syzbot

loop5: detected capacity change from 0 to 2048
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BUG: KCSAN: data-race in generic_file_read_iter / generic_write_end

write to 0xffff88810a080d08 of 8 bytes by task 14397 on cpu 1:
 i_size_write include/linux/fs.h:901 [inline]
 generic_write_end+0x9f/0x240 fs/buffer.c:2304
 fat_write_end+0x4e/0x160 fs/fat/inode.c:244
 generic_perform_write+0x26d/0x410 mm/filemap.c:3934
 __generic_file_write_iter+0xa1/0x120 mm/filemap.c:4018
 generic_file_write_iter+0x7d/0x1c0 mm/filemap.c:4044
 do_iter_write+0x4b4/0x7b0 fs/read_write.c:860
 vfs_iter_write+0x56/0x70 fs/read_write.c:901
 iter_file_splice_write+0x462/0x7e0 fs/splice.c:739
 do_splice_from fs/splice.c:934 [inline]
 direct_splice_actor+0x8a/0xb0 fs/splice.c:1143
 splice_direct_to_actor+0x31d/0x690 fs/splice.c:1089
 do_splice_direct+0x10d/0x190 fs/splice.c:1195
 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

read to 0xffff88810a080d08 of 8 bytes by task 14382 on cpu 0:
 i_size_read include/linux/fs.h:879 [inline]
 generic_file_read_iter+0x304/0x340 mm/filemap.c:2833
 call_read_iter include/linux/fs.h:1865 [inline]
 copy_splice_read+0x26b/0x4b0 fs/splice.c:367
 vfs_splice_read fs/splice.c:993 [inline]
 splice_direct_to_actor+0x2aa/0x690 fs/splice.c:1070
 do_splice_direct+0x10d/0x190 fs/splice.c:1195
 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: 0x0000000000008e00 -> 0x0000000000009000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 14382 Comm: syz-executor.5 Not tainted 6.5.0-rc2-syzkaller-00221-gf7e3a1bafdea #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023
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