Hi, I ran into a kernel bug related to blk-throttle on CentOS 7 AltArch for i386. Userspace programs may panic the kernel if they hit the I/O limit within 5 minutes after startup. Root cause: 1. jiffies was initialized to -300HZ during boot on 32bit machines 2. enable blkio cgroup hierarchy __DEVEL__sane_behavior for cgroup v1 or default hierarchy for cgroup v2 EL7 kernel modified throtl_pd_init and always enable hierarchical throttling 3. enable & trigger blkio throttling within 5 minutes after startup bio propagated from child tg to parent 4. enter throtl_start_new_slice_with_credit if(time_after_eq(start, tg->slice_start[rw])) aka. time_after_eq(0xFFFxxxxx, 0) does not hold parent tg->slice_start[rw] was zero-initialized and not updated 5. enter throtl_trim_slice BUG_ON(time_before(tg->slice_end[rw], tg->slice_start[rw])) aka. time_before(0xFFFxxxxx, 0) triggers a panic Reproducer: (tested on Alpine Linux x86 kernel 5.10.X) #!/bin/sh CGROUP_PATH="$(mktemp -d)" mount -t cgroup2 none "$CGROUP_PATH" echo +io >"$CGROUP_PATH/cgroup.subtree_control" mkdir "$CGROUP_PATH/child" echo "7:0 riops=2" >"$CGROUP_PATH/child/io.max" echo 0 >"$CGROUP_PATH/child/cgroup.procs" echo 3 >/proc/sys/vm/drop_caches dd if=/dev/loop0 of=/dev/null count=3
