This patch adds some fixes for the iso_listen_bis function:
The first commit fixes the circular locking dependency warning
caused by iso_listen_bis attempting to lock the hdev while the
socket is locked from the caller function.
The second commit fixes the fact that hci_dev_put is only called
if iso_listen_bis returns successfully. Otherwise, the hdev will
still be held from hci_get_route.
Iulia Tanasescu (2):
Bluetooth: ISO: Fix circular locking dependency warning
Bluetooth: ISO: Always release hdev at the end of iso_listen_bis
net/bluetooth/iso.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
--
2.39.2
This fixes the circular locking dependency warning caused
by iso_listen_bis acquiring the hdev lock while the socket
has been locked in the caller function.
======================================================
WARNING: possible circular locking dependency detected
6.8.0-rc5+ #1 Not tainted
------------------------------------------------------
iso-tester/2950 is trying to acquire lock:
ffff88817a048080 (&hdev->lock){+.+.}-{3:3}, at: iso_sock_listen+0x305/0x8d0
but task is already holding lock:
ffff888197c39278 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO){+.+.}-{0:0},
at: iso_sock_listen+0x91/0x8d0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO){+.+.}-{0:0}:
lock_sock_nested+0x3b/0xb0
iso_connect_cis+0x185/0x540
iso_sock_connect+0x445/0x7e0
__sys_connect_file+0xd5/0x100
__sys_connect+0x11e/0x150
__x64_sys_connect+0x42/0x60
do_syscall_64+0x8d/0x150
entry_SYSCALL_64_after_hwframe+0x6e/0x76
-> #0 (&hdev->lock){+.+.}-{3:3}:
__lock_acquire+0x208f/0x3720
lock_acquire+0x16d/0x3f0
__mutex_lock+0x155/0x1310
mutex_lock_nested+0x1b/0x30
iso_sock_listen+0x305/0x8d0
__sys_listen+0x106/0x190
__x64_sys_listen+0x30/0x40
do_syscall_64+0x8d/0x150
entry_SYSCALL_64_after_hwframe+0x6e/0x76
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(sk_lock-AF_BLUETOOTH-BTPROTO_ISO);
lock(&hdev->lock);
lock(sk_lock-AF_BLUETOOTH-BTPROTO_ISO);
lock(&hdev->lock);
*** DEADLOCK ***
1 lock held by iso-tester/2950:
0: ffff888197c39278 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO){+.+.}-{0:0},
at: iso_sock_listen+0x91/0x8d0
Signed-off-by: Iulia Tanasescu <[email protected]>
---
net/bluetooth/iso.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c
index 8af75d37b14c..d1608387fd85 100644
--- a/net/bluetooth/iso.c
+++ b/net/bluetooth/iso.c
@@ -1069,6 +1069,7 @@ static int iso_sock_connect(struct socket *sock, struct sockaddr *addr,
return err;
}
+/* This function requires the caller to hold sk lock */
static int iso_listen_bis(struct sock *sk)
{
struct hci_dev *hdev;
@@ -1095,7 +1096,15 @@ static int iso_listen_bis(struct sock *sk)
if (!hdev)
return -EHOSTUNREACH;
+ /* Prevent sk from being freed whilst unlocked */
+ sock_hold(sk);
+
+ /* To avoid circular locking dependencies,
+ * hdev should be locked first before sk.
+ */
+ release_sock(sk);
hci_dev_lock(hdev);
+ lock_sock(sk);
/* Fail if user set invalid QoS */
if (iso_pi(sk)->qos_user_set && !check_bcast_qos(&iso_pi(sk)->qos)) {
@@ -1128,7 +1137,13 @@ static int iso_listen_bis(struct sock *sk)
hci_dev_put(hdev);
unlock:
+ /* Unlock order should be in reverse from lock order. */
+ release_sock(sk);
hci_dev_unlock(hdev);
+ lock_sock(sk);
+
+ sock_put(sk);
+
return err;
}
--
2.39.2
Since hci_get_route holds the device before returning, the hdev
should be released with hci_dev_put at the end of iso_listen_bis
even if the function returns with an error.
Signed-off-by: Iulia Tanasescu <[email protected]>
---
net/bluetooth/iso.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c
index d1608387fd85..bd2271cba359 100644
--- a/net/bluetooth/iso.c
+++ b/net/bluetooth/iso.c
@@ -1134,14 +1134,14 @@ static int iso_listen_bis(struct sock *sk)
goto unlock;
}
- hci_dev_put(hdev);
-
unlock:
/* Unlock order should be in reverse from lock order. */
release_sock(sk);
hci_dev_unlock(hdev);
lock_sock(sk);
+ hci_dev_put(hdev);
+
sock_put(sk);
return err;
--
2.39.2
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=833415
---Test result---
Test Summary:
CheckPatch PASS 1.37 seconds
GitLint PASS 0.68 seconds
SubjectPrefix PASS 0.27 seconds
BuildKernel PASS 27.93 seconds
CheckAllWarning PASS 30.81 seconds
CheckSparse PASS 36.29 seconds
CheckSmatch PASS 99.01 seconds
BuildKernel32 PASS 27.04 seconds
TestRunnerSetup PASS 499.86 seconds
TestRunner_l2cap-tester PASS 19.96 seconds
TestRunner_iso-tester PASS 31.12 seconds
TestRunner_bnep-tester PASS 4.74 seconds
TestRunner_mgmt-tester PASS 109.98 seconds
TestRunner_rfcomm-tester PASS 7.30 seconds
TestRunner_sco-tester PASS 14.90 seconds
TestRunner_ioctl-tester PASS 7.80 seconds
TestRunner_mesh-tester PASS 5.93 seconds
TestRunner_smp-tester PASS 6.82 seconds
TestRunner_userchan-tester PASS 4.91 seconds
IncrementalBuild PASS 30.87 seconds
---
Regards,
Linux Bluetooth