rcu: Use task_state_to_char() in stall-warning prints

RCU stall warnings currently print task states as raw hexadecimal
values, requiring developers to manually decode them.

Use task_state_to_char() so that stall warnings show the same symbolic
task-state representation used elsewhere in the kernel.

For example:
	->state=0x402  becomes  ->state=I
	->state=0x0    becomes  ->state=R
	->state=0x2    becomes  ->state=D

This improves readability while preserving the underlying diagnostic
information.

Suggested-by: Zqiang <qiang.zhang@linux.dev>
Co-developed-by: Wang Lian <lianux.mm@gmail.com>
Signed-off-by: Wang Lian <lianux.mm@gmail.com>
Signed-off-by: Kunwu Chan <kunwu.chan@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Kunwu Chan 2026-06-12 10:34:12 +08:00 • committed by Paul E. McKenney
commit 1384ea908e