[PATCH v3] Bluetooth: Prevent double register of suspend
From: Abhishek Pandit-Subedi
Date: Wed Sep 28 2022 - 16:01:41 EST
From: Abhishek Pandit-Subedi <abhishekpandit@xxxxxxxxxxxx>
Suspend notifier should only be registered and unregistered once per
hdev. Simplify this by only registering during driver registration and
simply exiting early when HCI_USER_CHANNEL is set.
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Fixes: 359ee4f834f5 (Bluetooth: Unregister suspend with userchannel)
Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@xxxxxxxxxxxx>
---
This is fixing a syzbot reported warning. Tested in the following ways:
* Normal start-up of driver with bluez.
* Start/stop loop using HCI_USER_CHANNEL (sock path).
* USB reset triggering hci_dev_unregister (driver path).
------------[ cut here ]------------
double register detected
WARNING: CPU: 0 PID: 2657 at kernel/notifier.c:27
notifier_chain_register kernel/notifier.c:27 [inline]
WARNING: CPU: 0 PID: 2657 at kernel/notifier.c:27
notifier_chain_register+0x5c/0x124 kernel/notifier.c:22
Modules linked in:
CPU: 0 PID: 2657 Comm: syz-executor212 Not tainted
5.10.136-syzkaller-19376-g6f46a5fe0124 #0
8f0771607702f5ef7184d2ee33bd0acd70219fc4
Hardware name: Google Google Compute Engine/Google Compute Engine,
BIOS Google 07/22/2022
RIP: 0010:notifier_chain_register kernel/notifier.c:27 [inline]
RIP: 0010:notifier_chain_register+0x5c/0x124 kernel/notifier.c:22
Code: 6a 41 00 4c 8b 23 4d 85 e4 0f 84 88 00 00 00 e8 c2 1e 19 00 49
39 ec 75 18 e8 b8 1e 19 00 48 c7 c7 80 6d ca 84 e8 2c 68 48 03 <0f> 0b
e9 af 00 00 00 e8 a0 1e 19 00 48 8d 7d 10 48 89 f8 48 c1 e8
RSP: 0018:ffffc900009d7da8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff8881076fd1d8 RCX: 0000000000000000
RDX: 0000001810895100 RSI: ffff888110895100 RDI: fffff5200013afa7
RBP: ffff88811a4191d0 R08: ffffffff813b8ca1 R09: 0000000080000000
R10: 0000000000000000 R11: 0000000000000005 R12: ffff88811a4191d0
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 00005555571f5300(0000) GS:ffff8881f6c00000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000078e3857f3075 CR3: 000000010d668000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
blocking_notifier_chain_register+0x8c/0xa6 kernel/notifier.c:254
hci_register_suspend_notifier net/bluetooth/hci_core.c:2733
[inline]
hci_register_suspend_notifier+0x6b/0x7c
net/bluetooth/hci_core.c:2727
hci_sock_release+0x270/0x3cf net/bluetooth/hci_sock.c:889
__sock_release+0xcd/0x1de net/socket.c:597
sock_close+0x18/0x1c net/socket.c:1267
__fput+0x418/0x729 fs/file_table.c:281
task_work_run+0x12b/0x15b kernel/task_work.c:151
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_user_mode_loop kernel/entry/common.c:165 [inline]
exit_to_user_mode_prepare+0x8f/0x130 kernel/entry/common.c:192
syscall_exit_to_user_mode+0x172/0x1b2 kernel/entry/common.c:268
entry_SYSCALL_64_after_hwframe+0x61/0xc6
RIP: 0033:0x78e38575e1db
Code: 0f 05 48 3d 00 f0 ff ff 77 45 c3 0f 1f 40 00 48 83 ec 18 89
7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05
<48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44
RSP: 002b:00007ffffc20a0b0 EFLAGS: 00000293 ORIG_RAX:
0000000000000003
RAX: 0000000000000000 RBX: 0000000000000006 RCX: 000078e38575e1db
RDX: ffffffffffffffb8 RSI: 0000000020000000 RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000150
R10: 0000000000000000 R11: 0000000000000293 R12: 000000000000e155
R13: 00007ffffc20a140 R14: 00007ffffc20a130 R15: 00007ffffc20a0e8
Changes in v3:
- No changes.
Changes in v2:
- Removed suspend registration from hci_sock.
- Exit hci_suspend_notifier early if user channel.
net/bluetooth/hci_core.c | 4 ++++
net/bluetooth/hci_sock.c | 3 ---
2 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 66c7cdba0d32..86ce2dd1c7fb 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -2406,6 +2406,10 @@ static int hci_suspend_notifier(struct notifier_block *nb, unsigned long action,
container_of(nb, struct hci_dev, suspend_notifier);
int ret = 0;
+ /* Userspace has full control of this device. Do nothing. */
+ if (hci_dev_test_flag(hdev, HCI_USER_CHANNEL))
+ return NOTIFY_DONE;
+
if (action == PM_SUSPEND_PREPARE)
ret = hci_suspend_dev(hdev);
else if (action == PM_POST_SUSPEND)
diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
index b2a33a05c93e..06581223238c 100644
--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -887,7 +887,6 @@ static int hci_sock_release(struct socket *sock)
*/
hci_dev_do_close(hdev);
hci_dev_clear_flag(hdev, HCI_USER_CHANNEL);
- hci_register_suspend_notifier(hdev);
mgmt_index_added(hdev);
}
@@ -1216,7 +1215,6 @@ static int hci_sock_bind(struct socket *sock, struct sockaddr *addr,
}
mgmt_index_removed(hdev);
- hci_unregister_suspend_notifier(hdev);
err = hci_dev_open(hdev->id);
if (err) {
@@ -1231,7 +1229,6 @@ static int hci_sock_bind(struct socket *sock, struct sockaddr *addr,
err = 0;
} else {
hci_dev_clear_flag(hdev, HCI_USER_CHANNEL);
- hci_register_suspend_notifier(hdev);
mgmt_index_added(hdev);
hci_dev_put(hdev);
goto done;
--
2.38.0.rc1.362.ged0d419d3c-goog