WARNING in delete_node (2)

[syzbot <syzbot+6324a37c93030377021f@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    de2e69cf Add linux-next specific files for 20200721
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13645cef100000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a18f913b3827a63a
dashboard link: https://syzkaller.appspot.com/bug?extid=6324a37c93030377021f
compiler:       gcc (GCC) 10.1.0-syz 20200507

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6324a37c93030377021f@syzkaller.appspotmail.com

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WARNING: CPU: 1 PID: 17410 at lib/radix-tree.c:571 delete_node+0x1e7/0x8a0 lib/radix-tree.c:571
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 17410 Comm: syz-executor.5 Not tainted 5.8.0-rc6-next-20200721-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+0x18f/0x20d lib/dump_stack.c:118
 panic+0x2e3/0x75c kernel/panic.c:231
 __warn.cold+0x20/0x45 kernel/panic.c:600
 report_bug+0x1bd/0x210 lib/bug.c:198
 handle_bug+0x38/0x90 arch/x86/kernel/traps.c:234
 exc_invalid_op+0x14/0x40 arch/x86/kernel/traps.c:254
 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:545
RIP: 0010:delete_node+0x1e7/0x8a0 lib/radix-tree.c:571
Code: e2 48 c7 43 48 00 00 00 00 48 c1 ea 03 42 80 3c 2a 00 0f 85 bb 05 00 00 48 8b 55 18 49 39 d4 0f 84 8b 03 00 00 e8 e9 6c c3 fd <0f> 0b 48 c7 c6 d0 a6 b0 83 4c 89 e7 e8 b8 d7 b0 fd 4d 85 f6 0f 85
RSP: 0018:ffffc900078afd08 EFLAGS: 00010246
RAX: 0000000000040000 RBX: ffffffff89d2df00 RCX: ffffc90013fcd000
RDX: 0000000000040000 RSI: ffffffff83b0d377 RDI: ffff8880a9c90842
RBP: ffff88808a91ab40 R08: 0000000000000000 R09: ffff8880a9c90a6f
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88808a91ab58
R13: dffffc0000000000 R14: ffff8880a9c90840 R15: 000000000000000a
 __radix_tree_delete+0x190/0x370 lib/radix-tree.c:1378
 radix_tree_delete_item+0xe7/0x230 lib/radix-tree.c:1429
 mnt_free_id fs/namespace.c:131 [inline]
 cleanup_mnt+0x3db/0x500 fs/namespace.c:1140
 task_work_run+0xdd/0x190 kernel/task_work.c:135
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop arch/x86/entry/common.c:239 [inline]
 __prepare_exit_to_usermode+0x199/0x1c0 arch/x86/entry/common.c:269
 do_syscall_64+0x6c/0xe0 arch/x86/entry/common.c:393
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c1f9
Code: Bad RIP value.
RSP: 002b:00007fe40341bc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffe4 RBX: 000000000001fa40 RCX: 000000000045c1f9
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000020000080
RBP: 000000000078bf50 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000005010 R11: 0000000000000246 R12: 000000000078bf0c
R13: 00007ffc20fd1c9f R14: 00007fe40341c9c0 R15: 000000000078bf0c
Kernel Offset: disabled
Rebooting in 86400 seconds..


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