From: "Paul E. McKenney" <paulmck@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: peterz@infradead.org, mingo@kernel.org, tglx@linutronix.de,
bigeasy@linutronix.de, frederic@kernel.org
Subject: Re: [PATCH smp 0/2] Provide CSD lock timeout diagnostics
Date: Mon, 27 Jul 2020 16:53:43 -0700 [thread overview]
Message-ID: <20200727235343.GA30963@paulmck-ThinkPad-P72> (raw)
In-Reply-To: <20200709235436.GA20922@paulmck-ThinkPad-P72>
Hello!
This is version 2 of a sneak preview of a series providing diagnostics
to help track down problems that would result in excessive csd_unlock()
latencies:
1. Add source and destination CPUs to __call_single_data.
I freely admit that I found the union declaration a
bit confusing!
2. Provide CSD lock timeout diagnostics.
3. Add "static" to a local variable.
Changes since v1:
o Fix stack-out-of-bounds read in csd_lock_record located by syzbot.
o Fix KASAN-detected use-after-free issue reported by Qian Cai.
o Fix botched nr_cpu_ids comparison reported by Dan Carpenter.
o Fix numerous issues reported by Peter Zijlstra, including
annoying CPP macros, #ifdef consolidation, another use-after-free
issue, memory-ordering/comment issues, {} code-style issues.
This now has no effect unless CONFIG_CSD_LOCK_WAIT_DEBUG=y.
It also uses NSEC_PER_MSEC instead of cubing 1000.
Times are now printed in nanoseconds instead of decimal seconds.
Switched to C-language Classic Comment style.
Moved to x-mas tree variable-declaration order from alphabetic.
Avoided two prints via "CPU-1".
o This version still "handles" 32-bit VDSO build errors by
prohibiting CONFIG_CSD_LOCK_WAIT_DEBUG=y in 32-bit builds.
Thanx, Paul
------------------------------------------------------------------------
include/linux/smp.h | 3 +
include/linux/smp_types.h | 3 +
kernel/smp.c | 136 +++++++++++++++++++++++++++++++++++++++++++++-
lib/Kconfig.debug | 11 +++
4 files changed, 152 insertions(+), 1 deletion(-)
next prev parent reply other threads:[~2020-07-27 23:53 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-09 23:54 Paul E. McKenney
2020-07-09 23:55 ` [PATCH smp 1/2] smp: Add source and destination CPUs to __call_single_data paulmck
2020-07-09 23:55 ` [PATCH smp 2/2] kernel/smp: Provide CSD lock timeout diagnostics paulmck
2020-07-10 10:32 ` Peter Zijlstra
2020-07-10 21:28 ` Paul E. McKenney
2020-07-10 22:58 ` Paul E. McKenney
2020-07-23 13:55 ` Peter Zijlstra
2020-07-23 22:50 ` Paul E. McKenney
2020-07-24 18:19 ` Paul E. McKenney
2020-07-27 23:53 ` Paul E. McKenney [this message]
2020-07-27 23:55 ` [PATCH smp v2 1/3] smp: Add source and destination CPUs to __call_single_data paulmck
2020-07-27 23:55 ` [PATCH smp v2 2/3] kernel/smp: Provide CSD lock timeout diagnostics paulmck
2020-07-27 23:55 ` [PATCH smp v2 3/3] smp: Make symbol 'csd_bug_count' static paulmck
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