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>
Subject: [RFC patch 34/41] lockdep: Move stack trace logic into check_prev_add()
Date: Wed, 10 Apr 2019 12:28:28 +0200 [thread overview]
Message-ID: <20190410103646.667572056@linutronix.de> (raw)
In-Reply-To: 20190410102754.387743324@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.
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:[~2019-04-10 11:06 UTC|newest]
Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-10 10:27 [RFC patch 00/41] stacktrace: Avoid the pointless redirection through struct stack_trace Thomas Gleixner
2019-04-10 10:27 ` [RFC patch 01/41] um/stacktrace: Remove the pointless ULONG_MAX marker Thomas Gleixner
2019-04-14 20:34 ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:27 ` [RFC patch 02/41] x86/stacktrace: " Thomas Gleixner
2019-04-14 20:34 ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:27 ` [RFC patch 03/41] arm/stacktrace: " Thomas Gleixner
2019-04-14 20:35 ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:27 ` [RFC patch 04/41] sh/stacktrace: " Thomas Gleixner
2019-04-14 20:36 ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:27 ` [RFC patch 05/41] unicore32/stacktrace: " Thomas Gleixner
2019-04-14 20:36 ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 06/41] riscv/stacktrace: " Thomas Gleixner
2019-04-14 20:37 ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 07/41] arm64/stacktrace: " Thomas Gleixner
2019-04-14 20:38 ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 08/41] parisc/stacktrace: " Thomas Gleixner
2019-04-14 20:38 ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 09/41] s390/stacktrace: " Thomas Gleixner
2019-04-14 20:39 ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 10/41] lockdep: Remove the ULONG_MAX stack trace hackery Thomas Gleixner
2019-04-14 20:40 ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 11/41] mm/slub: " Thomas Gleixner
2019-04-14 20:40 ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 12/41] mm/page_owner: " Thomas Gleixner
2019-04-14 20:41 ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 13/41] mm/kasan: " Thomas Gleixner
2019-04-10 11:31 ` Dmitry Vyukov
2019-04-14 20:42 ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 14/41] latency_top: " Thomas Gleixner
2019-04-14 20:42 ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 15/41] drm: " Thomas Gleixner
2019-04-14 20:43 ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 16/41] tracing: " Thomas Gleixner
2019-04-11 2:34 ` Josh Poimboeuf
2019-04-11 3:07 ` Steven Rostedt
2019-04-14 20:44 ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 17/41] tracing: Make stack_trace_print() static and rename it Thomas Gleixner
2019-04-10 12:47 ` Steven Rostedt
2019-04-11 0:19 ` AKASHI Takahiro
2019-04-10 10:28 ` [RFC patch 18/41] stacktrace: Provide helpers for common stack trace operations Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 19/41] lib/stackdepot: Provide functions which operate on plain storage arrays Thomas Gleixner
2019-04-10 13:39 ` Alexander Potapenko
2019-04-10 10:28 ` [RFC patch 20/41] backtrace-test: Simplify stack trace handling Thomas Gleixner
2019-04-11 2:47 ` Josh Poimboeuf
2019-04-10 10:28 ` [RFC patch 21/41] proc: Simplify task stack retrieval Thomas Gleixner
2019-04-14 14:49 ` Alexey Dobriyan
2019-04-10 10:28 ` [RFC patch 22/41] latency_top: Simplify stack trace handling Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 23/41] mm/slub: Simplify stack trace retrieval Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 24/41] mm/kmemleak: Simplify stacktrace handling Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 25/41] mm/kasan: " Thomas Gleixner
2019-04-10 11:33 ` Dmitry Vyukov
2019-04-11 2:55 ` Josh Poimboeuf
2019-04-14 16:54 ` Thomas Gleixner
2019-04-14 17:00 ` Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 26/41] mm/page_owner: Simplify stack trace handling Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 27/41] fault-inject: Simplify stacktrace retrieval Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 28/41] dma/debug: Simplify stracktrace retrieval Thomas Gleixner
2019-04-10 11:08 ` Christoph Hellwig
2019-04-10 12:08 ` Thomas Gleixner
2019-04-10 12:25 ` Steven Rostedt
2019-04-11 17:21 ` Christoph Hellwig
2019-04-11 17:36 ` Steven Rostedt
2019-04-11 17:44 ` Christoph Hellwig
2019-04-11 3:02 ` Josh Poimboeuf
2019-04-11 3:09 ` Steven Rostedt
2019-04-10 10:28 ` [RFC patch 29/41] btrfs: ref-verify: Simplify stack trace retrieval Thomas Gleixner
2019-04-10 11:31 ` Johannes Thumshirn
2019-04-10 12:05 ` Thomas Gleixner
2019-04-10 12:38 ` Johannes Thumshirn
2019-04-10 12:50 ` David Sterba
2019-04-10 13:47 ` Alexander Potapenko
2019-04-10 10:28 ` [RFC patch 30/41] dm bufio: " Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 31/41] dm persistent data: Simplify stack trace handling Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 32/41] drm: Simplify stacktrace handling Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 33/41] lockdep: Remove unused trace argument from print_circular_bug() Thomas Gleixner
2019-04-10 10:28 ` Thomas Gleixner [this message]
2019-04-10 10:28 ` [RFC patch 35/41] lockdep: Simplify stack trace handling Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 36/41] tracing: Simplify stacktrace retrieval in histograms Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 37/41] tracing: Use percpu stack trace buffer more intelligently Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 38/41] tracing: Make ftrace_trace_userstack() static and conditional Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 39/41] tracing: Simplify stack trace retrieval Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 40/41] stacktrace: Remove obsolete functions Thomas Gleixner
2019-04-11 3:33 ` Josh Poimboeuf
2019-04-11 9:13 ` Peter Zijlstra
2019-04-11 13:00 ` Josh Poimboeuf
2019-04-10 10:28 ` [RFC patch 41/41] lib/stackdepot: " Thomas Gleixner
2019-04-10 13:49 ` Alexander Potapenko
2019-04-10 11:49 ` [RFC patch 00/41] stacktrace: Avoid the pointless redirection through struct stack_trace Peter Zijlstra
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