Affected: Linux

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

drm/amdgpu: Fix a null pointer access when the smc_rreg pointer is NULL

In certain types of chips, such as VEGA20, reading the amdgpu_regs_smc file could result in an abnormal null pointer access when the smc_rreg pointer is NULL. Below are the steps to reproduce this issue and the corresponding exception log:

1. Navigate to the directory: /sys/kernel/debug/dri/0 2. Execute command: cat amdgpu_regs_smc 3. Exception Log:: [4005007.702554] BUG: kernel NULL pointer dereference, address: 0000000000000000 [4005007.702562] #PF: supervisor instruction fetch in kernel mode [4005007.702567] #PF: error_code(0x0010) - not-present page [4005007.702570] PGD 0 P4D 0 [4005007.702576] Oops: 0010 [#1] SMP NOPTI [4005007.702581] CPU: 4 PID: 62563 Comm: cat Tainted: G OE 5.15.0-43-generic #46-Ubunt u [4005007.702590] RIP: 0010:0x0 [4005007.702598] Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. [4005007.702600] RSP: 0018:ffffa82b46d27da0 EFLAGS: 00010206 [4005007.702605] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffa82b46d27e68 [4005007.702609] RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff9940656e0000 [4005007.702612] RBP: ffffa82b46d27dd8 R08: 0000000000000000 R09: ffff994060c07980 [4005007.702615] R10: 0000000000020000 R11: 0000000000000000 R12: 00007f5e06753000 [4005007.702618] R13: ffff9940656e0000 R14: ffffa82b46d27e68 R15: 00007f5e06753000 [4005007.702622] FS: 00007f…