Package: crash Version: 8.0.2-1 Severity: grave Tags: patch X-Debbugs-Cc: [email protected]
Hello, Crash is currently not working when used to inspect the system on Debian 12. It returns "crash: cannot set context for pid: 498070" and then crashes. I identified the following commit solves the problem. Fix failure of gathering task table on Linux 6.5-rc1 and later https://github.com/crash-utility/crash/commit/88580068b7dd96bf679c82bdc05e146968ade10c I built different versions of crash version 8 from source and with the commit above applied, it works fine. Without it, the utility crashes and makes it non-functional. Default crash installed from the package. ``` user@debian:~$ sudo crash ~/vmlinux-6.1.0-50-amd64 crash 8.0.2 ... [snip GDB header] ... For help, type "help". Type "apropos word" to search for commands related to "word"... crash: cannot set context for pid: 498070 Segmentation fault user@debian:~$ ``` Crash 8 version built from commit 88580068b7dd96bf679c82bdc05e146968ade10c. ``` user@debian:~/crash$ sudo ./crash ~/vmlinux-6.1.0-50-amd64 crash 8.0.3++ ... [snip GDB header] ... For help, type "help". Type "apropos word" to search for commands related to "word"... KERNEL: /home/user/vmlinux-6.1.0-50-amd64 DUMPFILE: /proc/kcore CPUS: 4 DATE: Fri Jul 10 21:59:47 -03 2026 UPTIME: 01:22:49 LOAD AVERAGE: 3.22, 2.72, 2.32 TASKS: 215 NODENAME: debian RELEASE: 6.1.0-50-amd64 VERSION: #1 SMP PREEMPT_DYNAMIC Debian 6.1.176-1 (2026-07-02) MACHINE: x86_64 (2711 Mhz) MEMORY: 2 GB PID: 456429 COMMAND: "crash" TASK: ffff8b58c5eb3380 [THREAD_INFO: ffff8b58c5eb3380] CPU: 1 STATE: TASK_RUNNING (ACTIVE) crash> quit user@debian:~/crash$ git log commit 88580068b7dd96bf679c82bdc05e146968ade10c (HEAD) Author: Kazuhito Hagio <[email protected]> Date: Fri Jun 23 16:34:35 2023 +0900 Fix failure of gathering task table on Linux 6.5-rc1 and later Kernel commit b69f0aeb0689 ("pid: Replace struct pid 1-element array with flex-array") changed pid.numbers[1] to pid.numbers[]. With this, the size of struct pid does not contain the size of struct upid: (gdb) ptype /o struct pid /* offset | size */ type = struct pid { /* 0 | 4 */ refcount_t count; ... /* 96 | 0 */ struct upid numbers[]; ^^^^ ^^^ /* total size (bytes): 96 */ } ^^^^ As a result, in refresh_xarray_task_table(), crash does not read the data of pid.numbers[0].ns and cannot gather the task table correctly. $ crash vmlinux vmcore ... WARNING: active task ffff936992ad0000 on cpu 1 not found in PID hash ... crash> ps -S RU: 9 crash> Increase the size of reading struct pid by SIZE(upid) in this case. Signed-off-by: Kazuhito Hagio <[email protected]> ... user@debian:~/crash$ ``` Crash 8 version built from commit 7750e61fdb2a083f26156a5338aa2ebe26447f3f (parent of fix). ``` user@debian:~/crash$ sudo ./crash ~/vmlinux-6.1.0-50-amd64 crash 8.0.3++ ... [snip GDB header] ... For help, type "help". Type "apropos word" to search for commands related to "word"... crash: cannot set context for pid: 496536 Segmentation fault user@debian:~/crash$ git log commit 7750e61fdb2a083f26156a5338aa2ebe26447f3f (HEAD) Author: Kazuhito Hagio <[email protected]> Date: Thu Jun 22 16:09:07 2023 +0900 Support module memory layout change on Linux 6.4 Support module memory layout change on Linux 6.4 by kernel commit ac3b43283923 ("module: replace module_layout with module_memory") [1]. Without the patch, crash cannot even start a session with an error message like this: crash: invalid structure member offset: module_core_size FILE: kernel.c LINE: 3787 FUNCTION: module_init() [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ac3b43283923 Signed-off-by: Kazuhito Hagio <[email protected]> ... user@debian:~/crash$ ``` I recommend backporting commit 88580068b7dd96bf679c82bdc05e146968ade10c to make crash utility functional by default on Debian 12. -- System Information: Debian Release: 12.14 APT prefers oldstable-updates APT policy: (500, 'oldstable-updates'), (500, 'oldstable-security'), (500, 'oldstable') Architecture: amd64 (x86_64) Kernel: Linux 6.1.0-50-amd64 (SMP w/4 CPU threads; PREEMPT) Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set Shell: /bin/sh linked to /usr/bin/dash Init: systemd (via /run/systemd/system) LSM: AppArmor: enabled Versions of packages crash depends on: ii binutils 2.40-2 ii libc6 2.36-9+deb12u14 ii libgcc-s1 12.2.0-14+deb12u1 ii liblzo2-2 2.10-2 ii libncursesw6 6.4-4 ii libsnappy1v5 1.1.9-3 ii libstdc++6 12.2.0-14+deb12u1 ii libtinfo6 6.4-4 ii libzstd1 1.5.4+dfsg2-5 crash recommends no packages. Versions of packages crash suggests: pn kexec-tools <none> pn makedumpfile <none> -- no debconf information
