https://bugzilla.kernel.org/show_bug.cgi?id=214103 Bug ID: 214103 Summary: HCI_CHANNEL_USER sockets leave device running after exit Product: Drivers Version: 2.5 Kernel Version: 5.11.0-7620-generic Hardware: All OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Bluetooth Assignee: linux-bluetooth@xxxxxxxxxxxxxxx Reporter: pab@xxxxxxxxxxx Regression: No Created attachment 298353 --> https://bugzilla.kernel.org/attachment.cgi?id=298353&action=edit code to reproduce behavior HCI_CHANNEL_USER is documented[1] as providing an exclusive (?[2]) Bluetooth socket channel for application use given CAP_NET_ADMIN. This channel type requires that the device be down when the socket is bound. The device transitions to UP RUNNING as a side-effect of a successful binding. When the socket is closed and the application exits, the device remains up and running. It's unclear whether this is a bug or a feature; in any case it is not what somebody might expect, as it prevents the application from starting again without external action to bring the device back down. Reproducing example attached, and command sequence below. [1]: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.13.12&id=23500189d7e03a071f0746f43f2cce875a62c91c [2]: https://bugzilla.kernel.org/show_bug.cgi?id=135431 tirzah[1050]$ sudo hciconfig hci0 down tirzah[1051]$ hciconfig hci0 hci0: Type: Primary Bus: USB BD Address: A4:C3:F0:F2:23:E3 ACL MTU: 1021:4 SCO MTU: 96:6 DOWN RX bytes:64500 acl:0 sco:0 events:4125 errors:0 TX bytes:650824 acl:0 sco:0 commands:3992 errors:0 tirzah[1052]$ gcc repro.c tirzah[1053]$ sudo setcap cap_net_raw,cap_net_admin=ep ./a.out tirzah[1054]$ getcap ./a.out ./a.out = cap_net_admin,cap_net_raw+ep tirzah[1055]$ ./a.out opening device 0 dd=3; binding to user channel bound to user channel; closing closed tirzah[1056]$ hciconfig hci0 hci0: Type: Primary Bus: USB BD Address: A4:C3:F0:F2:23:E3 ACL MTU: 1021:4 SCO MTU: 96:6 UP RUNNING RX bytes:65256 acl:0 sco:0 events:4180 errors:0 TX bytes:653053 acl:0 sco:0 commands:4047 errors:0 tirzah[1057]$ -- You may reply to this email to add a comment. You are receiving this mail because: You are the assignee for the bug.
