| Message ID | ZNZblen+NXOrW9wE@p100 (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | devtmpfs: Add missing lockdep annotation | expand |
On Fri, Aug 11, 2023 at 06:02:29PM +0200, Helge Deller wrote: > Add the lockdep annotation to the setup_done completer to avoid this > kernel warning: > > Backtrace: > [<000000004030bcd0>] show_stack+0x74/0xb0 > [<000000004146c63c>] dump_stack_lvl+0x104/0x180 > [<000000004146c6ec>] dump_stack+0x34/0x48 > [<000000004040e5b4>] register_lock_class+0xd24/0xd30 > [<000000004040c21c>] __lock_acquire.isra.0+0xb4/0xac8 > [<000000004040cd60>] lock_acquire+0x130/0x298 > [<000000004147095c>] _raw_spin_lock_irq+0x60/0xb8 > [<0000000041474a4c>] wait_for_completion+0xa0/0x2d0 > [<000000004015d9f4>] devtmpfs_init+0x1e0/0x2b8 > [<000000004015d0e4>] driver_init+0x68/0x1b8 > [<0000000040102b68>] kernel_init_freeable+0x4ac/0x7f0 > [<000000004146df68>] kernel_init+0x64/0x3a8 > [<0000000040302020>] ret_from_kernel_thread+0x20/0x28 > > Signed-off-by: Helge Deller <deller@gmx.de> > > diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c > index b848764ef018..f98d58b0225c 100644 > --- a/drivers/base/devtmpfs.c > +++ b/drivers/base/devtmpfs.c > @@ -462,6 +462,7 @@ int __init devtmpfs_init(void) > return err; > } > > + init_completion(&setup_done); > thread = kthread_run(devtmpfsd, &err, "kdevtmpfs"); > if (!IS_ERR(thread)) { > wait_for_completion(&setup_done); What changed to required this now? What commit id does this fix? Why doesn't the declaration of DECLARE_COMPLETION() initialize this properly for us already? thanks, greg k-h
* Greg Kroah-Hartman <gregkh@linuxfoundation.org>: > On Fri, Aug 11, 2023 at 06:02:29PM +0200, Helge Deller wrote: > > Add the lockdep annotation to the setup_done completer to avoid this > > kernel warning: > > > > Backtrace: > > [<000000004030bcd0>] show_stack+0x74/0xb0 > > [<000000004146c63c>] dump_stack_lvl+0x104/0x180 > > [<000000004146c6ec>] dump_stack+0x34/0x48 > > [<000000004040e5b4>] register_lock_class+0xd24/0xd30 > > [<000000004040c21c>] __lock_acquire.isra.0+0xb4/0xac8 > > [<000000004040cd60>] lock_acquire+0x130/0x298 > > [<000000004147095c>] _raw_spin_lock_irq+0x60/0xb8 > > [<0000000041474a4c>] wait_for_completion+0xa0/0x2d0 > > [<000000004015d9f4>] devtmpfs_init+0x1e0/0x2b8 > > [<000000004015d0e4>] driver_init+0x68/0x1b8 > > [<0000000040102b68>] kernel_init_freeable+0x4ac/0x7f0 > > [<000000004146df68>] kernel_init+0x64/0x3a8 > > [<0000000040302020>] ret_from_kernel_thread+0x20/0x28 > > > > Signed-off-by: Helge Deller <deller@gmx.de> > > > > diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c > > index b848764ef018..f98d58b0225c 100644 > > --- a/drivers/base/devtmpfs.c > > +++ b/drivers/base/devtmpfs.c > > @@ -462,6 +462,7 @@ int __init devtmpfs_init(void) > > return err; > > } > > > > + init_completion(&setup_done); > > thread = kthread_run(devtmpfsd, &err, "kdevtmpfs"); > > if (!IS_ERR(thread)) { > > wait_for_completion(&setup_done); > > What changed to required this now? What commit id does this fix? Why > doesn't the declaration of DECLARE_COMPLETION() initialize this properly > for us already? You're right! The problem is not the missing init_completion() call. That part of the kernel warning indicates the real problem: INFO: trying to register non-static key. Lockdep uses static_obj() to check if the given lock is in "static" memory, aka inside a valid memory region: from &_stext to &_end. The "setup_done" completer is used at bootup only, and thus located in the __initdata section. And on parisc the __initdata section is outside of the &_stext to &_end range, so the static_obj() check fails. The patch below fixes it. I'll send a proper patch to the mailing list in a moment. Thanks! Helge diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 111607d91489..aa99245d8e12 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -855,6 +855,15 @@ static int static_obj(const void *obj) if (is_kernel_percpu_address(addr)) return 1; + /* + * in initdata section and used during bootup only? + * NOTE: On some platforms the initdata section is + * outside of the _stext ... _end range. + */ + if (system_state < SYSTEM_FREEING_INITMEM && + init_section_contains((void*)addr, 1)) + return 1; + /* * module static or percpu var? */
diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c index b848764ef018..f98d58b0225c 100644 --- a/drivers/base/devtmpfs.c +++ b/drivers/base/devtmpfs.c @@ -462,6 +462,7 @@ int __init devtmpfs_init(void) return err; } + init_completion(&setup_done); thread = kthread_run(devtmpfsd, &err, "kdevtmpfs"); if (!IS_ERR(thread)) { wait_for_completion(&setup_done);
Add the lockdep annotation to the setup_done completer to avoid this kernel warning: Backtrace: [<000000004030bcd0>] show_stack+0x74/0xb0 [<000000004146c63c>] dump_stack_lvl+0x104/0x180 [<000000004146c6ec>] dump_stack+0x34/0x48 [<000000004040e5b4>] register_lock_class+0xd24/0xd30 [<000000004040c21c>] __lock_acquire.isra.0+0xb4/0xac8 [<000000004040cd60>] lock_acquire+0x130/0x298 [<000000004147095c>] _raw_spin_lock_irq+0x60/0xb8 [<0000000041474a4c>] wait_for_completion+0xa0/0x2d0 [<000000004015d9f4>] devtmpfs_init+0x1e0/0x2b8 [<000000004015d0e4>] driver_init+0x68/0x1b8 [<0000000040102b68>] kernel_init_freeable+0x4ac/0x7f0 [<000000004146df68>] kernel_init+0x64/0x3a8 [<0000000040302020>] ret_from_kernel_thread+0x20/0x28 Signed-off-by: Helge Deller <deller@gmx.de>