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BUG: KCSAN: data-race in console_unlock / console_unlock

write to 0xffffffff8417c940 of 8 bytes by task 5882 on cpu 1:
 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
 fail_dump lib/fault-inject.c:45 [inline]
 should_fail+0x223/0x250 lib/fault-inject.c:146
 prepare_alloc_pages mm/page_alloc.c:5172 [inline]
 __alloc_pages+0x102/0x320 mm/page_alloc.c:5380
 alloc_pages+0x2e8/0x340 mm/mempolicy.c:2244
 __pte_alloc_one include/asm-generic/pgalloc.h:63 [inline]
 pte_alloc_one+0x29/0xb0 arch/x86/mm/pgtable.c:33
 __pte_alloc+0x2f/0x210 mm/memory.c:439
 do_anonymous_page+0x79b/0x8a0 mm/memory.c:3735
 handle_pte_fault mm/memory.c:4556 [inline]
 __handle_mm_fault mm/memory.c:4693 [inline]
 handle_mm_fault+0x98f/0x1a50 mm/memory.c:4791
 do_user_addr_fault+0x609/0xbe0 arch/x86/mm/fault.c:1390
 handle_page_fault arch/x86/mm/fault.c:1475 [inline]
 exc_page_fault+0x91/0x220 arch/x86/mm/fault.c:1531
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:568
 __put_user_nocheck_4+0x3/0x11
 n_tty_ioctl+0x1eb/0x200 drivers/tty/n_tty.c:2419
 tty_ioctl+0xa8f/0x1120 drivers/tty/tty_io.c:2814
 vfs_ioctl fs/ioctl.c:51 [inline]
 do_vfs_ioctl+0x770/0x1410 fs/ioctl.c:1029
 __do_sys_ioctl fs/ioctl.c:1067 [inline]
 __se_sys_ioctl+0x83/0x140 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 0xffffffff8417c940 of 8 bytes by task 5850 on cpu 0:
 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]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4c0 fs/read_write.c:866
 vfs_writev fs/read_write.c:939 [inline]
 do_writev+0x1e0/0x400 fs/read_write.c:982
 __do_sys_writev fs/read_write.c:1055 [inline]
 __se_sys_writev fs/read_write.c:1052 [inline]
 __x64_sys_writev+0x41/0x50 fs/read_write.c:1052
 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: 0x0000000000002783 -> 0x0000000000002784

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 5850 Comm: syz-executor.2 Not tainted 5.14.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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