper: thin: 253:5: failed to abort metadata transaction
[  301.849206] Aborting journal on device dm-26-8.
[  301.850489] EXT4-fs error (device dm-26) in __ext4_new_inode:943: Journal has aborted
[  301.851095] EXT4-fs (dm-26): Delayed block allocation failed for inode 398742 at logical offset 181 with max blocks 19 with error 30
[  301.854476] BUG: KASAN: use-after-free in dm_bm_set_read_only+0x3a/0x40 [dm_persistent_data]

Reason is:

 metadata_operation_failed
    abort_transaction
        dm_pool_abort_metadata
	    __create_persistent_data_objects
	        r = __open_or_format_metadata
	        if (r) --> If failed will free pmd->bm but pmd->bm not set NULL
		    dm_block_manager_destroy(pmd->bm);
    set_pool_mode
	dm_pool_metadata_read_only(pool->pmd);
	dm_bm_set_read_only(pmd->bm);  --> use-after-free

Add checks to see if pmd->bm is NULL in dm_bm_set_read_only and
dm_bm_set_read_write functions.  If bm is NULL it means creating the
bm failed and so dm_bm_is_read_only must return true.

Signed-off-by: Ye Bin <yebin10@huawei.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: xiejingfeng <xiejingfeng@linux.alibaba.com>
Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
---
 drivers/md/dm-thin-metadata.c                 |  2 +-
 drivers/md/persistent-data/dm-block-manager.c | 14 ++++++++------
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index 85077f4d257a..a6a5cee6b943 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -901,7 +901,7 @@ int dm_pool_metadata_close(struct dm_pool_metadata *pmd)
 		return -EBUSY;
 	}
 
-	if (!dm_bm_is_read_only(pmd->bm) && !pmd->fail_io) {
+	if (!pmd->fail_io && !dm_bm_is_read_only(pmd->bm)) {
 		r = __commit_transaction(pmd);
 		if (r < 0)
 			DMWARN("%s: __commit_transaction() failed, error = %d",
diff --git a/drivers/md/persistent-data/dm-block-manager.c b/drivers/md/persistent-data/dm-block-manager.c
index 492a3f8ac119..0401daa0f7fb 100644
--- a/drivers/md/persistent-data/dm-block-manager.c
+++ b/drivers/md/persistent-data/dm-block-manager.c
@@ -494,7 +494,7 @@ int dm_bm_write_lock(struct dm_block_manager *bm,
 	void *p;
 	int r;
 
-	if (bm->read_only)
+	if (dm_bm_is_read_only(bm))
 		return -EPERM;
 
 	p = dm_bufio_read(bm->bufio, b, (struct dm_buffer **) result);
@@ -563,7 +563,7 @@ int dm_bm_write_lock_zero(struct dm_block_manager *bm,
 	struct buffer_aux *aux;
 	void *p;
 
-	if (bm->read_only)
+	if (dm_bm_is_read_only(bm))
 		return -EPERM;
 
 	p = dm_bufio_new(bm->bufio, b, (struct dm_buffer **) result);
@@ -603,7 +603,7 @@ EXPORT_SYMBOL_GPL(dm_bm_unlock);
 
 int dm_bm_flush(struct dm_block_manager *bm)
 {
-	if (bm->read_only)
+	if (dm_bm_is_read_only(bm))
 		return -EPERM;
 
 	return dm_bufio_write_dirty_buffers(bm->bufio);
@@ -617,19 +617,21 @@ void dm_bm_prefetch(struct dm_block_manager *bm, dm_block_t b)
 
 bool dm_bm_is_read_only(struct dm_block_manager *bm)
 {
-	return bm->read_only;
+	return (bm ? bm->read_only : true);
 }
 EXPORT_SYMBOL_GPL(dm_bm_is_read_only);
 
 void dm_bm_set_read_only(struct dm_block_manager *bm)
 {
-	bm->read_only = true;
+	if (bm)
+		bm->read_only = true;
 }
 EXPORT_SYMBOL_GPL(dm_bm_set_read_only);
 
 void dm_bm_set_read_write(struct dm_block_manager *bm)
 {
-	bm->read_only = false;
+	if (bm)
+		bm->read_only = false;
 }
 EXPORT_SYMBOL_GPL(dm_bm_set_read_write);
 
-- 
2.27.0


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* [PATCH] dm thin metadata: Fix use-after-free in dm_bm_set_read_only
@ 2021-09-18  2:31 Jeffle Xu
  2021-09-18 12:17 ` Greg KH
  0 siblings, 1 reply; 4+ messages in thread
From: Jeffle Xu @ 2021-09-18  2:31 UTC (permalink / raw)
  To: gregkh, snitzer; +Cc: yebin10, stable, xiejingfeng, jefflexu, joseph.qi

From: Ye Bin <yebin10@huawei.com>

Hi Greg,

Ye Bin had ever fixed a use-after-free of dm-thin in v5.9, and the
complete patchset contains three patches:

[1/3] d16ff19e69ab  dm cache metadata: Avoid returning cmd->bm wild pointer on error
[2/3] 219403d7e56f dm thin metadata:  Avoid returning cmd->bm wild pointer on error
[3/3] 3a653b205f29 dm thin metadata: Fix use-after-free in dm_bm_set_read_only

However, 4.19.y stable only picks the former two patches [1]:
[1/3] 67f03c3d6829 dm cache metadata: Avoid returning cmd->bm wild pointer on error
[2/3] 2c00ee626ed4 dm thin metadata: Avoid returning cmd->bm wild pointer on error

We encountered a NULL crash and xiejingfeng found that the omitted patch 3 can
fix that. I'm not sure why patch 3 is not picked then, and we need this patch
to fix this issue.

[32402.449200] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
[32402.459553] Oops: 0002 [#1] SMP NOPTI
[32402.483982] RIP: 0010:dm_bm_set_read_only+0x5/0x10 [dm_persistent_data]
[32402.588073] Call Trace:
[32402.590522] dm_pool_metadata_read_only+0x22/0x30 [dm_thin_pool]
[32402.596526] set_pool_mode+0x209/0x2e0 [dm_thin_pool]
[32402.601579] metadata_operation_failed+0xd5/0xf0 [dm_thin_pool]
[32402.607499] commit+0x91/0xf0 [dm_thin_pool]
[32402.611771] pool_status+0x28a/0x700 [dm_thin_pool]
[32402.616652] retrieve_status+0xa1/0x1c0 [dm_mod]
[32402.627794] table_status+0x61/0xa0 [dm_mod]
[32402.632068] ctl_ioctl+0x1b3/0x480 [dm_mod]
[32402.636253] dm_ctl_ioctl+0xa/0x10 [dm_mod]
[32402.640440] do_vfs_ioctl+0x9f/0x610
[32402.653081] ksys_ioctl+0x70/0x80
[32402.656393] __x64_sys_ioctl+0x16/0x20
[32402.660145] do_syscall_64+0x7b/0x200
[32402.663813] entry_SYSCALL_64_after_hwframe+0x44/0xa9

[1] https://lore.kernel.org/lkml/20200908152225.086536876@linuxfoundation.org/

---
commit 3a653b205f29b3f9827a01a0c88bfbcb0d169494 upstream.

The following error ocurred when testing disk online/offline:

[  301.798344] device-mapper: thin: 253:5: aborting current metadata transaction
[  301.848441] device-mapper: thin: 253:5: failed to abort metadata transaction
[  301.849206] Aborting journal on device dm-26-8.
[  301.850489] EXT4-fs error (device dm-26) in __ext4_new_inode:943: Journal has aborted
[  301.851095] EXT4-fs (dm-26): Delayed block allocation failed for inode 398742 at logical offset 181 with max blocks 19 with error 30
[  301.854476] BUG: KASAN: use-after-free in dm_bm_set_read_only+0x3a/0x40 [dm_persistent_data]

Reason is:

 metadata_operation_failed
    abort_transaction
        dm_pool_abort_metadata
	    __create_persistent_data_objects
	        r = __open_or_format_metadata
	        if (r) --> If failed will free pmd->bm but pmd->bm not set NULL
		    dm_block_manager_destroy(pmd->bm);
    set_pool_mode
	dm_pool_metadata_read_only(pool->pmd);
	dm_bm_set_read_only(pmd->bm);  --> use-after-free

Add checks to see if pmd->bm is NULL in dm_bm_set_read_only and
dm_bm_set_read_write functions.  If bm is NULL it means creating the
bm failed and so dm_bm_is_read_only must return true.

Signed-off-by: Ye Bin <yebin10@huawei.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: xiejingfeng <xiejingfeng@linux.alibaba.com>
Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
---
 drivers/md/dm-thin-metadata.c                 |  2 +-
 drivers/md/persistent-data/dm-block-manager.c | 14 ++++++++------
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index 85077f4d257a..a6a5cee6b943 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -901,7 +901,7 @@ int dm_pool_metadata_close(struct dm_pool_metadata *pmd)
 		return -EBUSY;
 	}
 
-	if (!dm_bm_is_read_only(pmd->bm) && !pmd->fail_io) {
+	if (!pmd->fail_io && !dm_bm_is_read_only(pmd->bm)) {
 		r = __commit_transaction(pmd);
 		if (r < 0)
 			DMWARN("%s: __commit_transaction() failed, error = %d",
diff --git a/drivers/md/persistent-data/dm-block-manager.c b/drivers/md/persistent-data/dm-block-manager.c
index 492a3f8ac119..0401daa0f7fb 100644
--- a/drivers/md/persistent-data/dm-block-manager.c
+++ b/drivers/md/persistent-data/dm-block-manager.c
@@ -494,7 +494,7 @@ int dm_bm_write_lock(struct dm_block_manager *bm,
 	void *p;
 	int r;
 
-	if (bm->read_only)
+	if (dm_bm_is_read_only(bm))
 		return -EPERM;
 
 	p = dm_bufio_read(bm->bufio, b, (struct dm_buffer **) result);
@@ -563,7 +563,7 @@ int dm_bm_write_lock_zero(struct dm_block_manager *bm,
 	struct buffer_aux *aux;
 	void *p;
 
-	if (bm->read_only)
+	if (dm_bm_is_read_only(bm))
 		return -EPERM;
 
 	p = dm_bufio_new(bm->bufio, b, (struct dm_buffer **) result);
@@ -603,7 +603,7 @@ EXPORT_SYMBOL_GPL(dm_bm_unlock);
 
 int dm_bm_flush(struct dm_block_manager *bm)
 {
-	if (bm->read_only)
+	if (dm_bm_is_read_only(bm))
 		return -EPERM;
 
 	return dm_bufio_write_dirty_buffers(bm->bufio);
@@ -617,19 +617,21 @@ void dm_bm_prefetch(struct dm_block_manager *bm, dm_block_t b)
 
 bool dm_bm_is_read_only(struct dm_block_manager *bm)
 {
-	return bm->read_only;
+	return (bm ? bm->read_only : true);
 }
 EXPORT_SYMBOL_GPL(dm_bm_is_read_only);
 
 void dm_bm_set_read_only(struct dm_block_manager *bm)
 {
-	bm->read_only = true;
+	if (bm)
+		bm->read_only = true;
 }
 EXPORT_SYMBOL_GPL(dm_bm_set_read_only);
 
 void dm_bm_set_read_write(struct dm_block_manager *bm)
 {
-	bm->read_only = false;
+	if (bm)
+		bm->read_only = false;
 }
 EXPORT_SYMBOL_GPL(dm_bm_set_read_write);
 
-- 
2.27.0


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH] dm thin metadata: Fix use-after-free in dm_bm_set_read_only
  2021-09-18  2:26 Jeffle Xu
@ 2021-09-18  2:32 ` JeffleXu
  0 siblings, 0 replies; 4+ messages in thread
From: JeffleXu @ 2021-09-18  2:32 UTC (permalink / raw)
  To: gregkh, snitzer; +Cc: yebin10, stable, xiejingfeng, joseph.qi

Sorry, I misspelled the email address of Greg, please omit this email,
and I had sent a new one.

On 9/18/21 10:26 AM, Jeffle Xu wrote:
> From: Ye Bin <yebin10@huawei.com>
> 
> Hi Greg,
> 
> Ye Bin had ever fixed a use-after-free of dm-thin in v5.9, and the
> complete patchset contains three patches:
> 
> [1/3] d16ff19e69ab  dm cache metadata: Avoid returning cmd->bm wild pointer on error
> [2/3] 219403d7e56f dm thin metadata:  Avoid returning cmd->bm wild pointer on error
> [3/3] 3a653b205f29 dm thin metadata: Fix use-after-free in dm_bm_set_read_only
> 
> However, 4.19.y stable only picks the former two patches [1]:
> [1/3] 67f03c3d6829 dm cache metadata: Avoid returning cmd->bm wild pointer on error
> [2/3] 2c00ee626ed4 dm thin metadata: Avoid returning cmd->bm wild pointer on error
> 
> We encountered a NULL crash and xiejingfeng found that the omitted patch 3 can
> fix that. I'm not sure why patch 3 is not picked then, and we need this patch
> to fix this issue.
> 
> [32402.449200] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
> [32402.459553] Oops: 0002 [#1] SMP NOPTI
> [32402.483982] RIP: 0010:dm_bm_set_read_only+0x5/0x10 [dm_persistent_data]
> [32402.588073] Call Trace:
> [32402.590522] dm_pool_metadata_read_only+0x22/0x30 [dm_thin_pool]
> [32402.596526] set_pool_mode+0x209/0x2e0 [dm_thin_pool]
> [32402.601579] metadata_operation_failed+0xd5/0xf0 [dm_thin_pool]
> [32402.607499] commit+0x91/0xf0 [dm_thin_pool]
> [32402.611771] pool_status+0x28a/0x700 [dm_thin_pool]
> [32402.616652] retrieve_status+0xa1/0x1c0 [dm_mod]
> [32402.627794] table_status+0x61/0xa0 [dm_mod]
> [32402.632068] ctl_ioctl+0x1b3/0x480 [dm_mod]
> [32402.636253] dm_ctl_ioctl+0xa/0x10 [dm_mod]
> [32402.640440] do_vfs_ioctl+0x9f/0x610
> [32402.653081] ksys_ioctl+0x70/0x80
> [32402.656393] __x64_sys_ioctl+0x16/0x20
> [32402.660145] do_syscall_64+0x7b/0x200
> [32402.663813] entry_SYSCALL_64_after_hwframe+0x44/0xa9
> 
> [1] https://lore.kernel.org/lkml/20200908152225.086536876@linuxfoundation.org/
> 
> ---
> commit 3a653b205f29b3f9827a01a0c88bfbcb0d169494 upstream.
> 
> The following error ocurred when testing disk online/offline:
> 
> [  301.798344] device-mapper: thin: 253:5: aborting current metadata transaction
> [  301.848441] device-mapper: thin: 253:5: failed to abort metadata transaction
> [  301.849206] Aborting journal on device dm-26-8.
> [  301.850489] EXT4-fs error (device dm-26) in __ext4_new_inode:943: Journal has aborted
> [  301.851095] EXT4-fs (dm-26): Delayed block allocation failed for inode 398742 at logical offset 181 with max blocks 19 with error 30
> [  301.854476] BUG: KASAN: use-after-free in dm_bm_set_read_only+0x3a/0x40 [dm_persistent_data]
> 
> Reason is:
> 
>  metadata_operation_failed
>     abort_transaction
>         dm_pool_abort_metadata
> 	    __create_persistent_data_objects
> 	        r = __open_or_format_metadata
> 	        if (r) --> If failed will free pmd->bm but pmd->bm not set NULL
> 		    dm_block_manager_destroy(pmd->bm);
>     set_pool_mode
> 	dm_pool_metadata_read_only(pool->pmd);
> 	dm_bm_set_read_only(pmd->bm);  --> use-after-free
> 
> Add checks to see if pmd->bm is NULL in dm_bm_set_read_only and
> dm_bm_set_read_write functions.  If bm is NULL it means creating the
> bm failed and so dm_bm_is_read_only must return true.
> 
> Signed-off-by: Ye Bin <yebin10@huawei.com>
> Cc: stable@vger.kernel.org
> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
> Signed-off-by: xiejingfeng <xiejingfeng@linux.alibaba.com>
> Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
> ---
>  drivers/md/dm-thin-metadata.c                 |  2 +-
>  drivers/md/persistent-data/dm-block-manager.c | 14 ++++++++------
>  2 files changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
> index 85077f4d257a..a6a5cee6b943 100644
> --- a/drivers/md/dm-thin-metadata.c
> +++ b/drivers/md/dm-thin-metadata.c
> @@ -901,7 +901,7 @@ int dm_pool_metadata_close(struct dm_pool_metadata *pmd)
>  		return -EBUSY;
>  	}
>  
> -	if (!dm_bm_is_read_only(pmd->bm) && !pmd->fail_io) {
> +	if (!pmd->fail_io && !dm_bm_is_read_only(pmd->bm)) {
>  		r = __commit_transaction(pmd);
>  		if (r < 0)
>  			DMWARN("%s: __commit_transaction() failed, error = %d",
> diff --git a/drivers/md/persistent-data/dm-block-manager.c b/drivers/md/persistent-data/dm-block-manager.c
> index 492a3f8ac119..0401daa0f7fb 100644
> --- a/drivers/md/persistent-data/dm-block-manager.c
> +++ b/drivers/md/persistent-data/dm-block-manager.c
> @@ -494,7 +494,7 @@ int dm_bm_write_lock(struct dm_block_manager *bm,
>  	void *p;
>  	int r;
>  
> -	if (bm->read_only)
> +	if (dm_bm_is_read_only(bm))
>  		return -EPERM;
>  
>  	p = dm_bufio_read(bm->bufio, b, (struct dm_buffer **) result);
> @@ -563,7 +563,7 @@ int dm_bm_write_lock_zero(struct dm_block_manager *bm,
>  	struct buffer_aux *aux;
>  	void *p;
>  
> -	if (bm->read_only)
> +	if (dm_bm_is_read_only(bm))
>  		return -EPERM;
>  
>  	p = dm_bufio_new(bm->bufio, b, (struct dm_buffer **) result);
> @@ -603,7 +603,7 @@ EXPORT_SYMBOL_GPL(dm_bm_unlock);
>  
>  int dm_bm_flush(struct dm_block_manager *bm)
>  {
> -	if (bm->read_only)
> +	if (dm_bm_is_read_only(bm))
>  		return -EPERM;
>  
>  	return dm_bufio_write_dirty_buffers(bm->bufio);
> @@ -617,19 +617,21 @@ void dm_bm_prefetch(struct dm_block_manager *bm, dm_block_t b)
>  
>  bool dm_bm_is_read_only(struct dm_block_manager *bm)
>  {
> -	return bm->read_only;
> +	return (bm ? bm->read_only : true);
>  }
>  EXPORT_SYMBOL_GPL(dm_bm_is_read_only);
>  
>  void dm_bm_set_read_only(struct dm_block_manager *bm)
>  {
> -	bm->read_only = true;
> +	if (bm)
> +		bm->read_only = true;
>  }
>  EXPORT_SYMBOL_GPL(dm_bm_set_read_only);
>  
>  void dm_bm_set_read_write(struct dm_block_manager *bm)
>  {
> -	bm->read_only = false;
> +	if (bm)
> +		bm->read_only = false;
>  }
>  EXPORT_SYMBOL_GPL(dm_bm_set_read_write);
>  
> 

-- 
Thanks,
Jeffle

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] dm thin metadata: Fix use-after-free in dm_bm_set_read_only
  2021-09-18  2:31 [PATCH] dm thin metadata: Fix use-after-free in dm_bm_set_read_only Jeffle Xu
@ 2021-09-18 12:17 ` Greg KH
  0 siblings, 0 replies; 4+ messages in thread
From: Greg KH @ 2021-09-18 12:17 UTC (permalink / raw)
  To: Jeffle Xu; +Cc: snitzer, yebin10, stable, xiejingfeng, joseph.qi

On Sat, Sep 18, 2021 at 10:31:05AM +0800, Jeffle Xu wrote:
> From: Ye Bin <yebin10@huawei.com>
> 
> Hi Greg,
> 
> Ye Bin had ever fixed a use-after-free of dm-thin in v5.9, and the
> complete patchset contains three patches:
> 
> [1/3] d16ff19e69ab  dm cache metadata: Avoid returning cmd->bm wild pointer on error
> [2/3] 219403d7e56f dm thin metadata:  Avoid returning cmd->bm wild pointer on error
> [3/3] 3a653b205f29 dm thin metadata: Fix use-after-free in dm_bm_set_read_only
> 
> However, 4.19.y stable only picks the former two patches [1]:
> [1/3] 67f03c3d6829 dm cache metadata: Avoid returning cmd->bm wild pointer on error
> [2/3] 2c00ee626ed4 dm thin metadata: Avoid returning cmd->bm wild pointer on error
> 
> We encountered a NULL crash and xiejingfeng found that the omitted patch 3 can
> fix that. I'm not sure why patch 3 is not picked then, and we need this patch
> to fix this issue.
> 
> [32402.449200] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
> [32402.459553] Oops: 0002 [#1] SMP NOPTI
> [32402.483982] RIP: 0010:dm_bm_set_read_only+0x5/0x10 [dm_persistent_data]
> [32402.588073] Call Trace:
> [32402.590522] dm_pool_metadata_read_only+0x22/0x30 [dm_thin_pool]
> [32402.596526] set_pool_mode+0x209/0x2e0 [dm_thin_pool]
> [32402.601579] metadata_operation_failed+0xd5/0xf0 [dm_thin_pool]
> [32402.607499] commit+0x91/0xf0 [dm_thin_pool]
> [32402.611771] pool_status+0x28a/0x700 [dm_thin_pool]
> [32402.616652] retrieve_status+0xa1/0x1c0 [dm_mod]
> [32402.627794] table_status+0x61/0xa0 [dm_mod]
> [32402.632068] ctl_ioctl+0x1b3/0x480 [dm_mod]
> [32402.636253] dm_ctl_ioctl+0xa/0x10 [dm_mod]
> [32402.640440] do_vfs_ioctl+0x9f/0x610
> [32402.653081] ksys_ioctl+0x70/0x80
> [32402.656393] __x64_sys_ioctl+0x16/0x20
> [32402.660145] do_syscall_64+0x7b/0x200
> [32402.663813] entry_SYSCALL_64_after_hwframe+0x44/0xa9
> 
> [1] https://lore.kernel.org/lkml/20200908152225.086536876@linuxfoundation.org/
> 
> ---
> commit 3a653b205f29b3f9827a01a0c88bfbcb0d169494 upstream.
> 
> The following error ocurred when testing disk online/offline:

Now queued up, thanks.

greg k-h

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-09-18 12:18 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2021-09-18  2:31 [PATCH] dm thin metadata: Fix use-after-free in dm_bm_set_read_only Jeffle Xu
2021-09-18 12:17 ` Greg KH
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2021-09-18  2:26 Jeffle Xu
2021-09-18  2:32 ` JeffleXu

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