[moderation] [fs?] KCSAN: data-race in generic_file_direct_write / generic_file_read_iter (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c7402612e2e6 Merge tag 'net-6.7-rc6' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16addac6e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=d6f4b50a94fc12a6
dashboard link: https://syzkaller.appspot.com/bug?extid=da0b1e303c832184d763
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/13ad70d12e13/disk-c7402612.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e287dddd1052/vmlinux-c7402612.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b227f7f80f7e/bzImage-c7402612.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+da0b1e...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in generic_file_direct_write / generic_file_read_iter

write to 0xffff888107e93470 of 8 bytes by task 26618 on cpu 0:
i_size_write include/linux/fs.h:932 [inline]
generic_file_direct_write+0x19d/0x1f0 mm/filemap.c:3870
__generic_file_write_iter+0xae/0x120 mm/filemap.c:3999
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: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:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888107e93470 of 8 bytes by task 26627 on cpu 1:
i_size_read include/linux/fs.h:910 [inline]
generic_file_read_iter+0x2f4/0x330 mm/filemap.c:2768
call_read_iter include/linux/fs.h:2014 [inline]
copy_splice_read+0x26b/0x4b0 fs/splice.c:364
vfs_splice_read fs/splice.c:992 [inline]
splice_direct_to_actor+0x2aa/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: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:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000000000032a00 -> 0x0000000000032c00

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 26627 Comm: syz-executor.2 Not tainted 6.7.0-rc5-syzkaller-00125-gc7402612e2e6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
==================================================================


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[syzbot]

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