On 7/16/2021 12:32 PM, Heikki Krogerus wrote: > Fri, Jul 16, 2021 at 11:17:11AM +0300, laurentiu.tudor@xxxxxxx kirjoitti: >> 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> >> Signed-off-by: Laurentiu Tudor <laurentiu.tudor@xxxxxxx> >> --- >> drivers/base/swnode.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c >> index d1f1a8240120..907616ca487f 100644 >> --- a/drivers/base/swnode.c >> +++ b/drivers/base/swnode.c >> @@ -1113,6 +1113,8 @@ int device_create_managed_software_node(struct device *dev, >> to_swnode(fwnode)->managed = true; >> set_secondary_fwnode(dev, fwnode); >> >> + kobject_get(&to_swnode(fwnode)->kobj); >> + >> return 0; >> } >> EXPORT_SYMBOL_GPL(device_create_managed_software_node); > > We can't increment the refcount uncoditionally like that. Would this > work instead: > It works, thanks for the suggestion! I'll return with a non-RFC right away. --- Best Regards, Laurentiu
