From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 106476 invoked by alias); 27 Jan 2020 15:26:39 -0000 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 Received: (qmail 106363 invoked by uid 89); 27 Jan 2020 15:26:38 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-3.9 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,HTML_MESSAGE,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.1 spammy=H*f:e2Gc3g-5L, H*i:CAPTJ0XFVq_twO, H*i:e2Gc3g-5L, H*f:sk:GATJvDk X-HELO: mail-io1-f50.google.com Received: from mail-io1-f50.google.com (HELO mail-io1-f50.google.com) (209.85.166.50) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Mon, 27 Jan 2020 15:26:35 +0000 Received: by mail-io1-f50.google.com with SMTP id t26so10393132ioi.13 for ; Mon, 27 Jan 2020 07:26:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=gIh+U+djGTaItnNEHVvD8A2j3fEg9dIu1gCoXB5sKZg=; b=aODfHd2Wywa+i+bDHx4q+KkTMq5Q14yEupfrJbJMjrJ2YkP+nzAKNjxuG5gAd1rgOt GD9t80OyeiMdMaHCtP9o2iMha6jQmVj1G5QV+729k1rAQL9tU/iKTJRgFlit7huZcXda Ed92VZX6xY9M7RbDna8NRGzXXEhY8OrteyrYaOdewHUxv9seqtW0St1Kyn2cj64UZgTr BVVUH3DhJ3bVktvJUHTveP+cev2IYrDaH+eeSFhNGFMGSbivoNce1RnJ8/tuOLOkOIRE oCDbRfiMFthXeqeMUkLhRU0ZkjQuNiJAlgj6LYucsFaZZEDBIUwstNzIkpLaMU86hMdE sx8w== MIME-Version: 1.0 References: In-Reply-To: From: Abhi Arora Date: Mon, 27 Jan 2020 15:26:00 -0000 Message-ID: Subject: Re: Backtrace stopped: previous frame identical to this frame (corrupt stack?) To: Christian Biesinger Cc: gdb@sourceware.org Content-Type: text/plain; charset="UTF-8" X-IsSubscribed: yes X-SW-Source: 2020-01/txt/msg00068.txt.bz2 I will try to add debug symbols of libcurl and regenerate the crash. However, I also want to understand in which positive scenario (,i.e., stack is not corrupted) I can get this message and what does that mean? Consider the last two stack frame in Thread 1: #5 0x769ec986 in curl_easy_perform () from /opt/iotgw-debug/2.5.3/sysroots/armv7at2hf-neon-fslc-linux-gnueabi/usr/lib/libcurl.so.4 #6 0x76eb433e in ?? () Backtrace stopped: previous frame identical to this frame (corrupt stack?) 1. Does it mean stack frame #6 is similar to stack frame #7 (which is not printed?)? And that's why gdb stopped itself at #6 assuming #7 could be corrupted? 2. Does it compare whole stack frame (all the bytes) with the neighbour stack frame? 3. Can you please help me with a scenerio when two stack frame can be similar (when stack is not corrupted)? On Mon, Jan 27, 2020 at 7:01 PM Christian Biesinger wrote: > > > On Sun, Jan 26, 2020, 17:24 Abhi Arora wrote: > >> I am having an application with 16 Thread in ARM board running Linux. My >> problem crashed (Segmentation Fault) and I got the core dump. I was >> analyzing it and found out I was getting "Backtrace stopped: previous >> frame >> identical to this frame (corrupt stack?)" message for each of the thread >> except the "main" thread. >> >> I have posted backtrace of "main", thread that caused SEGV FAULT and a >> thread which was working fine. >> >> 1. I want to know why this message is coming up? What does this mean? >> One possibility is corrupt stack but what other times it can show up? >> Recursive function call? >> 2. I am not sure how to get more information from Thread 1. I want to know >> which function has called "curl_easy_perform". I want to get complete >> backtrace of Thread 1. I tried to "set $sp = " but looks like I can't >> modify the SP. I want someone to help with an article to unstack my Thread >> 1 further. Please advise. > > > You should try to install debug symbols for libcurl. GDB can't always > unwind stacks without symbols. > > FWIW, the stack for thread 5 is complete despite the message (it has > start_thread in it). > > Christian > > >> Thread 5 (LWP 3238): >> #0 __libc_do_syscall () at libc-do-syscall.S:48 >> #1 0x76ab0b00 in __GI___select (nfds=6, readfds=readfds@entry >> =0x7563ac58, >> writefds=writefds@entry=0x0, exceptfds=exceptfds@entry=0x0, >> timeout=timeout@entry=0x7563ac38) >> at >> /usr/src/debug/glibc/2.28-r0/git/sysdeps/unix/sysv/linux/select.c:41 >> #2 0x004a2ace in Isom::Checksafetybuttons (this=this@entry=0x158f780) at >> >> /home/abhishek/develop/gateway-app/GatewayApp/source/WebServer/isom.cpp:292 >> #3 0x004a3834 in StartIsom () at >> >> /home/abhishek/develop/gateway-app/GatewayApp/source/WebServer/isom.cpp:592 >> #4 0x00486494 in ns_Isom::isom_start_function (ptr=0x0) at >> >> /home/abhishek/develop/gateway-app/GatewayApp/source/GatewayAppMain.cpp:646 >> #5 0x76cc4afa in start_thread (arg=0xa9c8b261) at >> /usr/src/debug/glibc/2.28-r0/git/nptl/pthread_create.c:486 >> #6 0x76ab538c in ?? () at ../sysdeps/unix/sysv/linux/arm/clone.S:73 from >> >> /opt/iotgw-debug/2.5.3/sysroots/armv7at2hf-neon-fslc-linux-gnueabi/lib/libc.so.6 >> Backtrace stopped: previous frame identical to this frame (corrupt stack?) >> >> Thread 2 (LWP 3204): >> #0 __libc_do_syscall () at libc-do-syscall.S:48 >> #1 0x76cc5b18 in __GI___pthread_timedjoin_ex (threadid=1873773472, >> thread_return=0x0, abstime=, block=) >> at /usr/src/debug/glibc/2.28-r0/git/nptl/pthread_join_common.c:89 >> #2 0x76c40f3a in __gthread_join (__value_ptr=0x0, __threadid=> out>) >> at >> >> /usr/src/debug/gcc-runtime/7.3.0-r0/arm-fslc-linux-gnueabi/libstdc++-v3/include/arm-fslc-linux-gnueabi/bits/gthr-default.h:668 >> #3 std::thread::join (this=this@entry=0x7ebe1784) at >> /usr/src/debug/gcc-runtime/7.3.0-r0/libstdc++-v3/src/c++11/thread.cc:136 >> #4 0x00470198 in main (argc=, argv=) at >> >> /home/abhishek/develop/gateway-app/GatewayApp/source/GatewayAppMain.cpp:599 >> >> Thread 1 (LWP 3751): >> #0 0x769ec67a in Curl_strncasecompare () from >> >> /opt/iotgw-debug/2.5.3/sysroots/armv7at2hf-neon-fslc-linux-gnueabi/usr/lib/libcurl.so.4 >> #1 0x769ead58 in Curl_checkheaders () from >> >> /opt/iotgw-debug/2.5.3/sysroots/armv7at2hf-neon-fslc-linux-gnueabi/usr/lib/libcurl.so.4 >> #2 0x769de8fa in Curl_http () from >> >> /opt/iotgw-debug/2.5.3/sysroots/armv7at2hf-neon-fslc-linux-gnueabi/usr/lib/libcurl.so.4 >> #3 0x769f0e5c in multi_runsingle () from >> >> /opt/iotgw-debug/2.5.3/sysroots/armv7at2hf-neon-fslc-linux-gnueabi/usr/lib/libcurl.so.4 >> #4 0x769f1708 in curl_multi_perform () from >> >> /opt/iotgw-debug/2.5.3/sysroots/armv7at2hf-neon-fslc-linux-gnueabi/usr/lib/libcurl.so.4 >> #5 0x769ec986 in curl_easy_perform () from >> >> /opt/iotgw-debug/2.5.3/sysroots/armv7at2hf-neon-fslc-linux-gnueabi/usr/lib/libcurl.so.4 >> #6 0x76eb433e in ?? () >> Backtrace stopped: previous frame identical to this frame (corrupt stack?) >> >