syzbot

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BUG: KCSAN: data-race in do_mpage_readpage / set_blocksize

write to 0xffff8881006316f6 of 1 bytes by task 6733 on cpu 1:
 set_blocksize+0x227/0x290 block/bdev.c:160
 sb_set_blocksize block/bdev.c:170 [inline]
 sb_min_blocksize+0x83/0x110 block/bdev.c:186
 ext4_load_super fs/ext4/super.c:5025 [inline]
 __ext4_fill_super fs/ext4/super.c:5222 [inline]
 ext4_fill_super+0x39f/0x39d0 fs/ext4/super.c:5699
 get_tree_bdev+0x253/0x2e0 fs/super.c:1614
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5731
 vfs_get_tree+0x56/0x1d0 fs/super.c:1779
 do_new_mount+0x227/0x690 fs/namespace.c:3352
 path_mount+0x49b/0xb30 fs/namespace.c:3679
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x27f/0x2d0 fs/namespace.c:3875
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3875
 x64_sys_call+0x2591/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881006316f6 of 1 bytes by task 6050 on cpu 0:
 do_mpage_readpage+0x55/0xcb0 fs/mpage.c:162
 mpage_readahead+0x1ad/0x2d0 fs/mpage.c:381
 blkdev_readahead+0x1c/0x30 block/fops.c:443
 read_pages+0xa0/0x540 mm/readahead.c:160
 page_cache_ra_unbounded+0x2a4/0x2e0 mm/readahead.c:269
 do_page_cache_ra mm/readahead.c:299 [inline]
 force_page_cache_ra+0x18e/0x1d0 mm/readahead.c:330
 page_cache_sync_ra+0xcc/0xf0 mm/readahead.c:684
 page_cache_sync_readahead include/linux/pagemap.h:1300 [inline]
 filemap_get_pages+0x252/0xfb0 mm/filemap.c:2505
 filemap_read+0x21c/0x690 mm/filemap.c:2601
 blkdev_read_iter+0x217/0x2c0 block/fops.c:754
 call_read_iter include/linux/fs.h:2104 [inline]
 new_sync_read fs/read_write.c:395 [inline]
 vfs_read+0x5bc/0x6b0 fs/read_write.c:476
 ksys_read+0xeb/0x1b0 fs/read_write.c:619
 __do_sys_read fs/read_write.c:629 [inline]
 __se_sys_read fs/read_write.c:627 [inline]
 __x64_sys_read+0x42/0x50 fs/read_write.c:627
 x64_sys_call+0x27ad/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0c -> 0x0a

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 6050 Comm: udevd Tainted: G        W          6.9.0-rc6-syzkaller-00053-g0106679839f7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
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I/O error, dev loop2, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
I/O error, dev loop3, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0