Brett Creeley 17cf7f9a94 vfio/pds: Make sure migration file isn't accessed after reset ... [ Upstream commit 457f730825 ] It's possible the migration file is accessed after reset when it has been cleaned up, especially when it's initiated by the device. This is because the driver doesn't rip out the filep when cleaning up it only frees the related page structures and sets its local struct pds_vfio_lm_file pointer to NULL. This can cause a NULL pointer dereference, which is shown in the example below during a restore after a device initiated reset: BUG: kernel NULL pointer dereference, address: 000000000000000c PF: supervisor read access in kernel mode PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI RIP: 0010:pds_vfio_get_file_page+0x5d/0xf0 [pds_vfio_pci] [...] Call Trace: <TASK> pds_vfio_restore_write+0xf6/0x160 [pds_vfio_pci] vfs_write+0xc9/0x3f0 ? __fget_light+0xc9/0x110 ksys_write+0xb5/0xf0 __x64_sys_write+0x1a/0x20 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd [...] Add a disabled flag to the driver's struct pds_vfio_lm_file that gets set during cleanup. Then make sure to check the flag when the migration file is accessed via its file_operations. By default this flag will be false as the memory for struct pds_vfio_lm_file is kzalloc'd, which means the struct pds_vfio_lm_file is enabled and accessible. Also, since the file_operations and driver's migration file cleanup happen under the protection of the same pds_vfio_lm_file.lock, using this flag is thread safe. Fixes: 8512ed2563 ("vfio/pds: Always clear the save/restore FDs on reset") Reviewed-by: Shannon Nelson <shannon.nelson@amd.com> Signed-off-by: Brett Creeley <brett.creeley@amd.com> Link: https://lore.kernel.org/r/20240308182149.22036-2-brett.creeley@amd.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>		2024-04-03 15:32:44 +02:00
..
hisilicon	hisi_acc_vfio_pci: Update migration data pointer correctly on saving/resume	2024-01-05 09:06:45 -07:00
mlx5	iommufd for 6.7	2023-11-01 16:44:56 -10:00
pds	vfio/pds: Make sure migration file isn't accessed after reset	2024-04-03 15:32:44 +02:00
virtio	vfio/virtio: fix virtio-pci dependency	2024-01-10 15:10:41 -07:00
Kconfig	vfio/virtio: Introduce a vfio driver over virtio devices	2023-12-19 11:51:34 -07:00
Makefile	vfio/virtio: Introduce a vfio driver over virtio devices	2023-12-19 11:51:34 -07:00
trace.h
vfio_pci.c	vfio-iommufd: Add detach_ioas support for physical VFIO devices	2023-07-25 10:19:12 -06:00
vfio_pci_config.c	vfio/pci: Also demote hiding standard cap messages	2023-05-26 13:58:27 -06:00
vfio_pci_core.c	eventfd: simplify eventfd_signal()	2023-11-28 14:08:38 +01:00
vfio_pci_igd.c	vfio: Use GFP_KERNEL_ACCOUNT for userspace persistent allocations	2023-01-23 11:26:29 -07:00
vfio_pci_intrs.c	vfio/pci: Create persistent INTx handler	2024-04-03 15:32:30 +02:00
vfio_pci_priv.h	vfio/pci: Mask INTx during runtime suspend	2022-09-01 15:29:11 -06:00
vfio_pci_rdwr.c	vfio/pci: Expose vfio_pci_core_iowrite/read##size()	2023-12-19 11:51:33 -07:00
vfio_pci_zdev.c	Merge remote-tracking branch 'mlx5/mlx5-vfio' into v6.1/vfio/next	2022-09-08 10:44:34 -06:00