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Tue, 17 Jan 2023 21:03:23 -0500 X-MC-Unique: q98vjuXaOB6Fiv0QW974_Q-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id EF9D31869B6C; Wed, 18 Jan 2023 02:03:22 +0000 (UTC) Received: from localhost (ovpn-13-29.pek2.redhat.com [10.72.13.29]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 232D1492B10; Wed, 18 Jan 2023 02:03:21 +0000 (UTC) Date: Wed, 18 Jan 2023 10:03:18 +0800 From: Baoquan He To: Dan Carpenter Cc: linux-mm@kvack.org Subject: Re: [bug report] mm/vmalloc: explicitly identify vm_map_ram area when shown in /proc/vmcoreinfo Message-ID: References: MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Rspamd-Queue-Id: 34D6FA0018 X-Stat-Signature: 95z41wjfncp9niqtcqaadptxwpfyqe6j X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1674007405-66609 X-HE-Meta: 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 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: On 01/17/23 at 02:03pm, Dan Carpenter wrote: > Hello Baoquan He, > > This static checker warning is related to yesterdays, but more straight > forward to analyze. > > The patch ae5dfc510155: "mm/vmalloc: explicitly identify vm_map_ram > area when shown in /proc/vmcoreinfo" from Jan 13, 2023, leads to the > following Smatch static checker warning: > > mm/vmalloc.c:4244 s_show() > error: we previously assumed 'v' could be null (see line 4241) Thanks a lot, Dan. This is a good catch. Below change should fix it. There are concerns in the patchset thread where this patch is carried. I will reply and see if I need repost a new version, or append below draft patch and post. diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 320e3d77a9dd..a0cec3e27e2c 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -4125,10 +4125,11 @@ static int s_show(struct seq_file *m, void *p) va = list_entry(p, struct vmap_area, list); - if (!va->vm && (va->flags & VMAP_RAM)) { - seq_printf(m, "0x%pK-0x%pK %7ld vm_map_ram\n", - (void *)va->va_start, (void *)va->va_end, - va->va_end - va->va_start); + if (!va->vm) { + if (va->flags & VMAP_RAM) { + seq_printf(m, "0x%pK-0x%pK %7ld vm_map_ram\n", + (void *)va->va_start, (void *)va->va_end, + va->va_end - va->va_start); goto final; } > > mm/vmalloc.c > 4226 static int s_show(struct seq_file *m, void *p) > 4227 { > 4228 struct vmap_area *va; > 4229 struct vm_struct *v; > 4230 > 4231 va = list_entry(p, struct vmap_area, list); > 4232 > 4233 if (!va->vm && (va->flags & VMAP_RAM)) { > ^^^^^^ ^^^^^^^^^^^^^^^^^^^^ > Assume va->vm is NULL but the VMAP_RAM flag is not set. > > 4234 seq_printf(m, "0x%pK-0x%pK %7ld vm_map_ram\n", > 4235 (void *)va->va_start, (void *)va->va_end, > 4236 va->va_end - va->va_start); > 4237 > 4238 goto final; > 4239 } > 4240 > 4241 v = va->vm; > ^^^^^^^^^^ > Assignment > > 4242 > 4243 seq_printf(m, "0x%pK-0x%pK %7ld", > --> 4244 v->addr, v->addr + v->size, v->size); > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > Dead. > > 4245 > 4246 if (v->caller) > 4247 seq_printf(m, " %pS", v->caller); > 4248 > > regards, > dan carpenter >