[PATCH 0/3 stable 4.9] proc/sysctl: prune stale dentries during unregistering

[Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>]

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(-)

-- 
2.7.4