syzbot

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BUG: KCSAN: data-race in __add_to_page_cache_locked / kill_bdev

write to 0xffff88812528a9e8 of 8 bytes by task 4210 on cpu 0:
 __add_to_page_cache_locked+0x28a/0x770 mm/filemap.c:868
 add_to_page_cache_lru+0xc7/0x260 mm/filemap.c:921
 mpage_readpages+0x23c/0x370 fs/mpage.c:399
 blkdev_readpages+0x32/0x50 fs/block_dev.c:620
 read_pages+0xa2/0x2d0 mm/readahead.c:126
 __do_page_cache_readahead+0x358/0x380 mm/readahead.c:212
 force_page_cache_readahead+0x12c/0x1e0 mm/readahead.c:243
 page_cache_sync_readahead+0x1d1/0x1e0 mm/readahead.c:522
 generic_file_buffered_read mm/filemap.c:2029 [inline]
 generic_file_read_iter+0xeae/0x1490 mm/filemap.c:2302
 blkdev_read_iter+0xae/0xe0 fs/block_dev.c:2039
 call_read_iter include/linux/fs.h:1895 [inline]
 new_sync_read+0x306/0x450 fs/read_write.c:414
 __vfs_read+0x9e/0xb0 fs/read_write.c:427
 vfs_read fs/read_write.c:461 [inline]
 vfs_read+0x13e/0x2b0 fs/read_write.c:446
 ksys_read+0xc5/0x1a0 fs/read_write.c:587
 __do_sys_read fs/read_write.c:597 [inline]
 __se_sys_read fs/read_write.c:595 [inline]
 __x64_sys_read+0x49/0x60 fs/read_write.c:595
 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88812528a9e8 of 8 bytes by task 4117 on cpu 1:
 kill_bdev+0x37/0xa0 fs/block_dev.c:82
 set_blocksize+0x18e/0x1c0 fs/block_dev.c:136
 sb_set_blocksize+0x3d/0xc0 fs/block_dev.c:145
 ext4_fill_super+0x1752/0x7a40 fs/ext4/super.c:4087
 mount_bdev+0x264/0x2d0 fs/super.c:1417
 ext4_mount+0x38/0x50 fs/ext4/super.c:6077
 legacy_get_tree+0x78/0xf0 fs/fs_context.c:622
 vfs_get_tree+0x52/0x190 fs/super.c:1547
 do_new_mount fs/namespace.c:2822 [inline]
 do_mount+0xff0/0x14d0 fs/namespace.c:3107
 __do_sys_mount fs/namespace.c:3316 [inline]
 __se_sys_mount fs/namespace.c:3293 [inline]
 __x64_sys_mount+0x12b/0x1a0 fs/namespace.c:3293
 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4117 Comm: syz-executor.4 Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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