This feature will record the last two call_rcu() call stacks and
prints up to 2 call_rcu() call stacks in KASAN report.
When call_rcu() is called, we store the call_rcu() call stack into
slub alloc meta-data, so that the KASAN report can print rcu stack.
[1]https://bugzilla.kernel.org/show_bug.cgi?id=198437
[2]https://groups.google.com/forum/#!searchin/kasan-dev/better$20stack$20traces$20for$20rcu%7Csort:date/kasan-dev/KQsjT_88hDE/7rNUZprRBgAJ
Signed-off-by: Walter Wu <[email protected]>
Suggested-by: Dmitry Vyukov <[email protected]>
Acked-by: Paul E. McKenney <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Josh Triplett <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Andrey Konovalov <[email protected]>
---
include/linux/kasan.h | 2 ++
kernel/rcu/tree.c | 2 ++
mm/kasan/common.c | 4 ++--
mm/kasan/generic.c | 21 +++++++++++++++++++++
mm/kasan/kasan.h | 10 ++++++++++
mm/kasan/report.c | 24 ++++++++++++++++++++++++
6 files changed, 61 insertions(+), 2 deletions(-)
diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 31314ca7c635..23b7ee00572d 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -174,11 +174,13 @@ static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
void kasan_cache_shrink(struct kmem_cache *cache);
void kasan_cache_shutdown(struct kmem_cache *cache);
+void kasan_record_aux_stack(void *ptr);
#else /* CONFIG_KASAN_GENERIC */
static inline void kasan_cache_shrink(struct kmem_cache *cache) {}
static inline void kasan_cache_shutdown(struct kmem_cache *cache) {}
+static inline void kasan_record_aux_stack(void *ptr) {}
#endif /* CONFIG_KASAN_GENERIC */
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 06548e2ebb72..36a4ff7f320b 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -57,6 +57,7 @@
#include <linux/slab.h>
#include <linux/sched/isolation.h>
#include <linux/sched/clock.h>
+#include <linux/kasan.h>
#include "../time/tick-internal.h"
#include "tree.h"
@@ -2668,6 +2669,7 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func)
head->func = func;
head->next = NULL;
local_irq_save(flags);
+ kasan_record_aux_stack(head);
rdp = this_cpu_ptr(&rcu_data);
/* Add the callback to our list. */
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 2906358e42f0..8bc618289bb1 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -41,7 +41,7 @@
#include "kasan.h"
#include "../slab.h"
-static inline depot_stack_handle_t save_stack(gfp_t flags)
+depot_stack_handle_t kasan_save_stack(gfp_t flags)
{
unsigned long entries[KASAN_STACK_DEPTH];
unsigned int nr_entries;
@@ -54,7 +54,7 @@ static inline depot_stack_handle_t save_stack(gfp_t flags)
static inline void set_track(struct kasan_track *track, gfp_t flags)
{
track->pid = current->pid;
- track->stack = save_stack(flags);
+ track->stack = kasan_save_stack(flags);
}
void kasan_enable_current(void)
diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
index 56ff8885fe2e..8acf48882ba2 100644
--- a/mm/kasan/generic.c
+++ b/mm/kasan/generic.c
@@ -325,3 +325,24 @@ DEFINE_ASAN_SET_SHADOW(f2);
DEFINE_ASAN_SET_SHADOW(f3);
DEFINE_ASAN_SET_SHADOW(f5);
DEFINE_ASAN_SET_SHADOW(f8);
+
+void kasan_record_aux_stack(void *addr)
+{
+ struct page *page = kasan_addr_to_page(addr);
+ struct kmem_cache *cache;
+ struct kasan_alloc_meta *alloc_info;
+ void *object;
+
+ if (!(page && PageSlab(page)))
+ return;
+
+ cache = page->slab_cache;
+ object = nearest_obj(cache, page, addr);
+ alloc_info = get_alloc_info(cache, object);
+
+ /*
+ * record the last two call_rcu() call stacks.
+ */
+ alloc_info->aux_stack[1] = alloc_info->aux_stack[0];
+ alloc_info->aux_stack[0] = kasan_save_stack(GFP_NOWAIT);
+}
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index e8f37199d885..a7391bc83070 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -104,7 +104,15 @@ struct kasan_track {
struct kasan_alloc_meta {
struct kasan_track alloc_track;
+#ifdef CONFIG_KASAN_GENERIC
+ /*
+ * call_rcu() call stack is stored into struct kasan_alloc_meta.
+ * The free stack is stored into struct kasan_free_meta.
+ */
+ depot_stack_handle_t aux_stack[2];
+#else
struct kasan_track free_track[KASAN_NR_FREE_STACKS];
+#endif
#ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY
u8 free_pointer_tag[KASAN_NR_FREE_STACKS];
u8 free_track_idx;
@@ -159,6 +167,8 @@ void kasan_report_invalid_free(void *object, unsigned long ip);
struct page *kasan_addr_to_page(const void *addr);
+depot_stack_handle_t kasan_save_stack(gfp_t flags);
+
#if defined(CONFIG_KASAN_GENERIC) && \
(defined(CONFIG_SLAB) || defined(CONFIG_SLUB))
void quarantine_put(struct kasan_free_meta *info, struct kmem_cache *cache);
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 80f23c9da6b0..29a801d5cd74 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -105,6 +105,17 @@ static void end_report(unsigned long *flags)
kasan_enable_current();
}
+#ifdef CONFIG_KASAN_GENERIC
+static void print_stack(depot_stack_handle_t stack)
+{
+ unsigned long *entries;
+ unsigned int nr_entries;
+
+ nr_entries = stack_depot_fetch(stack, &entries);
+ stack_trace_print(entries, nr_entries, 0);
+}
+#endif
+
static void print_track(struct kasan_track *track, const char *prefix)
{
pr_err("%s by task %u:\n", prefix, track->pid);
@@ -192,6 +203,19 @@ static void describe_object(struct kmem_cache *cache, void *object,
free_track = kasan_get_free_track(cache, object, tag);
print_track(free_track, "Freed");
pr_err("\n");
+
+#ifdef CONFIG_KASAN_GENERIC
+ if (alloc_info->aux_stack[0]) {
+ pr_err("Last call_rcu():\n");
+ print_stack(alloc_info->aux_stack[0]);
+ pr_err("\n");
+ }
+ if (alloc_info->aux_stack[1]) {
+ pr_err("Second to last call_rcu():\n");
+ print_stack(alloc_info->aux_stack[1]);
+ pr_err("\n");
+ }
+#endif
}
describe_object_addr(cache, object, addr);
--
2.18.0
On Wed, May 20, 2020 at 2:34 PM Walter Wu <[email protected]> wrote:
>
> This feature will record the last two call_rcu() call stacks and
> prints up to 2 call_rcu() call stacks in KASAN report.
>
> When call_rcu() is called, we store the call_rcu() call stack into
> slub alloc meta-data, so that the KASAN report can print rcu stack.
>
> [1]https://bugzilla.kernel.org/show_bug.cgi?id=198437
> [2]https://groups.google.com/forum/#!searchin/kasan-dev/better$20stack$20traces$20for$20rcu%7Csort:date/kasan-dev/KQsjT_88hDE/7rNUZprRBgAJ
>
> Signed-off-by: Walter Wu <[email protected]>
> Suggested-by: Dmitry Vyukov <[email protected]>
> Acked-by: Paul E. McKenney <[email protected]>
> Cc: Andrey Ryabinin <[email protected]>
> Cc: Dmitry Vyukov <[email protected]>
> Cc: Alexander Potapenko <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Cc: Josh Triplett <[email protected]>
> Cc: Mathieu Desnoyers <[email protected]>
> Cc: Lai Jiangshan <[email protected]>
> Cc: Joel Fernandes <[email protected]>
> Cc: Andrey Konovalov <[email protected]>
> ---
> include/linux/kasan.h | 2 ++
> kernel/rcu/tree.c | 2 ++
> mm/kasan/common.c | 4 ++--
> mm/kasan/generic.c | 21 +++++++++++++++++++++
> mm/kasan/kasan.h | 10 ++++++++++
> mm/kasan/report.c | 24 ++++++++++++++++++++++++
> 6 files changed, 61 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> index 31314ca7c635..23b7ee00572d 100644
> --- a/include/linux/kasan.h
> +++ b/include/linux/kasan.h
> @@ -174,11 +174,13 @@ static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
>
> void kasan_cache_shrink(struct kmem_cache *cache);
> void kasan_cache_shutdown(struct kmem_cache *cache);
> +void kasan_record_aux_stack(void *ptr);
>
> #else /* CONFIG_KASAN_GENERIC */
>
> static inline void kasan_cache_shrink(struct kmem_cache *cache) {}
> static inline void kasan_cache_shutdown(struct kmem_cache *cache) {}
> +static inline void kasan_record_aux_stack(void *ptr) {}
>
> #endif /* CONFIG_KASAN_GENERIC */
>
> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> index 06548e2ebb72..36a4ff7f320b 100644
> --- a/kernel/rcu/tree.c
> +++ b/kernel/rcu/tree.c
> @@ -57,6 +57,7 @@
> #include <linux/slab.h>
> #include <linux/sched/isolation.h>
> #include <linux/sched/clock.h>
> +#include <linux/kasan.h>
> #include "../time/tick-internal.h"
>
> #include "tree.h"
> @@ -2668,6 +2669,7 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func)
> head->func = func;
> head->next = NULL;
> local_irq_save(flags);
> + kasan_record_aux_stack(head);
> rdp = this_cpu_ptr(&rcu_data);
>
> /* Add the callback to our list. */
> diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> index 2906358e42f0..8bc618289bb1 100644
> --- a/mm/kasan/common.c
> +++ b/mm/kasan/common.c
> @@ -41,7 +41,7 @@
> #include "kasan.h"
> #include "../slab.h"
>
> -static inline depot_stack_handle_t save_stack(gfp_t flags)
> +depot_stack_handle_t kasan_save_stack(gfp_t flags)
> {
> unsigned long entries[KASAN_STACK_DEPTH];
> unsigned int nr_entries;
> @@ -54,7 +54,7 @@ static inline depot_stack_handle_t save_stack(gfp_t flags)
> static inline void set_track(struct kasan_track *track, gfp_t flags)
> {
> track->pid = current->pid;
> - track->stack = save_stack(flags);
> + track->stack = kasan_save_stack(flags);
> }
>
> void kasan_enable_current(void)
> diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
> index 56ff8885fe2e..8acf48882ba2 100644
> --- a/mm/kasan/generic.c
> +++ b/mm/kasan/generic.c
> @@ -325,3 +325,24 @@ DEFINE_ASAN_SET_SHADOW(f2);
> DEFINE_ASAN_SET_SHADOW(f3);
> DEFINE_ASAN_SET_SHADOW(f5);
> DEFINE_ASAN_SET_SHADOW(f8);
> +
> +void kasan_record_aux_stack(void *addr)
> +{
> + struct page *page = kasan_addr_to_page(addr);
> + struct kmem_cache *cache;
> + struct kasan_alloc_meta *alloc_info;
> + void *object;
> +
> + if (!(page && PageSlab(page)))
> + return;
> +
> + cache = page->slab_cache;
> + object = nearest_obj(cache, page, addr);
> + alloc_info = get_alloc_info(cache, object);
> +
> + /*
> + * record the last two call_rcu() call stacks.
> + */
> + alloc_info->aux_stack[1] = alloc_info->aux_stack[0];
> + alloc_info->aux_stack[0] = kasan_save_stack(GFP_NOWAIT);
> +}
> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> index e8f37199d885..a7391bc83070 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -104,7 +104,15 @@ struct kasan_track {
>
> struct kasan_alloc_meta {
> struct kasan_track alloc_track;
> +#ifdef CONFIG_KASAN_GENERIC
> + /*
> + * call_rcu() call stack is stored into struct kasan_alloc_meta.
> + * The free stack is stored into struct kasan_free_meta.
> + */
> + depot_stack_handle_t aux_stack[2];
> +#else
> struct kasan_track free_track[KASAN_NR_FREE_STACKS];
> +#endif
> #ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY
> u8 free_pointer_tag[KASAN_NR_FREE_STACKS];
> u8 free_track_idx;
> @@ -159,6 +167,8 @@ void kasan_report_invalid_free(void *object, unsigned long ip);
>
> struct page *kasan_addr_to_page(const void *addr);
>
> +depot_stack_handle_t kasan_save_stack(gfp_t flags);
> +
> #if defined(CONFIG_KASAN_GENERIC) && \
> (defined(CONFIG_SLAB) || defined(CONFIG_SLUB))
> void quarantine_put(struct kasan_free_meta *info, struct kmem_cache *cache);
> diff --git a/mm/kasan/report.c b/mm/kasan/report.c
> index 80f23c9da6b0..29a801d5cd74 100644
> --- a/mm/kasan/report.c
> +++ b/mm/kasan/report.c
> @@ -105,6 +105,17 @@ static void end_report(unsigned long *flags)
> kasan_enable_current();
> }
>
> +#ifdef CONFIG_KASAN_GENERIC
> +static void print_stack(depot_stack_handle_t stack)
> +{
> + unsigned long *entries;
> + unsigned int nr_entries;
> +
> + nr_entries = stack_depot_fetch(stack, &entries);
> + stack_trace_print(entries, nr_entries, 0);
> +}
> +#endif
The idea of moving it here was to reuse print_stack() in print_track() :)
> +
> static void print_track(struct kasan_track *track, const char *prefix)
> {
> pr_err("%s by task %u:\n", prefix, track->pid);
> @@ -192,6 +203,19 @@ static void describe_object(struct kmem_cache *cache, void *object,
> free_track = kasan_get_free_track(cache, object, tag);
> print_track(free_track, "Freed");
> pr_err("\n");
> +
> +#ifdef CONFIG_KASAN_GENERIC
> + if (alloc_info->aux_stack[0]) {
> + pr_err("Last call_rcu():\n");
> + print_stack(alloc_info->aux_stack[0]);
> + pr_err("\n");
> + }
> + if (alloc_info->aux_stack[1]) {
> + pr_err("Second to last call_rcu():\n");
> + print_stack(alloc_info->aux_stack[1]);
> + pr_err("\n");
> + }
> +#endif
> }
>
> describe_object_addr(cache, object, addr);
> --
> 2.18.0
>
> --
> You received this message because you are subscribed to the Google Groups "kasan-dev" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
> To view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/20200520123434.3888-1-walter-zh.wu%40mediatek.com.
> On Wed, May 20, 2020 at 2:34 PM Walter Wu <[email protected]> wrote:
> >
> > This feature will record the last two call_rcu() call stacks and
> > prints up to 2 call_rcu() call stacks in KASAN report.
> >
> > When call_rcu() is called, we store the call_rcu() call stack into
> > slub alloc meta-data, so that the KASAN report can print rcu stack.
> >
> > [1]https://bugzilla.kernel.org/show_bug.cgi?id=198437
> > [2]https://groups.google.com/forum/#!searchin/kasan-dev/better$20stack$20traces$20for$20rcu%7Csort:date/kasan-dev/KQsjT_88hDE/7rNUZprRBgAJ
> >
> > Signed-off-by: Walter Wu <[email protected]>
> > Suggested-by: Dmitry Vyukov <[email protected]>
> > Acked-by: Paul E. McKenney <[email protected]>
> > Cc: Andrey Ryabinin <[email protected]>
> > Cc: Dmitry Vyukov <[email protected]>
> > Cc: Alexander Potapenko <[email protected]>
> > Cc: Andrew Morton <[email protected]>
> > Cc: Josh Triplett <[email protected]>
> > Cc: Mathieu Desnoyers <[email protected]>
> > Cc: Lai Jiangshan <[email protected]>
> > Cc: Joel Fernandes <[email protected]>
> > Cc: Andrey Konovalov <[email protected]>
> > ---
> > include/linux/kasan.h | 2 ++
> > kernel/rcu/tree.c | 2 ++
> > mm/kasan/common.c | 4 ++--
> > mm/kasan/generic.c | 21 +++++++++++++++++++++
> > mm/kasan/kasan.h | 10 ++++++++++
> > mm/kasan/report.c | 24 ++++++++++++++++++++++++
> > 6 files changed, 61 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> > index 31314ca7c635..23b7ee00572d 100644
> > --- a/include/linux/kasan.h
> > +++ b/include/linux/kasan.h
> > @@ -174,11 +174,13 @@ static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
> >
> > void kasan_cache_shrink(struct kmem_cache *cache);
> > void kasan_cache_shutdown(struct kmem_cache *cache);
> > +void kasan_record_aux_stack(void *ptr);
> >
> > #else /* CONFIG_KASAN_GENERIC */
> >
> > static inline void kasan_cache_shrink(struct kmem_cache *cache) {}
> > static inline void kasan_cache_shutdown(struct kmem_cache *cache) {}
> > +static inline void kasan_record_aux_stack(void *ptr) {}
> >
> > #endif /* CONFIG_KASAN_GENERIC */
> >
> > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> > index 06548e2ebb72..36a4ff7f320b 100644
> > --- a/kernel/rcu/tree.c
> > +++ b/kernel/rcu/tree.c
> > @@ -57,6 +57,7 @@
> > #include <linux/slab.h>
> > #include <linux/sched/isolation.h>
> > #include <linux/sched/clock.h>
> > +#include <linux/kasan.h>
> > #include "../time/tick-internal.h"
> >
> > #include "tree.h"
> > @@ -2668,6 +2669,7 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func)
> > head->func = func;
> > head->next = NULL;
> > local_irq_save(flags);
> > + kasan_record_aux_stack(head);
> > rdp = this_cpu_ptr(&rcu_data);
> >
> > /* Add the callback to our list. */
> > diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> > index 2906358e42f0..8bc618289bb1 100644
> > --- a/mm/kasan/common.c
> > +++ b/mm/kasan/common.c
> > @@ -41,7 +41,7 @@
> > #include "kasan.h"
> > #include "../slab.h"
> >
> > -static inline depot_stack_handle_t save_stack(gfp_t flags)
> > +depot_stack_handle_t kasan_save_stack(gfp_t flags)
> > {
> > unsigned long entries[KASAN_STACK_DEPTH];
> > unsigned int nr_entries;
> > @@ -54,7 +54,7 @@ static inline depot_stack_handle_t save_stack(gfp_t flags)
> > static inline void set_track(struct kasan_track *track, gfp_t flags)
> > {
> > track->pid = current->pid;
> > - track->stack = save_stack(flags);
> > + track->stack = kasan_save_stack(flags);
> > }
> >
> > void kasan_enable_current(void)
> > diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
> > index 56ff8885fe2e..8acf48882ba2 100644
> > --- a/mm/kasan/generic.c
> > +++ b/mm/kasan/generic.c
> > @@ -325,3 +325,24 @@ DEFINE_ASAN_SET_SHADOW(f2);
> > DEFINE_ASAN_SET_SHADOW(f3);
> > DEFINE_ASAN_SET_SHADOW(f5);
> > DEFINE_ASAN_SET_SHADOW(f8);
> > +
> > +void kasan_record_aux_stack(void *addr)
> > +{
> > + struct page *page = kasan_addr_to_page(addr);
> > + struct kmem_cache *cache;
> > + struct kasan_alloc_meta *alloc_info;
> > + void *object;
> > +
> > + if (!(page && PageSlab(page)))
> > + return;
> > +
> > + cache = page->slab_cache;
> > + object = nearest_obj(cache, page, addr);
> > + alloc_info = get_alloc_info(cache, object);
> > +
> > + /*
> > + * record the last two call_rcu() call stacks.
> > + */
> > + alloc_info->aux_stack[1] = alloc_info->aux_stack[0];
> > + alloc_info->aux_stack[0] = kasan_save_stack(GFP_NOWAIT);
> > +}
> > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> > index e8f37199d885..a7391bc83070 100644
> > --- a/mm/kasan/kasan.h
> > +++ b/mm/kasan/kasan.h
> > @@ -104,7 +104,15 @@ struct kasan_track {
> >
> > struct kasan_alloc_meta {
> > struct kasan_track alloc_track;
> > +#ifdef CONFIG_KASAN_GENERIC
> > + /*
> > + * call_rcu() call stack is stored into struct kasan_alloc_meta.
> > + * The free stack is stored into struct kasan_free_meta.
> > + */
> > + depot_stack_handle_t aux_stack[2];
> > +#else
> > struct kasan_track free_track[KASAN_NR_FREE_STACKS];
> > +#endif
> > #ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY
> > u8 free_pointer_tag[KASAN_NR_FREE_STACKS];
> > u8 free_track_idx;
> > @@ -159,6 +167,8 @@ void kasan_report_invalid_free(void *object, unsigned long ip);
> >
> > struct page *kasan_addr_to_page(const void *addr);
> >
> > +depot_stack_handle_t kasan_save_stack(gfp_t flags);
> > +
> > #if defined(CONFIG_KASAN_GENERIC) && \
> > (defined(CONFIG_SLAB) || defined(CONFIG_SLUB))
> > void quarantine_put(struct kasan_free_meta *info, struct kmem_cache *cache);
> > diff --git a/mm/kasan/report.c b/mm/kasan/report.c
> > index 80f23c9da6b0..29a801d5cd74 100644
> > --- a/mm/kasan/report.c
> > +++ b/mm/kasan/report.c
> > @@ -105,6 +105,17 @@ static void end_report(unsigned long *flags)
> > kasan_enable_current();
> > }
> >
> > +#ifdef CONFIG_KASAN_GENERIC
> > +static void print_stack(depot_stack_handle_t stack)
> > +{
> > + unsigned long *entries;
> > + unsigned int nr_entries;
> > +
> > + nr_entries = stack_depot_fetch(stack, &entries);
> > + stack_trace_print(entries, nr_entries, 0);
> > +}
> > +#endif
>
> The idea of moving it here was to reuse print_stack() in print_track() :)
>
Ok. I see. Next patch will fix it.
> > +
> > static void print_track(struct kasan_track *track, const char *prefix)
> > {
> > pr_err("%s by task %u:\n", prefix, track->pid);
> > @@ -192,6 +203,19 @@ static void describe_object(struct kmem_cache *cache, void *object,
> > free_track = kasan_get_free_track(cache, object, tag);
> > print_track(free_track, "Freed");
> > pr_err("\n");
> > +
> > +#ifdef CONFIG_KASAN_GENERIC
> > + if (alloc_info->aux_stack[0]) {
> > + pr_err("Last call_rcu():\n");
> > + print_stack(alloc_info->aux_stack[0]);
> > + pr_err("\n");
> > + }
> > + if (alloc_info->aux_stack[1]) {
> > + pr_err("Second to last call_rcu():\n");
> > + print_stack(alloc_info->aux_stack[1]);
> > + pr_err("\n");
> > + }
> > +#endif
> > }
> >
> > describe_object_addr(cache, object, addr);
> > --
> > 2.18.0
> >
> > --
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