From mboxrd@z Thu Jan 1 00:00:00 1970 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 969DDC54EBD for ; Tue, 10 Jan 2023 00:55:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235630AbjAJAzU (ORCPT ); Mon, 9 Jan 2023 19:55:20 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42638 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234513AbjAJAzQ (ORCPT ); Mon, 9 Jan 2023 19:55:16 -0500 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D29043BE8F; Mon, 9 Jan 2023 16:55:10 -0800 (PST) Received: from dggpeml100012.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4NrXP34BHszRqN6; Tue, 10 Jan 2023 08:53:27 +0800 (CST) Received: from [10.67.110.218] (10.67.110.218) by dggpeml100012.china.huawei.com (7.185.36.121) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.34; Tue, 10 Jan 2023 08:55:07 +0800 Message-ID: Date: Tue, 10 Jan 2023 08:55:07 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.6.0 Subject: Re: [PATCH v2] rcu: Avoid stack overflow due to __rcu_irq_enter_check_tick() being kprobe-ed Content-Language: en-US To: CC: , , , , , , , , , , References: <20230106035423.3376283-1-zhengyejian1@huawei.com> <20230106070934.3434031-1-zhengyejian1@huawei.com> <20230109200436.GY4028633@paulmck-ThinkPad-P17-Gen-1> From: Zheng Yejian In-Reply-To: <20230109200436.GY4028633@paulmck-ThinkPad-P17-Gen-1> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.110.218] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpeml100012.china.huawei.com (7.185.36.121) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/1/10 04:04, Paul E. McKenney wrote: > On Fri, Jan 06, 2023 at 03:09:34PM +0800, Zheng Yejian wrote: >> Register kprobe on __rcu_irq_enter_check_tick() can cause kernel stack >> overflow [1]. This issue can be reproduced by enabling CONFIG_NO_HZ_FULL >> and boot kernel with argument "nohz_full=" then execute like: >> # cd /sys/kernel/tracing/ >> # echo 'p:mp1 __rcu_irq_enter_check_tick' >> kprobe_events >> # echo 1 > events/kprobes/enable >> >> It seems __rcu_irq_enter_check_tick() should not be kprobe-ed, so add >> it into kprobe blacklist with NOKPROBE_SYMBOL(). This may have less impact >> than tagging as 'noinstr' which was discussed but not concluded in >> Link: https://lore.kernel.org/all/20221119040049.795065-1-zhengyejian1@huawei.com/ > > Queued for testing and further review, thank you! > > Could you please check the wordsmithed version below? It looks much better, thank you! -- Best regards, Zheng Yejian > > Thanx, Paul > > ------------------------------------------------------------------------ > > commit 5ceaf736da841c4bdb03049c7d6e0c0c41253161 > Author: Zheng Yejian > Date: Fri Jan 6 15:09:34 2023 +0800 > > rcu: Avoid stack overflow due to __rcu_irq_enter_check_tick() being kprobe-ed > > Registering a kprobe on __rcu_irq_enter_check_tick() can cause kernel > stack overflow as shown below. This issue can be reproduced by enabling > CONFIG_NO_HZ_FULL and booting the kernel with argument "nohz_full=", > and then giving the following commands at the shell prompt: > > # cd /sys/kernel/tracing/ > # echo 'p:mp1 __rcu_irq_enter_check_tick' >> kprobe_events > # echo 1 > events/kprobes/enable > > This commit therefore adds __rcu_irq_enter_check_tick() to the kprobes > blacklist using NOKPROBE_SYMBOL(). > > Insufficient stack space to handle exception! > ESR: 0x00000000f2000004 -- BRK (AArch64) > FAR: 0x0000ffffccf3e510 > Task stack: [0xffff80000ad30000..0xffff80000ad38000] > IRQ stack: [0xffff800008050000..0xffff800008058000] > Overflow stack: [0xffff089c36f9f310..0xffff089c36fa0310] > CPU: 5 PID: 190 Comm: bash Not tainted 6.2.0-rc2-00320-g1f5abbd77e2c #19 > Hardware name: linux,dummy-virt (DT) > pstate: 400003c5 (nZcv DAIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) > pc : __rcu_irq_enter_check_tick+0x0/0x1b8 > lr : ct_nmi_enter+0x11c/0x138 > sp : ffff80000ad30080 > x29: ffff80000ad30080 x28: ffff089c82e20000 x27: 0000000000000000 > x26: 0000000000000000 x25: ffff089c02a8d100 x24: 0000000000000000 > x23: 00000000400003c5 x22: 0000ffffccf3e510 x21: ffff089c36fae148 > x20: ffff80000ad30120 x19: ffffa8da8fcce148 x18: 0000000000000000 > x17: 0000000000000000 x16: 0000000000000000 x15: ffffa8da8e44ea6c > x14: ffffa8da8e44e968 x13: ffffa8da8e03136c x12: 1fffe113804d6809 > x11: ffff6113804d6809 x10: 0000000000000a60 x9 : dfff800000000000 > x8 : ffff089c026b404f x7 : 00009eec7fb297f7 x6 : 0000000000000001 > x5 : ffff80000ad30120 x4 : dfff800000000000 x3 : ffffa8da8e3016f4 > x2 : 0000000000000003 x1 : 0000000000000000 x0 : 0000000000000000 > Kernel panic - not syncing: kernel stack overflow > CPU: 5 PID: 190 Comm: bash Not tainted 6.2.0-rc2-00320-g1f5abbd77e2c #19 > Hardware name: linux,dummy-virt (DT) > Call trace: > dump_backtrace+0xf8/0x108 > show_stack+0x20/0x30 > dump_stack_lvl+0x68/0x84 > dump_stack+0x1c/0x38 > panic+0x214/0x404 > add_taint+0x0/0xf8 > panic_bad_stack+0x144/0x160 > handle_bad_stack+0x38/0x58 > __bad_stack+0x78/0x7c > __rcu_irq_enter_check_tick+0x0/0x1b8 > arm64_enter_el1_dbg.isra.0+0x14/0x20 > el1_dbg+0x2c/0x90 > el1h_64_sync_handler+0xcc/0xe8 > el1h_64_sync+0x64/0x68 > __rcu_irq_enter_check_tick+0x0/0x1b8 > arm64_enter_el1_dbg.isra.0+0x14/0x20 > el1_dbg+0x2c/0x90 > el1h_64_sync_handler+0xcc/0xe8 > el1h_64_sync+0x64/0x68 > __rcu_irq_enter_check_tick+0x0/0x1b8 > arm64_enter_el1_dbg.isra.0+0x14/0x20 > el1_dbg+0x2c/0x90 > el1h_64_sync_handler+0xcc/0xe8 > el1h_64_sync+0x64/0x68 > __rcu_irq_enter_check_tick+0x0/0x1b8 > [...] > el1_dbg+0x2c/0x90 > el1h_64_sync_handler+0xcc/0xe8 > el1h_64_sync+0x64/0x68 > __rcu_irq_enter_check_tick+0x0/0x1b8 > arm64_enter_el1_dbg.isra.0+0x14/0x20 > el1_dbg+0x2c/0x90 > el1h_64_sync_handler+0xcc/0xe8 > el1h_64_sync+0x64/0x68 > __rcu_irq_enter_check_tick+0x0/0x1b8 > arm64_enter_el1_dbg.isra.0+0x14/0x20 > el1_dbg+0x2c/0x90 > el1h_64_sync_handler+0xcc/0xe8 > el1h_64_sync+0x64/0x68 > __rcu_irq_enter_check_tick+0x0/0x1b8 > el1_interrupt+0x28/0x60 > el1h_64_irq_handler+0x18/0x28 > el1h_64_irq+0x64/0x68 > __ftrace_set_clr_event_nolock+0x98/0x198 > __ftrace_set_clr_event+0x58/0x80 > system_enable_write+0x144/0x178 > vfs_write+0x174/0x738 > ksys_write+0xd0/0x188 > __arm64_sys_write+0x4c/0x60 > invoke_syscall+0x64/0x180 > el0_svc_common.constprop.0+0x84/0x160 > do_el0_svc+0x48/0xe8 > el0_svc+0x34/0xd0 > el0t_64_sync_handler+0xb8/0xc0 > el0t_64_sync+0x190/0x194 > SMP: stopping secondary CPUs > Kernel Offset: 0x28da86000000 from 0xffff800008000000 > PHYS_OFFSET: 0xfffff76600000000 > CPU features: 0x00000,01a00100,0000421b > Memory Limit: none > > Link: https://lore.kernel.org/all/20221119040049.795065-1-zhengyejian1@huawei.com/ > Fixes: aaf2bc50df1f ("rcu: Abstract out rcu_irq_enter_check_tick() from rcu_nmi_enter()") > Signed-off-by: Zheng Yejian > Cc: stable@vger.kernel.org > Signed-off-by: Paul E. McKenney > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > index a6181b76fd5ab..63545d79da51c 100644 > --- a/kernel/rcu/tree.c > +++ b/kernel/rcu/tree.c > @@ -640,6 +640,7 @@ void __rcu_irq_enter_check_tick(void) > } > raw_spin_unlock_rcu_node(rdp->mynode); > } > +NOKPROBE_SYMBOL(__rcu_irq_enter_check_tick); > #endif /* CONFIG_NO_HZ_FULL */ > > /*