Re: [PATCH] iommu/iova: Remove stale cached32_node
On Sat, Jul 20, 2019 at 07:08:48PM +0100, Chris Wilson wrote: > --- > drivers/iommu/iova.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) Applied to iommu/fixes. ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
Re: [PATCH] iommu/iova: Remove stale cached32_node
Quoting Robin Murphy (2019-07-22 11:13:49) > Hi Chris, > > On 20/07/2019 19:08, Chris Wilson wrote: > > Since the cached32_node is allowed to be advanced above dma_32bit_pfn > > (to provide a shortcut into the limited range), we need to be careful to > > remove the to be freed node if it is the cached32_node. > > Thanks for digging in - just to confirm my understanding, the > problematic situation is where both 32-bit and 64-bit nodes have been > allocated, the topmost 32-bit node is freed, then the lowest 64-bit node > is freed, which leaves the pointer dangling because the second free > fails the "free->pfn_hi < iovad->dma_32bit_pfn" check. Does that match > your reasoning? Yes. Once cached32_node is set to the right of dma_32bit_pfn it fails to be picked up in the next cycle through __cached_rbnode_delete_update should cached32_node be the next victim. > Assuming I haven't completely misread the problem, I can't think of a > more appropriate way to fix it, so; > > Reviewed-by: Robin Murphy > > I could swear I did consider that corner case at some point, but since > Leizhen and I rewrote this stuff about 5 times between us I'm not > entirely surprised such a subtlety could have got lost again along the way. I admit to being impressed that rb_prev() does not appear high in the profiles -- though I guess that is more an artifact of the scary layers of caching above it. -Chris ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
Re: [PATCH] iommu/iova: Remove stale cached32_node
Hi Chris, On 20/07/2019 19:08, Chris Wilson wrote: Since the cached32_node is allowed to be advanced above dma_32bit_pfn (to provide a shortcut into the limited range), we need to be careful to remove the to be freed node if it is the cached32_node. Thanks for digging in - just to confirm my understanding, the problematic situation is where both 32-bit and 64-bit nodes have been allocated, the topmost 32-bit node is freed, then the lowest 64-bit node is freed, which leaves the pointer dangling because the second free fails the "free->pfn_hi < iovad->dma_32bit_pfn" check. Does that match your reasoning? Assuming I haven't completely misread the problem, I can't think of a more appropriate way to fix it, so; Reviewed-by: Robin Murphy I could swear I did consider that corner case at some point, but since Leizhen and I rewrote this stuff about 5 times between us I'm not entirely surprised such a subtlety could have got lost again along the way. Thanks, Robin. [ 48.43] BUG: KASAN: use-after-free in __cached_rbnode_delete_update+0x68/0x110 [ 48.477812] Read of size 8 at addr 88870fc19020 by task kworker/u8:1/37 [ 48.477843] [ 48.477879] CPU: 1 PID: 37 Comm: kworker/u8:1 Tainted: G U 5.2.0+ #735 [ 48.477915] Hardware name: Intel Corporation NUC7i5BNK/NUC7i5BNB, BIOS BNKBL357.86A.0052.2017.0918.1346 09/18/2017 [ 48.478047] Workqueue: i915 __i915_gem_free_work [i915] [ 48.478075] Call Trace: [ 48.478111] dump_stack+0x5b/0x90 [ 48.478137] print_address_description+0x67/0x237 [ 48.478178] ? __cached_rbnode_delete_update+0x68/0x110 [ 48.478212] __kasan_report.cold.3+0x1c/0x38 [ 48.478240] ? __cached_rbnode_delete_update+0x68/0x110 [ 48.478280] ? __cached_rbnode_delete_update+0x68/0x110 [ 48.478308] __cached_rbnode_delete_update+0x68/0x110 [ 48.478344] private_free_iova+0x2b/0x60 [ 48.478378] iova_magazine_free_pfns+0x46/0xa0 [ 48.478403] free_iova_fast+0x277/0x340 [ 48.478443] fq_ring_free+0x15a/0x1a0 [ 48.478473] queue_iova+0x19c/0x1f0 [ 48.478597] cleanup_page_dma.isra.64+0x62/0xb0 [i915] [ 48.478712] __gen8_ppgtt_cleanup+0x63/0x80 [i915] [ 48.478826] __gen8_ppgtt_cleanup+0x42/0x80 [i915] [ 48.478940] __gen8_ppgtt_clear+0x433/0x4b0 [i915] [ 48.479053] __gen8_ppgtt_clear+0x462/0x4b0 [i915] [ 48.479081] ? __sg_free_table+0x9e/0xf0 [ 48.479116] ? kfree+0x7f/0x150 [ 48.479234] i915_vma_unbind+0x1e2/0x240 [i915] [ 48.479352] i915_vma_destroy+0x3a/0x280 [i915] [ 48.479465] __i915_gem_free_objects+0xf0/0x2d0 [i915] [ 48.479579] __i915_gem_free_work+0x41/0xa0 [i915] [ 48.479607] process_one_work+0x495/0x710 [ 48.479642] worker_thread+0x4c7/0x6f0 [ 48.479687] ? process_one_work+0x710/0x710 [ 48.479724] kthread+0x1b2/0x1d0 [ 48.479774] ? kthread_create_worker_on_cpu+0xa0/0xa0 [ 48.479820] ret_from_fork+0x1f/0x30 [ 48.479864] [ 48.479907] Allocated by task 631: [ 48.479944] save_stack+0x19/0x80 [ 48.479994] __kasan_kmalloc.constprop.6+0xc1/0xd0 [ 48.480038] kmem_cache_alloc+0x91/0xf0 [ 48.480082] alloc_iova+0x2b/0x1e0 [ 48.480125] alloc_iova_fast+0x58/0x376 [ 48.480166] intel_alloc_iova+0x90/0xc0 [ 48.480214] intel_map_sg+0xde/0x1f0 [ 48.480343] i915_gem_gtt_prepare_pages+0xb8/0x170 [i915] [ 48.480465] huge_get_pages+0x232/0x2b0 [i915] [ 48.480590] i915_gem_object_get_pages+0x40/0xb0 [i915] [ 48.480712] __i915_gem_object_get_pages+0x90/0xa0 [i915] [ 48.480834] i915_gem_object_prepare_write+0x2d6/0x330 [i915] [ 48.480955] create_test_object.isra.54+0x1a9/0x3e0 [i915] [ 48.481075] igt_shared_ctx_exec+0x365/0x3c0 [i915] [ 48.481210] __i915_subtests.cold.4+0x30/0x92 [i915] [ 48.481341] __run_selftests.cold.3+0xa9/0x119 [i915] [ 48.481466] i915_live_selftests+0x3c/0x70 [i915] [ 48.481583] i915_pci_probe+0xe7/0x220 [i915] [ 48.481620] pci_device_probe+0xe0/0x180 [ 48.481665] really_probe+0x163/0x4e0 [ 48.481710] device_driver_attach+0x85/0x90 [ 48.481750] __driver_attach+0xa5/0x180 [ 48.481796] bus_for_each_dev+0xda/0x130 [ 48.481831] bus_add_driver+0x205/0x2e0 [ 48.481882] driver_register+0xca/0x140 [ 48.481927] do_one_initcall+0x6c/0x1af [ 48.481970] do_init_module+0x106/0x350 [ 48.482010] load_module+0x3d2c/0x3ea0 [ 48.482058] __do_sys_finit_module+0x110/0x180 [ 48.482102] do_syscall_64+0x62/0x1f0 [ 48.482147] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 48.482190] [ 48.482224] Freed by task 37: [ 48.482273] save_stack+0x19/0x80 [ 48.482318] __kasan_slab_free+0x12e/0x180 [ 48.482363] kmem_cache_free+0x70/0x140 [ 48.482406] __free_iova+0x1d/0x30 [ 48.482445] fq_ring_free+0x15a/0x1a0 [ 48.482490] queue_iova+0x19c/0x1f0 [ 48.482624] cleanup_page_dma.isra.64+0x62/0xb0 [i915] [ 48.482749] __gen8_ppgtt_cleanup+0x63/0x80 [i915] [ 48.482873] __gen8_ppgtt_cleanup+0x42/0x80 [i915] [ 48.482999] __gen8_ppgtt_clear+0x433/0x4b0 [i915] [ 48.483123]
Re: [PATCH] iommu/iova: Remove stale cached32_node
Hi,
[This is an automated email]
This commit has been processed because it contains a "Fixes:" tag,
fixing commit: e60aa7b53845 iommu/iova: Extend rbtree node caching.
The bot has tested the following trees: v5.2.1, v5.1.18, v4.19.59.
v5.2.1: Build OK!
v5.1.18: Build OK!
v4.19.59: Failed to apply! Possible dependencies:
bee60e94a1e2 ("iommu/iova: Optimise attempts to allocate iova from 32bit
address range")
NOTE: The patch will not be queued to stable trees until it is upstream.
How should we proceed with this patch?
--
Thanks,
Sasha
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[PATCH] iommu/iova: Remove stale cached32_node
Since the cached32_node is allowed to be advanced above dma_32bit_pfn (to provide a shortcut into the limited range), we need to be careful to remove the to be freed node if it is the cached32_node. [ 48.43] BUG: KASAN: use-after-free in __cached_rbnode_delete_update+0x68/0x110 [ 48.477812] Read of size 8 at addr 88870fc19020 by task kworker/u8:1/37 [ 48.477843] [ 48.477879] CPU: 1 PID: 37 Comm: kworker/u8:1 Tainted: G U 5.2.0+ #735 [ 48.477915] Hardware name: Intel Corporation NUC7i5BNK/NUC7i5BNB, BIOS BNKBL357.86A.0052.2017.0918.1346 09/18/2017 [ 48.478047] Workqueue: i915 __i915_gem_free_work [i915] [ 48.478075] Call Trace: [ 48.478111] dump_stack+0x5b/0x90 [ 48.478137] print_address_description+0x67/0x237 [ 48.478178] ? __cached_rbnode_delete_update+0x68/0x110 [ 48.478212] __kasan_report.cold.3+0x1c/0x38 [ 48.478240] ? __cached_rbnode_delete_update+0x68/0x110 [ 48.478280] ? __cached_rbnode_delete_update+0x68/0x110 [ 48.478308] __cached_rbnode_delete_update+0x68/0x110 [ 48.478344] private_free_iova+0x2b/0x60 [ 48.478378] iova_magazine_free_pfns+0x46/0xa0 [ 48.478403] free_iova_fast+0x277/0x340 [ 48.478443] fq_ring_free+0x15a/0x1a0 [ 48.478473] queue_iova+0x19c/0x1f0 [ 48.478597] cleanup_page_dma.isra.64+0x62/0xb0 [i915] [ 48.478712] __gen8_ppgtt_cleanup+0x63/0x80 [i915] [ 48.478826] __gen8_ppgtt_cleanup+0x42/0x80 [i915] [ 48.478940] __gen8_ppgtt_clear+0x433/0x4b0 [i915] [ 48.479053] __gen8_ppgtt_clear+0x462/0x4b0 [i915] [ 48.479081] ? __sg_free_table+0x9e/0xf0 [ 48.479116] ? kfree+0x7f/0x150 [ 48.479234] i915_vma_unbind+0x1e2/0x240 [i915] [ 48.479352] i915_vma_destroy+0x3a/0x280 [i915] [ 48.479465] __i915_gem_free_objects+0xf0/0x2d0 [i915] [ 48.479579] __i915_gem_free_work+0x41/0xa0 [i915] [ 48.479607] process_one_work+0x495/0x710 [ 48.479642] worker_thread+0x4c7/0x6f0 [ 48.479687] ? process_one_work+0x710/0x710 [ 48.479724] kthread+0x1b2/0x1d0 [ 48.479774] ? kthread_create_worker_on_cpu+0xa0/0xa0 [ 48.479820] ret_from_fork+0x1f/0x30 [ 48.479864] [ 48.479907] Allocated by task 631: [ 48.479944] save_stack+0x19/0x80 [ 48.479994] __kasan_kmalloc.constprop.6+0xc1/0xd0 [ 48.480038] kmem_cache_alloc+0x91/0xf0 [ 48.480082] alloc_iova+0x2b/0x1e0 [ 48.480125] alloc_iova_fast+0x58/0x376 [ 48.480166] intel_alloc_iova+0x90/0xc0 [ 48.480214] intel_map_sg+0xde/0x1f0 [ 48.480343] i915_gem_gtt_prepare_pages+0xb8/0x170 [i915] [ 48.480465] huge_get_pages+0x232/0x2b0 [i915] [ 48.480590] i915_gem_object_get_pages+0x40/0xb0 [i915] [ 48.480712] __i915_gem_object_get_pages+0x90/0xa0 [i915] [ 48.480834] i915_gem_object_prepare_write+0x2d6/0x330 [i915] [ 48.480955] create_test_object.isra.54+0x1a9/0x3e0 [i915] [ 48.481075] igt_shared_ctx_exec+0x365/0x3c0 [i915] [ 48.481210] __i915_subtests.cold.4+0x30/0x92 [i915] [ 48.481341] __run_selftests.cold.3+0xa9/0x119 [i915] [ 48.481466] i915_live_selftests+0x3c/0x70 [i915] [ 48.481583] i915_pci_probe+0xe7/0x220 [i915] [ 48.481620] pci_device_probe+0xe0/0x180 [ 48.481665] really_probe+0x163/0x4e0 [ 48.481710] device_driver_attach+0x85/0x90 [ 48.481750] __driver_attach+0xa5/0x180 [ 48.481796] bus_for_each_dev+0xda/0x130 [ 48.481831] bus_add_driver+0x205/0x2e0 [ 48.481882] driver_register+0xca/0x140 [ 48.481927] do_one_initcall+0x6c/0x1af [ 48.481970] do_init_module+0x106/0x350 [ 48.482010] load_module+0x3d2c/0x3ea0 [ 48.482058] __do_sys_finit_module+0x110/0x180 [ 48.482102] do_syscall_64+0x62/0x1f0 [ 48.482147] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 48.482190] [ 48.482224] Freed by task 37: [ 48.482273] save_stack+0x19/0x80 [ 48.482318] __kasan_slab_free+0x12e/0x180 [ 48.482363] kmem_cache_free+0x70/0x140 [ 48.482406] __free_iova+0x1d/0x30 [ 48.482445] fq_ring_free+0x15a/0x1a0 [ 48.482490] queue_iova+0x19c/0x1f0 [ 48.482624] cleanup_page_dma.isra.64+0x62/0xb0 [i915] [ 48.482749] __gen8_ppgtt_cleanup+0x63/0x80 [i915] [ 48.482873] __gen8_ppgtt_cleanup+0x42/0x80 [i915] [ 48.482999] __gen8_ppgtt_clear+0x433/0x4b0 [i915] [ 48.483123] __gen8_ppgtt_clear+0x462/0x4b0 [i915] [ 48.483250] i915_vma_unbind+0x1e2/0x240 [i915] [ 48.483378] i915_vma_destroy+0x3a/0x280 [i915] [ 48.483500] __i915_gem_free_objects+0xf0/0x2d0 [i915] [ 48.483622] __i915_gem_free_work+0x41/0xa0 [i915] [ 48.483659] process_one_work+0x495/0x710 [ 48.483704] worker_thread+0x4c7/0x6f0 [ 48.483748] kthread+0x1b2/0x1d0 [ 48.483787] ret_from_fork+0x1f/0x30 [ 48.483831] [ 48.483868] The buggy address belongs to the object at 88870fc19000 [ 48.483868] which belongs to the cache iommu_iova of size 40 [ 48.483920] The buggy address is located 32 bytes inside of [ 48.483920] 40-byte region [88870fc19000, 88870fc19028) [ 48.483964] The buggy address belongs to the page: [ 48.484006] page:ea001c3f0600 refcount:1
