syzbot

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BUG: KCSAN: data-race in __tty_check_change / tty_signal_session_leader

write to 0xffff88810b9c57d0 of 8 bytes by task 2505 on cpu 0:
 tty_signal_session_leader+0x10d/0x3c0 drivers/tty/tty_jobctrl.c:204
 __tty_hangup+0x31b/0x610 drivers/tty/tty_io.c:617
 tty_vhangup drivers/tty/tty_io.c:695 [inline]
 tty_ioctl+0x5a7/0x1030 drivers/tty/tty_io.c:2602
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:739
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:739
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810b9c57d0 of 8 bytes by task 17331 on cpu 1:
 __tty_check_change+0x44/0x210 drivers/tty/tty_jobctrl.c:38
 job_control drivers/tty/n_tty.c:2108 [inline]
 n_tty_read+0xe3/0x1250 drivers/tty/n_tty.c:2144
 tty_read+0xe6/0x200 drivers/tty/tty_io.c:866
 vfs_read+0x154/0x5c0 fs/read_write.c:494
 ksys_read+0xce/0x180 fs/read_write.c:634
 __do_sys_read fs/read_write.c:644 [inline]
 __se_sys_read fs/read_write.c:642 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:642
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 17331 Comm: agetty Not tainted 5.11.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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