From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Jiri Kosina <jkosina@suse.cz>, Michal Hocko <mhocko@suse.cz>,
Jan Kara <jack@suse.cz>, Frederic Weisbecker <fweisbec@gmail.com>,
Dave Anderson <anderson@redhat.com>,
Petr Mladek <pmladek@suse.cz>
Subject: [RFC][PATCH 0/3] x86/nmi: Print all cpu stacks from NMI safely
Date: Thu, 19 Jun 2014 17:33:29 -0400 [thread overview]
Message-ID: <20140619213329.478113470@goodmis.org> (raw)
This is my proposal to print the NMI stack traces from an RCU stall safely.
Here's the gist of it.
Patch 1: move the trace_seq out of the tracing code. It's useful for other
purposes too. Like writing from an NMI context.
Patch 2: Add a per_cpu "printk_func" that printk calls. By default it calls
vprintk_def() which does what it has always done. This allows us to
override what printk() calls normally on a per cpu basis.
Patch 3: Have the NMI handler that dumps the stack trace just change the
printk_func to call a NMI safe printk function that writes to a per cpu
trace_seq. When all NMI handlers chimed in, the original caller prints
out the trace_seqs for each CPU from a printk safe context.
This is much less intrusive than the other versions out there.
Note, The biggest change was the moving of trace_seq code out of trace_output.c
and into the new trace_seq.c library.
Thoughts?
Steven Rostedt (Red Hat) (3):
trace_seq: Move the trace_seq code to lib/
printk: Add per_cpu printk func to allow printk to be diverted
x86/nmi: Perform a safe NMI stack trace on all CPUs
----
arch/x86/kernel/apic/hw_nmi.c | 66 ++++++++-
include/linux/percpu.h | 3 +
include/linux/printk.h | 2 +
include/linux/trace_seq.h | 68 ++--------
kernel/printk/printk.c | 38 ++++--
kernel/trace/trace.c | 24 ----
kernel/trace/trace_output.c | 268 -------------------------------------
kernel/trace/trace_output.h | 16 ---
lib/Makefile | 2 +-
lib/trace_seq.c | 303 ++++++++++++++++++++++++++++++++++++++++++
10 files changed, 412 insertions(+), 378 deletions(-)
next reply other threads:[~2014-06-19 21:39 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-19 21:33 Steven Rostedt [this message]
2014-06-19 21:33 ` [RFC][PATCH 1/3] trace_seq: Move the trace_seq code to lib/ Steven Rostedt
2014-06-20 4:45 ` Linus Torvalds
2014-06-20 16:21 ` Steven Rostedt
2014-06-20 5:06 ` Andrew Morton
2014-06-20 16:58 ` Steven Rostedt
2014-06-20 17:12 ` Andrew Morton
2014-06-20 17:17 ` Steven Rostedt
2014-06-20 20:28 ` Steven Rostedt
2014-06-20 20:51 ` Steven Rostedt
2014-06-23 16:33 ` Petr Mládek
2014-06-23 17:03 ` Steven Rostedt
2014-06-22 7:38 ` Johannes Berg
2014-06-23 16:08 ` Steven Rostedt
2014-06-23 17:38 ` Johannes Berg
2014-06-23 18:04 ` Steven Rostedt
2014-06-24 8:19 ` Johannes Berg
2014-06-19 21:33 ` [RFC][PATCH 2/3] printk: Add per_cpu printk func to allow printk to be diverted Steven Rostedt
2014-06-23 16:06 ` Paul E. McKenney
2014-06-19 21:33 ` [RFC][PATCH 3/3] x86/nmi: Perform a safe NMI stack trace on all CPUs Steven Rostedt
2014-06-20 13:58 ` Don Zickus
2014-06-20 14:21 ` Steven Rostedt
2014-06-20 14:55 ` Petr Mládek
2014-06-20 15:17 ` Steven Rostedt
2014-06-23 16:12 ` Paul E. McKenney
2014-06-19 21:56 ` [RFC][PATCH 0/3] x86/nmi: Print all cpu stacks from NMI safely Jiri Kosina
2014-06-19 22:58 ` Steven Rostedt
2014-06-19 23:03 ` Jiri Kosina
2014-06-19 23:19 ` Steven Rostedt
2014-06-19 23:27 ` Jiri Kosina
2014-06-19 23:36 ` Steven Rostedt
2014-06-19 23:38 ` Jiri Kosina
2014-06-20 14:35 ` Petr Mládek
2014-06-24 13:32 ` Konstantin Khlebnikov
2014-06-25 10:01 ` Jiri Kosina
2014-06-25 11:04 ` Konstantin Khlebnikov
2014-06-25 11:57 ` Petr Mládek
2014-06-25 12:21 ` Petr Mládek
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