From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
x86@kernel.org, Andy Lutomirski <luto@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Alexander Potapenko <glider@google.com>,
Alexey Dobriyan <adobriyan@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Pekka Enberg <penberg@kernel.org>,
linux-mm@kvack.org, David Rientjes <rientjes@google.com>,
Christoph Lameter <cl@linux.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Dmitry Vyukov <dvyukov@google.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
kasan-dev@googlegroups.com,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Akinobu Mita <akinobu.mita@gmail.com>,
iommu@lists.linux-foundation.org,
Robin Murphy <robin.murphy@arm.com>,
Christoph Hellwig <hch@lst.de>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Johannes Thumshirn <jthumshirn@suse.de>,
David Sterba <dsterba@suse.com>, Chris Mason <clm@fb.com>,
Josef Bacik <josef@toxicpanda.com>,
linux-btrfs@vger.kernel.org, dm-devel@redhat.com,
Mike Snitzer <snitzer@redhat.com>,
Alasdair Kergon <agk@redhat.com>,
intel-gfx@lists.freedesktop.org,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
dri-devel@lists.freedesktop.org, David Airlie <airlied@linux.ie>,
Jani Nikula <jani.nikula@linux.intel.com>,
Daniel Vetter <daniel@ffwll.ch>,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
linux-arch@vger.kernel.org
Subject: [patch V2 18/29] lockdep: Move stack trace logic into check_prev_add()
Date: Thu, 18 Apr 2019 10:41:37 +0200 [thread overview]
Message-ID: <20190418084254.729689921@linutronix.de> (raw)
In-Reply-To: 20190418084119.056416939@linutronix.de
There is only one caller of check_prev_add() which hands in a zeroed struct
stack trace and a function pointer to save_stack(). Inside check_prev_add()
the stack_trace struct is checked for being empty, which is always
true. Based on that one code path stores a stack trace which is unused. The
comment there does not make sense either. It's all leftovers from
historical lockdep code (cross release).
Move the variable into check_prev_add() itself and cleanup the nonsensical
checks and the pointless stack trace recording.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/locking/lockdep.c | 30 ++++++++----------------------
1 file changed, 8 insertions(+), 22 deletions(-)
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2158,10 +2158,10 @@ check_deadlock(struct task_struct *curr,
*/
static int
check_prev_add(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next, int distance, struct stack_trace *trace,
- int (*save)(struct stack_trace *trace))
+ struct held_lock *next, int distance)
{
struct lock_list *uninitialized_var(target_entry);
+ struct stack_trace trace;
struct lock_list *entry;
struct lock_list this;
int ret;
@@ -2196,17 +2196,8 @@ check_prev_add(struct task_struct *curr,
this.class = hlock_class(next);
this.parent = NULL;
ret = check_noncircular(&this, hlock_class(prev), &target_entry);
- if (unlikely(!ret)) {
- if (!trace->entries) {
- /*
- * If @save fails here, the printing might trigger
- * a WARN but because of the !nr_entries it should
- * not do bad things.
- */
- save(trace);
- }
+ if (unlikely(!ret))
return print_circular_bug(&this, target_entry, next, prev);
- }
else if (unlikely(ret < 0))
return print_bfs_bug(ret);
@@ -2253,7 +2244,7 @@ check_prev_add(struct task_struct *curr,
return print_bfs_bug(ret);
- if (!trace->entries && !save(trace))
+ if (!save_trace(&trace))
return 0;
/*
@@ -2262,14 +2253,14 @@ check_prev_add(struct task_struct *curr,
*/
ret = add_lock_to_list(hlock_class(next), hlock_class(prev),
&hlock_class(prev)->locks_after,
- next->acquire_ip, distance, trace);
+ next->acquire_ip, distance, &trace);
if (!ret)
return 0;
ret = add_lock_to_list(hlock_class(prev), hlock_class(next),
&hlock_class(next)->locks_before,
- next->acquire_ip, distance, trace);
+ next->acquire_ip, distance, &trace);
if (!ret)
return 0;
@@ -2287,12 +2278,6 @@ check_prevs_add(struct task_struct *curr
{
int depth = curr->lockdep_depth;
struct held_lock *hlock;
- struct stack_trace trace = {
- .nr_entries = 0,
- .max_entries = 0,
- .entries = NULL,
- .skip = 0,
- };
/*
* Debugging checks.
@@ -2318,7 +2303,8 @@ check_prevs_add(struct task_struct *curr
* added:
*/
if (hlock->read != 2 && hlock->check) {
- int ret = check_prev_add(curr, hlock, next, distance, &trace, save_trace);
+ int ret = check_prev_add(curr, hlock, next, distance);
+
if (!ret)
return 0;
next prev parent reply other threads:[~2019-04-18 9:08 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-18 8:41 [patch V2 00/29] stacktrace: Consolidate stack trace usage Thomas Gleixner
2019-04-18 8:41 ` [patch V2 01/29] tracing: Cleanup stack trace code Thomas Gleixner
2019-04-18 13:57 ` Josh Poimboeuf
2019-04-18 21:14 ` Thomas Gleixner
2019-04-18 21:24 ` Steven Rostedt
2019-04-18 21:50 ` Steven Rostedt
2019-04-18 22:19 ` Steven Rostedt
2019-04-18 22:44 ` Thomas Gleixner
2019-04-19 0:39 ` Steven Rostedt
2019-04-18 8:41 ` [patch V2 02/29] stacktrace: Provide helpers for common stack trace operations Thomas Gleixner
2019-04-18 8:41 ` [patch V2 03/29] lib/stackdepot: Provide functions which operate on plain storage arrays Thomas Gleixner
2019-04-18 11:51 ` Mike Rapoport
2019-04-18 11:58 ` Thomas Gleixner
2019-04-18 8:41 ` [patch V2 04/29] backtrace-test: Simplify stack trace handling Thomas Gleixner
2019-04-18 8:41 ` [patch V2 05/29] proc: Simplify task stack retrieval Thomas Gleixner
2019-04-18 8:41 ` [patch V2 06/29] latency_top: Simplify stack trace handling Thomas Gleixner
2019-04-18 8:41 ` [patch V2 07/29] mm/slub: Simplify stack trace retrieval Thomas Gleixner
2019-04-18 8:41 ` [patch V2 08/29] mm/kmemleak: Simplify stacktrace handling Thomas Gleixner
2019-04-18 15:17 ` Catalin Marinas
2019-04-18 8:41 ` [patch V2 09/29] mm/kasan: " Thomas Gleixner
2019-04-18 10:39 ` Andrey Ryabinin
2019-04-18 11:53 ` Thomas Gleixner
2019-04-18 8:41 ` [patch V2 10/29] mm/page_owner: Simplify stack trace handling Thomas Gleixner
2019-04-18 8:41 ` [patch V2 11/29] fault-inject: Simplify stacktrace retrieval Thomas Gleixner
2019-04-18 8:41 ` [patch V2 12/29] dma/debug: Simplify stracktrace retrieval Thomas Gleixner
2019-04-19 7:05 ` Christoph Hellwig
2019-04-18 8:41 ` [patch V2 13/29] btrfs: ref-verify: Simplify stack trace retrieval Thomas Gleixner
2019-04-18 8:41 ` [patch V2 14/29] dm bufio: " Thomas Gleixner
2019-04-18 10:44 ` Alexander Potapenko
2019-04-18 11:54 ` Thomas Gleixner
2019-04-18 12:11 ` Alexander Potapenko
2019-04-18 13:33 ` Steven Rostedt
2019-04-18 8:41 ` [patch V2 15/29] dm persistent data: Simplify stack trace handling Thomas Gleixner
2019-04-18 8:41 ` [patch V2 16/29] drm: Simplify stacktrace handling Thomas Gleixner
2019-04-23 7:36 ` Daniel Vetter
2019-04-18 8:41 ` [patch V2 17/29] lockdep: Remove unused trace argument from print_circular_bug() Thomas Gleixner
2019-04-18 8:41 ` Thomas Gleixner [this message]
2019-04-24 19:45 ` [patch V2 18/29] lockdep: Move stack trace logic into check_prev_add() Peter Zijlstra
2019-04-24 19:51 ` Thomas Gleixner
2019-04-18 8:41 ` [patch V2 19/29] lockdep: Simplify stack trace handling Thomas Gleixner
2019-04-24 19:45 ` Peter Zijlstra
2019-04-18 8:41 ` [patch V2 20/29] tracing: Simplify stacktrace retrieval in histograms Thomas Gleixner
2019-04-18 13:40 ` Steven Rostedt
2019-04-18 19:58 ` Tom Zanussi
2019-04-18 20:13 ` Steven Rostedt
2019-04-18 20:22 ` Tom Zanussi
2019-04-18 8:41 ` [patch V2 21/29] tracing: Use percpu stack trace buffer more intelligently Thomas Gleixner
2019-04-18 14:53 ` Steven Rostedt
2019-04-18 15:43 ` Thomas Gleixner
2019-04-18 15:46 ` Steven Rostedt
2019-04-18 8:41 ` [patch V2 22/29] tracing: Make ftrace_trace_userstack() static and conditional Thomas Gleixner
2019-04-19 13:28 ` Steven Rostedt
2019-04-18 8:41 ` [patch V2 23/29] tracing: Simplify stack trace retrieval Thomas Gleixner
2019-04-19 20:11 ` Steven Rostedt
2019-04-18 8:41 ` [patch V2 24/29] tracing: Remove the last struct stack_trace usage Thomas Gleixner
2019-04-19 20:11 ` Steven Rostedt
2019-04-18 8:41 ` [patch V2 25/29] livepatch: Simplify stack trace retrieval Thomas Gleixner
2019-04-23 8:18 ` Miroslav Benes
2019-04-18 8:41 ` [patch V2 26/29] stacktrace: Remove obsolete functions Thomas Gleixner
2019-04-18 8:41 ` [patch V2 27/29] lib/stackdepot: " Thomas Gleixner
2019-04-18 8:41 ` [patch V2 28/29] stacktrace: Provide common infrastructure Thomas Gleixner
2019-04-18 11:52 ` Mike Rapoport
2019-04-18 11:57 ` Thomas Gleixner
2019-04-18 14:52 ` Josh Poimboeuf
2019-04-18 15:42 ` Thomas Gleixner
2019-04-19 7:02 ` Peter Zijlstra
2019-04-19 15:50 ` Josh Poimboeuf
2019-04-19 7:18 ` Peter Zijlstra
2019-04-19 8:32 ` Thomas Gleixner
2019-04-19 9:07 ` Peter Zijlstra
2019-04-19 16:17 ` Josh Poimboeuf
2019-04-18 8:41 ` [patch V2 29/29] x86/stacktrace: Use " Thomas Gleixner
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=20190418084254.729689921@linutronix.de \
--to=tglx@linutronix.de \
--cc=adobriyan@gmail.com \
--cc=agk@redhat.com \
--cc=airlied@linux.ie \
--cc=akinobu.mita@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=aryabinin@virtuozzo.com \
--cc=catalin.marinas@arm.com \
--cc=cl@linux.com \
--cc=clm@fb.com \
--cc=daniel@ffwll.ch \
--cc=dm-devel@redhat.com \
--cc=dri-devel@lists.freedesktop.org \
--cc=dsterba@suse.com \
--cc=dvyukov@google.com \
--cc=glider@google.com \
--cc=hch@lst.de \
--cc=intel-gfx@lists.freedesktop.org \
--cc=iommu@lists.linux-foundation.org \
--cc=jani.nikula@linux.intel.com \
--cc=joonas.lahtinen@linux.intel.com \
--cc=josef@toxicpanda.com \
--cc=jpoimboe@redhat.com \
--cc=jthumshirn@suse.de \
--cc=kasan-dev@googlegroups.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-btrfs@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=m.szyprowski@samsung.com \
--cc=maarten.lankhorst@linux.intel.com \
--cc=penberg@kernel.org \
--cc=rientjes@google.com \
--cc=robin.murphy@arm.com \
--cc=rodrigo.vivi@intel.com \
--cc=rostedt@goodmis.org \
--cc=rppt@linux.vnet.ibm.com \
--cc=snitzer@redhat.com \
--cc=x86@kernel.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).