Alex Williamson 6a45ece4c9 vfio/pci: Handle concurrent vma faults ... io_remap_pfn_range() will trigger a BUG_ON if it encounters a populated pte within the mapping range. This can occur because we map the entire vma on fault and multiple faults can be blocked behind the vma_lock. This leads to traces like the one reported below. We can use our vma_list to test whether a given vma is mapped to avoid this issue. [ 1591.733256] kernel BUG at mm/memory.c:2177! [ 1591.739515] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP [ 1591.747381] Modules linked in: vfio_iommu_type1 vfio_pci vfio_virqfd vfio pv680_mii(O) [ 1591.760536] CPU: 2 PID: 227 Comm: lcore-worker-2 Tainted: G O 5.11.0-rc3+ #1 [ 1591.770735] Hardware name: , BIOS HixxxxFPGA 1P B600 V121-1 [ 1591.778872] pstate: 40400009 (nZcv daif +PAN -UAO -TCO BTYPE=--) [ 1591.786134] pc : remap_pfn_range+0x214/0x340 [ 1591.793564] lr : remap_pfn_range+0x1b8/0x340 [ 1591.799117] sp : ffff80001068bbd0 [ 1591.803476] x29: ffff80001068bbd0 x28: 0000042eff6f0000 [ 1591.810404] x27: 0000001100910000 x26: 0000001300910000 [ 1591.817457] x25: 0068000000000fd3 x24: ffffa92f1338e358 [ 1591.825144] x23: 0000001140000000 x22: 0000000000000041 [ 1591.832506] x21: 0000001300910000 x20: ffffa92f141a4000 [ 1591.839520] x19: 0000001100a00000 x18: 0000000000000000 [ 1591.846108] x17: 0000000000000000 x16: ffffa92f11844540 [ 1591.853570] x15: 0000000000000000 x14: 0000000000000000 [ 1591.860768] x13: fffffc0000000000 x12: 0000000000000880 [ 1591.868053] x11: ffff0821bf3d01d0 x10: ffff5ef2abd89000 [ 1591.875932] x9 : ffffa92f12ab0064 x8 : ffffa92f136471c0 [ 1591.883208] x7 : 0000001140910000 x6 : 0000000200000000 [ 1591.890177] x5 : 0000000000000001 x4 : 0000000000000001 [ 1591.896656] x3 : 0000000000000000 x2 : 0168044000000fd3 [ 1591.903215] x1 : ffff082126261880 x0 : fffffc2084989868 [ 1591.910234] Call trace: [ 1591.914837] remap_pfn_range+0x214/0x340 [ 1591.921765] vfio_pci_mmap_fault+0xac/0x130 [vfio_pci] [ 1591.931200] __do_fault+0x44/0x12c [ 1591.937031] handle_mm_fault+0xcc8/0x1230 [ 1591.942475] do_page_fault+0x16c/0x484 [ 1591.948635] do_translation_fault+0xbc/0xd8 [ 1591.954171] do_mem_abort+0x4c/0xc0 [ 1591.960316] el0_da+0x40/0x80 [ 1591.965585] el0_sync_handler+0x168/0x1b0 [ 1591.971608] el0_sync+0x174/0x180 [ 1591.978312] Code: eb1b027f 540000c0 f9400022 b4fffe02 (d4210000) Fixes: 11c4cd07ba ("vfio-pci: Fault mmaps to enable vma tracking") Reported-by: Zeng Tao <prime.zeng@hisilicon.com> Suggested-by: Zeng Tao <prime.zeng@hisilicon.com> Link: https://lore.kernel.org/r/162497742783.3883260.3282953006487785034.stgit@omen Signed-off-by: Alex Williamson <alex.williamson@redhat.com>		2021-06-30 13:55:53 -06:00
..
Kconfig	vfio/pci: zap_vma_ptes() needs MMU	2021-05-24 13:40:13 -06:00
Makefile	vfio/pci: remove vfio_pci_nvlink2	2021-04-06 11:54:13 -06:00
trace.h	vfio/pci: Cleanup license mess	2019-01-22 11:06:05 -07:00
vfio_pci_config.c	vfio/pci: Fix error return code in vfio_ecap_init()	2021-05-24 12:14:18 -06:00
vfio_pci_igd.c	vfio/pci: Add support for opregion v2.1+	2021-04-06 11:53:50 -06:00
vfio_pci_intrs.c	vfio/pci: Clear token on bypass registration failure	2020-10-19 07:13:55 -06:00
vfio_pci_private.h	Merge branches 'v5.13/vfio/embed-vfio_device', 'v5.13/vfio/misc' and 'v5.13/vfio/nvlink' into v5.13/vfio/next	2021-04-06 12:01:51 -06:00
vfio_pci_rdwr.c	vfio/pci: Implement ioeventfd thread handler for contended memory lock	2020-11-03 11:07:40 -07:00
vfio_pci_zdev.c	vfio-pci/zdev: fix possible segmentation fault issue	2021-02-02 09:06:02 -07:00
vfio_pci.c	vfio/pci: Handle concurrent vma faults	2021-06-30 13:55:53 -06:00