From: Daisuke Matsuda Date: Sat, 24 May 2025 14:43:28 +0000 (+0000) Subject: RDMA/core: Avoid hmm_dma_map_alloc() for virtual DMA devices X-Git-Tag: v6.16-rc1~111^2~6 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=259e9bd07c57b0fd8588f68e9adbe2c41170f4fe;p=thirdparty%2Flinux.git RDMA/core: Avoid hmm_dma_map_alloc() for virtual DMA devices Drivers such as rxe, which use virtual DMA, must not call into the DMA mapping core since they lack physical DMA capabilities. Otherwise, a NULL pointer dereference is observed as shown below. This patch ensures the RDMA core handles virtual and physical DMA paths appropriately. This fixes the following kernel oops: BUG: kernel NULL pointer dereference, address: 00000000000002fc #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 1028eb067 P4D 1028eb067 PUD 105da0067 PMD 0 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 3 UID: 1000 PID: 1854 Comm: python3 Tainted: G W 6.15.0-rc1+ #11 PREEMPT(voluntary) Tainted: [W]=WARN Hardware name: Trigkey Key N/Key N, BIOS KEYN101 09/02/2024 RIP: 0010:hmm_dma_map_alloc+0x25/0x100 Code: 90 90 90 90 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 49 89 d6 49 c1 e6 0c 41 55 41 54 53 49 39 ce 0f 82 c6 00 00 00 49 89 fc 87 fc 02 00 00 20 0f 84 af 00 00 00 49 89 f5 48 89 d3 49 89 cf RSP: 0018:ffffd3d3420eb830 EFLAGS: 00010246 RAX: 0000000000001000 RBX: ffff8b727c7f7400 RCX: 0000000000001000 RDX: 0000000000000001 RSI: ffff8b727c7f74b0 RDI: 0000000000000000 RBP: ffffd3d3420eb858 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 00007262a622a000 R14: 0000000000001000 R15: ffff8b727c7f74b0 FS: 00007262a62a1080(0000) GS:ffff8b762ac3e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000002fc CR3: 000000010a1f0004 CR4: 0000000000f72ef0 PKRU: 55555554 Call Trace: ib_init_umem_odp+0xb6/0x110 [ib_uverbs] ib_umem_odp_get+0xf0/0x150 [ib_uverbs] rxe_odp_mr_init_user+0x71/0x170 [rdma_rxe] rxe_reg_user_mr+0x217/0x2e0 [rdma_rxe] ib_uverbs_reg_mr+0x19e/0x2e0 [ib_uverbs] ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0xd9/0x150 [ib_uverbs] ib_uverbs_cmd_verbs+0xd19/0xee0 [ib_uverbs] ? mmap_region+0x63/0xd0 ? __pfx_ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0x10/0x10 [ib_uverbs] ib_uverbs_ioctl+0xba/0x130 [ib_uverbs] __x64_sys_ioctl+0xa4/0xe0 x64_sys_call+0x1178/0x2660 do_syscall_64+0x7e/0x170 ? syscall_exit_to_user_mode+0x4e/0x250 ? do_syscall_64+0x8a/0x170 ? do_syscall_64+0x8a/0x170 ? syscall_exit_to_user_mode+0x4e/0x250 ? do_syscall_64+0x8a/0x170 ? syscall_exit_to_user_mode+0x4e/0x250 ? do_syscall_64+0x8a/0x170 ? do_user_addr_fault+0x1d2/0x8d0 ? irqentry_exit_to_user_mode+0x43/0x250 ? irqentry_exit+0x43/0x50 ? exc_page_fault+0x93/0x1d0 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7262a6124ded Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00 RSP: 002b:00007fffd08c3960 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fffd08c39f0 RCX: 00007262a6124ded RDX: 00007fffd08c3a10 RSI: 00000000c0181b01 RDI: 0000000000000007 RBP: 00007fffd08c39b0 R08: 0000000014107820 R09: 00007fffd08c3b44 R10: 000000000000000c R11: 0000000000000246 R12: 00007fffd08c3b44 R13: 000000000000000c R14: 00007fffd08c3b58 R15: 0000000014107960 Fixes: 1efe8c0670d6 ("RDMA/core: Convert UMEM ODP DMA mapping to caching IOVA and page linkage") Closes: https://lore.kernel.org/all/3e8f343f-7d66-4f7a-9f08-3910623e322f@gmail.com/ Signed-off-by: Daisuke Matsuda Link: https://patch.msgid.link/20250524144328.4361-1-dskmtsd@gmail.com Signed-off-by: Leon Romanovsky --- diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c index 51d518989914e..c752ae9fad6cf 100644 --- a/drivers/infiniband/core/umem_odp.c +++ b/drivers/infiniband/core/umem_odp.c @@ -60,9 +60,11 @@ static int ib_init_umem_odp(struct ib_umem_odp *umem_odp, { struct ib_device *dev = umem_odp->umem.ibdev; size_t page_size = 1UL << umem_odp->page_shift; + struct hmm_dma_map *map; unsigned long start; unsigned long end; - int ret; + size_t nr_entries; + int ret = 0; umem_odp->umem.is_odp = 1; mutex_init(&umem_odp->umem_mutex); @@ -75,9 +77,20 @@ static int ib_init_umem_odp(struct ib_umem_odp *umem_odp, if (unlikely(end < page_size)) return -EOVERFLOW; - ret = hmm_dma_map_alloc(dev->dma_device, &umem_odp->map, - (end - start) >> PAGE_SHIFT, - 1 << umem_odp->page_shift); + nr_entries = (end - start) >> PAGE_SHIFT; + if (!(nr_entries * PAGE_SIZE / page_size)) + return -EINVAL; + + map = &umem_odp->map; + if (ib_uses_virt_dma(dev)) { + map->pfn_list = kvcalloc(nr_entries, sizeof(*map->pfn_list), + GFP_KERNEL | __GFP_NOWARN); + if (!map->pfn_list) + ret = -ENOMEM; + } else + ret = hmm_dma_map_alloc(dev->dma_device, map, + (end - start) >> PAGE_SHIFT, + 1 << umem_odp->page_shift); if (ret) return ret; @@ -90,7 +103,10 @@ static int ib_init_umem_odp(struct ib_umem_odp *umem_odp, return 0; out_free_map: - hmm_dma_map_free(dev->dma_device, &umem_odp->map); + if (ib_uses_virt_dma(dev)) + kfree(map->pfn_list); + else + hmm_dma_map_free(dev->dma_device, map); return ret; } @@ -259,7 +275,10 @@ static void ib_umem_odp_free(struct ib_umem_odp *umem_odp) ib_umem_end(umem_odp)); mutex_unlock(&umem_odp->umem_mutex); mmu_interval_notifier_remove(&umem_odp->notifier); - hmm_dma_map_free(dev->dma_device, &umem_odp->map); + if (ib_uses_virt_dma(dev)) + kfree(umem_odp->map.pfn_list); + else + hmm_dma_map_free(dev->dma_device, &umem_odp->map); } void ib_umem_odp_release(struct ib_umem_odp *umem_odp) diff --git a/mm/hmm.c b/mm/hmm.c index a8bf097677f39..feac86196a65f 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -640,8 +640,7 @@ int hmm_dma_map_alloc(struct device *dev, struct hmm_dma_map *map, bool dma_need_sync = false; bool use_iova; - if (!(nr_entries * PAGE_SIZE / dma_entry_size)) - return -EINVAL; + WARN_ON_ONCE(!(nr_entries * PAGE_SIZE / dma_entry_size)); /* * The HMM API violates our normal DMA buffer ownership rules and can't