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Thu, 18 Jan 2024 01:27:18 +0000 (UTC) X-FDA: 81690693756.26.B060C1E Received: from out30-100.freemail.mail.aliyun.com (out30-100.freemail.mail.aliyun.com [115.124.30.100]) by imf11.hostedemail.com (Postfix) with ESMTP id A3F994000B for ; Thu, 18 Jan 2024 01:27:15 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=alibaba.com; spf=pass (imf11.hostedemail.com: domain of baolin.wang@linux.alibaba.com designates 115.124.30.100 as permitted sender) smtp.mailfrom=baolin.wang@linux.alibaba.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1705541237; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=I+PRpcwX9wnvo03lkp56Gl5Lbmir+UbsJRfSlpGG/KU=; b=ygU52bwDB2a40T81S8H5MLmBomyhuN0lh5xdgBAdFug2sXN9kkKmcY/mpfYTmwkVH/pXAg enchzAVU/mqoqDUIdx35ehyt7qq9VdPMo/9HR1kHTGCCiuzM9R7ebg+ELuMN5Gibc4eoVA 1lc5ugievULVKGljmniwIWHRBPXfm3M= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=alibaba.com; spf=pass (imf11.hostedemail.com: domain of baolin.wang@linux.alibaba.com designates 115.124.30.100 as permitted sender) smtp.mailfrom=baolin.wang@linux.alibaba.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1705541237; a=rsa-sha256; cv=none; b=tf/QiI0RcOm1auGmo3ZGkWTtqyX2+XvmFGkzeyey9K0yz8scibh3qLntOyc0LM1lIndn73 vszgfpB+v3kdmw+UsctJ/6/ZWXYjKGJGtadqJxCf0zLFuyIMDkop9eEfh9OwsfHP4Oc8ed lpOkzH/ASpKH8ScZScRT/EuY72J/dsA= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R591e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046050;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=8;SR=0;TI=SMTPD_---0W-qs3Uk_1705541230; Received: from 30.97.48.47(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0W-qs3Uk_1705541230) by smtp.aliyun-inc.com; Thu, 18 Jan 2024 09:27:10 +0800 Message-ID: <07ccff45-a728-4ed1-86f4-91517c656609@linux.alibaba.com> Date: Thu, 18 Jan 2024 09:27:41 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] fs: improve dump_mapping() robustness To: Christian Brauner Cc: willy@infradead.org, viro@zeniv.linux.org.uk, jack@suse.cz, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org References: <937ab1f87328516821d39be672b6bc18861d9d3e.1705391420.git.baolin.wang@linux.alibaba.com> <20240116-privat-zeitplan-21db23926f45@brauner> From: Baolin Wang In-Reply-To: <20240116-privat-zeitplan-21db23926f45@brauner> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: A3F994000B X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: 6muyr79qzgbcoq8z6x4npgmf7g744nog X-HE-Tag: 1705541235-968380 X-HE-Meta: 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 LrQ5YWax FwegHIz+g4BuiqPFUbznrZjMVNzM0uoqCZ0ce8ig3CW92lLREJ12Z8d5BrezfB9qsGuCjziHQqA5B+TCvA23P46Lnxb3T3ZaVzXwYSI/W162z8FrlV/mGvPXyEXJgeUP3Hi5Z7+fbG7SgrJTnwCmELdtxnEU8Qq04m1mrjuB4wkUEvimdppDTx66Wn3QiZDrRMGBnAT1kzb2qqTlYZy36AxA6jJ9SS73MqV23 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 1/16/2024 7:16 PM, Christian Brauner wrote: > On Tue, 16 Jan 2024 15:53:35 +0800, Baolin Wang wrote: >> We met a kernel crash issue when running stress-ng testing, and the >> system crashes when printing the dentry name in dump_mapping(). >> >> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 >> pc : dentry_name+0xd8/0x224 >> lr : pointer+0x22c/0x370 >> sp : ffff800025f134c0 >> ...... >> Call trace: >> dentry_name+0xd8/0x224 >> pointer+0x22c/0x370 >> vsnprintf+0x1ec/0x730 >> vscnprintf+0x2c/0x60 >> vprintk_store+0x70/0x234 >> vprintk_emit+0xe0/0x24c >> vprintk_default+0x3c/0x44 >> vprintk_func+0x84/0x2d0 >> printk+0x64/0x88 >> __dump_page+0x52c/0x530 >> dump_page+0x14/0x20 >> set_migratetype_isolate+0x110/0x224 >> start_isolate_page_range+0xc4/0x20c >> offline_pages+0x124/0x474 >> memory_block_offline+0x44/0xf4 >> memory_subsys_offline+0x3c/0x70 >> device_offline+0xf0/0x120 >> ...... >> >> [...] > > Seems fine for debugging purposes. Let me know if this needs to go through > somewhere else. Going through VFS tree is fine to me. Thanks.