* [PATCH] Bluetooth: l2cap: Fix MPS check in l2cap_ecred_reconf_req
@ 2026-04-13 8:56 Dudu Lu
2026-04-13 9:41 ` bluez.test.bot
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Dudu Lu @ 2026-04-13 8:56 UTC (permalink / raw)
To: linux-bluetooth; +Cc: marcel, luiz.dentz, Dudu Lu
The L2CAP Enhanced Credit Based Flow Control specification (Core Spec
5.4, Vol 3, Part A, Section 7.11) states that if more than one channel
is being reconfigured, the MPS shall not be decreased. The current code
uses `&& i` (loop index) to approximate "more than one channel", but
this incorrectly allows MPS decrease for the first channel (i==0) even
when multiple channels are being reconfigured, and incorrectly blocks
MPS decrease for subsequent channels even when only that single channel
is being reconfigured via index > 0.
Replace `&& i` with `&& num_scid > 1` which correctly checks whether
the reconfiguration request covers more than one channel, matching the
specification intent.
Signed-off-by: Dudu Lu <phx0fer@gmail.com>
---
net/bluetooth/l2cap_core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 95c65fece39b..b069f965a339 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -5428,7 +5428,7 @@ static inline int l2cap_ecred_reconf_req(struct l2cap_conn *conn,
* configured, the MPS field may be less than the current MPS
* of that channel.
*/
- if (chan[i]->remote_mps >= mps && i) {
+ if (chan[i]->remote_mps >= mps && num_scid > 1) {
BT_ERR("chan %p decreased MPS %u -> %u", chan[i],
chan[i]->remote_mps, mps);
result = L2CAP_RECONF_INVALID_MPS;
--
2.39.3 (Apple Git-145)
^ permalink raw reply related [flat|nested] 6+ messages in thread
* RE: Bluetooth: l2cap: Fix MPS check in l2cap_ecred_reconf_req
2026-04-13 8:56 [PATCH] Bluetooth: l2cap: Fix MPS check in l2cap_ecred_reconf_req Dudu Lu
@ 2026-04-13 9:41 ` bluez.test.bot
2026-04-13 17:16 ` [PATCH] " Luiz Augusto von Dentz
2026-04-13 21:02 ` bluez.test.bot
2 siblings, 0 replies; 6+ messages in thread
From: bluez.test.bot @ 2026-04-13 9:41 UTC (permalink / raw)
To: linux-bluetooth, phx0fer
[-- Attachment #1: Type: text/plain, Size: 6870 bytes --]
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=1080587
---Test result---
Test Summary:
CheckPatch PENDING 0.35 seconds
GitLint PENDING 0.30 seconds
SubjectPrefix PASS 0.12 seconds
BuildKernel PASS 26.08 seconds
CheckAllWarning PASS 29.06 seconds
CheckSparse PASS 28.35 seconds
BuildKernel32 PASS 26.03 seconds
TestRunnerSetup PASS 564.70 seconds
TestRunner_l2cap-tester PASS 28.13 seconds
TestRunner_iso-tester PASS 39.45 seconds
TestRunner_bnep-tester PASS 6.31 seconds
TestRunner_mgmt-tester FAIL 114.54 seconds
TestRunner_rfcomm-tester PASS 9.38 seconds
TestRunner_sco-tester FAIL 14.43 seconds
TestRunner_ioctl-tester PASS 10.18 seconds
TestRunner_mesh-tester FAIL 12.55 seconds
TestRunner_smp-tester PASS 8.56 seconds
TestRunner_userchan-tester PASS 6.84 seconds
TestRunner_6lowpan-tester FAIL 8.75 seconds
IncrementalBuild PENDING 0.26 seconds
Details
##############################
Test: CheckPatch - PENDING
Desc: Run checkpatch.pl script
Output:
##############################
Test: GitLint - PENDING
Desc: Run gitlint
Output:
##############################
Test: TestRunner_mgmt-tester - FAIL
Desc: Run mgmt-tester with test-runner
Output:
Total: 494, Passed: 489 (99.0%), Failed: 1, Not Run: 4
Failed Test Cases
Read Exp Feature - Success Failed 0.104 seconds
##############################
Test: TestRunner_sco-tester - FAIL
Desc: Run sco-tester with test-runner
Output:
WARNING: possible circular locking dependency detected
7.0.0-rc2-g8a170d9e02f8 #1 Not tainted
------------------------------------------------------
kworker/u5:2/117 is trying to acquire lock:
ffff888001946240 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_connect_cfm+0x358/0x8d0
but task is already holding lock:
ffff8880023c6220 (&conn->lock){+.+.}-{3:3}, at: sco_connect_cfm+0x22d/0x8d0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&conn->lock){+.+.}-{3:3}:
lock_acquire+0xf7/0x2c0
_raw_spin_lock+0x2a/0x40
sco_sock_connect+0x4d7/0x1280
__sys_connect+0x1a3/0x260
__x64_sys_connect+0x6e/0xb0
do_syscall_64+0xa0/0x570
entry_SYSCALL_64_after_hwframe+0x74/0x7c
-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
check_prev_add+0xe9/0xc70
__lock_acquire+0x1457/0x1df0
lock_acquire+0xf7/0x2c0
lock_sock_nested+0x36/0xd0
sco_connect_cfm+0x358/0x8d0
hci_sync_conn_complete_evt+0x3d3/0x8e0
hci_event_packet+0x74f/0xb10
hci_rx_work+0x398/0xd00
process_scheduled_works+0xb16/0x1ac0
worker_thread+0x4ff/0xba0
kthread+0x368/0x490
ret_from_fork+0x498/0x7e0
ret_from_fork_asm+0x19/0x30
other info that might help us debug this:
...
BUG: sleeping function called from invalid context at net/core/sock.c:3782
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 117, name: kworker/u5:2
preempt_count: 1, expected: 0
RCU nest depth: 0, expected: 0
INFO: lockdep is turned off.
CPU: 0 UID: 0 PID: 117 Comm: kworker/u5:2 Not tainted 7.0.0-rc2-g8a170d9e02f8 #1 PREEMPT(lazy)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014
Workqueue: hci0 hci_rx_work
Call Trace:
<TASK>
dump_stack_lvl+0x49/0x60
__might_resched+0x2ea/0x500
lock_sock_nested+0x47/0xd0
? sco_connect_cfm+0x358/0x8d0
sco_connect_cfm+0x358/0x8d0
? hci_debugfs_create_conn+0x190/0x210
? __pfx_sco_connect_cfm+0x10/0x10
hci_sync_conn_complete_evt+0x3d3/0x8e0
hci_event_packet+0x74f/0xb10
? __pfx_hci_sync_conn_complete_evt+0x10/0x10
? __pfx_hci_event_packet+0x10/0x10
? mark_held_locks+0x49/0x80
? lockdep_hardirqs_on_prepare+0xd4/0x180
? _raw_spin_unlock_irqrestore+0x2c/0x50
hci_rx_work+0x398/0xd00
process_scheduled_works+0xb16/0x1ac0
? __pfx_process_scheduled_works+0x10/0x10
? lock_acquire+0xf7/0x2c0
? lock_is_held_type+0x9b/0x110
? __pfx_hci_rx_work+0x10/0x10
worker_thread+0x4ff/0xba0
? _raw_spin_unlock_irqrestore+0x2c/0x50
? __pfx_worker_thread+0x10/0x10
kthread+0x368/0x490
? _raw_spin_unlock_irq+0x23/0x40
? __pfx_kthread+0x10/0x10
ret_from_fork+0x498/0x7e0
? __pfx_ret_from_fork+0x10/0x10
? __switch_to+0x9e4/0xe50
? __switch_to_asm+0x32/0x60
...
Total: 30, Passed: 30 (100.0%), Failed: 0, Not Run: 0
##############################
Test: TestRunner_mesh-tester - FAIL
Desc: Run mesh-tester with test-runner
Output:
Total: 10, Passed: 8 (80.0%), Failed: 2, Not Run: 0
Failed Test Cases
Mesh - Send cancel - 1 Timed out 2.733 seconds
Mesh - Send cancel - 2 Timed out 1.993 seconds
##############################
Test: TestRunner_6lowpan-tester - FAIL
Desc: Run 6lowpan-tester with test-runner
Output:
WARNING: possible circular locking dependency detected
7.0.0-rc2-g8a170d9e02f8 #1 Not tainted
------------------------------------------------------
kworker/0:1/11 is trying to acquire lock:
ffff888002777140 ((wq_completion)hci0#2){+.+.}-{0:0}, at: touch_wq_lockdep_map+0x75/0x180
but task is already holding lock:
ffffffffb964d720 (rtnl_mutex){+.+.}-{4:4}, at: lowpan_unregister_netdev+0xd/0x30
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (rtnl_mutex){+.+.}-{4:4}:
lock_acquire+0xf7/0x2c0
__mutex_lock+0x16b/0x1fc0
lowpan_register_netdev+0x11/0x30
chan_ready_cb+0x836/0xd00
l2cap_recv_frame+0x6465/0x8910
l2cap_recv_acldata+0x790/0xdf0
hci_rx_work+0x500/0xd00
process_scheduled_works+0xb16/0x1ac0
worker_thread+0x4ff/0xba0
kthread+0x368/0x490
ret_from_fork+0x498/0x7e0
ret_from_fork_asm+0x19/0x30
-> #3 (&chan->lock#3/1){+.+.}-{4:4}:
lock_acquire+0xf7/0x2c0
__mutex_lock+0x16b/0x1fc0
l2cap_chan_connect+0x74e/0x1980
lowpan_control_write+0x523/0x660
full_proxy_write+0x10b/0x190
vfs_write+0x1c0/0xf60
ksys_write+0xf1/0x1d0
do_syscall_64+0xa0/0x570
entry_SYSCALL_64_after_hwframe+0x74/0x7c
-> #2 (&conn->lock){+.+.}-{4:4}:
...
Total: 8, Passed: 8 (100.0%), Failed: 0, Not Run: 0
##############################
Test: IncrementalBuild - PENDING
Desc: Incremental build with the patches in the series
Output:
https://github.com/bluez/bluetooth-next/pull/78
---
Regards,
Linux Bluetooth
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] Bluetooth: l2cap: Fix MPS check in l2cap_ecred_reconf_req
2026-04-13 8:56 [PATCH] Bluetooth: l2cap: Fix MPS check in l2cap_ecred_reconf_req Dudu Lu
2026-04-13 9:41 ` bluez.test.bot
@ 2026-04-13 17:16 ` Luiz Augusto von Dentz
2026-04-13 21:02 ` bluez.test.bot
2 siblings, 0 replies; 6+ messages in thread
From: Luiz Augusto von Dentz @ 2026-04-13 17:16 UTC (permalink / raw)
To: Dudu Lu; +Cc: linux-bluetooth, marcel
Hi Dudu,
On Mon, Apr 13, 2026 at 4:56 AM Dudu Lu <phx0fer@gmail.com> wrote:
>
> The L2CAP Enhanced Credit Based Flow Control specification (Core Spec
> 5.4, Vol 3, Part A, Section 7.11) states that if more than one channel
> is being reconfigured, the MPS shall not be decreased. The current code
> uses `&& i` (loop index) to approximate "more than one channel", but
> this incorrectly allows MPS decrease for the first channel (i==0) even
> when multiple channels are being reconfigured, and incorrectly blocks
> MPS decrease for subsequent channels even when only that single channel
> is being reconfigured via index > 0.
>
> Replace `&& i` with `&& num_scid > 1` which correctly checks whether
> the reconfiguration request covers more than one channel, matching the
> specification intent.
>
> Signed-off-by: Dudu Lu <phx0fer@gmail.com>
> ---
> net/bluetooth/l2cap_core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> index 95c65fece39b..b069f965a339 100644
> --- a/net/bluetooth/l2cap_core.c
> +++ b/net/bluetooth/l2cap_core.c
> @@ -5428,7 +5428,7 @@ static inline int l2cap_ecred_reconf_req(struct l2cap_conn *conn,
> * configured, the MPS field may be less than the current MPS
> * of that channel.
> */
> - if (chan[i]->remote_mps >= mps && i) {
> + if (chan[i]->remote_mps >= mps && num_scid > 1) {
Still seem to be wrong, this should detect decreases but instead it
still flag as an error if reconfiguration has req->mps == mps:
https://sashiko.dev/#/patchset/20260413085600.75248-1-phx0fer%40gmail.com
> BT_ERR("chan %p decreased MPS %u -> %u", chan[i],
> chan[i]->remote_mps, mps);
> result = L2CAP_RECONF_INVALID_MPS;
> --
> 2.39.3 (Apple Git-145)
>
--
Luiz Augusto von Dentz
^ permalink raw reply [flat|nested] 6+ messages in thread
* RE: Bluetooth: l2cap: Fix MPS check in l2cap_ecred_reconf_req
2026-04-13 8:56 [PATCH] Bluetooth: l2cap: Fix MPS check in l2cap_ecred_reconf_req Dudu Lu
2026-04-13 9:41 ` bluez.test.bot
2026-04-13 17:16 ` [PATCH] " Luiz Augusto von Dentz
@ 2026-04-13 21:02 ` bluez.test.bot
2 siblings, 0 replies; 6+ messages in thread
From: bluez.test.bot @ 2026-04-13 21:02 UTC (permalink / raw)
To: linux-bluetooth, phx0fer
[-- Attachment #1: Type: text/plain, Size: 6870 bytes --]
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=1080587
---Test result---
Test Summary:
CheckPatch PENDING 0.00 seconds
GitLint PENDING 0.00 seconds
SubjectPrefix PASS 0.14 seconds
BuildKernel PASS 27.14 seconds
CheckAllWarning PASS 29.87 seconds
CheckSparse PASS 28.56 seconds
BuildKernel32 PASS 26.53 seconds
TestRunnerSetup PASS 580.32 seconds
TestRunner_l2cap-tester PASS 28.34 seconds
TestRunner_iso-tester PASS 46.27 seconds
TestRunner_bnep-tester PASS 6.43 seconds
TestRunner_mgmt-tester FAIL 115.20 seconds
TestRunner_rfcomm-tester PASS 9.52 seconds
TestRunner_sco-tester FAIL 14.31 seconds
TestRunner_ioctl-tester PASS 10.50 seconds
TestRunner_mesh-tester FAIL 12.22 seconds
TestRunner_smp-tester PASS 8.70 seconds
TestRunner_userchan-tester PASS 6.81 seconds
TestRunner_6lowpan-tester FAIL 8.57 seconds
IncrementalBuild PENDING 0.00 seconds
Details
##############################
Test: CheckPatch - PENDING
Desc: Run checkpatch.pl script
Output:
##############################
Test: GitLint - PENDING
Desc: Run gitlint
Output:
##############################
Test: TestRunner_mgmt-tester - FAIL
Desc: Run mgmt-tester with test-runner
Output:
Total: 494, Passed: 489 (99.0%), Failed: 1, Not Run: 4
Failed Test Cases
Read Exp Feature - Success Failed 0.107 seconds
##############################
Test: TestRunner_sco-tester - FAIL
Desc: Run sco-tester with test-runner
Output:
WARNING: possible circular locking dependency detected
7.0.0-rc2-gcd52505d5434 #1 Not tainted
------------------------------------------------------
kworker/u5:2/117 is trying to acquire lock:
ffff888001946240 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_connect_cfm+0x358/0x8d0
but task is already holding lock:
ffff888002090c20 (&conn->lock){+.+.}-{3:3}, at: sco_connect_cfm+0x22d/0x8d0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&conn->lock){+.+.}-{3:3}:
lock_acquire+0xf7/0x2c0
_raw_spin_lock+0x2a/0x40
sco_sock_connect+0x4d7/0x1280
__sys_connect+0x1a3/0x260
__x64_sys_connect+0x6e/0xb0
do_syscall_64+0xa0/0x570
entry_SYSCALL_64_after_hwframe+0x74/0x7c
-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
check_prev_add+0xe9/0xc70
__lock_acquire+0x1457/0x1df0
lock_acquire+0xf7/0x2c0
lock_sock_nested+0x36/0xd0
sco_connect_cfm+0x358/0x8d0
hci_sync_conn_complete_evt+0x3d3/0x8e0
hci_event_packet+0x74f/0xb10
hci_rx_work+0x398/0xd00
process_scheduled_works+0xb16/0x1ac0
worker_thread+0x4ff/0xba0
kthread+0x368/0x490
ret_from_fork+0x498/0x7e0
ret_from_fork_asm+0x19/0x30
other info that might help us debug this:
...
BUG: sleeping function called from invalid context at net/core/sock.c:3782
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 117, name: kworker/u5:2
preempt_count: 1, expected: 0
RCU nest depth: 0, expected: 0
INFO: lockdep is turned off.
CPU: 0 UID: 0 PID: 117 Comm: kworker/u5:2 Not tainted 7.0.0-rc2-gcd52505d5434 #1 PREEMPT(lazy)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014
Workqueue: hci0 hci_rx_work
Call Trace:
<TASK>
dump_stack_lvl+0x49/0x60
__might_resched+0x2ea/0x500
lock_sock_nested+0x47/0xd0
? sco_connect_cfm+0x358/0x8d0
sco_connect_cfm+0x358/0x8d0
? hci_debugfs_create_conn+0x190/0x210
? __pfx_sco_connect_cfm+0x10/0x10
hci_sync_conn_complete_evt+0x3d3/0x8e0
hci_event_packet+0x74f/0xb10
? __pfx_hci_sync_conn_complete_evt+0x10/0x10
? __pfx_hci_event_packet+0x10/0x10
? mark_held_locks+0x49/0x80
? lockdep_hardirqs_on_prepare+0xd4/0x180
? _raw_spin_unlock_irqrestore+0x2c/0x50
hci_rx_work+0x398/0xd00
process_scheduled_works+0xb16/0x1ac0
? __pfx_process_scheduled_works+0x10/0x10
? lock_acquire+0xf7/0x2c0
? lock_is_held_type+0x9b/0x110
? __pfx_hci_rx_work+0x10/0x10
worker_thread+0x4ff/0xba0
? _raw_spin_unlock_irqrestore+0x2c/0x50
? __pfx_worker_thread+0x10/0x10
kthread+0x368/0x490
? _raw_spin_unlock_irq+0x23/0x40
? __pfx_kthread+0x10/0x10
ret_from_fork+0x498/0x7e0
? __pfx_ret_from_fork+0x10/0x10
? __switch_to+0x9e4/0xe50
? __switch_to_asm+0x32/0x60
...
Total: 30, Passed: 30 (100.0%), Failed: 0, Not Run: 0
##############################
Test: TestRunner_mesh-tester - FAIL
Desc: Run mesh-tester with test-runner
Output:
Total: 10, Passed: 8 (80.0%), Failed: 2, Not Run: 0
Failed Test Cases
Mesh - Send cancel - 1 Timed out 2.654 seconds
Mesh - Send cancel - 2 Timed out 1.994 seconds
##############################
Test: TestRunner_6lowpan-tester - FAIL
Desc: Run 6lowpan-tester with test-runner
Output:
WARNING: possible circular locking dependency detected
7.0.0-rc2-gcd52505d5434 #1 Not tainted
------------------------------------------------------
kworker/0:1/14 is trying to acquire lock:
ffff88800275c140 ((wq_completion)hci0#2){+.+.}-{0:0}, at: touch_wq_lockdep_map+0x75/0x180
but task is already holding lock:
ffffffff9a44d720 (rtnl_mutex){+.+.}-{4:4}, at: lowpan_unregister_netdev+0xd/0x30
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (rtnl_mutex){+.+.}-{4:4}:
lock_acquire+0xf7/0x2c0
__mutex_lock+0x16b/0x1fc0
lowpan_register_netdev+0x11/0x30
chan_ready_cb+0x836/0xd00
l2cap_recv_frame+0x6465/0x8910
l2cap_recv_acldata+0x790/0xdf0
hci_rx_work+0x500/0xd00
process_scheduled_works+0xb16/0x1ac0
worker_thread+0x4ff/0xba0
kthread+0x368/0x490
ret_from_fork+0x498/0x7e0
ret_from_fork_asm+0x19/0x30
-> #3 (&chan->lock#3/1){+.+.}-{4:4}:
lock_acquire+0xf7/0x2c0
__mutex_lock+0x16b/0x1fc0
l2cap_chan_connect+0x74e/0x1980
lowpan_control_write+0x523/0x660
full_proxy_write+0x10b/0x190
vfs_write+0x1c0/0xf60
ksys_write+0xf1/0x1d0
do_syscall_64+0xa0/0x570
entry_SYSCALL_64_after_hwframe+0x74/0x7c
-> #2 (&conn->lock){+.+.}-{4:4}:
...
Total: 8, Passed: 8 (100.0%), Failed: 0, Not Run: 0
##############################
Test: IncrementalBuild - PENDING
Desc: Incremental build with the patches in the series
Output:
https://github.com/bluez/bluetooth-next/pull/78
---
Regards,
Linux Bluetooth
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH] Bluetooth: l2cap: fix MPS check in l2cap_ecred_reconf_req
@ 2026-04-15 10:43 Dudu Lu
2026-04-15 21:00 ` patchwork-bot+bluetooth
0 siblings, 1 reply; 6+ messages in thread
From: Dudu Lu @ 2026-04-15 10:43 UTC (permalink / raw)
To: linux-bluetooth; +Cc: marcel, luiz.dentz, Dudu Lu
The L2CAP specification states that if more than one channel is being
reconfigured, the MPS shall not be decreased. The current check has
two issues:
1) The comparison uses >= (greater-than-or-equal), which incorrectly
rejects reconfiguration requests where the MPS stays the same.
Since the spec says MPS "shall be greater than or equal to the
current MPS", only a strict decrease (remote_mps > mps) should be
rejected. Keeping the same MPS is valid.
2) The multi-channel guard uses `&& i` (loop index) to approximate
"more than one channel", but this incorrectly allows MPS decrease
for the first channel (i==0) even when multiple channels are being
reconfigured. Replace with `&& num_scid > 1` which correctly
checks whether the request covers more than one channel.
Signed-off-by: Dudu Lu <phx0fer@gmail.com>
---
net/bluetooth/l2cap_core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 95c65fece39b..29d793f3a2eb 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -5428,7 +5428,7 @@ static inline int l2cap_ecred_reconf_req(struct l2cap_conn *conn,
* configured, the MPS field may be less than the current MPS
* of that channel.
*/
- if (chan[i]->remote_mps >= mps && i) {
+ if (chan[i]->remote_mps > mps && num_scid > 1) {
BT_ERR("chan %p decreased MPS %u -> %u", chan[i],
chan[i]->remote_mps, mps);
result = L2CAP_RECONF_INVALID_MPS;
--
2.39.3 (Apple Git-145)
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] Bluetooth: l2cap: fix MPS check in l2cap_ecred_reconf_req
2026-04-15 10:43 [PATCH] Bluetooth: l2cap: fix " Dudu Lu
@ 2026-04-15 21:00 ` patchwork-bot+bluetooth
0 siblings, 0 replies; 6+ messages in thread
From: patchwork-bot+bluetooth @ 2026-04-15 21:00 UTC (permalink / raw)
To: Dudu Lu; +Cc: linux-bluetooth, marcel, luiz.dentz
Hello:
This patch was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>:
On Wed, 15 Apr 2026 18:43:55 +0800 you wrote:
> The L2CAP specification states that if more than one channel is being
> reconfigured, the MPS shall not be decreased. The current check has
> two issues:
>
> 1) The comparison uses >= (greater-than-or-equal), which incorrectly
> rejects reconfiguration requests where the MPS stays the same.
> Since the spec says MPS "shall be greater than or equal to the
> current MPS", only a strict decrease (remote_mps > mps) should be
> rejected. Keeping the same MPS is valid.
>
> [...]
Here is the summary with links:
- Bluetooth: l2cap: fix MPS check in l2cap_ecred_reconf_req
https://git.kernel.org/bluetooth/bluetooth-next/c/b1de65fd5f81
You are awesome, thank you!
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^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2026-04-15 21:00 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-04-13 8:56 [PATCH] Bluetooth: l2cap: Fix MPS check in l2cap_ecred_reconf_req Dudu Lu
2026-04-13 9:41 ` bluez.test.bot
2026-04-13 17:16 ` [PATCH] " Luiz Augusto von Dentz
2026-04-13 21:02 ` bluez.test.bot
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2026-04-15 10:43 [PATCH] Bluetooth: l2cap: fix " Dudu Lu
2026-04-15 21:00 ` patchwork-bot+bluetooth
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