syzbot

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BUG: KCSAN: data-race in filemap_read / truncate_setsize

read-write to 0xffff88813a844d28 of 8 bytes by task 3479 on cpu 1:
 i_size_write include/linux/fs.h:905 [inline]
 truncate_setsize+0x21/0xb0 mm/truncate.c:766
 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+0x1984/0x1d00 fs/namei.c:3791
 do_filp_open+0xf6/0x200 fs/namei.c:3818
 do_sys_openat2+0xb5/0x2a0 fs/open.c:1356
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_creat fs/open.c:1448 [inline]
 __se_sys_creat fs/open.c:1442 [inline]
 __x64_sys_creat+0x66/0x90 fs/open.c:1442
 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 0xffff88813a844d28 of 8 bytes by task 3478 on cpu 0:
 i_size_read include/linux/fs.h:883 [inline]
 filemap_read+0x247/0x680 mm/filemap.c:2703
 generic_file_read_iter+0x76/0x320 mm/filemap.c:2837
 call_read_iter include/linux/fs.h:1862 [inline]
 generic_file_splice_read+0xe3/0x290 fs/splice.c:419
 do_splice_to fs/splice.c:902 [inline]
 splice_direct_to_actor+0x25a/0x5f0 fs/splice.c:973
 do_splice_direct+0x104/0x180 fs/splice.c:1082
 do_sendfile+0x3b8/0x950 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: 0x000000000009c1e3 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3478 Comm: syz-executor.3 Not tainted 6.4.0-rc5-syzkaller-00178-g33f2b5785a2b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
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