[moderation] [fs?] KCSAN: data-race in filemap_splice_read / simple_write_end (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 23dfa043f6d5 Merge tag 'i2c-for-6.7-rc2' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11db2214e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=a91f789b98394377
dashboard link: https://syzkaller.appspot.com/bug?extid=aa8a574df17b7c7ee29c
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [bra...@kernel.org linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/106726d95b01/disk-23dfa043.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ef914c2de47e/vmlinux-23dfa043.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5f8f23b64902/bzImage-23dfa043.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+aa8a57...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in filemap_splice_read / simple_write_end

write to 0xffff8881402aaef0 of 8 bytes by task 15773 on cpu 1:
i_size_write include/linux/fs.h:932 [inline]
simple_write_end+0x26c/0x380 fs/libfs.c:886
generic_perform_write+0x267/0x410 mm/filemap.c:3929
__generic_file_write_iter+0xa1/0x120 mm/filemap.c:4013
generic_file_write_iter+0x7d/0x1c0 mm/filemap.c:4039
do_iter_write+0x4ad/0x770 fs/read_write.c:860
vfs_iter_write+0x56/0x70 fs/read_write.c:901
iter_file_splice_write+0x462/0x7e0 fs/splice.c:736
do_splice_from fs/splice.c:933 [inline]
direct_splice_actor+0x8a/0xb0 fs/splice.c:1142
splice_direct_to_actor+0x31d/0x690 fs/splice.c:1088
do_splice_direct+0x10d/0x190 fs/splice.c:1194
do_sendfile+0x3c4/0x980 fs/read_write.c:1254
__do_sys_sendfile64 fs/read_write.c:1316 [inline]
__se_sys_sendfile64 fs/read_write.c:1308 [inline]
__x64_sys_sendfile64+0xbd/0x150 fs/read_write.c:1308
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff8881402aaef0 of 8 bytes by task 15776 on cpu 0:
i_size_read include/linux/fs.h:910 [inline]
filemap_splice_read+0x1a1/0x7f0 mm/filemap.c:2856
vfs_splice_read fs/splice.c:993 [inline]
splice_direct_to_actor+0x28c/0x690 fs/splice.c:1069
do_splice_direct+0x10d/0x190 fs/splice.c:1194
do_sendfile+0x3c4/0x980 fs/read_write.c:1254
__do_sys_sendfile64 fs/read_write.c:1316 [inline]
__se_sys_sendfile64 fs/read_write.c:1308 [inline]
__x64_sys_sendfile64+0xbd/0x150 fs/read_write.c:1308
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000000000005668 -> 0x0000000000005684

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 15776 Comm: syz-executor.1 Not tainted 6.7.0-rc1-syzkaller-00304-g23dfa043f6d5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.