syzbot

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BUG: KCSAN: data-race in filemap_splice_read / filemap_splice_read

write to 0xffff888113862a70 of 8 bytes by task 4008 on cpu 1:
 filemap_splice_read+0x6c4/0x910 mm/filemap.c:2967
 ext4_file_splice_read+0x8f/0xb0 fs/ext4/file.c:158
 do_splice_read fs/splice.c:985 [inline]
 splice_direct_to_actor+0x269/0x670 fs/splice.c:1089
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x39b/0x970 fs/read_write.c:1388
 __do_sys_sendfile64 fs/read_write.c:1455 [inline]
 __se_sys_sendfile64 fs/read_write.c:1441 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1441
 x64_sys_call+0xed5/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

write to 0xffff888113862a70 of 8 bytes by task 4022 on cpu 0:
 filemap_splice_read+0x6c4/0x910 mm/filemap.c:2967
 ext4_file_splice_read+0x8f/0xb0 fs/ext4/file.c:158
 do_splice_read fs/splice.c:985 [inline]
 splice_direct_to_actor+0x269/0x670 fs/splice.c:1089
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x39b/0x970 fs/read_write.c:1388
 __do_sys_sendfile64 fs/read_write.c:1455 [inline]
 __se_sys_sendfile64 fs/read_write.c:1441 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1441
 x64_sys_call+0xed5/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000bf5 -> 0x0000000000000bf6

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 4022 Comm: syz.3.212 Tainted: G        W          6.12.0-rc1-syzkaller-00349-g8f602276d390 #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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