CVE-2026-68239

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> drm/ttm: Account for NULL and handle pages in ttm_pool_backup<br /> <br /> Pages in ttm_pool_backup can be NULL or backup handles<br /> (ttm_backup_page_ptr_is_handle()), neither of which can be passed to<br /> set_pages_array_wb() or freed. Add a dedicated WB pass before the<br /> dma/purge loop that walks allocations using the same i += num_pages<br /> stride, skipping NULL and handle entries, and calls set_pages_array_wb()<br /> once per contiguous run of real pages. Apply the same NULL/handle guard<br /> to the dma/purge loop.<br /> <br /> Fixes the following oops:<br /> <br /> Oops: general protection fault, kernel NULL pointer dereference 0x0: 0000 [#1] SMP NOPTI<br /> RIP: 0010:__cpa_process_fault+0xf8/0x770<br /> RSP: 0018:ffffc90000a87718 EFLAGS: 00010287<br /> RAX: 0000000000000000 RBX: ffffc90000a87868 RCX: 0000000000000000<br /> RDX: 0000000000001000 RSI: 0005088000000000 RDI: ffffffff827c5f34<br /> RBP: 0005088000000000 R08: ffffc90000a877cb R09: ffffc90000a877d0<br /> R10: 0000000000000000 R11: 000000000000001b R12: 000ffffffffff000<br /> R13: ffffc90000a87868 R14: ffffc90000a87868 R15: ffff88815b882ae0<br /> FS: 0000000000000000(0000) GS:ffff8884ec840000(0000) knlGS:0000000000000000<br /> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033<br /> CR2: 00007f930b844000 CR3: 000000000262e003 CR4: 0000000008f70ef0<br /> PKRU: 55555554<br /> Call Trace:<br /> <br /> __change_page_attr_set_clr+0x989/0xe90<br /> ? __purge_vmap_area_lazy+0x6c/0x3a0<br /> ? _vm_unmap_aliases+0x250/0x2a0<br /> set_pages_array_wb+0x7f/0x120<br /> ttm_pool_backup+0x4c9/0x5b0 [ttm]<br /> ? dma_resv_wait_timeout+0x3b/0xf0<br /> ttm_tt_backup+0x32/0x60 [ttm]<br /> ttm_bo_shrink+0x66/0x110 [ttm]<br /> xe_bo_shrink_purge+0x12b/0x1b0 [xe]<br /> xe_bo_shrink+0xbb/0x270 [xe]<br /> __xe_shrinker_walk+0xf7/0x160 [xe]<br /> xe_shrinker_walk+0x9d/0xc0 [xe]<br /> xe_shrinker_scan+0x11f/0x210 [xe]<br /> do_shrink_slab+0x13b/0x270<br /> shrink_slab+0xf1/0x400<br /> shrink_node+0x352/0x8a0<br /> balance_pgdat+0x32c/0x700<br /> kswapd+0x205/0x2f0<br /> ? __pfx_autoremove_wake_function+0x10/0x10<br /> ? __pfx_kswapd+0x10/0x10<br /> kthread+0xd1/0x110<br /> ? __pfx_kthread+0x10/0x10<br /> ret_from_fork+0x1b1/0x200<br /> ? __pfx_kthread+0x10/0x10<br /> ret_from_fork_asm+0x1a/0x30<br />