mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2025-01-17 18:56:24 +00:00
6d24b170a9
A CONFIG_DEBUG_KOBJECT_RELEASE test of removing a device-dax region
provider (like modprobe -r dax_hmem) yields:
kobject: 'mapping0' (ffff93eb460e8800): kobject_release, parent 0000000000000000 (delayed 2000)
[..]
DEBUG_LOCKS_WARN_ON(1)
WARNING: CPU: 23 PID: 282 at kernel/locking/lockdep.c:232 __lock_acquire+0x9fc/0x2260
[..]
RIP: 0010:__lock_acquire+0x9fc/0x2260
[..]
Call Trace:
<TASK>
[..]
lock_acquire+0xd4/0x2c0
? ida_free+0x62/0x130
_raw_spin_lock_irqsave+0x47/0x70
? ida_free+0x62/0x130
ida_free+0x62/0x130
dax_mapping_release+0x1f/0x30
device_release+0x36/0x90
kobject_delayed_cleanup+0x46/0x150
Due to attempting ida_free() on an ida object that has already been
freed. Devices typically only hold a reference on their parent while
registered. If a child needs a parent object to complete its release it
needs to hold a reference that it drops from its release callback.
Arrange for a dax_mapping to pin its parent dev_dax instance until
dax_mapping_release().
Fixes: 0b07ce872a9e ("device-dax: introduce 'mapping' devices")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/168577283412.1672036.16111545266174261446.stgit@dwillia2-xfh.jf.intel.com
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Fan Ni <fan.ni@samsung.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>