On Tue, Sep 14, 2021 at 05:44:09PM +0300, laurentiu.tudor@xxxxxxx wrote: > From: Laurentiu Tudor <laurentiu.tudor@xxxxxxx> > > software_node_notify(), on KOBJ_REMOVE drops the refcount twice on managed > software nodes, thus leading to underflow errors. Balance the refcount by > bumping it in the device_create_managed_software_node() function. > > The error [1] was encountered after adding a .shutdown() op to our > fsl-mc-bus driver. > > [1] > pc : refcount_warn_saturate+0xf8/0x150 > lr : refcount_warn_saturate+0xf8/0x150 > sp : ffff80001009b920 > x29: ffff80001009b920 x28: ffff1a2420318000 x27: 0000000000000000 > x26: ffffccac15e7a038 x25: 0000000000000008 x24: ffffccac168e0030 > x23: ffff1a2428a82000 x22: 0000000000080000 x21: ffff1a24287b5000 > x20: 0000000000000001 x19: ffff1a24261f4400 x18: ffffffffffffffff > x17: 6f72645f726f7272 x16: 0000000000000000 x15: ffff80009009b607 > x14: 0000000000000000 x13: ffffccac16602670 x12: 0000000000000a17 > x11: 000000000000035d x10: ffffccac16602670 x9 : ffffccac16602670 > x8 : 00000000ffffefff x7 : ffffccac1665a670 x6 : ffffccac1665a670 > x5 : 0000000000000000 x4 : 0000000000000000 x3 : 00000000ffffffff > x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff1a2420318000 > Call trace: > refcount_warn_saturate+0xf8/0x150 > kobject_put+0x10c/0x120 > software_node_notify+0xd8/0x140 > device_platform_notify+0x4c/0xb4 > device_del+0x188/0x424 > fsl_mc_device_remove+0x2c/0x4c > rebofind sp.c__fsl_mc_device_remove+0x14/0x2c > device_for_each_child+0x5c/0xac > dprc_remove+0x9c/0xc0 > fsl_mc_driver_remove+0x28/0x64 > __device_release_driver+0x188/0x22c > device_release_driver+0x30/0x50 > bus_remove_device+0x128/0x134 > device_del+0x16c/0x424 > fsl_mc_bus_remove+0x8c/0x114 > fsl_mc_bus_shutdown+0x14/0x20 > platform_shutdown+0x28/0x40 > device_shutdown+0x15c/0x330 > __do_sys_reboot+0x218/0x2a0 > __arm64_sys_reboot+0x28/0x34 > invoke_syscall+0x48/0x114 > el0_svc_common+0x40/0xdc > do_el0_svc+0x2c/0x94 > el0_svc+0x2c/0x54 > el0t_64_sync_handler+0xa8/0x12c > el0t_64_sync+0x198/0x19c > ---[ end trace 32eb1c71c7d86821 ]--- > > Reported-by: Jon Nettleton <jon@xxxxxxxxxxxxx> > Suggested-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx> > Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx> > Signed-off-by: Laurentiu Tudor <laurentiu.tudor@xxxxxxx> > --- > Changes since v1: > - added Heikki's Reviewed-by: (Thanks!) > > Changes since RFC: > - use software_node_notify(KOBJ_ADD) instead of directly bumping > refcount (Heikki) > > drivers/base/swnode.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c > index d1f1a8240120..bdb50a06c82a 100644 > --- a/drivers/base/swnode.c > +++ b/drivers/base/swnode.c > @@ -1113,6 +1113,9 @@ int device_create_managed_software_node(struct device *dev, > to_swnode(fwnode)->managed = true; > set_secondary_fwnode(dev, fwnode); > > + if (device_is_registered(dev)) > + software_node_notify(dev, KOBJ_ADD); > + > return 0; > } > EXPORT_SYMBOL_GPL(device_create_managed_software_node); > -- > 2.17.1 > I am seeing that this needs to go into 5.15-final, but how about any further back? Stable kernels? Does this "fix" a specific commit? thanks, greg k-h
