syzbot

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BUG: KCSAN: data-race in dput / step_into

write to 0xffff88811d44d180 of 4 bytes by task 27810 on cpu 0:
 retain_dentry fs/dcache.c:655 [inline]
 dput+0x409/0x700 fs/dcache.c:854
 __fput+0x2b1/0x500 fs/file_table.c:293
 ____fput+0x1b/0x30 fs/file_table.c:313
 task_work_run+0xba/0x120 kernel/task_work.c:123
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2ae/0x2c0 arch/x86/entry/common.c:165
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
 do_syscall_64+0x38b/0x3b0 arch/x86/entry/common.c:305
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88811d44d180 of 4 bytes by task 27811 on cpu 1:
 d_is_symlink include/linux/dcache.h:419 [inline]
 step_into+0xea/0x1090 fs/namei.c:1680
 walk_component+0xde/0x390 fs/namei.c:1852
 lookup_last fs/namei.c:2295 [inline]
 path_lookupat.isra.0+0x119/0x350 fs/namei.c:2319
 filename_lookup+0x145/0x2c0 fs/namei.c:2352
 kern_path+0x3b/0x50 fs/namei.c:2439
 create_local_trace_uprobe+0x4d/0x2a0 kernel/trace/trace_uprobe.c:1575
 perf_uprobe_init+0xee/0x1a0 kernel/trace/trace_event_perf.c:323
 perf_uprobe_event_init+0xc9/0x120 kernel/events/core.c:9471
 perf_try_init_event+0xba/0x310 kernel/events/core.c:10772
 perf_init_event kernel/events/core.c:10824 [inline]
 perf_event_alloc.part.0+0x8f3/0x1ec0 kernel/events/core.c:11100
 perf_event_alloc kernel/events/core.c:11479 [inline]
 __do_sys_perf_event_open+0x62e/0x1c80 kernel/events/core.c:11595
 __se_sys_perf_event_open kernel/events/core.c:11469 [inline]
 __x64_sys_perf_event_open+0x6b/0x80 kernel/events/core.c:11469
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 27811 Comm: syz-executor.0 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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