syzbot

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BUG: KCSAN: data-race in __percpu_ref_switch_mode / percpu_ref_switch_to_atomic_rcu

write to 0xffff888137120150 of 8 bytes by interrupt on cpu 1:
 percpu_ref_call_confirm_rcu lib/percpu-refcount.c:156 [inline]
 percpu_ref_switch_to_atomic_rcu+0x188/0x360 lib/percpu-refcount.c:205
 rcu_do_batch kernel/rcu/tree.c:2550 [inline]
 rcu_core+0xb95/0xd50 kernel/rcu/tree.c:2785
 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2798
 __do_softirq+0x12c/0x26e kernel/softirq.c:558
 run_ksoftirqd+0x13/0x20 kernel/softirq.c:920
 smpboot_thread_fn+0x22f/0x330 kernel/smpboot.c:164
 kthread+0x262/0x280 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

read to 0xffff888137120150 of 8 bytes by task 8321 on cpu 0:
 __percpu_ref_switch_mode+0xe6/0x3b0 lib/percpu-refcount.c:275
 percpu_ref_resurrect+0xc2/0x110 lib/percpu-refcount.c:473
 io_refs_resurrect fs/io_uring.c:1116 [inline]
 __io_uring_register fs/io_uring.c:10116 [inline]
 __do_sys_io_uring_register+0xd27/0x1ea0 fs/io_uring.c:10248
 __se_sys_io_uring_register fs/io_uring.c:10228 [inline]
 __x64_sys_io_uring_register+0x4f/0x60 fs/io_uring.c:10228
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0xffffffff818acaf0 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8321 Comm: syz-executor.2 Not tainted 5.14.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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