In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: iso: Fix circular lock in iso_conn_big_sync
This fixes the circular locking dependency warning below, by reworking iso_sock_recvmsg, to ensure that the socket lock is always released before calling a function that locks hdev.
[ 561.670344] ====================================================== [ 561.670346] WARNING: possible circular locking dependency detected [ 561.670349] 6.12.0-rc6+ #26 Not tainted [ 561.670351] ------------------------------------------------------ [ 561.670353] iso-tester/3289 is trying to acquire lock: [ 561.670355] ffff88811f600078 (&hdev->lock){+.+.}-{3:3}, at: iso_conn_big_sync+0x73/0x260 [bluetooth] [ 561.670405] but task is already holding lock: [ 561.670407] ffff88815af58258 (sk_lock-AF_BLUETOOTH){+.+.}-{0:0}, at: iso_sock_recvmsg+0xbf/0x500 [bluetooth] [ 561.670450] which lock already depends on the new lock.
[ 561.670452] the existing dependency chain (in reverse order) is: [ 561.670453] -> #2 (sk_lock-AF_BLUETOOTH){+.+.}-{0:0}: [ 561.670458] lock_acquire+0x7c/0xc0 [ 561.670463] lock_sock_nested+0x3b/0xf0 [ 561.670467] bt_accept_dequeue+0x1a5/0x4d0 [bluetooth] [ 561.670510] iso_sock_accept+0x271/0x830 [bluetooth] [ 561.670547] do_accept+0x3dd/0x610 [ 561.670550] __sys_accept4+0xd8/0x170 [ 561.670553] __x64_sys_accept+0x74/0xc0 [ 561.670556] x64_sys_call+0x17d6/0x25f0 [ 561.670559] do_syscall_64+0x87/0x150 [ 561.670563] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 561.670567] -> #1 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO){+.+.}-{0:0}: [ 561.670571] lock_acquire+0x7c/0xc0 [ 561.670574] lock_sock_nested+0x3b/0xf0 [ 561.670577] iso_sock_listen+0x2de/0xf30 [bluetooth] [ 561.670617] __sys_listen_socket+0xef/0x130 [ 561.670620] __x64_sys_listen+0xe1/0x190 [ 561.670623] x64_sys_call+0x2517/0x25f0 [ 561.670626] do_syscall_64+0x87/0x150 [ 561.670629] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 561.670632] -> #0 (&hdev->lock){+.+.}-{3:3}: [ 561.670636] __lock_acquire+0x32ad/0x6ab0 [ 561.670639] lock_acquire.part.0+0x118/0x360 [ 561.670642] lock_acquire+0x7c/0xc0 [ 561.670644] __mutex_lock+0x18d/0x12f0 [ 561.670647] mutex_lock_nested+0x1b/0x30 [ 561.670651] iso_conn_big_sync+0x73/0x260 [bluetooth] [ 561.670687] iso_sock_recvmsg+0x3e9/0x500 [bluetooth] [ 561.670722] sock_recvmsg+0x1d5/0x240 [ 561.670725] sock_read_iter+0x27d/0x470 [ 561.670727] vfs_read+0x9a0/0xd30 [ 561.670731] ksys_read+0x1a8/0x250 [ 561.670733] __x64_sys_read+0x72/0xc0 [ 561.670736] x64_sys_call+0x1b12/0x25f0 [ 561.670738] do_syscall_64+0x87/0x150 [ 561.670741] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 561.670744] other info that might help us debug this:
[ 561.670745] Chain exists of: &hdev->lock --> sk_lock-AF_BLUETOOTH-BTPROTO_ISO --> sk_lock-AF_BLUETOOTH
[ 561.670751] Possible unsafe locking scenario:
[ 561.670753] CPU0 CPU1 [ 561.670754] ---- ---- [ 561.670756] lock(sk_lock-AF_BLUETOOTH); [ 561.670758] lock(sk_lock AF_BLUETOOTH-BTPROTO_ISO); [ 561.670761] lock(sk_lock-AF_BLUETOOTH); [ 561.670764] lock(&hdev->lock); [ 561.670767] *** DEADLOCK ***
CVSS Details
- CVSS 3.1 Base Score: 5.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Debian | — | Upgrade linux | Jul 27, 2026 | Jul 27, 2026 |
| Ubuntu | — | Upgrade linux-image-oem-24.04bUpgrade linux-image-virtualUpgrade linux-image-6.11.0-21-genericUpgrade linux-image-oracleUpgrade linux-image-realtimeUpgrade linux-image-gcpUpgrade linux-image-virtual-hwe-24.04Upgrade linux-image-6.11.0-1011-awsUpgrade linux-image-lowlatency-64k-hwe-24.04Upgrade linux-image-6.11.0-1012-azure-fdeUpgrade linux-image-awsUpgrade linux-image-lowlatency-hwe-24.04Upgrade linux-image-oem-24.04aUpgrade linux-image-6.11.0-1011-gcp-64kUpgrade linux-image-generic-64k-hwe-24.04Upgrade linux-image-6.11.0-1011-lowlatency-64kUpgrade linux-image-oracle-64kUpgrade linux-image-oem-24.04Upgrade linux-image-6.11.0-1010-raspiUpgrade linux-image-azure-fdeUpgrade linux-image-6.11.0-1013-oracleUpgrade linux-image-generic-64kUpgrade linux-image-6.11.0-21-generic-64kUpgrade linux-image-6.11.0-1007-realtimeUpgrade linux-image-raspiUpgrade linux-image-6.11.0-1011-gcpUpgrade linux-image-6.11.0-1011-lowlatencyUpgrade linux-image-6.11.0-1012-azureUpgrade linux-image-6.11.0-1017-oemUpgrade linux-image-lowlatencyUpgrade linux-image-6.11.0-1013-oracle-64kUpgrade linux-image-realtime-hwe-24.04Upgrade linux-image-generic-hwe-24.04Upgrade linux-image-gcp-64kUpgrade linux-image-lowlatency-64kUpgrade linux-image-genericUpgrade linux-image-azure | Mar 28, 2025 | Jan 11, 2025 |
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