Description

In the Linux kernel, the following vulnerability has been resolved: PCI/DOE: Fix destroy_work_on_stack() race The following debug object splat was observed in testing: ODEBUG: free active (active state 0) object: 0000000097d23782 object type: work_struct hint: doe_statemachine_work+0x0/0x510 WARNING: CPU: 1 PID: 71 at lib/debugobjects.c:514 debug_print_object+0x7d/0xb0 ... Workqueue: pci 0000:36:00.0 DOE [1 doe_statemachine_work RIP: 0010:debug_print_object+0x7d/0xb0 ... Call Trace: ? debug_print_object+0x7d/0xb0 ? __pfx_doe_statemachine_work+0x10/0x10 debug_object_free.part.0+0x11b/0x150 doe_statemachine_work+0x45e/0x510 process_one_work+0x1d4/0x3c0 This occurs because destroy_work_on_stack() was called after signaling the completion in the calling thread. This creates a race between destroy_work_on_stack() and the task->work struct going out of scope in pci_doe(). Signal the work complete after destroying the work struct. This is safe because signal_task_complete() is the final thing the work item does and the workqueue code is careful not to access the work struct after.

References 4

• git.kernel.org https://git.kernel.org/stable/c/19cf3ba16dcc2ef059dcf010072d4f96d76486e0
• git.kernel.org https://git.kernel.org/stable/c/c4f9c0a3a6df143f2e1092823b7fa9e07d6ab57f
• git.kernel.org https://git.kernel.org/stable/c/d96799ee3b78962c80e4b6653734f488f999ca09
• git.kernel.org https://git.kernel.org/stable/c/e3a3a097eaebaf234a482b4d2f9f18fe989208c1

Remediation