linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: tip-bot for Peter Zijlstra <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: tglx@linutronix.de, peterz@infradead.org,
	akpm@linux-foundation.org, hpa@zytor.com,
	paulmck@linux.vnet.ibm.com, adobriyan@gmail.com,
	mingo@kernel.org, torvalds@linux-foundation.org,
	linux-kernel@vger.kernel.org
Subject: [tip:locking/core] locking/barriers: Validate lockless_dereference() is used on a pointer type
Date: Wed, 8 Jun 2016 07:19:38 -0700	[thread overview]
Message-ID: <tip-331b6d8c7afc2e5b900b9dcd850c265e1ba8d8e7@git.kernel.org> (raw)
In-Reply-To: <20160522104827.GP3193@twins.programming.kicks-ass.net>

Commit-ID:  331b6d8c7afc2e5b900b9dcd850c265e1ba8d8e7
Gitweb:     http://git.kernel.org/tip/331b6d8c7afc2e5b900b9dcd850c265e1ba8d8e7
Author:     Peter Zijlstra <peterz@infradead.org>
AuthorDate: Sun, 22 May 2016 12:48:27 +0200
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 8 Jun 2016 14:22:47 +0200

locking/barriers: Validate lockless_dereference() is used on a pointer type

Use the type to validate the argument @p is indeed a pointer type.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160522104827.GP3193@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 include/linux/compiler.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 793c082..06f27fd 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -545,10 +545,14 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
  * Similar to rcu_dereference(), but for situations where the pointed-to
  * object's lifetime is managed by something other than RCU.  That
  * "something other" might be reference counting or simple immortality.
+ *
+ * The seemingly unused void * variable is to validate @p is indeed a pointer
+ * type. All pointer types silently cast to void *.
  */
 #define lockless_dereference(p) \
 ({ \
 	typeof(p) _________p1 = READ_ONCE(p); \
+	__maybe_unused const void * const _________p2 = _________p1; \
 	smp_read_barrier_depends(); /* Dependency order vs. p above. */ \
 	(_________p1); \
 })

  parent reply	other threads:[~2016-06-08 14:20 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-21 20:14 [PATCH] seqlock: fix raw_read_seqcount_latch() Alexey Dobriyan
2016-05-22 10:48 ` Peter Zijlstra
2016-05-22 18:50   ` Alexey Dobriyan
2016-05-23  9:36     ` Peter Zijlstra
2016-05-25 19:57       ` Tejun Heo
2016-05-25 20:11         ` [PATCH] percpu: Revert ("percpu: Replace smp_read_barrier_depends() with lockless_dereference()") Tejun Heo
2016-06-03 10:58   ` [tip:locking/core] locking/barriers: Validate lockless_dereference() is used on a pointer type tip-bot for Peter Zijlstra
2016-06-06 21:31     ` Mateusz Guzik
2016-06-07  7:10       ` Peter Zijlstra
2016-06-08 14:19   ` tip-bot for Peter Zijlstra [this message]
2016-05-27 11:11 ` [PATCH] seqlock: fix raw_read_seqcount_latch() Peter Zijlstra
2016-06-03 10:46   ` [tip:locking/core] locking/seqcount: Re-fix raw_read_seqcount_latch() tip-bot for Peter Zijlstra

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=tip-331b6d8c7afc2e5b900b9dcd850c265e1ba8d8e7@git.kernel.org \
    --to=tipbot@zytor.com \
    --cc=adobriyan@gmail.com \
    --cc=akpm@linux-foundation.org \
    --cc=hpa@zytor.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-tip-commits@vger.kernel.org \
    --cc=mingo@kernel.org \
    --cc=paulmck@linux.vnet.ibm.com \
    --cc=peterz@infradead.org \
    --cc=tglx@linutronix.de \
    --cc=torvalds@linux-foundation.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).