syzbot

loop4: detected capacity change from 0 to 1024
EXT4-fs: Ignoring removed orlov option
EXT4-fs (loop4): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback.
==================================================================
BUG: KCSAN: data-race in filemap_read / filemap_read

write to 0xffff888101a7c9a8 of 8 bytes by task 11859 on cpu 0:
 filemap_read+0x974/0xa00 mm/filemap.c:2784
 generic_file_read_iter+0x79/0x330 mm/filemap.c:2903
 ext4_file_read_iter+0x1cc/0x290 fs/ext4/file.c:-1
 copy_splice_read+0x3c4/0x5f0 fs/splice.c:363
 do_splice_read fs/splice.c:978 [inline]
 splice_direct_to_actor+0x290/0x680 fs/splice.c:1083
 do_splice_direct_actor fs/splice.c:1201 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1227
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0xb39/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888101a7c9a8 of 8 bytes by task 11852 on cpu 1:
 filemap_read+0x6f/0xa00 mm/filemap.c:2685
 generic_file_read_iter+0x79/0x330 mm/filemap.c:2903
 ext4_file_read_iter+0x1cc/0x290 fs/ext4/file.c:-1
 copy_splice_read+0x3c4/0x5f0 fs/splice.c:363
 do_splice_read fs/splice.c:978 [inline]
 splice_direct_to_actor+0x290/0x680 fs/splice.c:1083
 do_splice_direct_actor fs/splice.c:1201 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1227
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0xb39/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x000000000000018f -> 0x0000000000000190

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 11852 Comm: syz.4.3175 Not tainted 6.16.0-rc6-syzkaller-00205-gd786aba32000 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================