syzbot


KCSAN: data-race in ext4_mb_find_by_goal / mb_mark_used (2)

Status: auto-closed as invalid on 2022/03/09 09:21
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 151d, last: 151d
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in ext4_mb_find_by_goal / mb_mark_used 326 195d 750d 0/22 auto-closed as invalid on 2022/01/24 21:39
upstream KCSAN: data-race in ext4_mb_find_by_goal / mb_mark_used (3) 2 53d 55d 0/22 closed as invalid on 2022/05/13 11:20

Sample crash report:
==================================================================
BUG: KCSAN: data-race in ext4_mb_find_by_goal / mb_mark_used

write to 0xffff888103816854 of 4 bytes by task 24535 on cpu 0:
 mb_mark_used+0x13b/0xc50 fs/ext4/mballoc.c:1947
 ext4_mb_use_best_found+0x102/0x300 fs/ext4/mballoc.c:2019
 ext4_mb_simple_scan_group+0x253/0x3a0 fs/ext4/mballoc.c:2297
 ext4_mb_regular_allocator+0x1918/0x24a0 fs/ext4/mballoc.c:2773
 ext4_mb_new_blocks+0x78c/0x1ee0 fs/ext4/mballoc.c:5582
 ext4_ext_map_blocks+0x1658/0x2110 fs/ext4/extents.c:4282
 ext4_map_blocks+0x757/0xfa0 fs/ext4/inode.c:638
 ext4_alloc_file_blocks+0x281/0x730 fs/ext4/extents.c:4467
 ext4_fallocate+0x297/0x530 fs/ext4/extents.c:4744
 vfs_fallocate+0x486/0x720 fs/open.c:308
 do_vfs_ioctl+0x13cb/0x14a0 fs/ioctl.c:853
 __do_sys_ioctl fs/ioctl.c:872 [inline]
 __se_sys_ioctl+0x83/0x140 fs/ioctl.c:860
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:860
 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 0xffff888103816854 of 4 bytes by task 24527 on cpu 1:
 ext4_mb_find_by_goal+0x13f/0x880 fs/ext4/mballoc.c:2207
 ext4_mb_regular_allocator+0x12b/0x24a0 fs/ext4/mballoc.c:2654
 ext4_mb_new_blocks+0x78c/0x1ee0 fs/ext4/mballoc.c:5582
 ext4_ext_map_blocks+0x1658/0x2110 fs/ext4/extents.c:4282
 ext4_map_blocks+0x757/0xfa0 fs/ext4/inode.c:638
 ext4_alloc_file_blocks+0x281/0x730 fs/ext4/extents.c:4467
 ext4_fallocate+0x297/0x530 fs/ext4/extents.c:4744
 vfs_fallocate+0x486/0x720 fs/open.c:308
 do_vfs_ioctl+0x13cb/0x14a0 fs/ioctl.c:853
 __do_sys_ioctl fs/ioctl.c:872 [inline]
 __se_sys_ioctl+0x83/0x140 fs/ioctl.c:860
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:860
 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: 0x00002000 -> 0x00001800

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 24527 Comm: syz-executor.5 Not tainted 5.17.0-rc2-syzkaller-00039-g9f7fb8de5d9b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2022/02/02 09:14 upstream 9f7fb8de5d9b 4ebb2798 .config log report info KCSAN: data-race in ext4_mb_find_by_goal / mb_mark_used