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McKenney" , "Josh Triplett" , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , Andrew Morton , Andrey Konovalov Subject: [PATCH v6 1/4] rcu/kasan: record and print call_rcu() call stack Date: Fri, 22 May 2020 10:00:59 +0800 Message-ID: <20200522020059.22332-1-walter-zh.wu@mediatek.com> X-Mailer: git-send-email 2.18.0 MIME-Version: 1.0 X-TM-SNTS-SMTP: 2AC2276E087F6D73DD4AF33E2264B3F334C3BE3B77DDB36EB8CAFEB4B585EE532000:8 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200521_190109_477922_071E3632 X-CRM114-Status: GOOD ( 14.49 ) X-Spam-Score: -0.2 (/) X-Spam-Report: SpamAssassin version 3.4.4 on bombadil.infradead.org summary: Content analysis details: (-0.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record 0.0 MIME_BASE64_TEXT RAW: Message text disguised using base64 encoding -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain 0.0 UNPARSEABLE_RELAY Informational: message has unparseable relay lines X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Walter Wu , wsd_upstream , linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org 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 Suggested-by: Dmitry Vyukov Acked-by: Paul E. McKenney Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Alexander Potapenko Cc: Andrew Morton Cc: Josh Triplett Cc: Mathieu Desnoyers Cc: Lai Jiangshan Cc: Joel Fernandes Cc: Andrey Konovalov --- 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(-) 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 #include #include +#include #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..2421a4bd9227 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -105,15 +105,20 @@ static void end_report(unsigned long *flags) 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"); } @@ -192,6 +197,19 @@ 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);