In the Linux kernel, the following vulnerability has been resolved:
drm/xe/pf: Fix sysfs initialization
In case of devm_add_action_or_reset() failure the provided cleanup
action will be run immediately on the not yet initialized kobject.
This may lead to errors like:
[ ] kobject: ‘(null)’ (ff110001393608e0): is not initialized, yet kobject_put() is being called.
[ ] WARNING: lib/kobject.c:734 at kobject_put+0xd9/0x250, CPU#0: kworker/0:0/9
[ ] RIP: 0010:kobject_put+0xdf/0x250
[ ] Call Trace:
[ ] xe_sriov_pf_sysfs_init+0x21/0x100 [xe]
[ ] xe_sriov_pf_init_late+0x87/0x2b0 [xe]
[ ] xe_sriov_init_late+0x5f/0x2c0 [xe]
[ ] xe_device_probe+0x5f2/0xc20 [xe]
[ ] xe_pci_probe+0x396/0x610 [xe]
[ ] local_pci_probe+0x47/0xb0
[ ] refcount_t: underflow; use-after-free.
[ ] WARNING: lib/refcount.c:28 at refcount_warn_saturate+0x68/0xb0, CPU#0: kworker/0:0/9
[ ] RIP: 0010:refcount_warn_saturate+0x68/0xb0
[ ] Call Trace:
[ ] kobject_put+0x174/0x250
[ ] xe_sriov_pf_sysfs_init+0x21/0x100 [xe]
[ ] xe_sriov_pf_init_late+0x87/0x2b0 [xe]
[ ] xe_sriov_init_late+0x5f/0x2c0 [xe]
[ ] xe_device_probe+0x5f2/0xc20 [xe]
[ ] xe_pci_probe+0x396/0x610 [xe]
[ ] local_pci_probe+0x47/0xb0
Fix that by calling kobject_init() and kobject_add() separately
and register cleanup action after the kobject is initialized.
Also make this cleanup registration a part of the create helper to
fix another mistake, as in the loop we were wrongly passing parent
kobject while registering cleanup action, and this resulted in some
undetected leaks.
(cherry picked from commit 98b16727f07e26a5d4de84d88805ce7ffcfdd324)
