Note, event changes go through the maintainer's tree where the events are used.
But from a tracing POV: Reviewed-by: Steven Rostedt (Google) <[email protected]> -- Steve On Wed, 28 Jan 2026 15:48:01 +0000 Daniel Thompson <[email protected]> wrote: > The arm-smmu driver is unable to allocate the blame for a page fault to > a specific device so it calls report_iommu_fault() with the dev argument > set to NULL. Normally this doesn't cause anything catastrophic but on a > system with the io_page_fault tracepoint enabled this results in a NULL > pointer deref (resulting in a fairly spectacular crash on the hardware > I'm currently working on). > > Fix this by adding logic to the tracepoint to safely propagate NULL. > > Fixes: f8f934c180f6 ("iommu/arm-smmu: Add support for driver IOMMU fault > handlers") > Signed-off-by: Daniel Thompson <[email protected]> > --- > Changes in v2: > - Add a Fixes:. It points to the earliest point I can find where it becomes > possible for the tracepoint to be triggered with dev set to NULL. > - Link to v1: > https://lore.kernel.org/r/20260116-iommu-io_page_fault_null_fix-v1-1-6c20c2e62...@riscstar.com > --- > include/trace/events/iommu.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/trace/events/iommu.h b/include/trace/events/iommu.h > index > 373007e567cb827458a729b8200bbcc1b7d76912..1315193f13b8812ad4e29e6b0c0c66ca806ce08d > 100644 > --- a/include/trace/events/iommu.h > +++ b/include/trace/events/iommu.h > @@ -131,8 +131,8 @@ DECLARE_EVENT_CLASS(iommu_error, > TP_ARGS(dev, iova, flags), > > TP_STRUCT__entry( > - __string(device, dev_name(dev)) > - __string(driver, dev_driver_string(dev)) > + __string(device, dev ? dev_name(dev) : NULL) > + __string(driver, dev ? dev_driver_string(dev) : NULL) > __field(u64, iova) > __field(int, flags) > ), > > --- > base-commit: 0f61b1860cc3f52aef9036d7235ed1f017632193 > change-id: 20260116-iommu-io_page_fault_null_fix-f81b4e8b5423 > > Best regards,
