CVE-2024-26940 — drm/vmwgfx: Create debugfs ttm_resource_manager entry only if needed

Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

drm/vmwgfx: Create debugfs ttm_resource_manager entry only if needed

The driver creates /sys/kernel/debug/dri/0/mob_ttm even when the corresponding ttm_resource_manager is not allocated. This leads to a crash when trying to read from this file.

Add a check to create mob_ttm, system_mob_ttm, and gmr_ttm debug file only when the corresponding ttm_resource_manager is allocated.

crash> bt PID: 3133409 TASK: ffff8fe4834a5000 CPU: 3 COMMAND: "grep" #0 [ffffb954506b3b20] machine_kexec at ffffffffb2a6bec3 #1 [ffffb954506b3b78] __crash_kexec at ffffffffb2bb598a #2 [ffffb954506b3c38] crash_kexec at ffffffffb2bb68c1 #3 [ffffb954506b3c50] oops_end at ffffffffb2a2a9b1 #4 [ffffb954506b3c70] no_context at ffffffffb2a7e913 #5 [ffffb954506b3cc8] __bad_area_nosemaphore at ffffffffb2a7ec8c #6 [ffffb954506b3d10] do_page_fault at ffffffffb2a7f887 #7 [ffffb954506b3d40] page_fault at ffffffffb360116e [exception RIP: ttm_resource_manager_debug+0x11] RIP: ffffffffc04afd11 RSP: ffffb954506b3df0 RFLAGS: 00010246 RAX: ffff8fe41a6d1200 RBX: 0000000000000000 RCX: 0000000000000940 RDX: 0000000000000000 RSI: ffffffffc04b4338 RDI: 0000000000000000 RBP: ffffb954506b3e08 R8: ffff8fee3ffad000 R9: 0000000000000000 R10: ffff8fe41a76a000 R11: 0000000000000001 R12: 00000000ffffffff R13: 0000000000000001 R14: ffff8fe5bb6f3900 R15: ffff8fe41a6d1200 ORIG_RAX: ffffffffffffffff CS: 0010 S…

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CVE-2024-26940 — drm/vmwgfx: Create debugfs ttm_resource_manager entry only if needed