Affected: Linux

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

drm/amd/display: fix divide error in DM plane scale calcs

dm_get_plane_scale doesn't take into account plane scaled size equal to zero, leading to a kernel oops due to division by zero. Fix by setting out-scale size as zero when the dst size is zero, similar to what is done by drm_calc_scale(). This issue started with the introduction of cursor ovelay mode that uses this function to assess cursor mode changes via dm_crtc_get_cursor_mode() before checking plane state.

[Dec17 17:14] Oops: divide error: 0000 [#1] PREEMPT SMP NOPTI [ +0.000018] CPU: 5 PID: 1660 Comm: surface-DP-1 Not tainted 6.10.0+ #231 [ +0.000007] Hardware name: Valve Jupiter/Jupiter, BIOS F7A0131 01/30/2024 [ +0.000004] RIP: 0010:dm_get_plane_scale+0x3f/0x60 [amdgpu] [ +0.000553] Code: 44 0f b7 41 3a 44 0f b7 49 3e 83 e0 0f 48 0f a3 c2 73 21 69 41 28 e8 03 00 00 31 d2 41 f7 f1 31 d2 89 06 69 41 2c e8 03 00 00 <41> f7 f0 89 07 e9 d7 d8 7e e9 44 89 c8 45 89 c1 41 89 c0 eb d4 66 [ +0.000005] RSP: 0018:ffffa8df0de6b8a0 EFLAGS: 00010246 [ +0.000006] RAX: 00000000000003e8 RBX: ffff9ac65c1f6e00 RCX: ffff9ac65d055500 [ +0.000003] RDX: 0000000000000000 RSI: ffffa8df0de6b8b0 RDI: ffffa8df0de6b8b4 [ +0.000004] RBP: ffff9ac64e7a5800 R08: 0000000000000000 R09: 0000000000000a00 [ +0.000003] R10: 00000000000000ff R11: 0000000000000054 R12: ffff9ac6d0700010 [ +0.000003] R13: ffff9ac65d054f00 R14: ffff9ac65d055500 R15: ffff9ac64e7a60a0 [ +0.000…