KCSAN: data-race in ext4_setattr / ext4_writepages (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3bb61aa6 Merge tag 'arm64-fixes' of git://git.kernel.org/p..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15c44ad9500000
kernel config: https://syzkaller.appspot.com/x/.config?x=c949fed53798f819
dashboard link: https://syzkaller.appspot.com/bug?extid=45f5c0f3f50968f9de83
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
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+45f5c0...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in ext4_setattr / ext4_writepages

write to 0xffff888045884670 of 8 bytes by task 1593 on cpu 1:
i_size_write include/linux/fs.h:871 [inline]
ext4_setattr+0xe27/0xf70 fs/ext4/inode.c:5470
notify_change+0x7b3/0xa50 fs/attr.c:336
do_truncate+0xe0/0x120 fs/open.c:64
handle_truncate fs/namei.c:2910 [inline]
do_open fs/namei.c:3256 [inline]
path_openat+0x1a37/0x20a0 fs/namei.c:3369
do_filp_open+0xbd/0x1d0 fs/namei.c:3396
do_sys_openat2+0xa3/0x240 fs/open.c:1168
do_sys_open fs/open.c:1184 [inline]
__do_sys_openat fs/open.c:1200 [inline]
__se_sys_openat fs/open.c:1195 [inline]
__x64_sys_openat+0xef/0x110 fs/open.c:1195
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888045884670 of 8 bytes by task 1567 on cpu 0:
i_size_read include/linux/fs.h:849 [inline]
mpage_submit_page fs/ext4/inode.c:2086 [inline]
mpage_map_and_submit_buffers fs/ext4/inode.c:2340 [inline]
mpage_map_and_submit_extent fs/ext4/inode.c:2479 [inline]
ext4_writepages+0xdf6/0x1e30 fs/ext4/inode.c:2792
do_writepages+0x7b/0x150 mm/page-writeback.c:2352
__filemap_fdatawrite_range+0x19d/0x1d0 mm/filemap.c:422
__filemap_fdatawrite mm/filemap.c:430 [inline]
filemap_flush+0x1f/0x30 mm/filemap.c:457
ext4_alloc_da_blocks+0x4a/0x100 fs/ext4/inode.c:3156
ext4_release_file+0x5b/0x1d0 fs/ext4/file.c:142
__fput+0x243/0x4d0 fs/file_table.c:281
____fput+0x11/0x20 fs/file_table.c:314
task_work_run+0x8e/0x110 kernel/task_work.c:151
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_user_mode_loop kernel/entry/common.c:164 [inline]
exit_to_user_mode_prepare+0x13c/0x170 kernel/entry/common.c:191
syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:266
do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1567 Comm: syz-executor.5 Not tainted 5.10.0-rc6-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.