From: Lukas Wunner lukas@wunner.de
commit 92dc899c3b4927f3cfa23f55bf759171234b5802 upstream.
Gregory Price reports a WARN splat with CONFIG_DEBUG_OBJECTS=y upon CXL probing because pci_doe_submit_task() invokes INIT_WORK() instead of INIT_WORK_ONSTACK() for a work_struct that was allocated on the stack.
All callers of pci_doe_submit_task() allocate the work_struct on the stack, so replace INIT_WORK() with INIT_WORK_ONSTACK() as a backportable short-term fix.
The long-term fix implemented by a subsequent commit is to move to a synchronous API which allocates the work_struct internally in the DOE library.
Stacktrace for posterity:
WARNING: CPU: 0 PID: 23 at lib/debugobjects.c:545 __debug_object_init.cold+0x18/0x183 CPU: 0 PID: 23 Comm: kworker/u2:1 Not tainted 6.1.0-0.rc1.20221019gitaae703b02f92.17.fc38.x86_64 #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 Call Trace: pci_doe_submit_task+0x5d/0xd0 pci_doe_discovery+0xb4/0x100 pcim_doe_create_mb+0x219/0x290 cxl_pci_probe+0x192/0x430 local_pci_probe+0x41/0x80 pci_device_probe+0xb3/0x220 really_probe+0xde/0x380 __driver_probe_device+0x78/0x170 driver_probe_device+0x1f/0x90 __driver_attach_async_helper+0x5c/0xe0 async_run_entry_fn+0x30/0x130 process_one_work+0x294/0x5b0
Fixes: 9d24322e887b ("PCI/DOE: Add DOE mailbox support functions") Link: https://lore.kernel.org/linux-cxl/Y1bOniJliOFszvIK@memverge.com/ Reported-by: Gregory Price gregory.price@memverge.com Tested-by: Ira Weiny ira.weiny@intel.com Tested-by: Gregory Price gregory.price@memverge.com Signed-off-by: Lukas Wunner lukas@wunner.de Reviewed-by: Ira Weiny ira.weiny@intel.com Reviewed-by: Dan Williams dan.j.williams@intel.com Reviewed-by: Gregory Price gregory.price@memverge.com Cc: stable@vger.kernel.org # v6.0+ Reviewed-by: Jonathan Cameron Jonathan.Cameron@huawei.com Acked-by: Bjorn Helgaas bhelgaas@google.com Link: https://lore.kernel.org/r/67a9117f463ecdb38a2dbca6a20391ce2f1e7a06.167854349... Signed-off-by: Dan Williams dan.j.williams@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/pci/doe.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/pci/doe.c +++ b/drivers/pci/doe.c @@ -523,6 +523,8 @@ EXPORT_SYMBOL_GPL(pci_doe_supports_prot) * task->complete will be called when the state machine is done processing this * task. * + * @task must be allocated on the stack. + * * Excess data will be discarded. * * RETURNS: 0 when task has been successfully queued, -ERRNO on error @@ -544,7 +546,7 @@ int pci_doe_submit_task(struct pci_doe_m return -EIO;
task->doe_mb = doe_mb; - INIT_WORK(&task->work, doe_statemachine_work); + INIT_WORK_ONSTACK(&task->work, doe_statemachine_work); queue_work(doe_mb->work_queue, &task->work); return 0; }