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BUG: KASAN: use-after-free in madvise_willneed mm/madvise.c:293 [inline]
BUG: KASAN: use-after-free in madvise_vma mm/madvise.c:942 [inline]
BUG: KASAN: use-after-free in do_madvise+0x11f1/0x2130 mm/madvise.c:1145
Read of size 8 at addr ffff88808992da90 by task syz-executor.0/5134

CPU: 1 PID: 5134 Comm: syz-executor.0 Not tainted 5.9.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1f0/0x31e lib/dump_stack.c:118
 print_address_description+0x66/0x620 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report+0x132/0x1d0 mm/kasan/report.c:530
 madvise_willneed mm/madvise.c:293 [inline]
 madvise_vma mm/madvise.c:942 [inline]
 do_madvise+0x11f1/0x2130 mm/madvise.c:1145
 __do_sys_madvise mm/madvise.c:1171 [inline]
 __se_sys_madvise mm/madvise.c:1169 [inline]
 __x64_sys_madvise+0x76/0x80 mm/madvise.c:1169
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45d4d9
Code: 5d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f91704cec78 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 0000000000020800 RCX: 000000000045d4d9
RDX: 0000000000000003 RSI: 0000000000600003 RDI: 0000000020000000
RBP: 000000000118d020 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cfec
R13: 00007ffc189f0dbf R14: 00007f91704cf9c0 R15: 000000000118cfec

Allocated by task 5130:
 kasan_save_stack mm/kasan/common.c:48 [inline]
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc+0x100/0x130 mm/kasan/common.c:461
 slab_post_alloc_hook+0x3e/0x290 mm/slab.h:518
 slab_alloc mm/slab.c:3312 [inline]
 kmem_cache_alloc+0x1d2/0x2d0 mm/slab.c:3482
 vm_area_alloc+0x20/0xf0 kernel/fork.c:347
 mmap_region+0x8a3/0x1bc0 mm/mmap.c:1743
 do_mmap+0xaa8/0x10e0 mm/mmap.c:1545
 vm_mmap_pgoff+0x12c/0x1c0 mm/util.c:506
 ksys_mmap_pgoff+0x358/0x4c0 mm/mmap.c:1596
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 5130:
 kasan_save_stack mm/kasan/common.c:48 [inline]
 kasan_set_track+0x3d/0x70 mm/kasan/common.c:56
 kasan_set_free_info+0x17/0x30 mm/kasan/generic.c:355
 __kasan_slab_free+0xdd/0x110 mm/kasan/common.c:422
 __cache_free mm/slab.c:3418 [inline]
 kmem_cache_free+0x79/0xf0 mm/slab.c:3693
 remove_vma mm/mmap.c:184 [inline]
 remove_vma_list mm/mmap.c:2613 [inline]
 __do_munmap+0x1148/0x1530 mm/mmap.c:2869
 do_munmap mm/mmap.c:2877 [inline]
 mmap_region+0x6dc/0x1bc0 mm/mmap.c:1716
 do_mmap+0xaa8/0x10e0 mm/mmap.c:1545
 vm_mmap_pgoff+0x12c/0x1c0 mm/util.c:506
 ksys_mmap_pgoff+0x358/0x4c0 mm/mmap.c:1596
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88808992da90
 which belongs to the cache vm_area_struct of size 200
The buggy address is located 0 bytes inside of
 200-byte region [ffff88808992da90, ffff88808992db58)
The buggy address belongs to the page:
page:000000005705f591 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x8992d
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00027aef88 ffffea0002a5c908 ffff8880aa46f600
raw: 0000000000000000 ffff88808992d040 000000010000000f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808992d980: fc fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808992da00: fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc
>ffff88808992da80: fc fc fa fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff88808992db00: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc
 ffff88808992db80: fc fc fc fb fb fb fb fb fb fb fb fb fb fb fb fb
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