On Wed, 20 Apr 2011, KOSAKI Motohiro wrote: > > That was true a while ago, but you now need to protect every thread's > > ->comm with get_task_comm() or ensuring task_lock() is held to protect > > against /proc/pid/comm which can change other thread's ->comm. That was > > different before when prctl(PR_SET_NAME) would only operate on current, so > > no lock was needed when reading current->comm. > > Right. /proc/pid/comm is evil. We have to fix it. otherwise we need change > all of current->comm user. It's very lots! > Fixing it in this case would be removing it and only allowing it for current via the usual prctl() :) The code was introduced in 4614a696bd1c (procfs: allow threads to rename siblings via /proc/pid/tasks/tid/comm) in December 2009 and seems to originally be meant for debugging. We simply can't continue to let it modify any thread's ->comm unless we change the over 300 current->comm deferences in the kernel. I'd prefer that we remove /proc/pid/comm entirely or at least prevent writing to it unless CONFIG_EXPERT. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>