6.4-stable review patch. If anyone has any objections, please let me know.
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From: Ira Weiny ira.weiny@intel.com
[ Upstream commit e3a3a097eaebaf234a482b4d2f9f18fe989208c1 ]
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.
Fixes: abf04be0e707 ("PCI/DOE: Fix memory leak with CONFIG_DEBUG_OBJECTS=y") Link: https://lore.kernel.org/r/20230726-doe-fix-v1-1-af07e614d4dd@intel.com Signed-off-by: Ira Weiny ira.weiny@intel.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com Reviewed-by: Lukas Wunner lukas@wunner.de Acked-by: Dan Williams dan.j.williams@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/doe.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pci/doe.c b/drivers/pci/doe.c index 1b97a5ab71a96..e3aab5edaf706 100644 --- a/drivers/pci/doe.c +++ b/drivers/pci/doe.c @@ -293,8 +293,8 @@ static int pci_doe_recv_resp(struct pci_doe_mb *doe_mb, struct pci_doe_task *tas static void signal_task_complete(struct pci_doe_task *task, int rv) { task->rv = rv; - task->complete(task); destroy_work_on_stack(&task->work); + task->complete(task); }
static void signal_task_abort(struct pci_doe_task *task, int rv)