syzbot

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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_flush arch/x86/mm/pat/set_memory.c:449 [inline]
BUG: KASAN: slab-out-of-bounds in change_page_attr_set_clr+0x625/0xfc0 arch/x86/mm/pat/set_memory.c:2115
Read of size 8 at addr ffff8880266dfcf8 by task syz.0.991/9589

CPU: 0 UID: 0 PID: 9589 Comm: syz.0.991 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 __cpa_addr arch/x86/mm/pat/set_memory.c:309 [inline]
 cpa_flush arch/x86/mm/pat/set_memory.c:449 [inline]
 change_page_attr_set_clr+0x625/0xfc0 arch/x86/mm/pat/set_memory.c:2115
 cpa_set_pages_array arch/x86/mm/pat/set_memory.c:2137 [inline]
 _set_pages_array+0x145/0x270 arch/x86/mm/pat/set_memory.c:2521
 drm_gem_shmem_get_pages_locked+0x2d0/0x440 drivers/gpu/drm/drm_gem_shmem_helper.c:214
 drm_gem_shmem_mmap+0x193/0x460 drivers/gpu/drm/drm_gem_shmem_helper.c:646
 drm_gem_mmap_obj+0x18a/0x4e0 drivers/gpu/drm/drm_gem.c:1167
 drm_gem_mmap+0x384/0x640 drivers/gpu/drm/drm_gem.c:1245
 vfs_mmap include/linux/fs.h:2405 [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 mm/vma.c:2670 [inline]
 mmap_region+0x18b4/0x2110 mm/vma.c:2740
 do_mmap+0xc45/0x10d0 mm/mmap.c:558
 vm_mmap_pgoff+0x2a6/0x4d0 mm/util.c:581
 ksys_mmap_pgoff+0x51f/0x760 mm/mmap.c:604
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1a5d18efc9
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:00007f1a5dfb8038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f1a5d3e6180 RCX: 00007f1a5d18efc9
RDX: 0000000000000004 RSI: 0000000000004000 RDI: 0000200000001000
RBP: 00007f1a5d211f91 R08: 000000000000000b R09: 0000000100000000
R10: 0000000000000011 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1a5d3e6218 R14: 00007f1a5d3e6180 R15: 00007f1a5d50fa28
 </TASK>

Allocated by task 9589:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417
 kasan_kmalloc include/linux/kasan.h:262 [inline]
 __do_kmalloc_node mm/slub.c:5634 [inline]
 __kvmalloc_node_noprof+0x5cd/0x910 mm/slub.c:7089
 kvmalloc_array_node_noprof include/linux/slab.h:1122 [inline]
 drm_gem_get_pages+0x166/0xa20 drivers/gpu/drm/drm_gem.c:647
 drm_gem_shmem_get_pages_locked+0x201/0x440 drivers/gpu/drm/drm_gem_shmem_helper.c:200
 drm_gem_shmem_mmap+0x193/0x460 drivers/gpu/drm/drm_gem_shmem_helper.c:646
 drm_gem_mmap_obj+0x18a/0x4e0 drivers/gpu/drm/drm_gem.c:1167
 drm_gem_mmap+0x384/0x640 drivers/gpu/drm/drm_gem.c:1245
 vfs_mmap include/linux/fs.h:2405 [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 mm/vma.c:2670 [inline]
 mmap_region+0x18b4/0x2110 mm/vma.c:2740
 do_mmap+0xc45/0x10d0 mm/mmap.c:558
 vm_mmap_pgoff+0x2a6/0x4d0 mm/util.c:581
 ksys_mmap_pgoff+0x51f/0x760 mm/mmap.c:604
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8880266dfc00
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 0 bytes to the right of
 allocated 248-byte region [ffff8880266dfc00, ffff8880266dfcf8)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x266de
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88813ffa6b40 ffffea0001ab9d80 dead000000000002
raw: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813ffa6b40 ffffea0001ab9d80 dead000000000002
head: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000
head: 00fff00000000001 ffffea000099b781 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5842, tgid 5842 (syz-executor), ts 72753091396, free_ts 72717720412
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850
 prep_new_page mm/page_alloc.c:1858 [inline]
 get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3884
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:3046 [inline]
 allocate_slab+0x96/0x3a0 mm/slub.c:3219
 new_slab mm/slub.c:3273 [inline]
 ___slab_alloc+0xe94/0x18a0 mm/slub.c:4643
 __slab_alloc+0x65/0x100 mm/slub.c:4762
 __slab_alloc_node mm/slub.c:4838 [inline]
 slab_alloc_node mm/slub.c:5260 [inline]
 __do_kmalloc_node mm/slub.c:5633 [inline]
 __kmalloc_noprof+0x471/0x7f0 mm/slub.c:5646
 kmalloc_noprof include/linux/slab.h:961 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 fib_create_info+0x172d/0x3210 net/ipv4/fib_semantics.c:1402
 fib_table_insert+0xc6/0x1b50 net/ipv4/fib_trie.c:1212
 fib_magic+0x2c4/0x390 net/ipv4/fib_frontend.c:1134
 fib_add_ifaddr+0x144/0x5f0 net/ipv4/fib_frontend.c:1156
 fib_inetaddr_event+0x12e/0x190 net/ipv4/fib_frontend.c:1470
 notifier_call_chain+0x1b6/0x3e0 kernel/notifier.c:85
 blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:380
 __inet_insert_ifa+0xa13/0xbf0 net/ipv4/devinet.c:566
page last free pid 5842 tgid 5842 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1394 [inline]
 __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2906
 rcu_do_batch kernel/rcu/tree.c:2605 [inline]
 rcu_core+0xcab/0x1770 kernel/rcu/tree.c:2861
 handle_softirqs+0x286/0x870 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697

Memory state around the buggy address:
 ffff8880266dfb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880266dfc00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880266dfc80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc
                                                                ^
 ffff8880266dfd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880266dfd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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