syzbot


KCSAN: data-race in __save_error_info / ext4_es_insert_delayed_block

Status: auto-closed as invalid on 2020/12/27 02:43
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+573bd33cef0f562839ed@syzkaller.appspotmail.com
First crash: 1250d, last: 1250d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __save_error_info / ext4_es_insert_delayed_block

read-write to 0xffff8881443988a8 of 2 bytes by task 12335 on cpu 0:
 __save_error_info+0x67/0x420 fs/ext4/super.c:433
 __ext4_grp_locked_error+0xbb/0x4b0 fs/ext4/super.c:985
 mb_free_blocks+0xa94/0xe00 fs/ext4/mballoc.c:1506
 ext4_mb_release_inode_pa+0x2d6/0x5a0 fs/ext4/mballoc.c:4177
 ext4_discard_preallocations+0x6e7/0xd50 fs/ext4/mballoc.c:4441
 ext4_truncate+0x7d8/0xbb0 fs/ext4/inode.c:4251
 ext4_setattr+0xbac/0xf70 fs/ext4/inode.c:5493
 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 0xffff8881443988a8 of 2 bytes by task 12337 on cpu 1:
 ext4_es_insert_delayed_block+0x59/0x3b0 fs/ext4/extents_status.c:1993
 ext4_insert_delayed_block fs/ext4/inode.c:1672 [inline]
 ext4_da_map_blocks fs/ext4/inode.c:1762 [inline]
 ext4_da_get_block_prep+0x582/0x9a0 fs/ext4/inode.c:1826
 ext4_block_write_begin+0x3f0/0xaa0 fs/ext4/inode.c:1068
 ext4_da_write_begin+0x50a/0xaf0 fs/ext4/inode.c:3007
 generic_perform_write+0x196/0x3a0 mm/filemap.c:3321
 ext4_buffered_write_iter+0x2e5/0x3d0 fs/ext4/file.c:270
 ext4_file_write_iter+0x45e/0x1090 fs/ext4/file.c:503
 call_write_iter include/linux/fs.h:1903 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x6d4/0x7c0 fs/read_write.c:605
 ksys_write+0xce/0x180 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write fs/read_write.c:667 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:667
 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: 12337 Comm: syz-executor.1 Not tainted 5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/11/22 02:42 upstream a349e4c65960 0d27f508 .config console log report info ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.