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BUG: KASAN: use-after-free in mas_safe_min lib/maple_tree.c:721 [inline]
BUG: KASAN: use-after-free in mas_next_nentry lib/maple_tree.c:4662 [inline]
BUG: KASAN: use-after-free in mas_next_entry+0x344/0x10f0 lib/maple_tree.c:4757
Read of size 8 at addr ffff8880433f2a20 by task syz-executor.3/31509

CPU: 1 PID: 31509 Comm: syz-executor.3 Not tainted 6.1.0-rc3-syzkaller-00288-gb208b9fbbcba #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_address_description+0x74/0x340 mm/kasan/report.c:284
 print_report+0x107/0x220 mm/kasan/report.c:395
 kasan_report+0x139/0x170 mm/kasan/report.c:495
 mas_safe_min lib/maple_tree.c:721 [inline]
 mas_next_nentry lib/maple_tree.c:4662 [inline]
 mas_next_entry+0x344/0x10f0 lib/maple_tree.c:4757
 userfaultfd_unregister+0x1251/0x13c0 fs/userfaultfd.c:1657
 userfaultfd_ioctl+0x5a1/0x3230 fs/userfaultfd.c:2005
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f1bdb48b5a9
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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1bda7de168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f1bdb5ac120 RCX: 00007f1bdb48b5a9
RDX: 00000000200000c0 RSI: 000000008010aa01 RDI: 0000000000000004
RBP: 00007f1bdb4e67b0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc9b5acf8f R14: 00007f1bda7de300 R15: 0000000000022000
 </TASK>

Allocated by task 31502:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4c/0x70 mm/kasan/common.c:52
 __kasan_slab_alloc+0x65/0x70 mm/kasan/common.c:325
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slab.h:737 [inline]
 kmem_cache_alloc_bulk+0x43d/0x580 mm/slub.c:3854
 mt_alloc_bulk lib/maple_tree.c:157 [inline]
 mas_alloc_nodes+0x386/0x650 lib/maple_tree.c:1256
 mas_node_count_gfp lib/maple_tree.c:1316 [inline]
 mas_preallocate+0x133/0x340 lib/maple_tree.c:5719
 __vma_adjust+0x886/0x2120 mm/mmap.c:716
 __split_vma+0x374/0x4f0
 mprotect_fixup+0x538/0x820 mm/mprotect.c:617
 do_mprotect_pkey+0x7fc/0xb20 mm/mprotect.c:792
 __do_sys_mprotect mm/mprotect.c:819 [inline]
 __se_sys_mprotect mm/mprotect.c:816 [inline]
 __x64_sys_mprotect+0x7c/0x90 mm/mprotect.c:816
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 31509:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4c/0x70 mm/kasan/common.c:52
 kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:511
 ____kasan_slab_free+0xd6/0x120 mm/kasan/common.c:236
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1724 [inline]
 slab_free_freelist_hook+0x12e/0x1a0 mm/slub.c:1750
 slab_free mm/slub.c:3661 [inline]
 kmem_cache_free_bulk+0x137/0x1a0 mm/slub.c:3779
 mt_free_bulk lib/maple_tree.c:163 [inline]
 mas_destroy+0x2d02/0x37b0 lib/maple_tree.c:5769
 mas_store_prealloc+0x35d/0x450 lib/maple_tree.c:5704
 vma_mas_store mm/mmap.c:435 [inline]
 __vma_adjust+0x162e/0x2120 mm/mmap.c:784
 __split_vma+0x374/0x4f0
 userfaultfd_unregister+0x114d/0x13c0 fs/userfaultfd.c:1636
 userfaultfd_ioctl+0x5a1/0x3230 fs/userfaultfd.c:2005
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff8880433f2a00
 which belongs to the cache maple_node of size 256
The buggy address is located 32 bytes inside of
 256-byte region [ffff8880433f2a00, ffff8880433f2b00)

The buggy address belongs to the physical page:
page:ffffea00010cfc80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x433f2
head:ffffea00010cfc80 order:1 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000122 ffff88801204fdc0
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 31502, tgid 31502 (syz-executor.3), ts 1601823825027, free_ts 1561104712716
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x72b/0x7a0 mm/page_alloc.c:4288
 __alloc_pages+0x259/0x560 mm/page_alloc.c:5555
 alloc_slab_page+0x70/0xf0 mm/slub.c:1794
 allocate_slab+0x5e/0x4b0 mm/slub.c:1939
 new_slab mm/slub.c:1992 [inline]
 ___slab_alloc+0x7f4/0xeb0 mm/slub.c:3180
 kmem_cache_alloc_bulk+0x1f1/0x580 mm/slub.c:3830
 mt_alloc_bulk lib/maple_tree.c:157 [inline]
 mas_alloc_nodes+0x386/0x650 lib/maple_tree.c:1256
 mas_node_count_gfp lib/maple_tree.c:1316 [inline]
 mas_preallocate+0x133/0x340 lib/maple_tree.c:5719
 __vma_adjust+0x886/0x2120 mm/mmap.c:716
 __split_vma+0x374/0x4f0
 mprotect_fixup+0x538/0x820 mm/mprotect.c:617
 do_mprotect_pkey+0x7fc/0xb20 mm/mprotect.c:792
 __do_sys_mprotect mm/mprotect.c:819 [inline]
 __se_sys_mprotect mm/mprotect.c:816 [inline]
 __x64_sys_mprotect+0x7c/0x90 mm/mprotect.c:816
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1459 [inline]
 free_pcp_prepare+0x80c/0x8f0 mm/page_alloc.c:1509
 free_unref_page_prepare mm/page_alloc.c:3387 [inline]
 free_unref_page+0x7d/0x630 mm/page_alloc.c:3483
 free_slab mm/slub.c:2031 [inline]
 discard_slab mm/slub.c:2037 [inline]
 __unfreeze_partials+0x1ab/0x200 mm/slub.c:2586
 put_cpu_partial+0x116/0x180 mm/slub.c:2662
 qlist_free_all+0x2b/0x70 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x169/0x180 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x1f/0x70 mm/kasan/common.c:302
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slab.h:737 [inline]
 slab_alloc_node mm/slub.c:3398 [inline]
 kmem_cache_alloc_node+0x1ca/0x340 mm/slub.c:3443
 __alloc_skb+0xd5/0x620 net/core/skbuff.c:497
 alloc_skb include/linux/skbuff.h:1267 [inline]
 nlmsg_new include/net/netlink.h:970 [inline]
 inet6_netconf_notify_devconf+0xf8/0x1b0 net/ipv6/addrconf.c:581
 __addrconf_sysctl_unregister net/ipv6/addrconf.c:7116 [inline]
 addrconf_exit_net+0xcd/0x2c0 net/ipv6/addrconf.c:7233
 ops_exit_list net/core/net_namespace.c:169 [inline]
 setup_net+0x8fd/0xc10 net/core/net_namespace.c:355
 copy_net_ns+0x359/0x5b0 net/core/net_namespace.c:478
 create_new_namespaces+0x4db/0x8e0 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x11e/0x180 kernel/nsproxy.c:226
 ksys_unshare+0x57f/0xb30 kernel/fork.c:3188

Memory state around the buggy address:
 ffff8880433f2900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880433f2980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880433f2a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff8880433f2a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880433f2b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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