Hi,
These patches fix a memory leak in per-cpu areas in v4.9.y
The following command sequence
while :; do c=$(docker create busybox) docker start $c docker stop $c docker rm $c done
causes the number of pcpu_get_vm_area entries in /proc/vmallocinfo to grow.
The commit d6cffbbe9a7e ("proc/sysctl: prune stale dentries during unregistering") fixes the issue and the commits ace0c791e6c3 ("proc/sysctl: Don't grab i_lock under sysctl_lock.") and 2fd1d2c4ceb2 ("proc: Fix proc_sys_prune_dcache to hold a sb reference") are the follow-up fixups.
I've also checked v4.4 and the issue does not appear there.
Eric W. Biederman (2): proc/sysctl: Don't grab i_lock under sysctl_lock. proc: Fix proc_sys_prune_dcache to hold a sb reference
Konstantin Khlebnikov (1): proc/sysctl: prune stale dentries during unregistering
fs/proc/inode.c | 3 +- fs/proc/internal.h | 7 +++-- fs/proc/proc_sysctl.c | 83 +++++++++++++++++++++++++++++++++++++++----------- include/linux/sysctl.h | 1 + 4 files changed, 74 insertions(+), 20 deletions(-)