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BUG: KASAN: slab-out-of-bounds in watch_queue_set_filter drivers/misc/watch_queue.c:516 [inline]
BUG: KASAN: slab-out-of-bounds in watch_queue_ioctl+0x15ed/0x16e0 drivers/misc/watch_queue.c:555
Write of size 4 at addr ffff8880a2c63b9c by task syz-executor.3/24121

CPU: 0 PID: 24121 Comm: syz-executor.3 Not tainted 5.5.0-rc5-next-20200110-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+0x197/0x210 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
 __kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:641
 __asan_report_store4_noabort+0x17/0x20 mm/kasan/generic_report.c:139
 watch_queue_set_filter drivers/misc/watch_queue.c:516 [inline]
 watch_queue_ioctl+0x15ed/0x16e0 drivers/misc/watch_queue.c:555
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x123/0x180 fs/ioctl.c:760
 __do_sys_ioctl fs/ioctl.c:769 [inline]
 __se_sys_ioctl fs/ioctl.c:767 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:767
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45af49
Code: ad b6 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f14325fcc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045af49
RDX: 0000000020000180 RSI: 0000000000005761 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f14325fd6d4
R13: 00000000004d0d88 R14: 00000000004da9f8 R15: 00000000ffffffff

Allocated by task 24121:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:515 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:488
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:529
 __do_kmalloc mm/slab.c:3656 [inline]
 __kmalloc+0x163/0x770 mm/slab.c:3665
 kmalloc include/linux/slab.h:560 [inline]
 kzalloc include/linux/slab.h:669 [inline]
 watch_queue_set_filter drivers/misc/watch_queue.c:505 [inline]
 watch_queue_ioctl+0xf57/0x16e0 drivers/misc/watch_queue.c:555
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x123/0x180 fs/ioctl.c:760
 __do_sys_ioctl fs/ioctl.c:769 [inline]
 __se_sys_ioctl fs/ioctl.c:767 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:767
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 23519:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:337 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:476
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:485
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x2c0 mm/slab.c:3757
 kvfree+0x4a/0x60 mm/util.c:603
 __vunmap+0x6ba/0x950 mm/vmalloc.c:2319
 __vfree+0x41/0xd0 mm/vmalloc.c:2363
 vfree+0x5f/0x90 mm/vmalloc.c:2393
 bpf_check+0xd64/0xad7e kernel/bpf/verifier.c:9949
 bpf_prog_load+0xeab/0x17f0 kernel/bpf/syscall.c:1859
 __do_sys_bpf+0x10c9/0x3710 kernel/bpf/syscall.c:3096
 __se_sys_bpf kernel/bpf/syscall.c:3055 [inline]
 __x64_sys_bpf+0x73/0xb0 kernel/bpf/syscall.c:3055
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880a2c63b80
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 28 bytes inside of
 32-byte region [ffff8880a2c63b80, ffff8880a2c63ba0)
The buggy address belongs to the page:
page:ffffea00028b18c0 refcount:1 mapcount:0 mapping:ffff8880aa4001c0 index:0xffff8880a2c63fc1
raw: 00fffe0000000200 ffffea000294c908 ffffea000254ce08 ffff8880aa4001c0
raw: ffff8880a2c63fc1 ffff8880a2c63000 000000010000003b 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a2c63a80: fb fb fb fb fc fc fc fc 00 00 00 fc fc fc fc fc
 ffff8880a2c63b00: fb fb fb fb fc fc fc fc 00 00 00 fc fc fc fc fc
>ffff8880a2c63b80: 00 00 00 fc fc fc fc fc fb fb fb fb fc fc fc fc
                            ^
 ffff8880a2c63c00: 00 00 fc fc fc fc fc fc 00 00 00 fc fc fc fc fc
 ffff8880a2c63c80: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
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