https://bugzilla.novell.com/show_bug.cgi?id=757783
https://bugzilla.novell.com/show_bug.cgi?id=757783#c0
Summary: clone() with CLONE_NEWPID leaks kernel memory
Classification: openSUSE
Product: openSUSE 12.1
Version: Final
Platform: x86-64
OS/Version: openSUSE 12.1
Status: NEW
Severity: Critical
Priority: P5 - None
Component: Kernel
AssignedTo: kernel-maintainers@forge.provo.novell.com
ReportedBy: ccrssaa@karelia.ru
QAContact: qa-bugs@suse.de
Found By: ---
Blocker: ---
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120312
Firefox/11.0 SeaMonkey/2.8
Server with vsftpd running started to die in agony with kswapd eating 100% cpu
after upgrading to openSUSE 12.1. Turned out that vsftpd isolates each process
using CLONE_NEWPID and 3.1.9-1.4 kernel does not free pid_namespace slabs.
Reproducible: Always
Steps to Reproduce:
1.
test.c:
#include
#include
#include
#include
#include
#include
#include
int main(int argc, char *argv[])
{
int i, ret;
for (i = 0; i < 10000; i++) {
if (0 == (ret = syscall(__NR_clone, CLONE_NEWPID | CLONE_NEWIPC |
CLONE_NEWNET | SIGCHLD, NULL)))
return 0;
if (-1 == ret) {
perror("clone");
break;
}
}
return 0;
}
simulates vsftpd sysdeputil.c
2. gcc -Wall test.c
3. run ./a.out as root
Actual Results:
# cat /proc/slabinfo | grep namespace
pid_namespace 0 0 2112 3 2 : tunables 24 12 8 :
slabdata 0 0 0
user_namespace 0 0 1072 7 2 : tunables 24 12 8 :
slabdata 0 0 0
net_namespace 0 0 2560 3 2 : tunables 24 12 8 :
slabdata 0 0 0
# ./a.out
# sleep 60
# cat /proc/slabinfo | grep namespace
pid_namespace 10000 10002 2112 3 2 : tunables 24 12 8 :
slabdata 3334 3334 0
user_namespace 0 0 1072 7 2 : tunables 24 12 8 :
slabdata 0 0 0
net_namespace 0 0 2560 3 2 : tunables 24 12 8 :
slabdata 0 0 0
net_namespace slabs are freed but pid_namespace stays forever.
Expected Results:
# ./a.out
# sleep 60
# cat /proc/slabinfo | grep namespace
pid_namespace 0 0 2112 3 2 : tunables 24 12 8 :
slabdata 0 0 0
net_namespace 0 0 2944 2 2 : tunables 24 12 8 :
slabdata 0 0 0
TWIMC: switched from vsftpd to proftpd as a workaround.
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