* + rcu-kasan-record-and-print-call_rcu-call-stack.patch added to -mm tree
@ 2020-07-03 17:28 akpm
0 siblings, 0 replies; only message in thread
From: akpm @ 2020-07-03 17:28 UTC (permalink / raw)
To: andreyknvl, aryabinin, corbet, dvyukov, glider, jiangshanlai,
joel, josh, mathieu.desnoyers, matthias.bgg, mm-commits, paulmck,
walter-zh.wu
The patch titled
Subject: rcu: kasan: record and print call_rcu() call stack
has been added to the -mm tree. Its filename is
rcu-kasan-record-and-print-call_rcu-call-stack.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/rcu-kasan-record-and-print-call_rcu-call-stack.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/rcu-kasan-record-and-print-call_rcu-call-stack.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Walter Wu <walter-zh.wu@mediatek.com>
Subject: rcu: kasan: record and print call_rcu() call stack
Patch series "kasan: memorize and print call_rcu stack", v7.
This patchset improves KASAN reports by making them to have call_rcu()
call stack information. It is useful for programmers to solve
use-after-free or double-free memory issue.
The KASAN report was as follows(cleaned up slightly):
BUG: KASAN: use-after-free in kasan_rcu_reclaim+0x58/0x60
Freed by task 0:
kasan_save_stack+0x24/0x50
kasan_set_track+0x24/0x38
kasan_set_free_info+0x18/0x20
__kasan_slab_free+0x10c/0x170
kasan_slab_free+0x10/0x18
kfree+0x98/0x270
kasan_rcu_reclaim+0x1c/0x60
Last call_rcu():
kasan_save_stack+0x24/0x50
kasan_record_aux_stack+0xbc/0xd0
call_rcu+0x8c/0x580
kasan_rcu_uaf+0xf4/0xf8
Generic KASAN will record the last two call_rcu() call stacks and print up
to 2 call_rcu() call stacks in KASAN report. it is only suitable for
generic KASAN.
This feature considers the size of struct kasan_alloc_meta and
kasan_free_meta, we try to optimize the structure layout and size, lets it
get better memory consumption.
[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
This patch (of 4):
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
Link: http://lkml.kernel.org/r/20200601050847.1096-1-walter-zh.wu@mediatek.com
Link: http://lkml.kernel.org/r/20200601050927.1153-1-walter-zh.wu@mediatek.com
Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com>
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
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 | 28 +++++++++++++++++++++++-----
6 files changed, 60 insertions(+), 7 deletions(-)
--- a/include/linux/kasan.h~rcu-kasan-record-and-print-call_rcu-call-stack
+++ a/include/linux/kasan.h
@@ -174,11 +174,13 @@ static inline size_t kasan_metadata_size
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 */
--- a/kernel/rcu/tree.c~rcu-kasan-record-and-print-call_rcu-call-stack
+++ a/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"
@@ -2876,6 +2877,7 @@ __call_rcu(struct rcu_head *head, rcu_ca
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. */
--- a/mm/kasan/common.c~rcu-kasan-record-and-print-call_rcu-call-stack
+++ a/mm/kasan/common.c
@@ -40,7 +40,7 @@
#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;
@@ -53,7 +53,7 @@ static inline depot_stack_handle_t save_
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)
--- a/mm/kasan/generic.c~rcu-kasan-record-and-print-call_rcu-call-stack
+++ a/mm/kasan/generic.c
@@ -324,3 +324,24 @@ 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);
+}
--- a/mm/kasan/kasan.h~rcu-kasan-record-and-print-call_rcu-call-stack
+++ a/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 *obj
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);
--- a/mm/kasan/report.c~rcu-kasan-record-and-print-call_rcu-call-stack
+++ a/mm/kasan/report.c
@@ -106,15 +106,20 @@ static void end_report(unsigned long *fl
kasan_enable_current();
}
+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);
+}
+
static void print_track(struct kasan_track *track, const char *prefix)
{
pr_err("%s by task %u:\n", prefix, track->pid);
if (track->stack) {
- unsigned long *entries;
- unsigned int nr_entries;
-
- nr_entries = stack_depot_fetch(track->stack, &entries);
- stack_trace_print(entries, nr_entries, 0);
+ print_stack(track->stack);
} else {
pr_err("(stack is not available)\n");
}
@@ -193,6 +198,19 @@ static void describe_object(struct kmem_
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);
_
Patches currently in -mm which might be from walter-zh.wu@mediatek.com are
rcu-kasan-record-and-print-call_rcu-call-stack.patch
kasan-record-and-print-the-free-track.patch
kasan-add-tests-for-call_rcu-stack-recording.patch
kasan-update-documentation-for-generic-kasan.patch
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2020-07-03 17:28 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-07-03 17:28 + rcu-kasan-record-and-print-call_rcu-call-stack.patch added to -mm tree akpm
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).