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BUG: KASAN: slab-out-of-bounds in change_page_attr_set_clr+0x625/0xfc0
Read of size 8 at addr ffff88810d5a8920 by task syz.8.2661/14653

CPU: 1 UID: 0 PID: 14653 Comm: syz.8.2661 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 print_report+0xca/0x240
 kasan_report+0x118/0x150
 change_page_attr_set_clr+0x625/0xfc0
 _set_pages_array+0x145/0x270
 drm_gem_shmem_get_pages_locked+0x2d0/0x440
 drm_gem_shmem_mmap+0x193/0x460
 drm_gem_mmap_obj+0x18a/0x4e0
 drm_gem_mmap+0x384/0x640
 mmap_region+0x1434/0x1c70
 do_mmap+0xc45/0x10d0
 vm_mmap_pgoff+0x2a6/0x4d0
 ksys_mmap_pgoff+0x51f/0x760
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8f4b38ec29
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:00007f8f4c1aa038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f8f4b5d6090 RCX: 00007f8f4b38ec29
RDX: 0000000000000004 RSI: 0000000000004000 RDI: 0000200000001000
RBP: 00007f8f4b411e41 R08: 0000000000000005 R09: 0000000100000000
R10: 0000000000000011 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8f4b5d6128 R14: 00007f8f4b5d6090 R15: 00007ffc78ca9398
 </TASK>

Allocated by task 14653:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kvmalloc_node_noprof+0x5cd/0x910
 drm_gem_get_pages+0x166/0xa20
 drm_gem_shmem_get_pages_locked+0x201/0x440
 drm_gem_shmem_mmap+0x193/0x460
 drm_gem_mmap_obj+0x18a/0x4e0
 drm_gem_mmap+0x384/0x640
 mmap_region+0x1434/0x1c70
 do_mmap+0xc45/0x10d0
 vm_mmap_pgoff+0x2a6/0x4d0
 ksys_mmap_pgoff+0x51f/0x760
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88810d5a8800
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 0 bytes to the right of
 allocated 288-byte region [ffff88810d5a8800, ffff88810d5a8920)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88810d5a9400 pfn:0x10d5a8
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0x57ff00000000040(head|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000040 ffff88801a841c80 0000000000000000 dead000000000001
raw: ffff88810d5a9400 000000008010000f 00000000f5000000 0000000000000000
head: 057ff00000000040 ffff88801a841c80 0000000000000000 dead000000000001
head: ffff88810d5a9400 000000008010000f 00000000f5000000 0000000000000000
head: 057ff00000000002 ffffea0004356a01 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5853, tgid 5853 (syz-executor), ts 66610734047, free_ts 66606289619
 post_alloc_hook+0x240/0x2a0
 get_page_from_freelist+0x21e4/0x22c0
 __alloc_frozen_pages_noprof+0x181/0x370
 alloc_pages_mpol+0x232/0x4a0
 allocate_slab+0x96/0x3a0
 ___slab_alloc+0xe94/0x1920
 __slab_alloc+0x65/0x100
 __kmalloc_noprof+0x471/0x7f0
 fib6_info_alloc+0x30/0xf0
 ip6_route_info_create+0x142/0x860
 ip6_route_add+0x49/0x1b0
 addrconf_add_dev+0x24f/0x340
 inet6_addr_add+0x1a1/0xc00
 inet6_rtm_newaddr+0x93d/0xd20
 rtnetlink_rcv_msg+0x7cf/0xb70
 netlink_rcv_skb+0x208/0x470
page last free pid 5851 tgid 5851 stack trace:
 __free_frozen_pages+0xbc4/0xd30
 __slab_free+0x2e7/0x390
 qlist_free_all+0x97/0x140
 kasan_quarantine_reduce+0x148/0x160
 __kasan_slab_alloc+0x22/0x80
 __kmalloc_cache_noprof+0x36f/0x6f0
 ref_tracker_alloc+0x133/0x460
 qdisc_alloc+0x789/0xaa0
 qdisc_create_dflt+0x8e/0x4e0
 dev_activate+0x378/0x1150
 __dev_open+0x69c/0x880
 __dev_change_flags+0x1ea/0x6d0
 netif_change_flags+0x88/0x1a0
 do_setlink+0xc55/0x41c0
 rtnl_newlink+0x160b/0x1c70
 rtnetlink_rcv_msg+0x7cf/0xb70

Memory state around the buggy address:
 ffff88810d5a8800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88810d5a8880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88810d5a8900: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc
                               ^
 ffff88810d5a8980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88810d5a8a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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