KCSAN: data-race in ext4_mpage_readpages / ext4_setattr (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b6505459 Linux 5.10-rc6
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16a4cd8b500000
kernel config: https://syzkaller.appspot.com/x/.config?x=c949fed53798f819
dashboard link: https://syzkaller.appspot.com/bug?extid=1c07301bb00f6574534a
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+1c0730...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in ext4_mpage_readpages / ext4_setattr

write to 0xffff88810d7fd730 of 8 bytes by task 27576 on cpu 0:
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_creat fs/open.c:1258 [inline]
__se_sys_creat fs/open.c:1252 [inline]
__x64_sys_creat+0x62/0x80 fs/open.c:1252
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810d7fd730 of 8 bytes by task 27563 on cpu 1:
ext4_readpage_limit fs/ext4/readpage.c:219 [inline]
ext4_mpage_readpages+0x50d/0x1360 fs/ext4/readpage.c:265
ext4_readahead+0x99/0xa0 fs/ext4/inode.c:3252
read_pages+0xa0/0x6e0 mm/readahead.c:130
page_cache_ra_unbounded+0x464/0x4c0 mm/readahead.c:238
ondemand_readahead+0x560/0x780 mm/readahead.c:267
page_cache_async_ra+0x1aa/0x1d0 mm/readahead.c:607
page_cache_async_readahead include/linux/pagemap.h:862 [inline]
generic_file_buffered_read+0x450/0x23a0 mm/filemap.c:2247
generic_file_read_iter+0x80/0x3d0 mm/filemap.c:2553
ext4_file_read_iter+0x2d0/0x420 fs/ext4/file.c:74
call_read_iter include/linux/fs.h:1897 [inline]
generic_file_splice_read+0x22a/0x310 fs/splice.c:311
do_splice_to fs/splice.c:788 [inline]
splice_direct_to_actor+0x2aa/0x650 fs/splice.c:867
do_splice_direct+0xf5/0x170 fs/splice.c:976
do_sendfile+0x5db/0xca0 fs/read_write.c:1257
__do_sys_sendfile64 fs/read_write.c:1312 [inline]
__se_sys_sendfile64 fs/read_write.c:1304 [inline]
__x64_sys_sendfile64+0xa9/0x130 fs/read_write.c:1304
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 27563 Comm: syz-executor.0 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.