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* [PATCHv7 0/8] printk: use printk_safe to handle printk() recursive calls
@ 2016-12-27 14:16 Sergey Senozhatsky
  2016-12-27 14:16 ` [PATCHv7 1/8] printk: use vprintk_func in vprintk() Sergey Senozhatsky
                   ` (8 more replies)
  0 siblings, 9 replies; 55+ messages in thread
From: Sergey Senozhatsky @ 2016-12-27 14:16 UTC (permalink / raw)
  To: Andrew Morton
  Cc: Petr Mladek, Linus Torvalds, Jan Kara, Tejun Heo, Calvin Owens,
	Steven Rostedt, Ingo Molnar, Peter Zijlstra, Andy Lutomirski,
	Peter Hurley, linux-kernel, Sergey Senozhatsky,
	Sergey Senozhatsky

Hello,

	This patch set extends a lock-less NMI per-cpu buffers idea to
handle recursive printk() calls. The basic mechanism is pretty much the
same -- at the beginning of a deadlock-prone section we switch to lock-less
printk callback, and return back to a default printk implementation at the
end; the messages are getting flushed to a logbuf buffer from a safer
context.

See patch 0006 for examples of possible deadlock scenarios that are
handled by printk-safe.


v7:
-- don't touch printk_nmi_enter/exit
-- new printk_safe macros naming: printk_safe_enter_irqsave/exit_irqrestore
-- added printk_safe_enter_irq/printk_safe_exit_irq
-- added patch that converts the rest of printk.c to printk-safe
-- fix build error on !NMI configs
-- improved lost_messages reporting

v6:
-- re-based
-- addressed Petr's review (added comments; moved lost accounting to seq buf)
...

[against next-20161224 + "printk: always report dropped messages" patch set]

Sergey Senozhatsky (8):
  printk: use vprintk_func in vprintk()
  printk: rename nmi.c and exported api
  printk: introduce per-cpu safe_print seq buffer
  printk: always use deferred printk when flush printk_safe lines
  printk: report lost messages in printk safe/nmi contexts
  printk: use printk_safe buffers in printk
  printk: remove zap_locks() function
  printk: convert the rest to printk-safe

 include/linux/printk.h                 |  21 ++-
 init/Kconfig                           |  16 ++-
 init/main.c                            |   2 +-
 kernel/kexec_core.c                    |   2 +-
 kernel/panic.c                         |   4 +-
 kernel/printk/Makefile                 |   2 +-
 kernel/printk/internal.h               |  79 ++++++-----
 kernel/printk/printk.c                 | 220 +++++++++++++------------------
 kernel/printk/{nmi.c => printk_safe.c} | 234 +++++++++++++++++++++++----------
 lib/nmi_backtrace.c                    |   2 +-
 10 files changed, 335 insertions(+), 247 deletions(-)
 rename kernel/printk/{nmi.c => printk_safe.c} (53%)

-- 
2.11.0

^ permalink raw reply	[flat|nested] 55+ messages in thread

end of thread, other threads:[~2017-02-23  9:23 UTC | newest]

Thread overview: 55+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-12-27 14:16 [PATCHv7 0/8] printk: use printk_safe to handle printk() recursive calls Sergey Senozhatsky
2016-12-27 14:16 ` [PATCHv7 1/8] printk: use vprintk_func in vprintk() Sergey Senozhatsky
2016-12-27 14:16 ` [PATCHv7 2/8] printk: rename nmi.c and exported api Sergey Senozhatsky
2017-01-04 13:07   ` Petr Mladek
2017-02-01 15:48   ` Steven Rostedt
2017-02-01 15:50     ` Steven Rostedt
2017-02-23  7:50   ` Geert Uytterhoeven
2017-02-23  8:02     ` Sergey Senozhatsky
2017-02-23  9:23       ` Geert Uytterhoeven
2016-12-27 14:16 ` [PATCHv7 3/8] printk: introduce per-cpu safe_print seq buffer Sergey Senozhatsky
2017-01-04 13:31   ` Petr Mladek
2017-01-05  1:01     ` Sergey Senozhatsky
2017-02-01 15:52   ` Steven Rostedt
2016-12-27 14:16 ` [PATCHv7 4/8] printk: always use deferred printk when flush printk_safe lines Sergey Senozhatsky
2017-02-01 16:06   ` Steven Rostedt
2017-02-02  6:05     ` Sergey Senozhatsky
2017-02-02 15:37       ` Petr Mladek
2017-02-02 15:52         ` Petr Mladek
2017-02-03  2:04           ` Sergey Senozhatsky
2017-02-03 11:18             ` Petr Mladek
2017-02-06  1:48               ` Sergey Senozhatsky
2017-02-06  2:08                 ` Sergey Senozhatsky
2017-02-06 12:16                   ` Petr Mladek
2017-02-06 13:27                     ` Steven Rostedt
2017-02-06 16:42                       ` Sergey Senozhatsky
2017-02-06 16:55                         ` Steven Rostedt
2016-12-27 14:16 ` [PATCHv7 5/8] printk: report lost messages in printk safe/nmi contexts Sergey Senozhatsky
2017-01-04 14:46   ` Petr Mladek
2017-01-05  1:01     ` Sergey Senozhatsky
2017-02-01 16:37   ` Steven Rostedt
2017-02-02  2:02     ` Sergey Senozhatsky
2017-02-02 14:34       ` Steven Rostedt
2017-02-02 16:13         ` Petr Mladek
2017-02-03  1:57         ` Sergey Senozhatsky
2017-02-03  3:13           ` Steven Rostedt
2016-12-27 14:16 ` [PATCHv7 6/8] printk: use printk_safe buffers in printk Sergey Senozhatsky
2017-01-31 17:27   ` Ross Zwisler
2017-02-01  9:06     ` Jan Kara
2017-02-01  9:37       ` Peter Zijlstra
2017-02-01 15:39         ` Petr Mladek
2017-02-01 16:15           ` Peter Zijlstra
2017-02-01 16:41             ` Steven Rostedt
2017-02-02  2:11           ` Sergey Senozhatsky
2017-02-02  9:07             ` Peter Zijlstra
2017-02-02 10:03               ` Sergey Senozhatsky
2017-02-02 15:20                 ` Petr Mladek
2017-02-03  2:45                   ` Sergey Senozhatsky
2017-02-02  1:59     ` Sergey Senozhatsky
2017-02-01 17:04   ` Steven Rostedt
2017-02-02  2:13     ` Sergey Senozhatsky
2016-12-27 14:16 ` [PATCHv7 7/8] printk: remove zap_locks() function Sergey Senozhatsky
2016-12-27 14:16 ` [PATCHv7 8/8] printk: convert the rest to printk-safe Sergey Senozhatsky
2017-01-04 16:28   ` Petr Mladek
2017-01-05  1:00     ` Sergey Senozhatsky
2017-01-05 16:58 ` [PATCHv7 0/8] printk: use printk_safe to handle printk() recursive calls Petr Mladek

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