syzbot

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BUG: KCSAN: data-race in block_read_full_folio / truncate_setsize

read-write to 0xffff88817b40e9e8 of 8 bytes by task 21872 on cpu 0:
 i_size_write include/linux/fs.h:888 [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:482
 do_truncate+0x116/0x150 fs/open.c:66
 handle_truncate fs/namei.c:3219 [inline]
 do_open fs/namei.c:3564 [inline]
 path_openat+0x1984/0x1d00 fs/namei.c:3715
 do_filp_open+0xf6/0x200 fs/namei.c:3742
 do_sys_openat2+0xb5/0x2a0 fs/open.c:1348
 do_sys_open fs/open.c:1364 [inline]
 __do_sys_creat fs/open.c:1440 [inline]
 __se_sys_creat fs/open.c:1434 [inline]
 __x64_sys_creat+0x66/0x90 fs/open.c:1434
 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 0xffff88817b40e9e8 of 8 bytes by task 21850 on cpu 1:
 i_size_read include/linux/fs.h:866 [inline]
 block_read_full_folio+0x78/0x6b0 fs/buffer.c:2291
 do_mpage_readpage+0xc93/0xdf0 fs/mpage.c:299
 mpage_read_folio+0x5b/0xd0 fs/mpage.c:374
 fat_read_folio+0x1c/0x20 fs/fat/inode.c:205
 filemap_read_folio mm/filemap.c:2424 [inline]
 filemap_update_page mm/filemap.c:2508 [inline]
 filemap_get_pages+0xc14/0xea0 mm/filemap.c:2622
 filemap_read+0x223/0x680 mm/filemap.c:2693
 generic_file_read_iter+0x76/0x320 mm/filemap.c:2840
 call_read_iter include/linux/fs.h:1845 [inline]
 generic_file_splice_read+0xe3/0x290 fs/splice.c:402
 do_splice_to fs/splice.c:885 [inline]
 splice_direct_to_actor+0x25a/0x5f0 fs/splice.c:956
 do_splice_direct+0x104/0x180 fs/splice.c:1065
 do_sendfile+0x3b8/0x950 fs/read_write.c:1255
 __do_sys_sendfile64 fs/read_write.c:1323 [inline]
 __se_sys_sendfile64 fs/read_write.c:1309 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1309
 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: 0x000000000007d319 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 21850 Comm: syz-executor.1 Not tainted 6.3.0-rc4-syzkaller-00243-g6ab608fe852b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
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