CVE-2022-50068

Published Jun 18, 2025

Last updated 7 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: drm/ttm: Fix dummy res NULL ptr deref bug Check the bo->resource value before accessing the resource mem_type. v2: Fix commit description unwrapped warning <log snip> [ 40.191227][ T184] general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] SMP KASAN PTI [ 40.192995][ T184] KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] [ 40.194411][ T184] CPU: 1 PID: 184 Comm: systemd-udevd Not tainted 5.19.0-rc4-00721-gb297c22b7070 #1 [ 40.196063][ T184] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-debian-1.16.0-4 04/01/2014 [ 40.199605][ T184] RIP: 0010:ttm_bo_validate+0x1b3/0x240 [ttm] [ 40.200754][ T184] Code: e8 72 c5 ff ff 83 f8 b8 74 d4 85 c0 75 54 49 8b 9e 58 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 10 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 04 3c 03 7e 44 8b 53 10 31 c0 85 d2 0f 85 58 [ 40.203685][ T184] RSP: 0018:ffffc900006df0c8 EFLAGS: 00010202 [ 40.204630][ T184] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff1102f4bb71b [ 40.205864][ T184] RDX: 0000000000000002 RSI: ffffc900006df208 RDI: 0000000000000010 [ 40.207102][ T184] RBP: 1ffff920000dbe1a R08: ffffc900006df208 R09: 0000000000000000 [ 40.208394][ T184] R10: ffff88817a5f0000 R11: 0000000000000001 R12: ffffc900006df110 [ 40.209692][ T184] R13: ffffc900006df0f0 R14: ffff88817a5db800 R15: ffffc900006df208 [ 40.210862][ T184] FS: 00007f6b1d16e8c0(0000) GS:ffff88839d700000(0000) knlGS:0000000000000000 [ 40.212250][ T184] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 40.213275][ T184] CR2: 000055a1001d4ff0 CR3: 00000001700f4000 CR4: 00000000000006e0 [ 40.214469][ T184] Call Trace: [ 40.214974][ T184] <TASK> [ 40.215438][ T184] ? ttm_bo_bounce_temp_buffer+0x140/0x140 [ttm] [ 40.216572][ T184] ? mutex_spin_on_owner+0x240/0x240 [ 40.217456][ T184] ? drm_vma_offset_add+0xaa/0x100 [drm] [ 40.218457][ T184] ttm_bo_init_reserved+0x3d6/0x540 [ttm] [ 40.219410][ T184] ? shmem_get_inode+0x744/0x980 [ 40.220231][ T184] ttm_bo_init_validate+0xb1/0x200 [ttm] [ 40.221172][ T184] ? bo_driver_evict_flags+0x340/0x340 [drm_vram_helper] [ 40.222530][ T184] ? ttm_bo_init_reserved+0x540/0x540 [ttm] [ 40.223643][ T184] ? __do_sys_finit_module+0x11a/0x1c0 [ 40.224654][ T184] ? __shmem_file_setup+0x102/0x280 [ 40.234764][ T184] drm_gem_vram_create+0x305/0x480 [drm_vram_helper] [ 40.235766][ T184] ? bo_driver_evict_flags+0x340/0x340 [drm_vram_helper] [ 40.236846][ T184] ? __kasan_slab_free+0x108/0x180 [ 40.237650][ T184] drm_gem_vram_fill_create_dumb+0x134/0x340 [drm_vram_helper] [ 40.238864][ T184] ? local_pci_probe+0xdf/0x180 [ 40.239674][ T184] ? drmm_vram_helper_init+0x400/0x400 [drm_vram_helper] [ 40.240826][ T184] drm_client_framebuffer_create+0x19c/0x400 [drm] [ 40.241955][ T184] ? drm_client_buffer_delete+0x200/0x200 [drm] [ 40.243001][ T184] ? drm_client_pick_crtcs+0x554/0xb80 [drm] [ 40.244030][ T184] drm_fb_helper_generic_probe+0x23f/0x940 [drm_kms_helper] [ 40.245226][ T184] ? __cond_resched+0x1c/0xc0 [ 40.245987][ T184] ? drm_fb_helper_memory_range_to_clip+0x180/0x180 [drm_kms_helper] [ 40.247316][ T184] ? mutex_unlock+0x80/0x100 [ 40.248005][ T184] ? __mutex_unlock_slowpath+0x2c0/0x2c0 [ 40.249083][ T184] drm_fb_helper_single_fb_probe+0x907/0xf00 [drm_kms_helper] [ 40.250314][ T184] ? drm_fb_helper_check_var+0x1180/0x1180 [drm_kms_helper] [ 40.251540][ T184] ? __cond_resched+0x1c/0xc0 [ 40.252321][ T184] ? mutex_lock+0x9f/0x100 [ 40.253062][ T184] __drm_fb_helper_initial_config_and_unlock+0xb9/0x2c0 [drm_kms_helper] [ 40.254394][ T184] drm_fbdev_client_hotplug+0x56f/0x840 [drm_kms_helper] [ 40.255477][ T184] drm_fbdev_generic_setup+0x165/0x3c0 [drm_kms_helper] [ 40.256607][ T184] bochs_pci_probe+0x6b7/0x900 [bochs] [ ---truncated---
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
CWE-476

Social media

Hype score
Not currently trending

Configurations

  1. In the Linux kernel, the following vulnerability has been resolved: coresight: tmc-etr: Fix race condition between sysfs and perf mode When trying to run perf and sysfs mode simultaneously, the WARN_ON() in tmc_etr_enable_hw() is triggered sometimes: WARNING: CPU: 42 PID: 3911571 at drivers/hwtracing/coresight/coresight-tmc-etr.c:1060 tmc_etr_enable_hw+0xc0/0xd8 [coresight_tmc] [..snip..] Call trace: tmc_etr_enable_hw+0xc0/0xd8 [coresight_tmc] (P) tmc_enable_etr_sink+0x11c/0x250 [coresight_tmc] (L) tmc_enable_etr_sink+0x11c/0x250 [coresight_tmc] coresight_enable_path+0x1c8/0x218 [coresight] coresight_enable_sysfs+0xa4/0x228 [coresight] enable_source_store+0x58/0xa8 [coresight] dev_attr_store+0x20/0x40 sysfs_kf_write+0x4c/0x68 kernfs_fop_write_iter+0x120/0x1b8 vfs_write+0x2c8/0x388 ksys_write+0x74/0x108 __arm64_sys_write+0x24/0x38 el0_svc_common.constprop.0+0x64/0x148 do_el0_svc+0x24/0x38 el0_svc+0x3c/0x130 el0t_64_sync_handler+0xc8/0xd0 el0t_64_sync+0x1ac/0x1b0 ---[ end trace 0000000000000000 ]--- Since the enablement of sysfs mode is separeted into two critical regions, one for sysfs buffer allocation and another for hardware enablement, it's possible to race with the perf mode. Fix this by double check whether the perf mode's been used before enabling the hardware in sysfs mode. mode: [sysfs mode] [perf mode] tmc_etr_get_sysfs_buffer() spin_lock(&drvdata->spinlock) [sysfs buffer allocation] spin_unlock(&drvdata->spinlock) spin_lock(&drvdata->spinlock) tmc_etr_enable_hw() drvdata->etr_buf = etr_perf->etr_buf spin_unlock(&drvdata->spinlock) spin_lock(&drvdata->spinlock) tmc_etr_enable_hw() WARN_ON(drvdata->etr_buf) // WARN sicne etr_buf initialized at the perf side spin_unlock(&drvdata->spinlock) With this fix, we retain the check for CS_MODE_PERF in get_etr_sysfs_buf. This ensures we verify whether the perf mode's already running before we actually allocate the buffer. Then we can save the time of allocating/freeing the sysfs buffer if race with the perf mode.CVE-2026-46272