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BUG: KCSAN: data-race in n_tty_receive_char / n_tty_receive_char

write to 0xffffc9000f5f5000 of 8 bytes by task 23128 on cpu 1:
 put_tty_queue drivers/tty/n_tty.c:316 [inline]
 n_tty_receive_char+0x622/0x6c0 drivers/tty/n_tty.c:1416
 n_tty_receive_buf_standard drivers/tty/n_tty.c:1560 [inline]
 __receive_buf drivers/tty/n_tty.c:1577 [inline]
 n_tty_receive_buf_common+0xf2e/0x4e70 drivers/tty/n_tty.c:1674
 n_tty_receive_buf+0x2b/0x40 drivers/tty/n_tty.c:1703
 tiocsti drivers/tty/tty_io.c:2311 [inline]
 tty_ioctl+0x968/0x1120 drivers/tty/tty_io.c:2719
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:866 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:852
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:852
 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

read to 0xffffc9000f5f5000 of 8 bytes by task 24387 on cpu 0:
 put_tty_queue drivers/tty/n_tty.c:315 [inline]
 n_tty_receive_char+0x5fc/0x6c0 drivers/tty/n_tty.c:1416
 n_tty_receive_buf_standard drivers/tty/n_tty.c:1560 [inline]
 __receive_buf drivers/tty/n_tty.c:1577 [inline]
 n_tty_receive_buf_common+0xf2e/0x4e70 drivers/tty/n_tty.c:1674
 n_tty_receive_buf2+0x2e/0x40 drivers/tty/n_tty.c:1709
 tty_ldisc_receive_buf+0x5b/0xf0 drivers/tty/tty_buffer.c:471
 paste_selection+0x215/0x300 drivers/tty/vt/selection.c:408
 tioclinux+0xe5/0x450 drivers/tty/vt/vt.c:3187
 vt_ioctl+0x27f/0x20c0 drivers/tty/vt/vt_ioctl.c:762
 tty_ioctl+0xa24/0x1120 drivers/tty/tty_io.c:2805
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:866 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:852
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:852
 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: 0x0000000000000b5b -> 0x0000000000000b5c

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 24387 Comm: syz-executor.5 Not tainted 5.14.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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==================================================================
BUG: KCSAN: data-race in n_tty_receive_char / n_tty_receive_char

write to 0xffffc9000f5f5018 of 8 bytes by task 23128 on cpu 1:
 add_echo_byte drivers/tty/n_tty.c:842 [inline]
 echo_char drivers/tty/n_tty.c:945 [inline]
 n_tty_receive_char+0x46c/0x6c0 drivers/tty/n_tty.c:1410
 n_tty_receive_buf_standard drivers/tty/n_tty.c:1560 [inline]
 __receive_buf drivers/tty/n_tty.c:1577 [inline]
 n_tty_receive_buf_common+0xf2e/0x4e70 drivers/tty/n_tty.c:1674
 n_tty_receive_buf+0x2b/0x40 drivers/tty/n_tty.c:1703
 tiocsti drivers/tty/tty_io.c:2311 [inline]
 tty_ioctl+0x968/0x1120 drivers/tty/tty_io.c:2719
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:866 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:852
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:852
 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

read to 0xffffc9000f5f5018 of 8 bytes by task 24387 on cpu 0:
 echo_char drivers/tty/n_tty.c:841 [inline]
 n_tty_receive_char+0x4ae/0x6c0 drivers/tty/n_tty.c:1410
 n_tty_receive_buf_standard drivers/tty/n_tty.c:1560 [inline]
 __receive_buf drivers/tty/n_tty.c:1577 [inline]
 n_tty_receive_buf_common+0xf2e/0x4e70 drivers/tty/n_tty.c:1674
 n_tty_receive_buf2+0x2e/0x40 drivers/tty/n_tty.c:1709
 tty_ldisc_receive_buf+0x5b/0xf0 drivers/tty/tty_buffer.c:471
 paste_selection+0x215/0x300 drivers/tty/vt/selection.c:408
 tioclinux+0xe5/0x450 drivers/tty/vt/vt.c:3187
 vt_ioctl+0x27f/0x20c0 drivers/tty/vt/vt_ioctl.c:762
 tty_ioctl+0xa24/0x1120 drivers/tty/tty_io.c:2805
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:866 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:852
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:852
 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: 0x0000000000000bbf -> 0x0000000000000bc1

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 24387 Comm: syz-executor.5 Not tainted 5.14.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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