From patchwork Wed Aug 2 03:45:16 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Leizhen (ThunderTown)" X-Patchwork-Id: 13337591 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1131EC001E0 for ; Wed, 2 Aug 2023 03:46:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231864AbjHBDqB (ORCPT ); Tue, 1 Aug 2023 23:46:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35630 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230401AbjHBDp7 (ORCPT ); Tue, 1 Aug 2023 23:45:59 -0400 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6E1A419B9; Tue, 1 Aug 2023 20:45:56 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.143]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTP id 4RFyYp6hHpz4f4K0W; Wed, 2 Aug 2023 11:45:50 +0800 (CST) Received: from huaweicloud.com (unknown [10.174.178.55]) by APP4 (Coremail) with SMTP id gCh0CgD3X7Nq0clky7F2PQ--.46299S5; Wed, 02 Aug 2023 11:45:53 +0800 (CST) From: thunder.leizhen@huaweicloud.com To: Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Vlastimil Babka , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, linux-mm@kvack.org, "Paul E . McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Zqiang , rcu@vger.kernel.org, linux-kernel@vger.kernel.org, openeuler Subject: [PATCH v3 1/2] mm: Provide empty function for kmem_dump_obj() when CONFIG_PRINTK=n Date: Wed, 2 Aug 2023 11:45:16 +0800 Message-Id: <20230802034518.1115-2-thunder.leizhen@huaweicloud.com> X-Mailer: git-send-email 2.37.3.windows.1 In-Reply-To: <20230802034518.1115-1-thunder.leizhen@huaweicloud.com> References: <20230802034518.1115-1-thunder.leizhen@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: gCh0CgD3X7Nq0clky7F2PQ--.46299S5 X-Coremail-Antispam: 1UD129KBjvdXoW7Xr4kZFyrZF47Xw48CryxGrg_yoWDArcEy3 4fXw1xWr4xXF1xC3Wjyw4fZF1rGw4UJFy3A3sYkr13Zr1Yvanxtw4DJFn0v3yUuFs5Jr9F 9a18Ca93KrnFqjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUb6kYFVCjjxCrM7AC8VAFwI0_Wr0E3s1l1xkIjI8I6I8E6xAIw20E Y4v20xvaj40_JFC_Wr1l1IIY67AEw4v_Jr0_Jr4l82xGYIkIc2x26280x7IE14v26r18M2 8IrcIa0xkI8VCY1x0267AKxVW5JVCq3wA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK 021l84ACjcxK6xIIjxv20xvE14v26w1j6s0DM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r 4UJVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_ GcCE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx 0E2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWU JVW8JwACjcxG0xvY0x0EwIxGrwACI402YVCY1x02628vn2kIc2xKxwAKzVCY07xG64k0F2 4l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWU JVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6rW5MIIYrxkI7V AKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42 IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxUwjjgUUUUU X-CM-SenderInfo: hwkx0vthuozvpl2kv046kxt4xhlfz01xgou0bp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org From: Zhen Lei Commit 5bb1bb353cfe ("mm: Don't build mm_dump_obj() on CONFIG_PRINTK=n kernels") only provides static inline empty function for mem_dump_obj(). But functions kmem_valid_obj() and kmem_dump_obj() are also exported, they may be called by functions other than mem_dump_obj(), so their empty functions should also be provided when CONFIG_PRINTK=n. Signed-off-by: Zhen Lei --- include/linux/slab.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/include/linux/slab.h b/include/linux/slab.h index 848c7c82ad5ad0b..fc05fe288d176b4 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -246,6 +246,9 @@ size_t ksize(const void *objp); #ifdef CONFIG_PRINTK bool kmem_valid_obj(void *object); void kmem_dump_obj(void *object); +#else +static inline bool kmem_valid_obj(void *object) { return false; } +static inline void kmem_dump_obj(void *object) {} #endif /* From patchwork Wed Aug 2 03:45:17 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Leizhen (ThunderTown)" X-Patchwork-Id: 13337590 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 17368C04A6A for ; Wed, 2 Aug 2023 03:46:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231742AbjHBDqB (ORCPT ); Tue, 1 Aug 2023 23:46:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35632 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230109AbjHBDp7 (ORCPT ); Tue, 1 Aug 2023 23:45:59 -0400 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D5471BC3; Tue, 1 Aug 2023 20:45:57 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.143]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTP id 4RFyYq6nBXz4f3lJw; Wed, 2 Aug 2023 11:45:51 +0800 (CST) Received: from huaweicloud.com (unknown [10.174.178.55]) by APP4 (Coremail) with SMTP id gCh0CgD3X7Nq0clky7F2PQ--.46299S6; Wed, 02 Aug 2023 11:45:54 +0800 (CST) From: thunder.leizhen@huaweicloud.com To: Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Vlastimil Babka , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, linux-mm@kvack.org, "Paul E . McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Zqiang , rcu@vger.kernel.org, linux-kernel@vger.kernel.org, openeuler Subject: [PATCH v3 2/2] rcu: Dump memory object info if callback function is invalid Date: Wed, 2 Aug 2023 11:45:17 +0800 Message-Id: <20230802034518.1115-3-thunder.leizhen@huaweicloud.com> X-Mailer: git-send-email 2.37.3.windows.1 In-Reply-To: <20230802034518.1115-1-thunder.leizhen@huaweicloud.com> References: <20230802034518.1115-1-thunder.leizhen@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: gCh0CgD3X7Nq0clky7F2PQ--.46299S6 X-Coremail-Antispam: 1UD129KBjvJXoWxtF47WrW7Kw1fury3tFWrZrb_yoW7Xr48pr ykuFyUKw4kXFyrtay7Zw18WrWUA39Ygayaka95Crn3Cw4Ykw10gFyqyF12qrWYqFyrK34a qF1YqF43Kw48AwUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBEb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6r1S6rWUM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUXw A2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVWDJVCq3wA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV W8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMc Ij6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_ Jr0_Gr1lF7xvr2IYc2Ij64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1lw4CEc2x0rVAKj4 xxMxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_ Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVW8ZVWrXwCIc40Y0x 0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVWx JVW8Jr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMI IF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x07UtR67UUUUU = X-CM-SenderInfo: hwkx0vthuozvpl2kv046kxt4xhlfz01xgou0bp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org From: Zhen Lei When a structure containing an RCU callback rhp is (incorrectly) freed and reallocated after rhp is passed to call_rcu(), it is not unusual for rhp->func to be set to NULL. This defeats the debugging prints used by __call_rcu_common() in kernels built with CONFIG_DEBUG_OBJECTS_RCU_HEAD=y, which expect to identify the offending code using the identity of this function. And in kernels build without CONFIG_DEBUG_OBJECTS_RCU_HEAD=y, things are even worse, as can be seen from this splat: Unable to handle kernel NULL pointer dereference at virtual address 0 ... ... PC is at 0x0 LR is at rcu_do_batch+0x1c0/0x3b8 ... ... (rcu_do_batch) from (rcu_core+0x1d4/0x284) (rcu_core) from (__do_softirq+0x24c/0x344) (__do_softirq) from (__irq_exit_rcu+0x64/0x108) (__irq_exit_rcu) from (irq_exit+0x8/0x10) (irq_exit) from (__handle_domain_irq+0x74/0x9c) (__handle_domain_irq) from (gic_handle_irq+0x8c/0x98) (gic_handle_irq) from (__irq_svc+0x5c/0x94) (__irq_svc) from (arch_cpu_idle+0x20/0x3c) (arch_cpu_idle) from (default_idle_call+0x4c/0x78) (default_idle_call) from (do_idle+0xf8/0x150) (do_idle) from (cpu_startup_entry+0x18/0x20) (cpu_startup_entry) from (0xc01530) This commit therefore adds calls to mem_dump_obj(rhp) to output some information, for example: slab kmalloc-256 start ffff410c45019900 pointer offset 0 size 256 This provides the rough size of the memory block and the offset of the rcu_head structure, which as least provides at least a few clues to help locate the problem. If the problem is reproducible, additional slab debugging can be enabled, for example, CONFIG_DEBUG_SLAB=y, which can provide significantly more information. Signed-off-by: Zhen Lei Signed-off-by: Paul E. McKenney --- kernel/rcu/rcu.h | 9 +++++++++ kernel/rcu/srcutiny.c | 1 + kernel/rcu/srcutree.c | 1 + kernel/rcu/tasks.h | 1 + kernel/rcu/tiny.c | 1 + kernel/rcu/tree.c | 1 + 6 files changed, 14 insertions(+) diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h index d1dcb09750efbd6..30a7b0a79ae7a67 100644 --- a/kernel/rcu/rcu.h +++ b/kernel/rcu/rcu.h @@ -10,6 +10,7 @@ #ifndef __LINUX_RCU_H #define __LINUX_RCU_H +#include #include /* @@ -248,6 +249,14 @@ static inline void debug_rcu_head_unqueue(struct rcu_head *head) } #endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */ +static inline void debug_rcu_head_callback(struct rcu_head *rhp) +{ + if (unlikely(!rhp->func)) { + if (kmem_valid_obj(rhp)) + kmem_dump_obj(rhp); + } +} + extern int rcu_cpu_stall_suppress_at_boot; static inline bool rcu_stall_is_suppressed_at_boot(void) diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c index 336af24e0fe358a..c38e5933a5d6937 100644 --- a/kernel/rcu/srcutiny.c +++ b/kernel/rcu/srcutiny.c @@ -138,6 +138,7 @@ void srcu_drive_gp(struct work_struct *wp) while (lh) { rhp = lh; lh = lh->next; + debug_rcu_head_callback(rhp); local_bh_disable(); rhp->func(rhp); local_bh_enable(); diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index f1a905200fc2f79..833a8f848a90ae6 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -1710,6 +1710,7 @@ static void srcu_invoke_callbacks(struct work_struct *work) rhp = rcu_cblist_dequeue(&ready_cbs); for (; rhp != NULL; rhp = rcu_cblist_dequeue(&ready_cbs)) { debug_rcu_head_unqueue(rhp); + debug_rcu_head_callback(rhp); local_bh_disable(); rhp->func(rhp); local_bh_enable(); diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 7294be62727b12c..148ac6a464bfb12 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -538,6 +538,7 @@ static void rcu_tasks_invoke_cbs(struct rcu_tasks *rtp, struct rcu_tasks_percpu raw_spin_unlock_irqrestore_rcu_node(rtpcp, flags); len = rcl.len; for (rhp = rcu_cblist_dequeue(&rcl); rhp; rhp = rcu_cblist_dequeue(&rcl)) { + debug_rcu_head_callback(rhp); local_bh_disable(); rhp->func(rhp); local_bh_enable(); diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c index 42f7589e51e09e7..fec804b7908032d 100644 --- a/kernel/rcu/tiny.c +++ b/kernel/rcu/tiny.c @@ -97,6 +97,7 @@ static inline bool rcu_reclaim_tiny(struct rcu_head *head) trace_rcu_invoke_callback("", head); f = head->func; + debug_rcu_head_callback(head); WRITE_ONCE(head->func, (rcu_callback_t)0L); f(head); rcu_lock_release(&rcu_callback_map); diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 7c79480bfaa04e4..927c5ba0ae42269 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2135,6 +2135,7 @@ static void rcu_do_batch(struct rcu_data *rdp) trace_rcu_invoke_callback(rcu_state.name, rhp); f = rhp->func; + debug_rcu_head_callback(rhp); WRITE_ONCE(rhp->func, (rcu_callback_t)0L); f(rhp);