From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 32452 invoked by alias); 11 Jul 2012 10:12:03 -0000 Received: (qmail 32436 invoked by uid 22791); 11 Jul 2012 10:12:01 -0000 X-SWARE-Spam-Status: No, hits=-3.0 required=5.0 tests=AWL,BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,KHOP_RCVD_TRUST,RCVD_IN_DNSWL_LOW,RCVD_IN_HOSTKARMA_YE X-Spam-Check-By: sourceware.org Received: from mail-yx0-f169.google.com (HELO mail-yx0-f169.google.com) (209.85.213.169) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 11 Jul 2012 10:11:44 +0000 Received: by yenr5 with SMTP id r5so1155648yen.0 for ; Wed, 11 Jul 2012 03:11:44 -0700 (PDT) MIME-Version: 1.0 Received: by 10.50.12.165 with SMTP id z5mr13929891igb.65.1342001503676; Wed, 11 Jul 2012 03:11:43 -0700 (PDT) Received: by 10.64.137.134 with HTTP; Wed, 11 Jul 2012 03:11:43 -0700 (PDT) Date: Wed, 11 Jul 2012 10:12:00 -0000 Message-ID: Subject: How can I explain for this? what is __kernel_vsyscall () ? From: Tom Frank To: gdb@sourceware.org Content-Type: text/plain; charset=ISO-8859-1 X-IsSubscribed: yes Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org X-SW-Source: 2012-07/txt/msg00022.txt.bz2 I debug a multithreads programme with gdb,as it runs I use the 'info threads' command, and find that most of the threads running at __kernel_vsyscall () function as below: 6 Thread 0xb61e4b90 (LWP 322) 0x008e7402 in __kernel_vsyscall () 5 Thread 0xb6be5b90 (LWP 320) 0x008e7402 in __kernel_vsyscall () 4 Thread 0xb7fe7b90 (LWP 318) 0x008e7402 in __kernel_vsyscall () 3 Thread 0xb75e6b90 (LWP 316) 0x008e7402 in __kernel_vsyscall () * 1 Thread 0xb7fe86d0 (LWP 312) 0x0074c2b8 in clone () from /lib/i686/nosegneg/libc.so.6 what is __kernel_vsyscall (), why most threads's frame is in that step ?