KCSAN: data-race in ext4_setattr / filemap_read

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3f667b5d4053 Merge tag 'tty-5.16-rc6' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=129d7543b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=de0414680adf699a
dashboard link: https://syzkaller.appspot.com/bug?extid=b2d3f646575c298b4d51
compiler: Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.2
CC: [adilger...@dilger.ca linux...@vger.kernel.org linux-...@vger.kernel.org ty...@mit.edu]

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b2d3f6...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in ext4_setattr / filemap_read

write to 0xffff88815025dac8 of 8 bytes by task 304 on cpu 0:
i_size_write include/linux/fs.h:913 [inline]
ext4_setattr+0xd7e/0xf20 fs/ext4/inode.c:5451
notify_change+0x8a3/0xac0 fs/attr.c:410
do_truncate+0xf7/0x140 fs/open.c:64
handle_truncate fs/namei.c:3082 [inline]
do_open fs/namei.c:3430 [inline]
path_openat+0x191f/0x1eb0 fs/namei.c:3559
do_filp_open+0x105/0x220 fs/namei.c:3586
do_sys_openat2+0xb5/0x2b0 fs/open.c:1212
do_sys_open fs/open.c:1228 [inline]
__do_sys_creat fs/open.c:1304 [inline]
__se_sys_creat fs/open.c:1298 [inline]
__x64_sys_creat+0x62/0x80 fs/open.c:1298
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88815025dac8 of 8 bytes by task 303 on cpu 1:
i_size_read include/linux/fs.h:891 [inline]
filemap_read+0x1208/0x16d0 mm/filemap.c:2654
generic_file_read_iter+0x72/0x2a0 mm/filemap.c:2792
ext4_file_read_iter+0x1db/0x290
call_read_iter include/linux/fs.h:2156 [inline]
generic_file_splice_read+0x24f/0x330 fs/splice.c:311
do_splice_to fs/splice.c:796 [inline]
splice_direct_to_actor+0x2aa/0x650 fs/splice.c:870
do_splice_direct+0x106/0x190 fs/splice.c:979
do_sendfile+0x675/0xc40 fs/read_write.c:1245
__do_sys_sendfile64 fs/read_write.c:1310 [inline]
__se_sys_sendfile64 fs/read_write.c:1296 [inline]
__x64_sys_sendfile64+0x102/0x140 fs/read_write.c:1296
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x000000000046a401 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 303 Comm: syz-executor.1 Not tainted 5.16.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


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[syzbot]

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