From: Xiu Jianfeng <[email protected]>
When booting kernel with lockdown=confidentiality parameter, the system
will hang at rv_register_reactor() due to waiting for rv_interface_lock,
as shown in the following log,
INFO: task swapper/0:1 blocked for more than 122 seconds.
Not tainted 6.17.0-rc6-next-20250915+ #29
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:swapper/0 state:D stack:0 pid:1 tgid:1 ppid:0
Call Trace:
<TASK>
__schedule+0x492/0x1600
schedule+0x27/0xf0
schedule_preempt_disabled+0x15/0x30
__mutex_lock.constprop.0+0x538/0x9e0
? vprintk+0x18/0x50
? _printk+0x5f/0x90
__mutex_lock_slowpath+0x13/0x20
mutex_lock+0x3b/0x50
rv_register_reactor+0x48/0xe0
? __pfx_register_react_printk+0x10/0x10
register_react_printk+0x15/0x20
do_one_initcall+0x5d/0x340
kernel_init_freeable+0x351/0x540
? __pfx_kernel_init+0x10/0x10
kernel_init+0x1b/0x200
? __pfx_kernel_init+0x10/0x10
ret_from_fork+0x1fb/0x220
? __pfx_kernel_init+0x10/0x10
ret_from_fork_asm+0x1a/0x30
The root cause is that, when the kernel lockdown is in confidentiality
mode, rv_create_dir(), which is essentially tracefs_create_dir(), will
return NULL. This, in turn, causes create_monitor_dir() to return
-ENOMEM, and finally leading to the mutex not being unlocked.
Fixes: 24cbfe18d55a ("rv: Merge struct rv_monitor_def into struct rv_monitor")
Signed-off-by: Xiu Jianfeng <[email protected]>
---
kernel/trace/rv/rv.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/rv/rv.c b/kernel/trace/rv/rv.c
index 1482e91c39f4..e35565dd2dc5 100644
--- a/kernel/trace/rv/rv.c
+++ b/kernel/trace/rv/rv.c
@@ -805,7 +805,7 @@ int rv_register_monitor(struct rv_monitor *monitor, struct
rv_monitor *parent)
retval = create_monitor_dir(monitor, parent);
if (retval)
- return retval;
+ goto out_unlock;
/* keep children close to the parent for easier visualisation */
if (parent)
--
2.43.0
