syzbot


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

Status: closed as invalid on 2022/05/13 11:20
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 200d, last: 199d
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_mark_used 850 340d 1139d 0/24 auto-closed as invalid on 2022/01/25 08:47
upstream KCSAN: data-race in ext4_mb_good_group / mb_mark_used (2) 4 295d 297d 0/24 auto-closed as invalid on 2022/03/10 23:58

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

read-write to 0xffff888101bec6d4 of 4 bytes by task 4239 on cpu 1:
 mb_mark_used+0x124/0xb80 fs/ext4/mballoc.c:1947
 ext4_mb_use_best_found+0x105/0x440 fs/ext4/mballoc.c:2019
 ext4_mb_find_by_goal+0x589/0x660
 ext4_mb_regular_allocator+0x12b/0x1ff0 fs/ext4/mballoc.c:2654
 ext4_mb_new_blocks+0x839/0xfd0 fs/ext4/mballoc.c:5616
 ext4_ext_map_blocks+0xd55/0x1bb0 fs/ext4/extents.c:4281
 ext4_map_blocks+0x75b/0xfc0 fs/ext4/inode.c:636
 ext4_alloc_file_blocks+0x281/0x730 fs/ext4/extents.c:4466
 ext4_zero_range+0x4db/0x880 fs/ext4/extents.c:4619
 ext4_fallocate+0x230/0x420 fs/ext4/extents.c:4716
 vfs_fallocate+0x355/0x3d0 fs/open.c:308
 do_vfs_ioctl+0x12d9/0x1390 fs/ioctl.c:849
 __do_sys_ioctl fs/ioctl.c:868 [inline]
 __se_sys_ioctl+0x83/0x140 fs/ioctl.c:856
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888101bec6d4 of 4 bytes by task 4244 on cpu 0:
 ext4_mb_good_group+0x136/0x380 fs/ext4/mballoc.c:2432
 ext4_mb_good_group_nolock fs/ext4/mballoc.c:2545 [inline]
 ext4_mb_regular_allocator+0x1554/0x1ff0 fs/ext4/mballoc.c:2747
 ext4_mb_new_blocks+0x839/0xfd0 fs/ext4/mballoc.c:5616
 ext4_ext_map_blocks+0xd55/0x1bb0 fs/ext4/extents.c:4281
 ext4_map_blocks+0x75b/0xfc0 fs/ext4/inode.c:636
 ext4_alloc_file_blocks+0x281/0x730 fs/ext4/extents.c:4466
 ext4_zero_range+0x37b/0x880 fs/ext4/extents.c:4583
 ext4_fallocate+0x230/0x420 fs/ext4/extents.c:4716
 vfs_fallocate+0x355/0x3d0 fs/open.c:308
 do_vfs_ioctl+0x12d9/0x1390 fs/ioctl.c:849
 __do_sys_ioctl fs/ioctl.c:868 [inline]
 __se_sys_ioctl+0x83/0x140 fs/ioctl.c:856
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x000071ec -> 0x000069ec

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 4244 Comm: syz-executor.0 Not tainted 5.18.0-rc6-syzkaller-00009-gfeb9c5e19e91 #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 2022/05/11 16:49 upstream feb9c5e19e91 beb0b407 .config log report info KCSAN: data-race in ext4_mb_good_group / mb_mark_used
ci2-upstream-kcsan-gce 2022/05/11 02:16 upstream feb9c5e19e91 8d7b3b67 .config log report info KCSAN: data-race in ext4_mb_good_group / mb_mark_used
ci2-upstream-kcsan-gce 2022/05/09 21:26 upstream 9be9ed2612b5 8b277b8e .config log report info KCSAN: data-race in ext4_mb_good_group / mb_mark_used
* Struck through repros no longer work on HEAD.