| Message ID | 9eb6af0763f1ec05673a7dd6731d9fd646cf1dd4.1669608950.git.lukas@wunner.de |
|---|---|
| State | New |
| Headers | show |
| Series | DOE WARN splat be gone | expand |
On Mon, 28 Nov 2022 05:25:51 +0100 Lukas Wunner <lukas@wunner.de> wrote: > 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. > > 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> > Signed-off-by: Lukas Wunner <lukas@wunner.de> > Cc: stable@vger.kernel.org # v6.0+ > Cc: Ira Weiny <ira.weiny@intel.com> > Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> > --- > 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 66d9ab288646..52541eac17f1 100644 > --- a/drivers/pci/doe.c > +++ b/drivers/pci/doe.c > @@ -541,7 +541,7 @@ 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); If we go this way, add a comment to say 'why' it is ONSTACK or add to the function description to say it 'must be on stack'. > queue_work(doe_mb->work_queue, &task->work); > return 0; > }
On Wed, Nov 30, 2022 at 03:36:58PM +0000, Jonathan Cameron wrote: > On Mon, 28 Nov 2022 05:25:51 +0100 > Lukas Wunner <lukas@wunner.de> wrote: > > > 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. > > > > 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> > > Signed-off-by: Lukas Wunner <lukas@wunner.de> > > Cc: stable@vger.kernel.org # v6.0+ > > Cc: Ira Weiny <ira.weiny@intel.com> > > Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> > > --- > > 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 66d9ab288646..52541eac17f1 100644 > > --- a/drivers/pci/doe.c > > +++ b/drivers/pci/doe.c > > @@ -541,7 +541,7 @@ 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); > > If we go this way, add a comment to say 'why' it is ONSTACK > or add to the function description to say it 'must be on stack'. My apologies, I somehow missed this series with the chaos of my personal life. I do like this as a backportable fix and I'm not opposed to it. I think Lukas will need to determine how much he needs the async support. So I'm going to back off and let him deal with this. Ira > > > queue_work(doe_mb->work_queue, &task->work); > > return 0; > > } >
diff --git a/drivers/pci/doe.c b/drivers/pci/doe.c index 66d9ab288646..52541eac17f1 100644 --- a/drivers/pci/doe.c +++ b/drivers/pci/doe.c @@ -541,7 +541,7 @@ 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; }
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. 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> Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: stable@vger.kernel.org # v6.0+ Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> --- drivers/pci/doe.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)