Adding workqueue and lockdep people into Cc. On Fri 2023-08-11 19:11:46, Helge Deller wrote: > Fully initialize detector_work work struct to avoid this kernel warning > when lockdep is enabled: > > ===================================== > WARNING: bad unlock balance detected! > 6.5.0-rc5+ #687 Not tainted > ------------------------------------- > swapper/0/1 is trying to release lock (detector_work) at: > [<000000004037e554>] __flush_work+0x60/0x658 > but there are no more locks to release! > > other info that might help us debug this: > no locks held by swapper/0/1. > > stack backtrace: > CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.5.0-rc5+ #687 > Hardware name: 9000/785/C3700 > Backtrace: > [<0000000041455d5c>] print_unlock_imbalance_bug.part.0+0x20c/0x230 > [<000000004040d5e8>] lock_release+0x2e8/0x3f8 > [<000000004037e5cc>] __flush_work+0xd8/0x658 > [<000000004037eb7c>] flush_work+0x30/0x60 > [<000000004011f140>] lockup_detector_check+0x54/0x128 > [<0000000040306430>] do_one_initcall+0x9c/0x408 > [<0000000040102d44>] kernel_init_freeable+0x688/0x7f0 > [<000000004146df68>] kernel_init+0x64/0x3a8 > [<0000000040302020>] ret_from_kernel_thread+0x20/0x28 > > Signed-off-by: Helge Deller <deller@xxxxxx> > > --- > > diff --git a/kernel/watchdog.c b/kernel/watchdog.c > index be38276a365f..eab0dfcfa3f9 100644 > --- a/kernel/watchdog.c > +++ b/kernel/watchdog.c > @@ -1022,5 +1022,6 @@ void __init lockup_detector_init(void) > else > allow_lockup_detector_init_retry = true; > > + INIT_WORK(&detector_work, lockup_detector_delay_init); > lockup_detector_setup(); > } Strange. The work is initialized when declared: static struct work_struct detector_work __initdata = __WORK_INITIALIZER(detector_work, lockup_detector_delay_init); , which should initialize the lockdep map as well. I would expect this is enough. And I do not see this on x86_64 with CONFIG_PROVE_LOCKING=y on today's Linus' tree. And the flush_work() is always called from the lockup_detector_check() late init call. IMHO, it must be a bug somewhere else. Otherwise, many other users of DECLARE_WORK() or __WORK_INITIALIZER() would have the same problem. Or do I miss something? Best Regards, Petr
