syzbot


KCSAN: data-race in ext4_mb_good_group / mb_free_blocks (3)

Status: auto-closed as invalid on 2022/01/11 14:33
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 369d, last: 364d
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in ext4_mb_good_group / mb_free_blocks (2) 132 406d 578d 0/24 auto-closed as invalid on 2021/11/30 12:17
upstream KCSAN: data-race in ext4_mb_good_group / mb_free_blocks 273 674d 979d 0/24 auto-closed as invalid on 2021/03/07 11:56

Sample crash report:
==================================================================
BUG: KCSAN: data-race in ext4_mb_good_group / mb_free_blocks

write to 0xffff88810137eb54 of 4 bytes by task 1401 on cpu 0:
 mb_free_blocks+0x156/0xb40 fs/ext4/mballoc.c:1802
 ext4_free_data_in_buddy fs/ext4/mballoc.c:3662 [inline]
 ext4_process_freed_data+0x488/0x900 fs/ext4/mballoc.c:3713
 ext4_journal_commit_callback+0x83/0x1a0 fs/ext4/super.c:449
 jbd2_journal_commit_transaction+0x2b1f/0x3460 fs/jbd2/commit.c:1171
 kjournald2+0x263/0x480 fs/jbd2/journal.c:213
 kthread+0x2c7/0x2e0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30

read to 0xffff88810137eb54 of 4 bytes by task 1822 on cpu 1:
 ext4_mb_good_group+0x136/0x370 fs/ext4/mballoc.c:2432
 ext4_mb_good_group_nolock fs/ext4/mballoc.c:2545 [inline]
 ext4_mb_regular_allocator+0x15c2/0x24a0 fs/ext4/mballoc.c:2747
 ext4_mb_new_blocks+0x78c/0x1ee0 fs/ext4/mballoc.c:5586
 ext4_ext_map_blocks+0x1658/0x2120 fs/ext4/extents.c:4285
 ext4_map_blocks+0x71e/0xf00 fs/ext4/inode.c:637
 ext4_getblk+0xc6/0x3e0 fs/ext4/inode.c:847
 ext4_bread+0x28/0x100 fs/ext4/inode.c:900
 ext4_append+0xd1/0x1c0 fs/ext4/namei.c:67
 ext4_init_new_dir+0x177/0x500 fs/ext4/namei.c:2893
 ext4_mkdir+0x329/0x760 fs/ext4/namei.c:2939
 vfs_mkdir+0x2c8/0x3d0 fs/namei.c:3883
 do_mkdirat+0x12e/0x2c0 fs/namei.c:3909
 __do_sys_mkdir fs/namei.c:3929 [inline]
 __se_sys_mkdir fs/namei.c:3927 [inline]
 __x64_sys_mkdir+0x40/0x50 fs/namei.c:3927
 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

value changed: 0x000007a8 -> 0x000007d8

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1822 Comm: syz-executor.1 Not tainted 5.16.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (3):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2021/12/07 14:31 upstream cd8c917a56f2 0230ba3e .config log report info KCSAN: data-race in ext4_mb_good_group / mb_free_blocks
ci2-upstream-kcsan-gce 2021/12/05 22:12 upstream 944207047ca4 a617004c .config log report info KCSAN: data-race in ext4_mb_good_group / mb_free_blocks
ci2-upstream-kcsan-gce 2021/12/01 19:29 upstream 58e1100fdc59 61f86278 .config log report info KCSAN: data-race in ext4_mb_good_group / mb_free_blocks
* Struck through repros no longer work on HEAD.