syzbot

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BUG: KCSAN: data-race in do_mpage_readpage / set_blocksize

write to 0xffff8881023e2b1e of 1 bytes by task 7020 on cpu 0:
 set_blocksize+0x20a/0x270 block/bdev.c:151
 sb_set_blocksize block/bdev.c:161 [inline]
 sb_min_blocksize+0x92/0x110 block/bdev.c:177
 isofs_fill_super+0x702/0x17b0 fs/isofs/inode.c:658
 mount_bdev+0x1e2/0x280 fs/super.c:1400
 isofs_mount+0x2d/0x40 fs/isofs/inode.c:1567
 legacy_get_tree+0x70/0xc0 fs/fs_context.c:610
 vfs_get_tree+0x49/0x190 fs/super.c:1530
 do_new_mount+0x200/0x650 fs/namespace.c:3040
 path_mount+0x4ad/0xbb0 fs/namespace.c:3370
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount+0x281/0x2d0 fs/namespace.c:3568
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3568
 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 0xffff8881023e2b1e of 1 bytes by task 6448 on cpu 1:
 do_mpage_readpage+0x6c/0xcf0 fs/mpage.c:137
 mpage_readahead+0x27f/0x3a0 fs/mpage.c:361
 blkdev_readahead+0x18/0x20 block/fops.c:386
 read_pages+0xa5/0x790 mm/readahead.c:158
 page_cache_ra_unbounded+0x2a8/0x2e0 mm/readahead.c:263
 do_page_cache_ra mm/readahead.c:293 [inline]
 force_page_cache_ra+0x1c6/0x200 mm/readahead.c:324
 page_cache_sync_ra+0xc8/0xf0 mm/readahead.c:695
 page_cache_sync_readahead include/linux/pagemap.h:1215 [inline]
 filemap_get_pages mm/filemap.c:2566 [inline]
 filemap_read+0x3ef/0x1430 mm/filemap.c:2660
 blkdev_read_iter+0x2c6/0x370 block/fops.c:598
 call_read_iter include/linux/fs.h:2181 [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: 6448 Comm: udevd Not tainted 6.0.0-syzkaller-03015-g2bca25eaeba6-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
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I/O error, dev loop3, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2
I/O error, dev loop3, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2
I/O error, dev loop3, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2
I/O error, dev loop3, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2
I/O error, dev loop3, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2