From: Steven Rostedt <rostedt@goodmis.org>
To: Yunseong Kim <ysk@kzalloc.com>
Cc: Dmitry Vyukov <dvyukov@google.com>,
Andrey Konovalov <andreyknvl@gmail.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
Byungchul Park <byungchul@sk.com>,
max.byungchul.park@gmail.com, Yeoreum Yun <yeoreum.yun@arm.com>,
ppbuk5246@gmail.com, linux-usb@vger.kernel.org,
linux-rt-devel@lists.linux.dev, syzkaller@googlegroups.com,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH v3 0/4] kcov, usb: Fix invalid context sleep in softirq path on PREEMPT_RT
Date: Mon, 4 Aug 2025 12:24:05 -0400 [thread overview]
Message-ID: <20250804122405.3e9d83ed@gandalf.local.home> (raw)
In-Reply-To: <20250803072044.572733-2-ysk@kzalloc.com>
On Sun, 3 Aug 2025 07:20:41 +0000
Yunseong Kim <ysk@kzalloc.com> wrote:
> This patch series resolves a sleeping function called from invalid context
> bug that occurs when fuzzing USB with syzkaller on a PREEMPT_RT kernel.
>
> The regression was introduced by the interaction of two separate patches:
> one that made kcov's internal locks sleep on PREEMPT_RT for better latency
Just so I fully understand this change. It is basically reverting the
"better latency" changes? That is, with KCOV anyone running with PREEMPT_RT
can expect non deterministic latency behavior?
This should be fully documented. I assume this will not be a problem as
kcov is more for debugging and should not be enabled in production.
-- Steve
next prev parent reply other threads:[~2025-08-04 16:23 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-03 7:20 [PATCH v3 0/4] kcov, usb: Fix invalid context sleep in softirq path on PREEMPT_RT Yunseong Kim
2025-08-03 7:20 ` [PATCH 1/4] kcov: Use raw_spinlock_t for kcov->lock and kcov_remote_lock Yunseong Kim
2025-08-03 7:23 ` kernel test robot
2025-08-04 16:27 ` Steven Rostedt
2025-08-05 15:33 ` Yunseong Kim
2025-08-03 7:20 ` [PATCH 2/4] kcov: Replace per-CPU local_lock with local_irq_save/restore Yunseong Kim
2025-08-04 16:37 ` Steven Rostedt
2025-08-05 15:41 ` Yunseong Kim
2025-08-03 7:20 ` [PATCH 3/4] kcov: Separate KCOV_REMOTE_ENABLE ioctl helper function Yunseong Kim
2025-08-03 7:20 ` [PATCH 4/4] kcov: move remote handle allocation outside raw spinlock Yunseong Kim
2025-08-04 16:24 ` Steven Rostedt [this message]
2025-08-05 15:27 ` [PATCH v3 0/4] kcov, usb: Fix invalid context sleep in softirq path on PREEMPT_RT Yunseong Kim
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