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From: Tony Rodriguez <unixpro1970@gmail.com>
To: davem@davemloft.net, sparclinux@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, andreas@gaisler.com,
	tglx@kernel.org, thomas.weissschuh@linutronix.de,
	regressions@lists.linux.dev, glaubitz@physik.fu-berlin.de,
	linux@leemhuis.info, torvalds@linux-foundation.org,
	Tony Rodriguez <unixpro1970@gmail.com>
Subject: [PATCH v2 1/1] sparc64: Fix comparator problem with timer interrupts
Date: Mon, 18 May 2026 19:24:08 -0700	[thread overview]
Message-ID: <20260519022421.5978-1-unixpro1970@gmail.com> (raw)

sparc64: Fix comparator problem with timer interrupts

This patch fixes SPARC64 tick/stick comparator logic that can cause missed
timer interrupts

Full dmesg and crash dumps:
https://github.com/unixpro1970/Sparc64-Kernel-Debugging-Dumps/blob/main/s7-2-05122026-dump.tar.gz

Debugging discussion:
https://lore.kernel.org/all/87tssb6olo.ffs@tglx/
https://lore.kernel.org/all/871pfcznw0.ffs@tglx/

Short dmesg excerpt:
[   48.632215] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
[   48.676018] rcu: rcu_sched kthread timer wakeup didn't happen for 5259 jiffies!
[   48.743621] rcu:     Possible timer handling issue on cpu=100 timer-softirq=15

Test summary:
After applying this patch, S7-2 and T7-1 systems no longer hang on v7 and v7.1 kernels.

Tony Rodriguez (1):
  sparc64: Fix comparator problem with timer interrupts

 arch/sparc/kernel/time_64.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--
2.53.0


             reply	other threads:[~2026-05-19  2:24 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-19  2:24 Tony Rodriguez [this message]
2026-05-19  2:24 ` Tony Rodriguez
2026-05-19 14:22   ` Thomas Gleixner
2026-05-19 23:25     ` Tony Rodriguez

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