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authorEric Paris <eparis@redhat.com>2007-06-04 17:41:22 -0400
committerJames Morris <jmorris@namei.org>2007-07-11 22:52:23 -0400
commit9dc9978084ea2a96b9f42752753d9e38a9f9d7b2 (patch)
tree24aac2351df72f9f12fa9143a7746a2e83d24899 /security
parente47c8fc582a2c9f3cba059e543c4a056cd6bf8c4 (diff)
downloadlinux-linaro-9dc9978084ea2a96b9f42752753d9e38a9f9d7b2.tar.gz
selinux: introduce schedule points in policydb_destroy()
During the LSPP testing we found that it was possible for policydb_destroy() to take 10+ seconds of kernel time to complete. Basically all policydb_destroy() does is walk some (possibly long) lists and free the memory it finds. Turning off slab debugging config options made the problem go away since the actual functions which took most of the time were (as seen by oprofile) > 121202 23.9879 .check_poison_obj > 78247 15.4864 .check_slabp were caused by that. So I decided to also add some voluntary schedule points in that code so config voluntary preempt would be enough to solve the problem. Something similar was done in places like shmem_free_pages() when we have to walk a list of memory and free it. This was tested by the LSPP group on the hardware which could reproduce the problem just loading a new policy and was found to not trigger the softlock detector. It takes just as much processing time, but the kernel doesn't spend all that time stuck doing one thing and never scheduling. Someday a better way to handle memory might make the time needed in this function a lot less, but this fixes the current issue as it stands today. Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security')
-rw-r--r--security/selinux/ss/policydb.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index 0ac1021734c..f05f97a2bc3 100644
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -21,6 +21,7 @@
*/
#include <linux/kernel.h>
+#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/errno.h>
@@ -598,6 +599,7 @@ void policydb_destroy(struct policydb *p)
struct range_trans *rt, *lrt = NULL;
for (i = 0; i < SYM_NUM; i++) {
+ cond_resched();
hashtab_map(p->symtab[i].table, destroy_f[i], NULL);
hashtab_destroy(p->symtab[i].table);
}
@@ -612,6 +614,7 @@ void policydb_destroy(struct policydb *p)
avtab_destroy(&p->te_avtab);
for (i = 0; i < OCON_NUM; i++) {
+ cond_resched();
c = p->ocontexts[i];
while (c) {
ctmp = c;
@@ -623,6 +626,7 @@ void policydb_destroy(struct policydb *p)
g = p->genfs;
while (g) {
+ cond_resched();
kfree(g->fstype);
c = g->head;
while (c) {
@@ -639,18 +643,21 @@ void policydb_destroy(struct policydb *p)
cond_policydb_destroy(p);
for (tr = p->role_tr; tr; tr = tr->next) {
+ cond_resched();
kfree(ltr);
ltr = tr;
}
kfree(ltr);
for (ra = p->role_allow; ra; ra = ra -> next) {
+ cond_resched();
kfree(lra);
lra = ra;
}
kfree(lra);
for (rt = p->range_tr; rt; rt = rt -> next) {
+ cond_resched();
if (lrt) {
ebitmap_destroy(&lrt->target_range.level[0].cat);
ebitmap_destroy(&lrt->target_range.level[1].cat);