KCSAN: data-race in __delete_from_page_cache / page_mapping (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3cea11cd Linux 5.10-rc2
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=113f3b46500000
kernel config: https://syzkaller.appspot.com/x/.config?x=76dfc991796328d4
dashboard link: https://syzkaller.appspot.com/bug?extid=f8460ec03e7576b674d7
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [ak...@linux-foundation.org linux-...@vger.kernel.org linu...@kvack.org]

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+f8460e...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __delete_from_page_cache / page_mapping

write to 0xffffea000479e3d8 of 8 bytes by task 15550 on cpu 0:
page_cache_delete mm/filemap.c:141 [inline]
__delete_from_page_cache+0x22a/0x340 mm/filemap.c:239
delete_from_page_cache+0x84/0x260 mm/filemap.c:274
truncate_inode_page mm/truncate.c:228 [inline]
truncate_inode_pages_range+0xb89/0xf20 mm/truncate.c:449
truncate_inode_pages mm/truncate.c:476 [inline]
truncate_pagecache+0x4f/0x70 mm/truncate.c:839
ext4_setattr+0xaf9/0xf60 fs/ext4/inode.c:5486
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 0xffffea000479e3d8 of 8 bytes by task 15518 on cpu 1:
page_mapping+0x13b/0x200 mm/util.c:694
wait_on_page_writeback+0x60/0x130 mm/page-writeback.c:2836
__filemap_fdatawait_range+0xdd/0x1b0 mm/filemap.c:527
filemap_fdatawait_range+0x21/0xd0 mm/filemap.c:554
filemap_fdatawait include/linux/fs.h:2617 [inline]
__writeback_single_inode+0xe1/0x560 fs/fs-writeback.c:1471
writeback_single_inode+0x126/0x580 fs/fs-writeback.c:1570
sync_inode fs/fs-writeback.c:2606 [inline]
sync_inode_metadata+0x52/0x70 fs/fs-writeback.c:2626
ext4_fsync_nojournal fs/ext4/fsync.c:92 [inline]
ext4_sync_file+0x327/0x6a0 fs/ext4/fsync.c:170
vfs_fsync_range+0x107/0x120 fs/sync.c:200
generic_write_sync include/linux/fs.h:2723 [inline]
ext4_buffered_write_iter+0x384/0x3d0 fs/ext4/file.c:278
ext4_file_write_iter+0x45e/0x1090 fs/ext4/file.c:503
call_write_iter include/linux/fs.h:1887 [inline]
do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
do_iter_write+0x112/0x4b0 fs/read_write.c:866
vfs_iter_write+0x4c/0x70 fs/read_write.c:907
iter_file_splice_write+0x42a/0x780 fs/splice.c:686
do_splice_from fs/splice.c:764 [inline]
direct_splice_actor+0x80/0xa0 fs/splice.c:933
splice_direct_to_actor+0x345/0x650 fs/splice.c:888
do_splice_direct+0xf5/0x170 fs/splice.c:976
do_sendfile+0x574/0xb70 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: 15518 Comm: syz-executor.0 Not tainted 5.10.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[syzbot]

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