Bug#950168: pstack always fails with "crawl: Input/output error"
On 01.02.20 13:44, Andreas Beckmann wrote: > On Wed, 29 Jan 2020 19:51:22 +0100 =?utf-8?q?Tim_R=C3=BChsen?= > The manpage (dated Feb 25 2002) says: > > RESTRICTIONS >pstack currently works only on Linux, only on an x86 machine >running 32 bit ELF binaries (64 bit not supported). Also, >for symbolic information, you need to use a GNU compiler to >generate your program, and you can't strip symbols from the >binaries. For thread information to be dumped, you have to >use the debug-aware version of the LinuxThreads libpthread.so >library. (To check, run nm(1) on your pthreads library, and >make sure that the symbol "__pthread_threads_debug" is >defined.) Threads are not supported with the newer NPTL >libpthread.so library. > > So the pstack tool is probably useless on modern systems. I believe the man page and the top comment within pstack.c are is wrong. The source code explicitly supports 64bit ELF, you can build it for amd64, it does some work, but fails on 'crawl...'. The man page of ptrace() gives no obvious hint why it may fail on amd64 and not on x86 here. Regards, Tim signature.asc Description: OpenPGP digital signature
Bug#950168: pstack always fails with "crawl: Input/output error"
On Wed, 29 Jan 2020 19:51:22 +0100 =?utf-8?q?Tim_R=C3=BChsen?= wrote: > Web searches so far didn't help. > > Any ideas / hints ? The manpage (dated Feb 25 2002) says: RESTRICTIONS pstack currently works only on Linux, only on an x86 machine running 32 bit ELF binaries (64 bit not supported). Also, for symbolic information, you need to use a GNU compiler to generate your program, and you can't strip symbols from the binaries. For thread information to be dumped, you have to use the debug-aware version of the LinuxThreads libpthread.so library. (To check, run nm(1) on your pthreads library, and make sure that the symbol "__pthread_threads_debug" is defined.) Threads are not supported with the newer NPTL libpthread.so library. So the pstack tool is probably useless on modern systems. Andreas
Bug#950168: pstack always fails with "crawl: Input/output error"
Package: pstack Version: 1.3.1-1+b1 Severity: grave Justification: renders package unusable Dear Maintainer, I can't get pstack working as expected. Even not as root. Example: # pstack 2280 2280: /usr/lib/upower/upowerd (No symbols found) 0x7fbfe723dd0f: (55babe9e5900, 51, 0, 0, 0, 7fbfe7593f30) + aa46415ffdb3 crawl: Input/output error Error tracing through process 2280 0x10008: I assume there something going on with ptrace(), as I see the same issue with a ptrace example code that uses PTRACE_PEEKDATA. PTRACE_ATTACH seems to work, but PTRACE_PEEKDATA returns error (errno is 5). strace and gdb work well. Web searches so far didn't help. Any ideas / hints ? Regards, Tim -- System Information: Debian Release: bullseye/sid APT prefers unstable APT policy: (500, 'unstable'), (1, 'experimental') Architecture: amd64 (x86_64) Foreign Architectures: i386 Kernel: Linux 5.4.0-3-amd64 (SMP w/12 CPU cores) Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8), LANGUAGE= (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Init: systemd (via /run/systemd/system) LSM: AppArmor: enabled Versions of packages pstack depends on: ii libc6 2.29-9 pstack recommends no packages. pstack suggests no packages. -- no debconf information
