linux-kernel - [PATCH v6 0/2] Make printing of spin_dump() deferred to avoid a deadlock

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Message-Id: <1457692627-14076-1-git-send-email-byungchul.park@lge.com>
Date:	Fri, 11 Mar 2016 19:37:05 +0900
From:	Byungchul Park <byungchul.park@....com>
To:	akpm@...ux-foundation.org, mingo@...nel.org
Cc:	linux-kernel@...r.kernel.org, akinobu.mita@...il.com, jack@...e.cz,
	sergey.senozhatsky.work@...il.com, peter@...leysoftware.com,
	tglx@...utronix.de, peterz@...radead.org, rostedt@...dmis.org
Subject: [PATCH v6 0/2] Make printing of spin_dump() deferred to avoid a deadlock

changes from v5 to v6
- define the problem clearly and solve it by using irq work.

changes from v4 to v5
- found out a clear scenario which make a system crazy. at least it
  should not be caused by the debug code.

changes from v3 to v4
- reuse a existing code as much as possible for preventing an infinite
  recursive cycle.

changes from v2 to v3
- avoid printk() only in case of lockup suspected, not real lockup in
  which case it does not help at all.
- consider not only console_sem.lock but also logbuf_lock which is used
  by printk().

changes from v1 to v2
- only change comment and commit message esp. replacing "deadlock" with
  "infinite recursive cycle", since it is not an actual deadlock.

Thanks,
Byungchul

Byungchul Park (2):
  printk: Factor out buffering and irq work queuing in printk_deferred
  printk: Make printing of spin_dump() deferred to avoid a deadlock

 include/linux/printk.h          | 11 +++++++++++
 kernel/locking/spinlock_debug.c | 33 ++++++++++++++++++++++++++++++++-
 kernel/printk/printk.c          | 25 ++++++++++++++++++++++---
 3 files changed, 65 insertions(+), 4 deletions(-)

-- 
1.9.1