CVE-2023-53352

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

drm/ttm: check null pointer before accessing when swapping

Add a check to avoid null pointer dereference as below:

[ 90.002283] general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI [ 90.002292] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] [ 90.002346] ? excgeneralprotection+0x159/0x240 [ 90.002352] ? asmexcgeneralprotection+0x26/0x30 [ 90.002357] ? ttmboevictswapoutallowable+0x322/0x5e0 [ttm] [ 90.002365] ? ttmboevictswapoutallowable+0x42e/0x5e0 [ttm] [ 90.002373] ttmboswapout+0x134/0x7f0 [ttm] [ 90.002383] ? _pfxttmboswapout+0x10/0x10 [ttm] [ 90.002391] ? lockacquire+0x44d/0x4f0 [ 90.002398] ? ttmdeviceswapout+0xa5/0x260 [ttm] [ 90.002412] ? lockacquired+0x355/0xa00 [ 90.002416] ? dorawspintrylock+0xb6/0x190 [ 90.002421] ? _pfxlockacquired+0x10/0x10 [ 90.002426] ? ttmglobalswapout+0x25/0x210 [ttm] [ 90.002442] ttmdeviceswapout+0x198/0x260 [ttm] [ 90.002456] ? _pfxttmdeviceswapout+0x10/0x10 [ttm] [ 90.002472] ttmglobalswapout+0x75/0x210 [ttm] [ 90.002486] ttmttpopulate+0x187/0x3f0 [ttm] [ 90.002501] ttmbohandlemovemem+0x437/0x590 [ttm] [ 90.002517] ttmbovalidate+0x275/0x430 [ttm] [ 90.002530] ? _pfxttmbovalidate+0x10/0x10 [ttm] [ 90.002544] ? kasansavestack+0x33/0x60 [ 90.002550] ? kasansettrack+0x25/0x30 [ 90.002554] ? _kasankmalloc+0x8f/0xa0 [ 90.002558] ? amdgpugttmgrnew+0x81/0x420 [amdgpu] [ 90.003023] ? ttmresourcealloc+0xf6/0x220 [ttm] [ 90.003038] amdgpubopinrestricted+0x2dd/0x8b0 [amdgpu] [ 90.003210] ? _x64sysioctl+0x131/0x1a0 [ 90.003210] ? dosyscall64+0x60/0x90