Thanks for the help Glenn - I now have more details. The process triggering the warning is system_server, and this is running as user "system".
It is trying to write the pid of various other processes (com.android.inputmethod.latin, com.android.phone. com.android.launcher, etc) into /dev/inputctl/tasks But these other processes have a different uid (they run as user app_16, app_20, radio, etc) So the kernel/cgroups.c file does: if (cred->euid && cred->euid != tcred->uid && cred->euid != tcred->suid) { rcu_read_unlock(); cgroup_unlock(); return -EACCES; } It fails on the uid check, and returns an error. (I put a printk here to confirm this, and confirm the difference in euid and uid) Is system_server supposed to be running as user "system", and is it supposed to be trying to change the cgroup of process owned by another user? Thanks, John On Friday, 5 October 2012 17:14:25 UTC+1, Glenn Kasten wrote: > > I suggest getting a stack trace at the time of log, to see what is > happening. > For example at that ALOGE also log the tid and fd, and then do an abort() > or *(char*) 0 = 0; > This will prevent the system from running of course, but a logcat during > bootup should show why it's failing. > > > On Wednesday, October 3, 2012 2:10:48 PM UTC-7, John Tapsell wrote: >> >> Hi Glenn, >> >> Can you give any more hints about what to look for in init.rc ? The >> cgroups code is exactly the same in my init.rc >> >> I have: >> >> > ls -l /dev/cpuctl/tasks >> >> -rwxrwxrwx system system 0 2000-01-01 00:23 tasks >> >> Yet I still get: >> >> W/SchedPolicy( 189): add_tid_to_cgroup failed to write '435' (Permission >> denied); background=0 >> >> etc. >> >> Any ideas please? >> >> John >> >> >> >> On Monday, 13 August 2012 17:44:35 UTC+1, Glenn Kasten wrote: >>> >>> Sometimes this is caused by incorrect init.rc. Make sure your init.rc >>> has all of the latest changes from system/core/rootdir/init.rc especially >>> if you have forked it. >>> >>> You mentioned a "lot of people" have seen this .. were these on other >>> external postings or bug reports? if so can you please supply a link to >>> these, it will help diagnose to see the other reports. >>> >>> On Friday, August 10, 2012 2:46:18 AM UTC-7, failuch wrote: >>>> >>>> Hello all, >>>> >>>> I saw that a lot of people encountered these error : >>>> >>>> W/ActivityManager( 349): Failed setting process group of 4911 to 0 >>>> W/SchedPolicy( 349): add_tid_to_cgroup failed to write '4911' >>>> (Permission denie >>>> d); background=1 >>>> >>>> >>>> >>>> And I was unable to find explanation/solution for this problem, >>>> although >>>> >>>> I have checked cgroups are mounted and /dev/cpuctl/tasks exist >>>> >>>> Can you please to comment ? >>>> >>>> >>>> ThX >>>> >>> -- unsubscribe: android-kernel+unsubscr...@googlegroups.com website: http://groups.google.com/group/android-kernel