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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+0x9e4/0xab0 lib/maple_tree.c:4662
Read of size 8 at addr ffff88807cfff620 by task syz-executor.2/24672

CPU: 1 PID: 24672 Comm: syz-executor.2 Not tainted 6.0.0-rc6-next-20220923-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:284 [inline]
 print_report+0x15e/0x45d mm/kasan/report.c:395
 kasan_report+0xbb/0x1f0 mm/kasan/report.c:495
 mas_safe_min lib/maple_tree.c:721 [inline]
 mas_next_nentry+0x9e4/0xab0 lib/maple_tree.c:4662
 mas_next_entry lib/maple_tree.c:4757 [inline]
 mas_next+0x1fb/0xc90 lib/maple_tree.c:5868
 userfaultfd_unregister fs/userfaultfd.c:1657 [inline]
 userfaultfd_ioctl+0x33c3/0x4200 fs/userfaultfd.c:2005
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f2e8868a5a9
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:00007f2e89889168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f2e887abf80 RCX: 00007f2e8868a5a9
RDX: 0000000020000000 RSI: 000000008010aa01 RDI: 0000000000000003
RBP: 00007f2e886e5580 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc6f7e7a2f R14: 00007f2e89889300 R15: 0000000000022000
 </TASK>

Allocated by task 3645:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:45
 kasan_set_track+0x21/0x30 mm/kasan/common.c:52
 __kasan_slab_alloc+0x7e/0x80 mm/kasan/common.c:325
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slab.h:754 [inline]
 kmem_cache_alloc_bulk+0x3f8/0x860 mm/slub.c:3792
 mt_alloc_bulk lib/maple_tree.c:157 [inline]
 mas_alloc_nodes+0x309/0x810 lib/maple_tree.c:1256
 mas_node_count_gfp+0x106/0x140 lib/maple_tree.c:1316
 mas_node_count lib/maple_tree.c:1330 [inline]
 mas_expected_entries+0x113/0x200 lib/maple_tree.c:5822
 dup_mmap+0x4ca/0x10b0 kernel/fork.c:616
 dup_mm+0x91/0x370 kernel/fork.c:1529
 copy_mm kernel/fork.c:1578 [inline]
 copy_process+0x3bc6/0x71b0 kernel/fork.c:2256
 kernel_clone+0xe7/0x980 kernel/fork.c:2676
 __do_sys_clone+0xba/0x100 kernel/fork.c:2817
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 24672:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:45
 kasan_set_track+0x21/0x30 mm/kasan/common.c:52
 kasan_save_free_info+0x2a/0x40 mm/kasan/generic.c:511
 ____kasan_slab_free mm/kasan/common.c:236 [inline]
 ____kasan_slab_free+0x160/0x1c0 mm/kasan/common.c:200
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1669 [inline]
 slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1695
 slab_free mm/slub.c:3599 [inline]
 kmem_cache_free_bulk.part.0+0x205/0x780 mm/slub.c:3717
 mt_free_bulk lib/maple_tree.c:163 [inline]
 mas_destroy+0x394/0x5c0 lib/maple_tree.c:5769
 mas_store_prealloc+0xec/0x150 lib/maple_tree.c:5704
 __vma_adjust+0xc47/0x1a70 mm/mmap.c:783
 vma_adjust include/linux/mm.h:2664 [inline]
 __split_vma+0x4b0/0x5c0 mm/mmap.c:2236
 split_vma+0x9f/0xe0 mm/mmap.c:2272
 userfaultfd_unregister fs/userfaultfd.c:1636 [inline]
 userfaultfd_ioctl+0x3855/0x4200 fs/userfaultfd.c:2005
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff88807cfff600
 which belongs to the cache maple_node of size 256
The buggy address is located 32 bytes inside of
 256-byte region [ffff88807cfff600, ffff88807cfff700)

The buggy address belongs to the physical page:
page:ffffea0001f3ff80 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffffea0001f77c80 pfn:0x7cffe
head:ffffea0001f3ff80 order:1 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffff88801184fdc0 dead000000100010 0000000000000000
raw: ffffea0001f77c80 dead000000000002 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 0x152800(GFP_NOWAIT|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 3643, tgid 3643 (syz-executor.1), ts 888808132549, free_ts 886794789134
 prep_new_page mm/page_alloc.c:2538 [inline]
 get_page_from_freelist+0x1092/0x2d20 mm/page_alloc.c:4287
 __alloc_pages+0x1c7/0x5a0 mm/page_alloc.c:5546
 alloc_pages+0x1a6/0x270 mm/mempolicy.c:2280
 alloc_slab_page mm/slub.c:1739 [inline]
 allocate_slab+0x213/0x300 mm/slub.c:1884
 new_slab mm/slub.c:1937 [inline]
 ___slab_alloc+0xac1/0x1430 mm/slub.c:3119
 kmem_cache_alloc_bulk+0x291/0x860 mm/slub.c:3768
 mt_alloc_bulk lib/maple_tree.c:157 [inline]
 mas_alloc_nodes+0x309/0x810 lib/maple_tree.c:1256
 mas_node_count_gfp+0x106/0x140 lib/maple_tree.c:1316
 mas_node_count lib/maple_tree.c:1330 [inline]
 mas_expected_entries+0x113/0x200 lib/maple_tree.c:5822
 dup_mmap+0x4ca/0x10b0 kernel/fork.c:616
 dup_mm+0x91/0x370 kernel/fork.c:1529
 copy_mm kernel/fork.c:1578 [inline]
 copy_process+0x3bc6/0x71b0 kernel/fork.c:2256
 kernel_clone+0xe7/0x980 kernel/fork.c:2676
 __do_sys_clone+0xba/0x100 kernel/fork.c:2817
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 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:1458 [inline]
 free_pcp_prepare+0x65c/0xd90 mm/page_alloc.c:1508
 free_unref_page_prepare mm/page_alloc.c:3386 [inline]
 free_unref_page+0x19/0x4d0 mm/page_alloc.c:3482
 __unfreeze_partials+0x17c/0x1a0 mm/slub.c:2532
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x62/0x80 mm/kasan/common.c:302
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slab.h:754 [inline]
 slab_alloc_node mm/slub.c:3336 [inline]
 slab_alloc mm/slub.c:3344 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3351 [inline]
 kmem_cache_alloc+0x2b7/0x3d0 mm/slub.c:3360
 getname_flags.part.0+0x50/0x4f0 fs/namei.c:139
 getname_flags include/linux/audit.h:320 [inline]
 getname fs/namei.c:218 [inline]
 __do_sys_unlink fs/namei.c:4345 [inline]
 __se_sys_unlink fs/namei.c:4343 [inline]
 __x64_sys_unlink+0xb1/0x110 fs/namei.c:4343
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
 ffff88807cfff500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88807cfff580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88807cfff600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff88807cfff680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807cfff700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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