Hello, I hit this TASKS03 hung in D-state at synchronize_rcu_mult_test() but only once and cannot reproduce it. I am sharing it here just for tracking. Let me know any feedback. I'll continue to monitor/debug it. This is excerpt from dmesg with full logs at the link: http://box.joelfernandes.org:9080/job/rcutorture_stable/job/linux-5.15.y/49/artifact/tools/testing/selftests/rcutorture/res/2023.08.03-11.12.30/TASKS03/console.log [ 592.563051] kvm-clock: cpu 2, msr 61a3081, secondary cpu clock [ 2791.512132] kvm-guest: stealtime: cpu 2, msr 1f51b140 [ 2791.689159] tasks-torture: rtc: 0000000079608068 ver: 1879 tfle: 0 rta: 1880 rtaf: 0 rtf: 1870 rtmbe: 0 rtmbkf: 0/1648 rtbe: 0 rtbke: 0 rtbre: 0 rtbf: 0 rtb: 0 nt: 208618 onoff: 187/188:188/188 60,424:14,382 29372:19593 (HZ=1000) barrier: 1556/1557:0 read-exits: 662 nocb-toggles: 0:0 [ 2791.753481] tasks-torture: Reader Pipe: 1294864132 635 0 0 0 0 0 0 0 0 0 [ 2791.765096] tasks-torture: Reader Batch: 1294864767 0 0 0 0 0 0 0 0 0 0 [ 2791.774413] tasks-torture: Free-Block Circulation: 1879 1878 1877 1876 1875 1874 1873 1872 1871 1870 0 [ 2791.789398] ??? Writer stall state RTWS_EXP_SYNC(4) g0 f0x0 ->state 0x2 cpu 3 [ 2791.800678] task:rcu_torture_wri state:D stack:14752 pid: 75 ppid: 2 flags:0x00004000 [ 2791.814827] Call Trace: [ 2791.819597] <TASK> [ 2791.823774] __schedule+0x299/0x720 [ 2791.830734] schedule+0x57/0xe0 [ 2791.836622] schedule_timeout+0x113/0x150 [ 2791.844009] wait_for_completion+0x87/0xe0 [ 2791.851416] __wait_rcu_gp+0x126/0x130 [ 2791.858109] synchronize_rcu_mult_test+0x47/0x70 [ 2791.865706] ? rcu_tasks_trace_postgp+0x320/0x320 [ 2791.873743] ? rcu_nocb_gp_kthread+0xab0/0xab0 [ 2791.881410] ? perf_trace_rcu_torture_read+0x140/0x140 [ 2791.890288] rcu_torture_writer+0x237/0x6e0 [ 2791.897484] ? rcu_torture_pipe_update+0x130/0x130 [ 2791.905824] kthread+0x12d/0x160 [ 2791.911068] ? set_kthread_struct+0x40/0x40 [ 2791.923480] ret_from_fork+0x22/0x30 [ 2791.929779] </TASK> [ 2791.933912] rcu_tasks: RTGS_WAIT_SCAN_HOLDOUTS(6) since 78 g:3027 i:0/0 kC [ 2791.946351] Dumping ftrace buffer: [ 2791.956592] (ftrace buffer empty)
