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BUG: KCSAN: data-race in ep_modify / ep_poll_callback

write to 0xffff88815ff13a68 of 4 bytes by task 9851 on cpu 1:
 ep_modify+0x51/0x410 fs/eventpoll.c:1724
 do_epoll_ctl+0x4ee/0x950 fs/eventpoll.c:2349
 __do_sys_epoll_ctl fs/eventpoll.c:2386 [inline]
 __se_sys_epoll_ctl fs/eventpoll.c:2377 [inline]
 __x64_sys_epoll_ctl+0xc6/0xf0 fs/eventpoll.c:2377
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x72/0x7a

read to 0xffff88815ff13a68 of 4 bytes by task 6980 on cpu 0:
 ep_poll_callback+0x4a8/0x5b0 fs/eventpoll.c:1351
 __wake_up_common kernel/sched/wait.c:89 [inline]
 __wake_up_common_lock kernel/sched/wait.c:106 [inline]
 __wake_up+0x65/0xb0 kernel/sched/wait.c:127
 ucma_event_handler+0x335/0x4d0 drivers/infiniband/core/ucma.c:356
 cma_cm_event_handler+0x30/0x1f0 drivers/infiniband/core/cma.c:2152
 addr_handler+0x1da/0x290 drivers/infiniband/core/cma.c:3515
 process_one_req+0x207/0x2f0 drivers/infiniband/core/addr.c:646
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0x465/0x990 kernel/workqueue.c:3335
 worker_thread+0x526/0x730 kernel/workqueue.c:3416
 kthread+0x1d1/0x210 kernel/kthread.c:388
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243

value changed: 0x00000018 -> 0x0000001b

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 6980 Comm: kworker/u8:6 Tainted: G        W          6.9.0-rc2-syzkaller-00080-gc85af715cac0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: ib_addr process_one_req
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