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BUG: KCSAN: data-race in console_unlock / console_unlock

write to 0xffffffff8417d940 of 8 bytes by task 16526 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
 prepare_alloc_pages mm/page_alloc.c:5171 [inline]
 __alloc_pages+0x102/0x320 mm/page_alloc.c:5379
 alloc_pages_vma+0x513/0x680 mm/mempolicy.c:2208
 do_anonymous_page+0x16e/0x8a0 mm/memory.c:3767
 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
 faultin_page mm/gup.c:951 [inline]
 __get_user_pages+0x32b/0xbc0 mm/gup.c:1173
 __get_user_pages_locked mm/gup.c:1359 [inline]
 get_user_pages_unlocked+0x175/0x630 mm/gup.c:2083
 __gup_longterm_unlocked+0x47/0x100 mm/gup.c:2660
 internal_get_user_pages_fast+0x763/0x860 mm/gup.c:2748
 get_user_pages_fast+0x5d/0x80 mm/gup.c:2840
 iov_iter_get_pages+0x199/0x7e0 lib/iov_iter.c:1484
 __bio_iov_iter_get_pages block/bio.c:1013 [inline]
 bio_iov_iter_get_pages+0x4cf/0xd00 block/bio.c:1121
 iomap_dio_bio_actor+0x673/0xb50 fs/iomap/direct-io.c:317
 iomap_dio_actor+0x26e/0x3b0 fs/iomap/direct-io.c:417
 iomap_apply+0x1df/0x400 fs/iomap/apply.c:84
 __iomap_dio_rw+0x62e/0xa60 fs/iomap/direct-io.c:561
 iomap_dio_rw+0x30/0x70 fs/iomap/direct-io.c:649
 ext4_dio_read_iter fs/ext4/file.c:77 [inline]
 ext4_file_read_iter+0x21a/0x290 fs/ext4/file.c:128
 call_read_iter include/linux/fs.h:2108 [inline]
 aio_read+0x1c1/0x280 fs/aio.c:1538
 __io_submit_one fs/aio.c:1835 [inline]
 io_submit_one+0x7fb/0x1350 fs/aio.c:1880
 __do_sys_io_submit fs/aio.c:1939 [inline]
 __se_sys_io_submit+0xf5/0x260 fs/aio.c:1909
 __x64_sys_io_submit+0x3f/0x50 fs/aio.c:1909
 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 16524 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
 do_output_char+0x47f/0x4f0 drivers/tty/n_tty.c:444
 process_output drivers/tty/n_tty.c:511 [inline]
 n_tty_write+0x7f8/0xaf0 drivers/tty/n_tty.c:2300
 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_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x40a/0x750 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x650 fs/splice.c:891
 do_splice_direct+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x773/0xda0 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311
 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: 0x0000000000008283 -> 0x0000000000008284

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 16524 Comm: syz-executor.2 Tainted: G        W         5.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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