syzbot

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BUG: KCSAN: data-race in do_mpage_readpage / set_blocksize

write to 0xffff88810047349e of 1 bytes by task 23232 on cpu 0:
 set_blocksize+0x238/0x2a0 block/bdev.c:151
 sb_set_blocksize block/bdev.c:161 [inline]
 sb_min_blocksize+0x91/0x120 block/bdev.c:177
 ext4_load_super fs/ext4/super.c:4931 [inline]
 __ext4_fill_super fs/ext4/super.c:5056 [inline]
 ext4_fill_super+0x35f/0x4500 fs/ext4/super.c:5644
 get_tree_bdev+0x2b4/0x3b0 fs/super.c:1282
 ext4_get_tree+0x18/0x20 fs/ext4/super.c:5675
 vfs_get_tree+0x49/0x190 fs/super.c:1489
 do_new_mount+0x200/0x650 fs/namespace.c:3145
 path_mount+0x4aa/0xb70 fs/namespace.c:3475
 do_mount fs/namespace.c:3488 [inline]
 __do_sys_mount fs/namespace.c:3697 [inline]
 __se_sys_mount+0x281/0x2d0 fs/namespace.c:3674
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3674
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88810047349e of 1 bytes by task 15737 on cpu 1:
 do_mpage_readpage+0x6c/0xcf0 fs/mpage.c:137
 mpage_readahead+0x19f/0x2c0 fs/mpage.c:361
 blkdev_readahead+0x18/0x20 block/fops.c:386
 read_pages+0xa6/0x560 mm/readahead.c:161
 page_cache_ra_unbounded+0x2de/0x320 mm/readahead.c:270
 do_page_cache_ra mm/readahead.c:300 [inline]
 force_page_cache_ra+0x1c6/0x200 mm/readahead.c:331
 page_cache_sync_ra+0xc8/0xf0 mm/readahead.c:705
 page_cache_sync_readahead include/linux/pagemap.h:1210 [inline]
 filemap_get_pages mm/filemap.c:2600 [inline]
 filemap_read+0x3fd/0x1510 mm/filemap.c:2694
 blkdev_read_iter+0x2c6/0x370 block/fops.c:591
 call_read_iter include/linux/fs.h:2180 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x3a5/0x560 fs/read_write.c:470
 ksys_read+0xe8/0x1a0 fs/read_write.c:613
 __do_sys_read fs/read_write.c:623 [inline]
 __se_sys_read fs/read_write.c:621 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:621
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0c -> 0x0a

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 15737 Comm: udevd Not tainted 6.2.0-rc1-syzkaller-00043-g2258c2dc850b-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
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I/O error, dev loop1, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2
I/O error, dev loop1, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2
I/O error, dev loop0, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2
I/O error, dev loop1, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2