syzbot


KCSAN: data-race in ext4_write_end / ext4_writepages (5)

Status: auto-closed as invalid on 2022/03/10 10:14
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 302d, last: 302d
similar bugs (4):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in ext4_write_end / ext4_writepages (2) 6 595d 674d 0/24 auto-closed as invalid on 2021/05/21 11:18
upstream KCSAN: data-race in ext4_write_end / ext4_writepages (4) 2 388d 399d 0/24 auto-closed as invalid on 2021/12/15 03:02
upstream KCSAN: data-race in ext4_write_end / ext4_writepages (3) 1 457d 457d 0/24 auto-closed as invalid on 2021/10/06 19:55
upstream KCSAN: data-race in ext4_write_end / ext4_writepages 1 780d 780d 0/24 auto-closed as invalid on 2020/11/17 08:49

Sample crash report:
==================================================================
BUG: KCSAN: data-race in ext4_write_end / ext4_writepages

write to 0xffff8881344b8c48 of 8 bytes by task 2093 on cpu 1:
 i_size_write include/linux/fs.h:907 [inline]
 ext4_update_inode_size fs/ext4/ext4.h:3427 [inline]
 ext4_write_end+0x16d/0x710 fs/ext4/inode.c:1305
 ext4_da_write_end+0x6d/0x630 fs/ext4/inode.c:3009
 generic_perform_write+0x261/0x400 mm/filemap.c:3776
 ext4_buffered_write_iter+0x244/0x360 fs/ext4/file.c:268
 ext4_file_write_iter+0x2e7/0x11f0
 call_write_iter include/linux/fs.h:2074 [inline]
 new_sync_write fs/read_write.c:503 [inline]
 vfs_write+0x7f5/0x950 fs/read_write.c:590
 ksys_write+0xd9/0x190 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:652
 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 0xffff8881344b8c48 of 8 bytes by task 1850 on cpu 0:
 i_size_read include/linux/fs.h:885 [inline]
 mpage_submit_page fs/ext4/inode.c:2074 [inline]
 mpage_map_and_submit_buffers fs/ext4/inode.c:2326 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2465 [inline]
 ext4_writepages+0x10b6/0x1e80 fs/ext4/inode.c:2778
 do_writepages+0x1cb/0x330 mm/page-writeback.c:2364
 __writeback_single_inode+0x81/0x590 fs/fs-writeback.c:1618
 writeback_sb_inodes+0x677/0xdf0 fs/fs-writeback.c:1891
 wb_writeback+0x26b/0x650 fs/fs-writeback.c:2064
 wb_do_writeback+0x101/0x560 fs/fs-writeback.c:2207
 wb_workfn+0xc8/0x440 fs/fs-writeback.c:2248
 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307
 worker_thread+0x616/0xa70 kernel/workqueue.c:2454
 kthread+0x1bf/0x1e0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30

value changed: 0x0000000000f7d000 -> 0x0000000000f7e000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1850 Comm: kworker/u4:6 Not tainted 5.17.0-rc2-syzkaller-00060-g88808fbbead4 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: writeback wb_workfn (flush-8:0)
==================================================================
vhci_hcd: stop threads
vhci_hcd: release socket
vhci_hcd: disconnect device

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2022/02/03 10:14 upstream 88808fbbead4 4ebb2798 .config log report info KCSAN: data-race in ext4_write_end / ext4_writepages
* Struck through repros no longer work on HEAD.