On Wed, 2025-09-17 at 12:57 +0000, Xiu Jianfeng wrote: > 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, >
Thanks for finding this, the problem was already fixed in [1], which is on its way to getting merged. [1] - https://lore.kernel.org/all/[email protected] > 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)
