[moderation] [fs?] [mm?] KCSAN: data-race in __writeback_single_inode / xas_set_mark (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fca7526b7d89 drm/tests/drm_buddy: fix build failure on 32-..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=104b9002180000
kernel config: https://syzkaller.appspot.com/x/.config?x=7507056e4ee79a
dashboard link: https://syzkaller.appspot.com/bug?extid=99016f42ee1dc331e820
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ak...@linux-foundation.org linux-...@vger.kernel.org linux-...@vger.kernel.org linu...@kvack.org wi...@infradead.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c63152c2a9c6/disk-fca7526b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6f039180eecf/vmlinux-fca7526b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0340d7a9d91f/bzImage-fca7526b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+99016f...@syzkaller.appspotmail.com

EXT4-fs (loop4): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
==================================================================
BUG: KCSAN: data-race in __writeback_single_inode / xas_set_mark

write to 0xffff88810698197c of 4 bytes by task 15869 on cpu 0:
xa_mark_set lib/xarray.c:71 [inline]
xas_set_mark+0x131/0x140 lib/xarray.c:892
__folio_start_writeback+0x1f1/0x450 mm/page-writeback.c:3007
ext4_bio_write_folio+0x592/0x9a0 fs/ext4/page-io.c:557
mpage_submit_folio fs/ext4/inode.c:1869 [inline]
mpage_process_page_bufs+0x488/0x5d0 fs/ext4/inode.c:1982
mpage_prepare_extent_to_map+0x780/0xb70 fs/ext4/inode.c:2490
ext4_do_writepages+0xa20/0x2100 fs/ext4/inode.c:2677
ext4_writepages+0x15e/0x2e0 fs/ext4/inode.c:2768
do_writepages+0x1c2/0x340 mm/page-writeback.c:2553
filemap_fdatawrite_wbc+0xdb/0xf0 mm/filemap.c:388
__filemap_fdatawrite_range mm/filemap.c:421 [inline]
file_write_and_wait_range+0xf4/0x190 mm/filemap.c:779
generic_buffers_fsync_noflush+0x4c/0x120 fs/buffer.c:602
ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
ext4_sync_file+0x206/0x6c0 fs/ext4/fsync.c:151
vfs_fsync_range+0x111/0x120 fs/sync.c:188
generic_write_sync include/linux/fs.h:2732 [inline]
ext4_buffered_write_iter+0x334/0x370 fs/ext4/file.c:305
ext4_file_write_iter+0x297/0xe10
call_write_iter include/linux/fs.h:2085 [inline]
iter_file_splice_write+0x5de/0x950 fs/splice.c:743
do_splice_from fs/splice.c:941 [inline]
direct_splice_actor+0x167/0x2c0 fs/splice.c:1164
splice_direct_to_actor+0x2fb/0x660 fs/splice.c:1108
do_splice_direct_actor fs/splice.c:1207 [inline]
do_splice_direct+0xd7/0x150 fs/splice.c:1233
do_sendfile+0x3b9/0x960 fs/read_write.c:1295
__do_sys_sendfile64 fs/read_write.c:1362 [inline]
__se_sys_sendfile64 fs/read_write.c:1348 [inline]
__x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff88810698197c of 4 bytes by task 15863 on cpu 1:
xa_marked include/linux/xarray.h:420 [inline]
mapping_tagged include/linux/fs.h:507 [inline]
__writeback_single_inode+0x21d/0x860 fs/fs-writeback.c:1676
writeback_single_inode+0x12f/0x4a0 fs/fs-writeback.c:1746
sync_inode_metadata+0x56/0x80 fs/fs-writeback.c:2808
generic_buffers_fsync_noflush+0xe4/0x120 fs/buffer.c:612
ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
ext4_sync_file+0x206/0x6c0 fs/ext4/fsync.c:151
vfs_fsync_range+0x111/0x120 fs/sync.c:188
generic_write_sync include/linux/fs.h:2732 [inline]
ext4_buffered_write_iter+0x334/0x370 fs/ext4/file.c:305
ext4_file_write_iter+0x297/0xe10
call_write_iter include/linux/fs.h:2085 [inline]
iter_file_splice_write+0x5de/0x950 fs/splice.c:743
do_splice_from fs/splice.c:941 [inline]
direct_splice_actor+0x167/0x2c0 fs/splice.c:1164
splice_direct_to_actor+0x2fb/0x660 fs/splice.c:1108
do_splice_direct_actor fs/splice.c:1207 [inline]
do_splice_direct+0xd7/0x150 fs/splice.c:1233
do_sendfile+0x3b9/0x960 fs/read_write.c:1295
__do_sys_sendfile64 fs/read_write.c:1362 [inline]
__se_sys_sendfile64 fs/read_write.c:1348 [inline]
__x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x14000021 -> 0x08000021

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 15863 Comm: syz-executor.4 Not tainted 6.8.0-rc5-syzkaller-00002-gfca7526b7d89 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
==================================================================


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