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BUG: KASAN: slab-out-of-bounds in __cpa_addr arch/x86/mm/pat/set_memory.c:309 [inline]
BUG: KASAN: slab-out-of-bounds in __cpa_addr+0x1a2/0x200 arch/x86/mm/pat/set_memory.c:306
Read of size 8 at addr ffff8881123028f8 by task syz.3.17/3606

CPU: 0 UID: 0 PID: 3606 Comm: syz.3.17 Not tainted syzkaller #0 PREEMPT(none) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x5a/0x90 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xcd/0x630 mm/kasan/report.c:482
 kasan_report+0xe0/0x110 mm/kasan/report.c:595
 __cpa_addr arch/x86/mm/pat/set_memory.c:309 [inline]
 __cpa_addr+0x1a2/0x200 arch/x86/mm/pat/set_memory.c:306
 cpa_flush+0x201/0x830 arch/x86/mm/pat/set_memory.c:449
 change_page_attr_set_clr+0x269/0x3b0 arch/x86/mm/pat/set_memory.c:2115
 cpa_set_pages_array arch/x86/mm/pat/set_memory.c:2137 [inline]
 _set_pages_array+0x14f/0x1f0 arch/x86/mm/pat/set_memory.c:2521
 drm_gem_shmem_get_pages_locked+0x299/0x380 drivers/gpu/drm/drm_gem_shmem_helper.c:214
 drm_gem_shmem_mmap drivers/gpu/drm/drm_gem_shmem_helper.c:646 [inline]
 drm_gem_shmem_mmap+0xae/0x470 drivers/gpu/drm/drm_gem_shmem_helper.c:620
 drm_gem_mmap_obj+0x157/0x470 drivers/gpu/drm/drm_gem.c:1139
 drm_gem_mmap+0x33f/0x5d0 drivers/gpu/drm/drm_gem.c:1217
 vfs_mmap include/linux/fs.h:2289 [inline]
 mmap_file mm/internal.h:167 [inline]
 __mmap_new_file_vma mm/vma.c:2413 [inline]
 __mmap_new_vma mm/vma.c:2476 [inline]
 __mmap_region+0x132c/0x21f0 mm/vma.c:2669
 mmap_region+0x11d/0x2f0 mm/vma.c:2739
 do_mmap+0xa6b/0xf60 mm/mmap.c:558
 vm_mmap_pgoff+0x217/0x390 mm/util.c:580
 ksys_mmap_pgoff+0x2e9/0x450 mm/mmap.c:604
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x6d/0x2f0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f35bad8eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f35bbc6b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f35bafe5fa0 RCX: 00007f35bad8eec9
RDX: 0000000000000004 RSI: 0000000000004000 RDI: 0000200000001000
RBP: 00007f35bae11f91 R08: 0000000000000003 R09: 0000000100000000
R10: 0000000000000011 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f35bafe6038 R14: 00007f35bafe5fa0 R15: 00007ffefeb3bfb8
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888112301800 pfn:0x112300
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x100000000000040(head|node=0|zone=2)
page_type: f8(unknown)
raw: 0100000000000040 0000000000000000 dead000000000122 0000000000000000
raw: ffff888112301800 0000000000000000 00000000f8000000 0000000000000000
head: 0100000000000040 0000000000000000 dead000000000122 0000000000000000
head: ffff888112301800 0000000000000000 00000000f8000000 0000000000000000
head: 0100000000000002 ffffea000448c001 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x428c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_COMP), pid 3606, tgid 3605 (syz.3.17), ts 71150223140, free_ts 71137866445
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x168/0x1d0 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x115d/0x4310 mm/page_alloc.c:3858
 __alloc_frozen_pages_noprof+0x20c/0x470 mm/page_alloc.c:5148
 alloc_pages_mpol+0x135/0x400 mm/mempolicy.c:2416
 ___kmalloc_large_node+0xf0/0x130 mm/slub.c:4306
 __kmalloc_large_node_noprof+0x18/0xc0 mm/slub.c:4337
 __do_kmalloc_node mm/slub.c:4353 [inline]
 __kvmalloc_node_noprof+0x4bd/0x660 mm/slub.c:5052
 kvmalloc_array_node_noprof include/linux/slab.h:1065 [inline]
 drm_gem_get_pages+0x114/0x720 drivers/gpu/drm/drm_gem.c:640
 drm_gem_shmem_get_pages_locked+0x15c/0x380 drivers/gpu/drm/drm_gem_shmem_helper.c:200
 drm_gem_shmem_mmap drivers/gpu/drm/drm_gem_shmem_helper.c:646 [inline]
 drm_gem_shmem_mmap+0xae/0x470 drivers/gpu/drm/drm_gem_shmem_helper.c:620
 drm_gem_mmap_obj+0x157/0x470 drivers/gpu/drm/drm_gem.c:1139
 drm_gem_mmap+0x33f/0x5d0 drivers/gpu/drm/drm_gem.c:1217
 vfs_mmap include/linux/fs.h:2289 [inline]
 mmap_file mm/internal.h:167 [inline]
 __mmap_new_file_vma mm/vma.c:2413 [inline]
 __mmap_new_vma mm/vma.c:2476 [inline]
 __mmap_region+0x132c/0x21f0 mm/vma.c:2669
 mmap_region+0x11d/0x2f0 mm/vma.c:2739
 do_mmap+0xa6b/0xf60 mm/mmap.c:558
 vm_mmap_pgoff+0x217/0x390 mm/util.c:580
page last free pid 3606 tgid 3605 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0x801/0x1120 mm/page_alloc.c:2895
 stack_depot_save_flags+0x345/0x8d0 lib/stackdepot.c:727
 kasan_save_stack+0x42/0x60 mm/kasan/common.c:48
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:330 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:356
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4180 [inline]
 slab_alloc_node mm/slub.c:4229 [inline]
 kmem_cache_alloc_noprof+0x1c9/0x3f0 mm/slub.c:4236
 radix_tree_node_alloc.constprop.0+0x185/0x300 lib/radix-tree.c:253
 idr_get_free+0x49e/0x860 lib/radix-tree.c:1506
 idr_alloc_u32+0x148/0x270 lib/idr.c:46
 idr_alloc+0x75/0xc0 lib/idr.c:87
 drm_gem_handle_create_tail+0xf2/0x450 drivers/gpu/drm/drm_gem.c:452
 drm_gem_shmem_create_with_handle drivers/gpu/drm/drm_gem_shmem_helper.c:446 [inline]
 drm_gem_shmem_dumb_create+0x1a1/0x260 drivers/gpu/drm/drm_gem_shmem_helper.c:534
 drm_ioctl_kernel+0x165/0x2e0 drivers/gpu/drm/drm_ioctl.c:796
 drm_ioctl+0x4af/0xb00 drivers/gpu/drm/drm_ioctl.c:893
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:598 [inline]
 __se_sys_ioctl fs/ioctl.c:584 [inline]
 __x64_sys_ioctl+0x134/0x1c0 fs/ioctl.c:584
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x6d/0x2f0 arch/x86/entry/syscall_64.c:94

Memory state around the buggy address:
 ffff888112302780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888112302800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888112302880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fe
                                                                ^
 ffff888112302900: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
 ffff888112302980: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
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