lkml.org 
[lkml]   [2019]   [Apr]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:core/stacktrace] lockdep: Simplify stack trace handling
Commit-ID:  c120bce78065cbea460a58b1572c215db9c148ba
Gitweb: https://git.kernel.org/tip/c120bce78065cbea460a58b1572c215db9c148ba
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Thu, 25 Apr 2019 11:45:12 +0200
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Mon, 29 Apr 2019 12:37:54 +0200

lockdep: Simplify stack trace handling

Replace the indirection through struct stack_trace by using the storage
array based interfaces and storing the information is a small lockdep
specific data structure.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: linux-mm@kvack.org
Cc: David Rientjes <rientjes@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: kasan-dev@googlegroups.com
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: iommu@lists.linux-foundation.org
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: David Sterba <dsterba@suse.com>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: linux-btrfs@vger.kernel.org
Cc: dm-devel@redhat.com
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: intel-gfx@lists.freedesktop.org
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: dri-devel@lists.freedesktop.org
Cc: David Airlie <airlied@linux.ie>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: linux-arch@vger.kernel.org
Link: https://lkml.kernel.org/r/20190425094802.891724020@linutronix.de

---
include/linux/lockdep.h | 9 ++++++--
kernel/locking/lockdep.c | 55 ++++++++++++++++++++++++------------------------
2 files changed, 35 insertions(+), 29 deletions(-)

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 79c3873d58ac..6f165d625320 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -66,6 +66,11 @@ struct lock_class_key {

extern struct lock_class_key __lockdep_no_validate__;

+struct lock_trace {
+ unsigned int nr_entries;
+ unsigned int offset;
+};
+
#define LOCKSTAT_POINTS 4

/*
@@ -100,7 +105,7 @@ struct lock_class {
* IRQ/softirq usage tracking bits:
*/
unsigned long usage_mask;
- struct stack_trace usage_traces[XXX_LOCK_USAGE_STATES];
+ struct lock_trace usage_traces[XXX_LOCK_USAGE_STATES];

/*
* Generation counter, when doing certain classes of graph walking,
@@ -188,7 +193,7 @@ struct lock_list {
struct list_head entry;
struct lock_class *class;
struct lock_class *links_to;
- struct stack_trace trace;
+ struct lock_trace trace;
int distance;

/*
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 3603893d5bbd..45bcaf2e4cb6 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -434,18 +434,14 @@ static void print_lockdep_off(const char *bug_msg)
#endif
}

-static int save_trace(struct stack_trace *trace)
+static int save_trace(struct lock_trace *trace)
{
- trace->nr_entries = 0;
- trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
- trace->entries = stack_trace + nr_stack_trace_entries;
-
- trace->skip = 3;
-
- save_stack_trace(trace);
-
- trace->max_entries = trace->nr_entries;
+ unsigned long *entries = stack_trace + nr_stack_trace_entries;
+ unsigned int max_entries;

+ trace->offset = nr_stack_trace_entries;
+ max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
+ trace->nr_entries = stack_trace_save(entries, max_entries, 3);
nr_stack_trace_entries += trace->nr_entries;

if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) {
@@ -1196,7 +1192,7 @@ static struct lock_list *alloc_list_entry(void)
static int add_lock_to_list(struct lock_class *this,
struct lock_class *links_to, struct list_head *head,
unsigned long ip, int distance,
- struct stack_trace *trace)
+ struct lock_trace *trace)
{
struct lock_list *entry;
/*
@@ -1415,6 +1411,13 @@ static inline int __bfs_backwards(struct lock_list *src_entry,
* checking.
*/

+static void print_lock_trace(struct lock_trace *trace, unsigned int spaces)
+{
+ unsigned long *entries = stack_trace + trace->offset;
+
+ stack_trace_print(entries, trace->nr_entries, spaces);
+}
+
/*
* Print a dependency chain entry (this is only done when a deadlock
* has been detected):
@@ -1427,8 +1430,7 @@ print_circular_bug_entry(struct lock_list *target, int depth)
printk("\n-> #%u", depth);
print_lock_name(target->class);
printk(KERN_CONT ":\n");
- print_stack_trace(&target->trace, 6);
-
+ print_lock_trace(&target->trace, 6);
return 0;
}

@@ -1740,7 +1742,7 @@ static void print_lock_class_header(struct lock_class *class, int depth)

len += printk("%*s %s", depth, "", usage_str[bit]);
len += printk(KERN_CONT " at:\n");
- print_stack_trace(class->usage_traces + bit, len);
+ print_lock_trace(class->usage_traces + bit, len);
}
}
printk("%*s }\n", depth, "");
@@ -1765,7 +1767,7 @@ print_shortest_lock_dependencies(struct lock_list *leaf,
do {
print_lock_class_header(entry->class, depth);
printk("%*s ... acquired at:\n", depth, "");
- print_stack_trace(&entry->trace, 2);
+ print_lock_trace(&entry->trace, 2);
printk("\n");

if (depth == 0 && (entry != root)) {
@@ -1878,14 +1880,14 @@ print_bad_irq_dependency(struct task_struct *curr,
print_lock_name(backwards_entry->class);
pr_warn("\n... which became %s-irq-safe at:\n", irqclass);

- print_stack_trace(backwards_entry->class->usage_traces + bit1, 1);
+ print_lock_trace(backwards_entry->class->usage_traces + bit1, 1);

pr_warn("\nto a %s-irq-unsafe lock:\n", irqclass);
print_lock_name(forwards_entry->class);
pr_warn("\n... which became %s-irq-unsafe at:\n", irqclass);
pr_warn("...");

- print_stack_trace(forwards_entry->class->usage_traces + bit2, 1);
+ print_lock_trace(forwards_entry->class->usage_traces + bit2, 1);

pr_warn("\nother info that might help us debug this:\n\n");
print_irq_lock_scenario(backwards_entry, forwards_entry,
@@ -2158,7 +2160,7 @@ check_deadlock(struct task_struct *curr, struct held_lock *next,
*/
static int
check_prev_add(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next, int distance, struct stack_trace *trace)
+ struct held_lock *next, int distance, struct lock_trace *trace)
{
struct lock_list *uninitialized_var(target_entry);
struct lock_list *entry;
@@ -2196,7 +2198,7 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
this.parent = NULL;
ret = check_noncircular(&this, hlock_class(prev), &target_entry);
if (unlikely(!ret)) {
- if (!trace->entries) {
+ if (!trace->nr_entries) {
/*
* If save_trace fails here, the printing might
* trigger a WARN but because of the !nr_entries it
@@ -2252,7 +2254,7 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
return print_bfs_bug(ret);


- if (!trace->entries && !save_trace(trace))
+ if (!trace->nr_entries && !save_trace(trace))
return 0;

/*
@@ -2284,14 +2286,9 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
static int
check_prevs_add(struct task_struct *curr, struct held_lock *next)
{
+ struct lock_trace trace = { .nr_entries = 0 };
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.
@@ -2719,6 +2716,10 @@ static inline int validate_chain(struct task_struct *curr,
{
return 1;
}
+
+static void print_lock_trace(struct lock_trace *trace, unsigned int spaces)
+{
+}
#endif

/*
@@ -2815,7 +2816,7 @@ print_usage_bug(struct task_struct *curr, struct held_lock *this,
print_lock(this);

pr_warn("{%s} state was registered at:\n", usage_str[prev_bit]);
- print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1);
+ print_lock_trace(hlock_class(this)->usage_traces + prev_bit, 1);

print_irqtrace_events(curr);
pr_warn("\nother info that might help us debug this:\n");
\
 
 \ /
  Last update: 2019-04-29 20:45    [W:0.229 / U:10.408 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site