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X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Apr 2023 17:25:09.9491 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 7f97d654-90f4-438c-29e1-08db47445a3e X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.160];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: CO1NAM11FT040.eop-nam11.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA3PR12MB8809 On Thu, Apr 27, 2023 at 10:35:11AM +0100, Robin Murphy wrote: > On 2023-04-27 04:37, Nicolin Chen wrote: > > On Thu, Apr 27, 2023 at 11:20:40AM +0800, Baolu Lu wrote: > > > > > > Attaching WARNINGs: > > > > [ 19.680725] ------------[ cut here ]------------ > > > > [ 19.681083] WARNING: CPU: 0 PID: 561 at include/linux/mmap_lock.h:161 track_pfn_remap+0xf5/0x100 > > > > > > [ 19.684817] Call Trace: > > > > [ 19.684893] > > > > [ 19.684967] remap_pfn_range+0x3e/0xa0 > > > > [ 19.685084] vfio_pci_mmap_fault+0x8a/0x160 [vfio_pci_core] > > > > > I took a quick look. It seems that above warnings are irrelevant to this > > > commit. Can you please simply revert this commit and check whether there > > > are any changes? > > > > I tried on top of the v6.3-rc5 tag. The warnings were triggered > > constantly. And reverting the commit fixes it: > > nicolinc@Asurada-Nvidia:~/work/mkt/images/nicolinc/src/kernel$ git log --oneline -2 > > cb3dc9b2417e (HEAD -> v6.3-rc5) Revert "iommu/vt-d: Remove unnecessary locking in intel_irq_remapping_alloc()" > > 7e364e56293b (tag: v6.3-rc5, jgg/linus) Linux 6.3-rc5 > > > > I don't think the commit is the causation yet there seems to be > > a strong correlation here... > > The correlation is probably that you're now getting to see a genuine > warning from lockdep_assert_held(), since intel-iommu is no longer > causing debug_locks to be turned off earlier. Hmm, looks like so. The mmap_lock is held with a read permission, in arch/x86/mm/fault.c file, v.s. the expectation of a write one by remap_pfn_range(). Thanks Nicolin