syzbot

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BUG: KCSAN: data-race in do_sys_poll / pollwake

write to 0xffffc90001187bd0 of 4 bytes by task 3055 on cpu 1:
 __pollwake fs/select.c:195 [inline]
 pollwake+0xbe/0x110 fs/select.c:215
 __wake_up_common kernel/sched/wait.c:89 [inline]
 __wake_up_common_lock kernel/sched/wait.c:106 [inline]
 __wake_up_sync_key+0x51/0x80 kernel/sched/wait.c:173
 sock_def_readable+0x70/0x1b0 net/core/sock.c:3448
 unix_dgram_sendmsg+0xc76/0xff0 net/unix/af_unix.c:2167
 sock_sendmsg_nosec net/socket.c:711 [inline]
 __sock_sendmsg+0x140/0x180 net/socket.c:726
 sock_write_iter+0x15e/0x1a0 net/socket.c:1147
 do_iter_readv_writev+0x394/0x450
 vfs_writev+0x2d4/0x880 fs/read_write.c:1050
 do_writev+0xf4/0x220 fs/read_write.c:1096
 __do_sys_writev fs/read_write.c:1164 [inline]
 __se_sys_writev fs/read_write.c:1161 [inline]
 __x64_sys_writev+0x45/0x50 fs/read_write.c:1161
 x64_sys_call+0x1fab/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:21
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffc90001187bd0 of 4 bytes by task 3056 on cpu 0:
 poll_schedule_timeout fs/select.c:240 [inline]
 do_poll fs/select.c:958 [inline]
 do_sys_poll+0x95d/0xc20 fs/select.c:1009
 __do_sys_ppoll fs/select.c:1115 [inline]
 __se_sys_ppoll+0x1af/0x1f0 fs/select.c:1095
 __x64_sys_ppoll+0x67/0x80 fs/select.c:1095
 x64_sys_call+0x2acc/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:272
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3056 Comm: dhcpcd Not tainted 6.12.0-syzkaller-01892-g8f7c8b88bda4 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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