watchdog/softlockup: fix sample ring index wrap in need_counting_irqs()

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[ Upstream commit cafe4074a7 ]

cpustat_tail indexes cpustat_util[], which is a NUM_SAMPLE_PERIODS-sized
ring buffer. need_counting_irqs() currently wraps the index using
NUM_HARDIRQ_REPORT, which only happens to match NUM_SAMPLE_PERIODS.

Use NUM_SAMPLE_PERIODS for the wrap to keep the ring math correct even if
the NUM_HARDIRQ_REPORT or  NUM_SAMPLE_PERIODS changes.

Link: https://lkml.kernel.org/r/tencent_7068189CB6D6689EB353F3D17BF5A5311A07@qq.com
Fixes: e9a9292e23 ("watchdog/softlockup: Report the most frequent interrupts")
Signed-off-by: Shengming Hu <hu.shengming@zte.com.cn>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Zhang Run <zhang.run@zte.com.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Shengming Hu 2026-01-19 21:59:05 +08:00 • committed by Sasha Levin

parent d14871ce0b

commit 5e227857fc

1 changed files with 1 additions and 1 deletions

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kernel/watchdog.c

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