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@xxxxxxxxxxxx/
Reported-by: Gregory Price <gregory.price@xxxxxxxxxxxx>
Tested-by: Ira Weiny <ira.weiny@xxxxxxxxx>
Tested-by: Gregory Price <gregory.price@xxxxxxxxxxxx>
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx>
Reviewed-by: Gregory Price <gregory.price@xxxxxxxxxxxx>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v6.0+
---
Changes v2 -> v3:
* Explain in commit message what the long-term fix implemented by
a subsequent commit is (Jonathan)
drivers/pci/doe.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/doe.c b/drivers/pci/doe.c
index 69efa9a250b9..c20ca62a8c9d 100644
--- 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_mb *doe_mb, struct pci_doe_task *task)
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;
}
--
2.39.1
