On Thu, Jun 11, 2026 at 03:32:01PM +0800, Kunwu Chan wrote:
> From: Kunwu Chan <[email protected]>
>
> RCU stall warnings currently print task states as raw hexadecimal
> values (e.g., ->state=0x402), forcing developers to manually decode
> them from memory.
>
> Replace these raw hex values with the compact, single-letter symbols
> already established by sched_show_task():
>
> ->state=0x402 becomes ->state=I (TASK_IDLE)
> ->state=0x0 becomes ->state=R (TASK_RUNNING)
> ->state=0x2 becomes ->state=D (TASK_UNINTERRUPTIBLE)
>
> Convert five print sites across tree_stall.h, rcutorture.c, and
> hazptrtorture.c to use task_state_to_char() instead of the raw
> ->__state value.
>
> Suggested-by: Zqiang <[email protected]>
> Co-developed-by: Wang Lian <[email protected]>
> Signed-off-by: Wang Lian <[email protected]>
> Signed-off-by: Kunwu Chan <[email protected]>
Nice!
But could you please split this into three commits, one for each file?
That makes it easier to create branches to send to Linus. Especially
since hazptrtorture.c will likely be in a different pull request. ;-)
Thanx, Paul
> ---
> Based on: linux-rcu repo (dev branch)
> URL: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
> base-commit: 85bf11e84 ("smp: Make CSD lock acquisition atomic for debug
> mode")
> ---
> kernel/rcu/hazptrtorture.c | 4 ++--
> kernel/rcu/rcutorture.c | 4 ++--
> kernel/rcu/tree_stall.h | 12 ++++++------
> 3 files changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/kernel/rcu/hazptrtorture.c b/kernel/rcu/hazptrtorture.c
> index 0da0a4606..19ea479c9 100644
> --- a/kernel/rcu/hazptrtorture.c
> +++ b/kernel/rcu/hazptrtorture.c
> @@ -497,10 +497,10 @@ hazptr_torture_stats_print(void)
> unsigned long __maybe_unused gp_seq = 0;
>
> wtp = READ_ONCE(writer_task);
> - pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x
> cpu %d\n",
> + pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %c
> cpu %d\n",
> hazptr_torture_writer_state_getname(),
> hazptr_torture_writer_state, gp_seq, flags,
> - wtp == NULL ? ~0U : wtp->__state,
> + wtp == NULL ? '?' : task_state_to_char(wtp),
> wtp == NULL ? -1 : (int)task_cpu(wtp));
> if (!splatted && wtp) {
> sched_show_task(wtp);
> diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
> index fcb421ced..4d4ebeeea 100644
> --- a/kernel/rcu/rcutorture.c
> +++ b/kernel/rcu/rcutorture.c
> @@ -3074,10 +3074,10 @@ rcu_torture_stats_print(void)
> if (cur_ops->get_gp_data)
> cur_ops->get_gp_data(&flags, &gp_seq);
> wtp = READ_ONCE(writer_task);
> - pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x
> cpu %d\n",
> + pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %c
> cpu %d\n",
> rcu_torture_writer_state_getname(),
> rcu_torture_writer_state, gp_seq, flags,
> - wtp == NULL ? ~0U : wtp->__state,
> + wtp == NULL ? '?' : task_state_to_char(wtp),
> wtp == NULL ? -1 : (int)task_cpu(wtp));
> if (!splatted && wtp) {
> sched_show_task(wtp);
> diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
> index 317ef91b1..7ca434b08 100644
> --- a/kernel/rcu/tree_stall.h
> +++ b/kernel/rcu/tree_stall.h
> @@ -596,13 +596,13 @@ static void rcu_check_gp_kthread_starvation(void)
>
> if (rcu_is_gp_kthread_starving(&j)) {
> cpu = gpk ? task_cpu(gpk) : -1;
> - pr_err("%s kthread starved for %ld jiffies! g%ld f%#x %s(%d)
> ->state=%#x ->cpu=%d\n",
> + pr_err("%s kthread starved for %ld jiffies! g%ld f%#x %s(%d)
> ->state=%c ->cpu=%d\n",
> rcu_state.name, j,
> (long)rcu_seq_current(&rcu_state.gp_seq),
> data_race(READ_ONCE(rcu_state.gp_flags)),
> gp_state_getname(rcu_state.gp_state),
> data_race(READ_ONCE(rcu_state.gp_state)),
> - gpk ? data_race(READ_ONCE(gpk->__state)) : ~0, cpu);
> + gpk ? task_state_to_char(gpk) : '?', cpu);
> if (gpk) {
> struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
>
> @@ -639,12 +639,12 @@ static void rcu_check_gp_kthread_expired_fqs_timer(void)
> time_after(jiffies, jiffies_fqs + RCU_STALL_MIGHT_MIN) &&
> gpk && !READ_ONCE(gpk->on_rq)) {
> cpu = task_cpu(gpk);
> - pr_err("%s kthread timer wakeup didn't happen for %ld jiffies!
> g%ld f%#x %s(%d) ->state=%#x\n",
> + pr_err("%s kthread timer wakeup didn't happen for %ld jiffies!
> g%ld f%#x %s(%d) ->state=%c\n",
> rcu_state.name, (jiffies - jiffies_fqs),
> (long)rcu_seq_current(&rcu_state.gp_seq),
> data_race(READ_ONCE(rcu_state.gp_flags)), // Diagnostic
> read
> gp_state_getname(RCU_GP_WAIT_FQS), RCU_GP_WAIT_FQS,
> - data_race(READ_ONCE(gpk->__state)));
> + task_state_to_char(gpk));
> pr_err("\tPossible timer handling issue on cpu=%d
> timer-softirq=%u\n",
> cpu, kstat_softirqs_cpu(TIMER_SOFTIRQ, cpu));
> }
> @@ -971,10 +971,10 @@ void show_rcu_gp_kthreads(void)
> jr = j - data_race(READ_ONCE(rcu_state.gp_req_activity));
> js = j - data_race(READ_ONCE(rcu_state.gp_start));
> jw = j - data_race(READ_ONCE(rcu_state.gp_wake_time));
> - pr_info("%s: wait state: %s(%d) ->state: %#x ->rt_priority %u delta
> ->gp_start %lu ->gp_activity %lu ->gp_req_activity %lu ->gp_wake_time %lu
> ->gp_wake_seq %ld ->gp_seq %ld ->gp_seq_needed %ld ->gp_max %lu ->gp_flags
> %#x\n",
> + pr_info("%s: wait state: %s(%d) ->state: %c ->rt_priority %u delta
> ->gp_start %lu ->gp_activity %lu ->gp_req_activity %lu ->gp_wake_time %lu
> ->gp_wake_seq %ld ->gp_seq %ld ->gp_seq_needed %ld ->gp_max %lu ->gp_flags
> %#x\n",
> rcu_state.name, gp_state_getname(rcu_state.gp_state),
> data_race(READ_ONCE(rcu_state.gp_state)),
> - t ? data_race(READ_ONCE(t->__state)) : 0x1ffff, t ?
> t->rt_priority : 0xffU,
> + t ? task_state_to_char(t) : '?', t ? t->rt_priority : 0xffU,
> js, ja, jr, jw,
> (long)data_race(READ_ONCE(rcu_state.gp_wake_seq)),
> (long)data_race(READ_ONCE(rcu_state.gp_seq)),
> (long)data_race(READ_ONCE(rcu_get_root()->gp_seq_needed)),
> --
> 2.43.0
>
>
