diff mbox series

Bluetooth: btmtk: avoid UAF in btmtk_process_coredump

Message ID 20240731190330.1619718-1-cascardo@igalia.com
State New
Headers show
Series Bluetooth: btmtk: avoid UAF in btmtk_process_coredump | expand

Commit Message

Thadeu Lima de Souza Cascardo July 31, 2024, 7:03 p.m. UTC
hci_devcd_append may lead to the release of the skb, so it cannot be
accessed once it is called.

==================================================================
BUG: KASAN: slab-use-after-free in btmtk_process_coredump+0x2a7/0x2d0 [btmtk]
Read of size 4 at addr ffff888033cfabb0 by task kworker/0:3/82

CPU: 0 PID: 82 Comm: kworker/0:3 Tainted: G     U             6.6.40-lockdep-03464-g1d8b4eb3060e #1 b0b3c1cc0c842735643fb411799d97921d1f688c
Hardware name: Google Yaviks_Ufs/Yaviks_Ufs, BIOS Google_Yaviks_Ufs.15217.552.0 05/07/2024
Workqueue: events btusb_rx_work [btusb]
Call Trace:
 <TASK>
 dump_stack_lvl+0xfd/0x150
 print_report+0x131/0x780
 kasan_report+0x177/0x1c0
 btmtk_process_coredump+0x2a7/0x2d0 [btmtk 03edd567dd71a65958807c95a65db31d433e1d01]
 btusb_recv_acl_mtk+0x11c/0x1a0 [btusb 675430d1e87c4f24d0c1f80efe600757a0f32bec]
 btusb_rx_work+0x9e/0xe0 [btusb 675430d1e87c4f24d0c1f80efe600757a0f32bec]
 worker_thread+0xe44/0x2cc0
 kthread+0x2ff/0x3a0
 ret_from_fork+0x51/0x80
 ret_from_fork_asm+0x1b/0x30
 </TASK>

Allocated by task 82:
 stack_trace_save+0xdc/0x190
 kasan_set_track+0x4e/0x80
 __kasan_slab_alloc+0x4e/0x60
 kmem_cache_alloc+0x19f/0x360
 skb_clone+0x132/0xf70
 btusb_recv_acl_mtk+0x104/0x1a0 [btusb]
 btusb_rx_work+0x9e/0xe0 [btusb]
 worker_thread+0xe44/0x2cc0
 kthread+0x2ff/0x3a0
 ret_from_fork+0x51/0x80
 ret_from_fork_asm+0x1b/0x30

Freed by task 1733:
 stack_trace_save+0xdc/0x190
 kasan_set_track+0x4e/0x80
 kasan_save_free_info+0x28/0xb0
 ____kasan_slab_free+0xfd/0x170
 kmem_cache_free+0x183/0x3f0
 hci_devcd_rx+0x91a/0x2060 [bluetooth]
 worker_thread+0xe44/0x2cc0
 kthread+0x2ff/0x3a0
 ret_from_fork+0x51/0x80
 ret_from_fork_asm+0x1b/0x30

The buggy address belongs to the object at ffff888033cfab40
 which belongs to the cache skbuff_head_cache of size 232
The buggy address is located 112 bytes inside of
 freed 232-byte region [ffff888033cfab40, ffff888033cfac28)

The buggy address belongs to the physical page:
page:00000000a174ba93 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x33cfa
head:00000000a174ba93 order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0x4000000000000840(slab|head|zone=1)
page_type: 0xffffffff()
raw: 4000000000000840 ffff888100848a00 0000000000000000 0000000000000001
raw: 0000000000000000 0000000080190019 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888033cfaa80: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
 ffff888033cfab00: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
>ffff888033cfab80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff888033cfac00: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
 ffff888033cfac80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Check if we need to call hci_devcd_complete before calling
hci_devcd_append. That requires that we check data->cd_info.cnt >=
MTK_COREDUMP_NUM instead of data->cd_info.cnt > MTK_COREDUMP_NUM, as we
increment data->cd_info.cnt only once the call to hci_devcd_append
succeeds.

Fixes: 0b7015132878 ("Bluetooth: btusb: mediatek: add MediaTek devcoredump support")
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
---
 drivers/bluetooth/btmtk.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

Comments

bluez.test.bot@gmail.com July 31, 2024, 7:33 p.m. UTC | #1
This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=875598

---Test result---

Test Summary:
CheckPatch                    FAIL      0.94 seconds
GitLint                       FAIL      0.50 seconds
SubjectPrefix                 PASS      0.83 seconds
BuildKernel                   PASS      30.40 seconds
CheckAllWarning               PASS      45.30 seconds
CheckSparse                   PASS      38.73 seconds
CheckSmatch                   PASS      104.59 seconds
BuildKernel32                 PASS      29.56 seconds
TestRunnerSetup               PASS      539.78 seconds
TestRunner_l2cap-tester       PASS      20.46 seconds
TestRunner_iso-tester         PASS      41.69 seconds
TestRunner_bnep-tester        PASS      5.08 seconds
TestRunner_mgmt-tester        PASS      119.77 seconds
TestRunner_rfcomm-tester      PASS      7.79 seconds
TestRunner_sco-tester         PASS      15.28 seconds
TestRunner_ioctl-tester       PASS      8.33 seconds
TestRunner_mesh-tester        PASS      6.25 seconds
TestRunner_smp-tester         PASS      7.19 seconds
TestRunner_userchan-tester    PASS      5.36 seconds
IncrementalBuild              PASS      28.58 seconds

Details
##############################
Test: CheckPatch - FAIL
Desc: Run checkpatch.pl script
Output:
Bluetooth: btmtk: avoid UAF in btmtk_process_coredump
WARNING: Prefer a maximum 75 chars per line (possible unwrapped commit description?)
#81: 
CPU: 0 PID: 82 Comm: kworker/0:3 Tainted: G     U             6.6.40-lockdep-03464-g1d8b4eb3060e #1 b0b3c1cc0c842735643fb411799d97921d1f688c

total: 0 errors, 1 warnings, 37 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
      mechanically convert to the typical style using --fix or --fix-inplace.

/github/workspace/src/src/13749065.patch has style problems, please review.

NOTE: Ignored message types: UNKNOWN_COMMIT_ID

NOTE: If any of the errors are false positives, please report
      them to the maintainer, see CHECKPATCH in MAINTAINERS.


##############################
Test: GitLint - FAIL
Desc: Run gitlint
Output:
Bluetooth: btmtk: avoid UAF in btmtk_process_coredump

WARNING: I3 - ignore-body-lines: gitlint will be switching from using Python regex 'match' (match beginning) to 'search' (match anywhere) semantics. Please review your ignore-body-lines.regex option accordingly. To remove this warning, set general.regex-style-search=True. More details: https://jorisroovers.github.io/gitlint/configuration/#regex-style-search
10: B1 Line exceeds max length (140>80): "CPU: 0 PID: 82 Comm: kworker/0:3 Tainted: G     U             6.6.40-lockdep-03464-g1d8b4eb3060e #1 b0b3c1cc0c842735643fb411799d97921d1f688c"
11: B1 Line exceeds max length (90>80): "Hardware name: Google Yaviks_Ufs/Yaviks_Ufs, BIOS Google_Yaviks_Ufs.15217.552.0 05/07/2024"
18: B1 Line exceeds max length (84>80): " btmtk_process_coredump+0x2a7/0x2d0 [btmtk 03edd567dd71a65958807c95a65db31d433e1d01]"
58: B1 Line exceeds max length (90>80): "page:00000000a174ba93 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x33cfa"


---
Regards,
Linux Bluetooth
Thadeu Lima de Souza Cascardo Aug. 22, 2024, 9:57 a.m. UTC | #2
On Wed, Jul 31, 2024 at 04:03:30PM -0300, Thadeu Lima de Souza Cascardo wrote:
> hci_devcd_append may lead to the release of the skb, so it cannot be
> accessed once it is called.
> 
> ==================================================================
> BUG: KASAN: slab-use-after-free in btmtk_process_coredump+0x2a7/0x2d0 [btmtk]
> Read of size 4 at addr ffff888033cfabb0 by task kworker/0:3/82
> 
> CPU: 0 PID: 82 Comm: kworker/0:3 Tainted: G     U             6.6.40-lockdep-03464-g1d8b4eb3060e #1 b0b3c1cc0c842735643fb411799d97921d1f688c
> Hardware name: Google Yaviks_Ufs/Yaviks_Ufs, BIOS Google_Yaviks_Ufs.15217.552.0 05/07/2024
> Workqueue: events btusb_rx_work [btusb]
> Call Trace:
>  <TASK>
>  dump_stack_lvl+0xfd/0x150
>  print_report+0x131/0x780
>  kasan_report+0x177/0x1c0
>  btmtk_process_coredump+0x2a7/0x2d0 [btmtk 03edd567dd71a65958807c95a65db31d433e1d01]
>  btusb_recv_acl_mtk+0x11c/0x1a0 [btusb 675430d1e87c4f24d0c1f80efe600757a0f32bec]
>  btusb_rx_work+0x9e/0xe0 [btusb 675430d1e87c4f24d0c1f80efe600757a0f32bec]
>  worker_thread+0xe44/0x2cc0
>  kthread+0x2ff/0x3a0
>  ret_from_fork+0x51/0x80
>  ret_from_fork_asm+0x1b/0x30
>  </TASK>
> 
> Allocated by task 82:
>  stack_trace_save+0xdc/0x190
>  kasan_set_track+0x4e/0x80
>  __kasan_slab_alloc+0x4e/0x60
>  kmem_cache_alloc+0x19f/0x360
>  skb_clone+0x132/0xf70
>  btusb_recv_acl_mtk+0x104/0x1a0 [btusb]
>  btusb_rx_work+0x9e/0xe0 [btusb]
>  worker_thread+0xe44/0x2cc0
>  kthread+0x2ff/0x3a0
>  ret_from_fork+0x51/0x80
>  ret_from_fork_asm+0x1b/0x30
> 
> Freed by task 1733:
>  stack_trace_save+0xdc/0x190
>  kasan_set_track+0x4e/0x80
>  kasan_save_free_info+0x28/0xb0
>  ____kasan_slab_free+0xfd/0x170
>  kmem_cache_free+0x183/0x3f0
>  hci_devcd_rx+0x91a/0x2060 [bluetooth]
>  worker_thread+0xe44/0x2cc0
>  kthread+0x2ff/0x3a0
>  ret_from_fork+0x51/0x80
>  ret_from_fork_asm+0x1b/0x30
> 
> The buggy address belongs to the object at ffff888033cfab40
>  which belongs to the cache skbuff_head_cache of size 232
> The buggy address is located 112 bytes inside of
>  freed 232-byte region [ffff888033cfab40, ffff888033cfac28)
> 
> The buggy address belongs to the physical page:
> page:00000000a174ba93 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x33cfa
> head:00000000a174ba93 order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0
> anon flags: 0x4000000000000840(slab|head|zone=1)
> page_type: 0xffffffff()
> raw: 4000000000000840 ffff888100848a00 0000000000000000 0000000000000001
> raw: 0000000000000000 0000000080190019 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
> 
> Memory state around the buggy address:
>  ffff888033cfaa80: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
>  ffff888033cfab00: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
> >ffff888033cfab80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>                                      ^
>  ffff888033cfac00: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
>  ffff888033cfac80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ==================================================================
> 
> Check if we need to call hci_devcd_complete before calling
> hci_devcd_append. That requires that we check data->cd_info.cnt >=
> MTK_COREDUMP_NUM instead of data->cd_info.cnt > MTK_COREDUMP_NUM, as we
> increment data->cd_info.cnt only once the call to hci_devcd_append
> succeeds.
> 
> Fixes: 0b7015132878 ("Bluetooth: btusb: mediatek: add MediaTek devcoredump support")
> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
> ---
>  drivers/bluetooth/btmtk.c | 20 ++++++++++++--------
>  1 file changed, 12 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
> index b7c348687a77..46f605249df7 100644
> --- a/drivers/bluetooth/btmtk.c
> +++ b/drivers/bluetooth/btmtk.c
> @@ -395,6 +395,7 @@ int btmtk_process_coredump(struct hci_dev *hdev, struct sk_buff *skb)
>  {
>  	struct btmtk_data *data = hci_get_priv(hdev);
>  	int err;
> +	bool complete = false;
>  
>  	if (!IS_ENABLED(CONFIG_DEV_COREDUMP)) {
>  		kfree_skb(skb);
> @@ -416,19 +417,22 @@ int btmtk_process_coredump(struct hci_dev *hdev, struct sk_buff *skb)
>  		fallthrough;
>  	case HCI_DEVCOREDUMP_ACTIVE:
>  	default:
> +		/* Mediatek coredump data would be more than MTK_COREDUMP_NUM */
> +		if (data->cd_info.cnt >= MTK_COREDUMP_NUM &&
> +		    skb->len > MTK_COREDUMP_END_LEN)
> +			if (!memcmp((char *)&skb->data[skb->len - MTK_COREDUMP_END_LEN],
> +				    MTK_COREDUMP_END, MTK_COREDUMP_END_LEN - 1))
> +				complete = true;
> +
>  		err = hci_devcd_append(hdev, skb);
>  		if (err < 0)
>  			break;
>  		data->cd_info.cnt++;
>  
> -		/* Mediatek coredump data would be more than MTK_COREDUMP_NUM */
> -		if (data->cd_info.cnt > MTK_COREDUMP_NUM &&
> -		    skb->len > MTK_COREDUMP_END_LEN)
> -			if (!memcmp((char *)&skb->data[skb->len - MTK_COREDUMP_END_LEN],
> -				    MTK_COREDUMP_END, MTK_COREDUMP_END_LEN - 1)) {
> -				bt_dev_info(hdev, "Mediatek coredump end");
> -				hci_devcd_complete(hdev);
> -			}
> +		if (complete) {
> +			bt_dev_info(hdev, "Mediatek coredump end");
> +			hci_devcd_complete(hdev);
> +		}
>  
>  		break;
>  	}
> -- 
> 2.34.1
> 
> 

Hi, anyone can help review this?

Thanks.
Cascardo.
Chris Lu Sept. 2, 2024, 3:39 a.m. UTC | #3
On Thu, 2024-08-22 at 06:57 -0300, Thadeu Lima de Souza Cascardo wrote:
>  	 
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
>  On Wed, Jul 31, 2024 at 04:03:30PM -0300, Thadeu Lima de Souza
> Cascardo wrote:
> > hci_devcd_append may lead to the release of the skb, so it cannot
> be
> > accessed once it is called.
> > 
> > ==================================================================
> > BUG: KASAN: slab-use-after-free in
> btmtk_process_coredump+0x2a7/0x2d0 [btmtk]
> > Read of size 4 at addr ffff888033cfabb0 by task kworker/0:3/82
> > 
> > CPU: 0 PID: 82 Comm: kworker/0:3 Tainted:
> G     U             6.6.40-lockdep-03464-g1d8b4eb3060e #1
> b0b3c1cc0c842735643fb411799d97921d1f688c
> > Hardware name: Google Yaviks_Ufs/Yaviks_Ufs, BIOS
> Google_Yaviks_Ufs.15217.552.0 05/07/2024
> > Workqueue: events btusb_rx_work [btusb]
> > Call Trace:
> >  <TASK>
> >  dump_stack_lvl+0xfd/0x150
> >  print_report+0x131/0x780
> >  kasan_report+0x177/0x1c0
> >  btmtk_process_coredump+0x2a7/0x2d0 [btmtk
> 03edd567dd71a65958807c95a65db31d433e1d01]
> >  btusb_recv_acl_mtk+0x11c/0x1a0 [btusb
> 675430d1e87c4f24d0c1f80efe600757a0f32bec]
> >  btusb_rx_work+0x9e/0xe0 [btusb
> 675430d1e87c4f24d0c1f80efe600757a0f32bec]
> >  worker_thread+0xe44/0x2cc0
> >  kthread+0x2ff/0x3a0
> >  ret_from_fork+0x51/0x80
> >  ret_from_fork_asm+0x1b/0x30
> >  </TASK>
> > 
> > Allocated by task 82:
> >  stack_trace_save+0xdc/0x190
> >  kasan_set_track+0x4e/0x80
> >  __kasan_slab_alloc+0x4e/0x60
> >  kmem_cache_alloc+0x19f/0x360
> >  skb_clone+0x132/0xf70
> >  btusb_recv_acl_mtk+0x104/0x1a0 [btusb]
> >  btusb_rx_work+0x9e/0xe0 [btusb]
> >  worker_thread+0xe44/0x2cc0
> >  kthread+0x2ff/0x3a0
> >  ret_from_fork+0x51/0x80
> >  ret_from_fork_asm+0x1b/0x30
> > 
> > Freed by task 1733:
> >  stack_trace_save+0xdc/0x190
> >  kasan_set_track+0x4e/0x80
> >  kasan_save_free_info+0x28/0xb0
> >  ____kasan_slab_free+0xfd/0x170
> >  kmem_cache_free+0x183/0x3f0
> >  hci_devcd_rx+0x91a/0x2060 [bluetooth]
> >  worker_thread+0xe44/0x2cc0
> >  kthread+0x2ff/0x3a0
> >  ret_from_fork+0x51/0x80
> >  ret_from_fork_asm+0x1b/0x30
> > 
> > The buggy address belongs to the object at ffff888033cfab40
> >  which belongs to the cache skbuff_head_cache of size 232
> > The buggy address is located 112 bytes inside of
> >  freed 232-byte region [ffff888033cfab40, ffff888033cfac28)
> > 
> > The buggy address belongs to the physical page:
> > page:00000000a174ba93 refcount:1 mapcount:0
> mapping:0000000000000000 index:0x0 pfn:0x33cfa
> > head:00000000a174ba93 order:1 entire_mapcount:0 nr_pages_mapped:0
> pincount:0
> > anon flags: 0x4000000000000840(slab|head|zone=1)
> > page_type: 0xffffffff()
> > raw: 4000000000000840 ffff888100848a00 0000000000000000
> 0000000000000001
> > raw: 0000000000000000 0000000080190019 00000001ffffffff
> 0000000000000000
> > page dumped because: kasan: bad access detected
> > 
> > Memory state around the buggy address:
> >  ffff888033cfaa80: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
> >  ffff888033cfab00: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
> > >ffff888033cfab80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> >                                      ^
> >  ffff888033cfac00: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
> >  ffff888033cfac80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > ==================================================================
> > 
> > Check if we need to call hci_devcd_complete before calling
> > hci_devcd_append. That requires that we check data->cd_info.cnt >=
> > MTK_COREDUMP_NUM instead of data->cd_info.cnt > MTK_COREDUMP_NUM,
> as we
> > increment data->cd_info.cnt only once the call to hci_devcd_append
> > succeeds.
> > 
> > Fixes: 0b7015132878 ("Bluetooth: btusb: mediatek: add MediaTek
> devcoredump support")
> > Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
> > ---
> >  drivers/bluetooth/btmtk.c | 20 ++++++++++++--------
> >  1 file changed, 12 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
> > index b7c348687a77..46f605249df7 100644
> > --- a/drivers/bluetooth/btmtk.c
> > +++ b/drivers/bluetooth/btmtk.c
> > @@ -395,6 +395,7 @@ int btmtk_process_coredump(struct hci_dev
> *hdev, struct sk_buff *skb)
> >  {
> >  struct btmtk_data *data = hci_get_priv(hdev);
> >  int err;
> > +bool complete = false;
> >  
> >  if (!IS_ENABLED(CONFIG_DEV_COREDUMP)) {
> >  kfree_skb(skb);
> > @@ -416,19 +417,22 @@ int btmtk_process_coredump(struct hci_dev
> *hdev, struct sk_buff *skb)
> >  fallthrough;
> >  case HCI_DEVCOREDUMP_ACTIVE:
> >  default:
> > +/* Mediatek coredump data would be more than MTK_COREDUMP_NUM */
> > +if (data->cd_info.cnt >= MTK_COREDUMP_NUM &&
> > +    skb->len > MTK_COREDUMP_END_LEN)
> > +if (!memcmp((char *)&skb->data[skb->len - MTK_COREDUMP_END_LEN],
> > +    MTK_COREDUMP_END, MTK_COREDUMP_END_LEN - 1))
> > +complete = true;
> > +
> >  err = hci_devcd_append(hdev, skb);
> >  if (err < 0)
> >  break;
> >  data->cd_info.cnt++;
> >  
> > -/* Mediatek coredump data would be more than MTK_COREDUMP_NUM */
> > -if (data->cd_info.cnt > MTK_COREDUMP_NUM &&
> > -    skb->len > MTK_COREDUMP_END_LEN)
> > -if (!memcmp((char *)&skb->data[skb->len - MTK_COREDUMP_END_LEN],
> > -    MTK_COREDUMP_END, MTK_COREDUMP_END_LEN - 1)) {
> > -bt_dev_info(hdev, "Mediatek coredump end");
> > -hci_devcd_complete(hdev);
> > -}
> > +if (complete) {
> > +bt_dev_info(hdev, "Mediatek coredump end");
> > +hci_devcd_complete(hdev);
> > +}
> >  
> >  break;
> >  }
> > -- 
> > 2.34.1
> > 
> > 
> 
> Hi, anyone can help review this?
> 
> Thanks.

Hi Thadeu,

Sorry for late reply.
I've also verified on the platform which supports devcoredump feature
that Bluetooth can recover after triggerring devcoredump.
LGTM. It may need maintainer's approval for the next step.


Thanks a lot!
Chris

> Cascardo.
diff mbox series

Patch

diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
index b7c348687a77..46f605249df7 100644
--- a/drivers/bluetooth/btmtk.c
+++ b/drivers/bluetooth/btmtk.c
@@ -395,6 +395,7 @@  int btmtk_process_coredump(struct hci_dev *hdev, struct sk_buff *skb)
 {
 	struct btmtk_data *data = hci_get_priv(hdev);
 	int err;
+	bool complete = false;
 
 	if (!IS_ENABLED(CONFIG_DEV_COREDUMP)) {
 		kfree_skb(skb);
@@ -416,19 +417,22 @@  int btmtk_process_coredump(struct hci_dev *hdev, struct sk_buff *skb)
 		fallthrough;
 	case HCI_DEVCOREDUMP_ACTIVE:
 	default:
+		/* Mediatek coredump data would be more than MTK_COREDUMP_NUM */
+		if (data->cd_info.cnt >= MTK_COREDUMP_NUM &&
+		    skb->len > MTK_COREDUMP_END_LEN)
+			if (!memcmp((char *)&skb->data[skb->len - MTK_COREDUMP_END_LEN],
+				    MTK_COREDUMP_END, MTK_COREDUMP_END_LEN - 1))
+				complete = true;
+
 		err = hci_devcd_append(hdev, skb);
 		if (err < 0)
 			break;
 		data->cd_info.cnt++;
 
-		/* Mediatek coredump data would be more than MTK_COREDUMP_NUM */
-		if (data->cd_info.cnt > MTK_COREDUMP_NUM &&
-		    skb->len > MTK_COREDUMP_END_LEN)
-			if (!memcmp((char *)&skb->data[skb->len - MTK_COREDUMP_END_LEN],
-				    MTK_COREDUMP_END, MTK_COREDUMP_END_LEN - 1)) {
-				bt_dev_info(hdev, "Mediatek coredump end");
-				hci_devcd_complete(hdev);
-			}
+		if (complete) {
+			bt_dev_info(hdev, "Mediatek coredump end");
+			hci_devcd_complete(hdev);
+		}
 
 		break;
 	}