syzbot

loop1: detected capacity change from 0 to 8192
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BUG: KCSAN: data-race in block_read_full_folio / truncate_setsize

read-write to 0xffff888102109318 of 8 bytes by task 28888 on cpu 0:
 i_size_write include/linux/fs.h:901 [inline]
 truncate_setsize+0x21/0xb0 mm/truncate.c:765
 fat_setattr+0x71f/0x840 fs/fat/file.c:550
 notify_change+0x8c3/0x930 fs/attr.c:483
 do_truncate+0x116/0x150 fs/open.c:66
 handle_truncate fs/namei.c:3295 [inline]
 do_open fs/namei.c:3640 [inline]
 path_openat+0x1993/0x1d10 fs/namei.c:3793
 do_filp_open+0xf6/0x200 fs/namei.c:3820
 do_sys_openat2+0xab/0x110 fs/open.c:1407
 do_sys_open fs/open.c:1422 [inline]
 __do_sys_creat fs/open.c:1498 [inline]
 __se_sys_creat fs/open.c:1492 [inline]
 __x64_sys_creat+0x66/0x90 fs/open.c:1492
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff888102109318 of 8 bytes by task 28868 on cpu 1:
 i_size_read include/linux/fs.h:879 [inline]
 block_read_full_folio+0x6f/0x720 fs/buffer.c:2384
 do_mpage_readpage+0xc93/0xdf0 fs/mpage.c:325
 mpage_read_folio+0x5b/0xd0 fs/mpage.c:400
 fat_read_folio+0x1c/0x20 fs/fat/inode.c:205
 filemap_read_folio mm/filemap.c:2389 [inline]
 filemap_update_page mm/filemap.c:2473 [inline]
 filemap_get_pages+0xc11/0xea0 mm/filemap.c:2587
 filemap_splice_read+0x23a/0x810 mm/filemap.c:2925
 vfs_splice_read fs/splice.c:996 [inline]
 splice_direct_to_actor+0x28c/0x690 fs/splice.c:1072
 do_splice_direct+0x10d/0x190 fs/splice.c:1197
 do_sendfile+0x3b6/0x9a0 fs/read_write.c:1254
 __do_sys_sendfile64 fs/read_write.c:1322 [inline]
 __se_sys_sendfile64 fs/read_write.c:1308 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1308
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000000000a816b -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 28868 Comm: syz-executor.1 Not tainted 6.5.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
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