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BUG: KCSAN: data-race in console_unlock / console_unlock

write to 0xffffffff8417d940 of 8 bytes by task 29752 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
 disk_unlock_native_capacity block/partitions/core.c:537 [inline]
 blk_add_partitions block/partitions/core.c:647 [inline]
 bdev_disk_changed+0xd98/0xea0 block/partitions/core.c:697
 loop_reread_partitions drivers/block/loop.c:693 [inline]
 loop_set_status+0x4dc/0x5a0 drivers/block/loop.c:1576
 lo_ioctl+0x7af/0x1340 drivers/block/loop.c:1686
 blkdev_ioctl+0x1d0/0x3c0 block/ioctl.c:585
 block_ioctl+0x6d/0x80 fs/block_dev.c:1604
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:1069 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:1055
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:1055
 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 0xffffffff8417d940 of 8 bytes by task 29753 on cpu 1:
 console_unlock+0x9f5/0xb30 kernel/printk/printk.c:2667
 con_flush_chars+0xc1/0x400 drivers/tty/vt/vt.c:3329
 con_write+0x2a/0x40 drivers/tty/vt/vt.c:3256
 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: 0x00000000000179a1 -> 0x00000000000179a2

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 29753 Comm: syz-executor.1 Not tainted 5.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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