CVE-2024-26984

CVE Details

Release Date:

2024-05-01

Description

In the Linux kernel, the following vulnerability has been resolved:\nnouveau: fix instmem race condition around ptr stores\nRunning a lot of VK CTS in parallel against nouveau, once every\nfew hours you might see something like this crash.\nBUG: kernel NULL pointer dereference, address: 0000000000000008\nPGD 8000000114e6e067 P4D 8000000114e6e067 PUD 109046067 PMD 0\nOops: 0000 [#1] PREEMPT SMP PTI\nCPU: 7 PID: 53891 Comm: deqp-vk Not tainted 6.8.0-rc6+ #27\nHardware name: Gigabyte Technology Co., Ltd. Z390 I AORUS PRO WIFI/Z390 I AORUS PRO WIFI-CF, BIOS F8 11/05/2021\nRIP: 0010:gp100_vmm_pgt_mem+0xe3/0x180 [nouveau]\nCode: c7 48 01 c8 49 89 45 58 85 d2 0f 84 95 00 00 00 41 0f b7 46 12 49 8b 7e 08 89 da 42 8d 2c f8 48 8b 47 08 41 83 c7 01 48 89 ee <48> 8b 40 08 ff d0 0f 1f 00 49 8b 7e 08 48 89 d9 48 8d 75 04 48 c1\nRSP: 0000:ffffac20c5857838 EFLAGS: 00010202\nRAX: 0000000000000000 RBX: 00000000004d8001 RCX: 0000000000000001\nRDX: 00000000004d8001 RSI: 00000000000006d8 RDI: ffffa07afe332180\nRBP: 00000000000006d8 R08: ffffac20c5857ad0 R09: 0000000000ffff10\nR10: 0000000000000001 R11: ffffa07af27e2de0 R12: 000000000000001c\nR13: ffffac20c5857ad0 R14: ffffa07a96fe9040 R15: 000000000000001c\nFS: 00007fe395eed7c0(0000) GS:ffffa07e2c980000(0000) knlGS:0000000000000000\nCS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 0000000000000008 CR3: 000000011febe001 CR4: 00000000003706f0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\nCall Trace:\n...\n? gp100_vmm_pgt_mem+0xe3/0x180 [nouveau]\n? gp100_vmm_pgt_mem+0x37/0x180 [nouveau]\nnvkm_vmm_iter+0x351/0xa20 [nouveau]\n? __pfx_nvkm_vmm_ref_ptes+0x10/0x10 [nouveau]\n? __pfx_gp100_vmm_pgt_mem+0x10/0x10 [nouveau]\n? __pfx_gp100_vmm_pgt_mem+0x10/0x10 [nouveau]\n? __lock_acquire+0x3ed/0x2170\n? __pfx_gp100_vmm_pgt_mem+0x10/0x10 [nouveau]\nnvkm_vmm_ptes_get_map+0xc2/0x100 [nouveau]\n? __pfx_nvkm_vmm_ref_ptes+0x10/0x10 [nouveau]\n? __pfx_gp100_vmm_pgt_mem+0x10/0x10 [nouveau]\nnvkm_vmm_map_locked+0x224/0x3a0 [nouveau]\nAdding any sort of useful debug usually makes it go away, so I hand\nwrote the function in a line, and debugged the asm.\nEvery so often pt->memory->ptrs is NULL. This ptrs ptr is set in\nthe nv50_instobj_acquire called from nvkm_kmap.\nIf Thread A and Thread B both get to nv50_instobj_acquire around\nthe same time, and Thread A hits the refcount_set line, and in\nlockstep thread B succeeds at refcount_inc_not_zero, there is a\nchance the ptrs value won't have been stored since refcount_set\nis unordered. Force a memory barrier here, I picked smp_mb, since\nwe want it on all CPUs and it's write followed by a read.\nv2: use paired smp_rmb/smp_wmb.

See more information about CVE-2024-26984 from MITRE CVE dictionary and NIST NVD

CVSS Scoring

NOTE: The following CVSS v3.1 metrics and score provided are preliminary and subject to review.

Base Score:	5.5	CVSS Vector:	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector:	Local network	Attack Complexity:	Low
Privileges Required:	Low	User Interaction:	None
Scope:	Unchanged	Confidentiality Impact:	None
Integrity Impact:	None	Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 9 (kernel)	ELSA-2024-9315	2024-11-14