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BUG: KCSAN: data-race in __add_to_page_cache_locked / jbd2_journal_submit_inode_data_buffers

write to 0xffff888009f79398 of 8 bytes by task 14053 on cpu 0:
 __add_to_page_cache_locked+0x3ad/0x6e0 mm/filemap.c:890
 add_to_page_cache_lru+0xa0/0x1b0 mm/filemap.c:943
 page_cache_ra_unbounded+0x272/0x4c0 mm/readahead.c:222
 ondemand_readahead+0x560/0x780 mm/readahead.c:267
 page_cache_sync_ra+0x18f/0x1a0 mm/readahead.c:577
 page_cache_sync_readahead include/linux/pagemap.h:839 [inline]
 generic_file_buffered_read_get_pages+0x234/0xaf0 mm/filemap.c:2365
 generic_file_buffered_read+0x26e/0x9c0 mm/filemap.c:2485
 generic_file_read_iter+0x82/0x3e0 mm/filemap.c:2637
 ext4_file_read_iter+0x2e0/0x430 fs/ext4/file.c:74
 call_read_iter include/linux/fs.h:1895 [inline]
 generic_file_splice_read+0x22a/0x310 fs/splice.c:311
 do_splice_to fs/splice.c:788 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:867
 do_splice_direct+0xf5/0x170 fs/splice.c:976
 do_sendfile+0x5e0/0xcf0 fs/read_write.c:1257
 __do_sys_sendfile64 fs/read_write.c:1318 [inline]
 __se_sys_sendfile64 fs/read_write.c:1304 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1304
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888009f79398 of 8 bytes by task 4840 on cpu 1:
 jbd2_journal_submit_inode_data_buffers+0x40/0xe0 fs/jbd2/commit.c:195
 ext4_journal_submit_inode_data_buffers+0x53/0x120 fs/ext4/super.c:533
 journal_submit_data_buffers+0xf0/0x260 fs/jbd2/commit.c:256
 jbd2_journal_commit_transaction+0x819/0x32b0 fs/jbd2/commit.c:591
 kjournald2+0x263/0x480 fs/jbd2/journal.c:213
 kthread+0x20b/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4840 Comm: jbd2/sda1-8 Not tainted 5.11.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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