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Tue, 24 Sep 2024 07:34:12 -0400 X-MC-Unique: zQLxxr_HMwSthCQWFjHHHw-1 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (unknown [10.30.177.15]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4D88618EB2CC; Tue, 24 Sep 2024 11:34:11 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.45.226.71]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id AF405195608A; Tue, 24 Sep 2024 11:34:07 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Tue, 24 Sep 2024 13:33:58 +0200 (CEST) Date: Tue, 24 Sep 2024 13:33:54 +0200 From: Oleg Nesterov To: "qiwu.chen" Cc: corbet@lwn.net, catalin.marinas@arm.com, will@kernel.org, paulmck@kernel.org, akpm@linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, "qiwu.chen" Subject: Re: [PATCH v4 1/2] panic: add option to dump task maps info in panic_print Message-ID: <20240924113322.GA7248@redhat.com> References: <20240924074341.37272-1-qiwu.chen@transsion.com> MIME-Version: 1.0 In-Reply-To: <20240924074341.37272-1-qiwu.chen@transsion.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Stat-Signature: iby9uk3ihxjc56gcuzei7u5tu97j9ct5 X-Rspamd-Queue-Id: B18DF4001D X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1727177656-380239 X-HE-Meta: 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 ZvSJuWuy LzqoCQGNeamAEYfPfG4K5SapRzDQZHDbFTII9KQDxd6SMBckmAcYjLykfMXhjW3ttcezeX1m5Z4g5+D8smak9tZ8jhNPnN37y/B4awrBTlaL6LQVpbZc5NGyndokUAA7J59/FdZiS0OUl4Y3zEcSv3JeIhSWQ+wGBxgAqj46slSbpPTv96hus/oiLJneIbU+Wg1J6Bn+mPmcXLs7V+uapQ1a4axSbvsCayXwz8OVvT3sAXyqqSiWaYGVBcSJEld+jzOhCmP3psoJRjT5pZcva/9Dtsc4Ln8tXnOaJvGwY083XjHil/YcGBxXjI5fzcszSTTWFtaloTxjtlzbY1SmCDNYgN4gWIRYbjsVKLAwsn2BO3MCQaGuiL8zxQEaVmIe7IZ7oxDXRJBiBpFimeOO1JwpMDA== 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 09/24, qiwu.chen wrote: > > +EXPORT_SYMBOL(get_vma_name); Why? > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -3566,6 +3566,10 @@ static inline bool range_in_vma(struct vm_area_struct *vma, > #ifdef CONFIG_MMU > pgprot_t vm_get_page_prot(unsigned long vm_flags); > void vma_set_page_prot(struct vm_area_struct *vma); > +void get_vma_name(struct vm_area_struct *vma, > + const struct path **path, > + const char **name, > + const char **name_fmt); > #else You didn't move get_vma_name() from fs/proc/task_mmu.c, so it also depends on CONFIG_PROC_FS. > +/* > + * This function is called in panic proccess if the PANIC_PRINT_TASK_MAPS_INFO > + * flag is specified in panic_print, which is helpful to debug panic issues due > + * to an unhandled falut in user mode such as kill init. > + */ > +static void dump_task_maps_info(struct task_struct *tsk) > +{ > + struct pt_regs *user_ret = task_pt_regs(tsk); > + struct mm_struct *mm = tsk->mm; > + struct vm_area_struct *vma; > + > + if (!mm || !user_mode(user_ret)) > + return; > + > + pr_info("Dump task %s:%d maps start\n", tsk->comm, task_pid_nr(tsk)); > + mmap_read_lock(mm); > + VMA_ITERATOR(vmi, mm, 0); > + for_each_vma(vmi, vma) { > + int flags = vma->vm_flags; > + unsigned long long pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT; > + const struct path *path; > + const char *name_fmt, *name; > + char name_buf[SZ_256]; > + > + get_vma_name(vma, &path, &name, &name_fmt); So this code won't compile if CONFIG_MMU=n ? > + if (path) { > + name = d_path(path, name_buf, sizeof(name_buf)); > + name = IS_ERR(name) ? "?" : name; perhaps this needs mangle_path() ... > + } else if (name || name_fmt) { > + snprintf(name_buf, sizeof(name_buf), name_fmt ?: "%s", name); > + name = name_buf; > + } Why not } else if (name_fmt) { snprintf(name_buf, sizeof(name_buf), name_fmt, name); name = name_buf; } ? > + if (name) > + pr_info("%08lx-%08lx %c%c%c%c %08llx %s\n", > + vma->vm_start, vma->vm_end, > + flags & VM_READ ? 'r' : '-', > + flags & VM_WRITE ? 'w' : '-', > + flags & VM_EXEC ? 'x' : '-', > + flags & VM_MAYSHARE ? 's' : 'p', > + pgoff, name); I don't really understand why you skip vma if !name... Oleg.