Source: linux Severity: normal Dear Ben, dear maintainers,
starting from a Debian bug report of mine, Gerlof Langeveld, developer of system and process monitor atop¹, found two issues with process accounting². I also started an LKML thread about these³. [1] http://atoptool.nl/ [2] #833997 atop: process accounting does not work: https://bugs.debian.org/833997 [3] [REGRESSION] Two issues that prevent process accounting (taskstats) from working correctly: https://lkml.org/lkml/2016/12/19/182 I am reporting the two issues separately. I am currently not running Debian a kernel, but Gerlof verified the issue with Debian kernel. Pprocess accounting works with 3.16, but fails with 4.8 and 4.7 at least. I think it also fails with earlier versions, but I do not know exactly since which version. I reported the first issue as: Bug#848682: process accounting sometimes does not work https://bugs.debian.org/848682 2) When using the NETLINK inface, the command TASKSTATS_CMD_GET consequently returns -EINVAL. Bug 190711 - Process accounting: Using the NETLINK inface, the command TASKSTATS_CMD_GET returns -EINVAL https://bugzilla.kernel.org/show_bug.cgi?id=190711 The code that is used by the atopacctd daemon is based on the demo code 'getdelays.c' that can be found in the kernel source code tree (..../linux/Documentation/accounting/getdelays.c). Also this 'getdelays' program does not work any more (also -EINVAL on the same call) with the newer kernels. I really spent a lot of time on this issue to get the code running (there are many places in the kernel code where -EINVAL for this call can be given), but I did not succeed. It is really an incompatibility introduced by the kernel code. It would be nice if the kernel maintainers provide a working version of the getdelays program in the kernel source tree. I only experience this problem on Debian8 with a 4.8 kernel (virtual machine with 4 cores). On CentOS7 with a 4.8 kernel it works fine (physical machine with 4 cores). I will anyhow adapt atopacctd for this issue that it detects and logs the -EINVAL and terminates. The current version of atopacctd keeps running which is not useful at all. Marc Haber, maintainer of atop package, Gerlof Langeveld, developer of atop and I are currently discussing workarounds with atop and/or systemd service fail for the time till upstream kernels with this issues fixed are shipped by distributions. Still it would be nice to remove those work-arounds and have the kernel work correctly again at some time in the future. Thanks, Martin -- System Information: Debian Release: stretch/sid APT prefers unstable APT policy: (500, 'unstable'), (200, 'experimental') Architecture: amd64 (x86_64) Foreign Architectures: i386 Kernel: Linux 4.8.14-tp520-btrfstrim+ (SMP w/4 CPU cores; PREEMPT) Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Init: sysvinit (via /sbin/init)
