On Mon, Aug 18, 2025 at 11:17:51AM -0300, Jason Gunthorpe wrote: > On Fri, Aug 15, 2025 at 08:24:57AM +0000, Tian, Kevin wrote: > > > From: Nicolin Chen <nicolinc@xxxxxxxxxx> > > > Sent: Tuesday, August 12, 2025 6:59 AM > > > > > > The iommu_deferred_attach() is a runtime asynchronous function called by > > > iommu-dma function, which could race against other attach functions if it > > > accesses something in the dev->iommu_group. > > > > Is there a real racing scenario being observed or more theoretical? > > I think the commit message should explain the actual reason this is > being done, which AFAICT because the new lockdeps added in following > patches will fail on this path otherwise. Hmm, I can mention that. But I think that's just a part of the reason. It still doesn't seem correct to invoke an attach_dev function without the lock since iommu_group_mutex_assert() may be used in the path? Thanks Nicolin
