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BUG: KCSAN: data-race in console_unlock / console_unlock

write to 0xffffffff8417c940 of 8 bytes by task 32751 on cpu 0:
 console_unlock+0x570/0xb30 kernel/printk/printk.c:2632
 vprintk_emit+0x125/0x3d0 kernel/printk/printk.c:2174
 vprintk_default+0x22/0x30 kernel/printk/printk.c:2185
 vprintk+0x15a/0x170 kernel/printk/printk_safe.c:392
 printk+0x62/0x87 kernel/printk/printk.c:2216
 printk_stack_address arch/x86/kernel/dumpstack.c:72 [inline]
 show_trace_log_lvl+0x587/0x600 arch/x86/kernel/dumpstack.c:282
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xb7/0x103 lib/dump_stack.c:105
 dump_stack+0x11/0x1a lib/dump_stack.c:112
 fail_dump lib/fault-inject.c:52 [inline]
 should_fail+0x23c/0x250 lib/fault-inject.c:146
 should_fail_usercopy+0x16/0x20 lib/fault-inject-usercopy.c:37
 copyout lib/iov_iter.c:153 [inline]
 _copy_to_iter+0x131/0xbc0 lib/iov_iter.c:620
 copy_to_iter include/linux/uio.h:139 [inline]
 seq_read_iter+0x7f2/0x930 fs/seq_file.c:281
 seq_read+0x221/0x260 fs/seq_file.c:162
 pde_read fs/proc/inode.c:311 [inline]
 proc_reg_read+0x119/0x1b0 fs/proc/inode.c:323
 do_loop_readv_writev fs/read_write.c:761 [inline]
 do_iter_read+0x2be/0x4b0 fs/read_write.c:803
 vfs_readv fs/read_write.c:921 [inline]
 do_preadv+0x13b/0x230 fs/read_write.c:1013
 __do_sys_preadv fs/read_write.c:1063 [inline]
 __se_sys_preadv fs/read_write.c:1058 [inline]
 __x64_sys_preadv+0x54/0x60 fs/read_write.c:1058
 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 0xffffffff8417c940 of 8 bytes by task 32714 on cpu 1:
 console_unlock+0x9f5/0xb30 kernel/printk/printk.c:2667
 do_con_write+0x5d29/0x5d90 drivers/tty/vt/vt.c:270
 con_write+0x20/0x40 drivers/tty/vt/vt.c:3255
 process_output_block drivers/tty/n_tty.c:592 [inline]
 n_tty_write+0x77b/0xaf0 drivers/tty/n_tty.c:2288
 do_tty_write drivers/tty/tty_io.c:1038 [inline]
 file_tty_write+0x409/0x660 drivers/tty/tty_io.c:1110
 tty_write+0x24/0x30 drivers/tty/tty_io.c:1131
 call_write_iter include/linux/fs.h:2114 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x69d/0x770 fs/read_write.c:605
 ksys_write+0xce/0x180 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write fs/read_write.c:667 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:667
 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: 0x0000000000001727 -> 0x0000000000001728

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 32714 Comm: syz-executor.0 Not tainted 5.14.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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