> ## Documentation Index > Fetch the complete documentation index at: https://dragonwingdocs.qualcomm.com/llms.txt > Use this file to discover all available pages before exploring further. # Debug using the crash utility tool Crash utility is an open-source tool to debug kernel using a gdb-based command-line interface over RAM dumps. ## **Prerequisites** * `kaslr_offset` and `kimage_voffset` values By default, the Qualcomm Linux build has the Kernel Address Space Layout Randomization (KASLR) feature enabled. For the crash utility to work on a KASLR-enabled kernel, you need the values of the `kaslr_offset` and `kimage_voffset` parameters, which you can extract from the `dmesg_TZ.txt` RAMparser output file. The following is an excerpt from the sample RAMparser output file, `dmesg_TZ.txt`, providing the `kaslr_offset` and `kimage_voffset` values. The kaslr\_offset extracted is: 0x340c3d320000 ... The kimage\_voffset extracted is: ffffb40bbf600000 * Base address of the kernel binaries (`DDRCS*.BIN`) When you use PCAT to capture the RAM dump, it also captures the `dump_info.txt` and `load.cmm` files. These files contain the base address of the kernel binaries (`DDRCS*.BIN`). ## **Download and build the crash utility tool on Linux host** * To download and build the crash utility, run the following commands: > ```text theme={null} > git clone https://github.com/crash-utility/crash > ``` > > ```text theme={null} > make target=ARM64 > ``` > > ```text theme={null} > make extensions=ARM64 > ``` For more information, see [crash/README at master · crash-utility/crash· GitHub](https://github.com/crash-utility/crash/blob/master/README). ## **Run the crash utility tool** The following is the sample command to run the crash utility on an Ubuntu host: ```text theme={null} ./crash /vmlinux /DDRCS0_0.BIN@0x80000000,/DDRCS1_0.BIN@0x100000000,/DDRCS1_1.BIN@0x180000000 -m vabits_actual=48 -m max_physmem_bits=48 -m kimage_voffset=0xffffb40bbf600000 --kaslr=0x340c3d320000 ``` * Replace `` with the vmlinux RAM dump path. * Extract `kimage_voffset`, and `kaslr` from the `dmesg_TZ.txt` RAMparser output file. * Extract the DDR offsets such as `0x80000000` from the `dump_info.txt` file available in the RAM dump collected using PCAT. **Sample output:** ```text theme={null} crash 8.0.4 Copyright (C) 2002-2022 Red Hat, Inc. Copyright (C) 2004, 2005, 2006, 2010 IBM Corporation Copyright (C) 1999-2006 Hewlett-Packard Co Copyright (C) 2005, 2006, 2011, 2012 Fujitsu Limited Copyright (C) 2006, 2007 VA Linux Systems Japan K.K. Copyright (C) 2005, 2011, 2020-2022 NEC Corporation Copyright (C) 1999, 2002, 2007 Silicon Graphics, Inc. Copyright (C) 1999, 2000, 2001, 2002 Mission Critical Linux, Inc. Copyright (C) 2015, 2021 VMware, Inc. This program is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Enter "help copying" to see the conditions. This program has absolutely no warranty. Enter "help warranty" for details. NOTE: setting vabits_actual to: 48 NOTE: setting max_physmem_bits to: 48 GNU gdb (GDB) 10.2 Copyright (C) 2021 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "--host=x86_64-pc-linux-gnu --target=aarch64-elf-linux". Type "show configuration" for configuration details. Find the GDB manual and other documentation resources online at: . For help, type "help". Type "apropos word" to search for commands related to "word"... WARNING: cpu 0: cannot find NT_PRSTATUS note WARNING: cpu 1: cannot find NT_PRSTATUS note WARNING: cpu 2: cannot find NT_PRSTATUS note WARNING: cpu 3: cannot find NT_PRSTATUS note WARNING: cpu 4: cannot find NT_PRSTATUS note WARNING: cpu 5: cannot find NT_PRSTATUS note WARNING: cpu 6: cannot find NT_PRSTATUS note WARNING: cpu 7: cannot find NT_PRSTATUS note KERNEL: /test/vmlinux [TAINTED] DUMPFILES: /var/tmp/ramdump_elf_PBaLfj [temporary ELF header] /test/DDRCS0_0.BIN /test/DDRCS1_0.BIN /test/DDRCS1_1.BIN CPUS: 8 [OFFLINE: 7] DATE: Sun Jan 6 05:30:34 +0530 1980 UPTIME: 00:00:48 LOAD AVERAGE: 1.60, 0.51, 0.18 TASKS: 532 RELEASE: 6.6.17-debug VERSION: #1 SMP PREEMPT Mon Mar 25 04:52:52 UTC 2024 MACHINE: aarch64 (unknown Mhz) MEMORY: 5.5 GB PANIC: "Kernel panic - not syncing: sysrq triggered crash" PID: 1419 COMMAND: "sh" TASK: ffff1756f61ea000 [THREAD_INFO: ffff1756f61ea000] CPU: 0 STATE: TASK_RUNNING (PANIC) ``` **Sample command:** ```text theme={null} crash> man ``` **Sample output:** ```text theme={null} * files mod sbitmapq union alias foreach mount search vm ascii fuser net set vtop bpf gdb p sig waitq bt help ps struct whatis btop ipcs pte swap wr dev irq ptob sym q dis kmem ptov sys eval list rd task exit log repeat timer extend mach runq tree crash version: 8.0.4 gdb version: 10.2 For help on any command above, enter "help ". For help on input options, enter "help input". For help on output options, enter "help output". ``` **Sample command:** ```text theme={null} crash> log ``` **Sample output:** ```text theme={null} [ 0.000000] Booting Linux on physical CPU 0x0000000000 [0x412fd050] [ 0.000000] Linux version 6.6.17-debug (oe-user@oe-host) (aarch64-qcom-linux-gcc (GCC) 11.4.0, GNU ld (GNU Binutils) 2.38.20220708) #1 SMP PREEMPT Mon Mar 25 04:52:52 UTC 2024 [ 0.000000] KASLR enabled [ 0.000000] Machine model: Qualcomm Technologies, Inc. Robotics RB3gen2 addons vision mezz platform [ 0.000000] efi: EFI v2.7 by Qualcomm Technologies, Inc. [ 0.000000] efi: MEMATTR=0x9ccf6018 INITRD=0x9cceaf18 RNG=0x9cce3018 MEMRESERVE=0x9ccea818 [ 0.000000] random: crng init done [ 0.000000] Reserved memory: created CMA memory pool at 0x00000000fd000000, size 12 MiB [ 0.000000] OF: reserved mem: initialized node adsp-heap, compatible id shared-dma-pool ``` **Sample command:** ```text theme={null} crash> p memdump ``` **Sample output:** ```text theme={null} memdump = $1 = { table_phys = 4110417920, table = 0xffff80008087d000 } ``` For more information about the crash utility, see the following: * [Crash utility](https://crash-utility.github.io/) * [Crash-Linux manual page](https://man7.org/linux/man-pages/man8/crash.8.html)