summaryrefslogtreecommitdiff
path: root/kernel/tsacct.c
diff options
context:
space:
mode:
authorOleg Nesterov <oleg@tv-sign.ru>2006-10-29 22:46:43 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-30 12:08:41 -0800
commitf0ec1aaf54caddd21c259aea8b2ecfbde4ee4fb9 (patch)
tree61202a09a030d659064df65e127b9be1c571c48c /kernel/tsacct.c
parentd45e44d4be60ef508579001792f33753b5cb6d36 (diff)
downloadlinux-sh-f0ec1aaf54caddd21c259aea8b2ecfbde4ee4fb9.tar.gz
[PATCH] xacct_add_tsk: fix pure theoretical ->mm use-after-free
Paranoid fix. The task can free its ->mm after the 'if (p->mm)' check. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Shailabh Nagar <nagar@watson.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Jay Lan <jlan@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/tsacct.c')
-rw-r--r--kernel/tsacct.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/kernel/tsacct.c b/kernel/tsacct.c
index 65a5036a3d95..96f77013d3f0 100644
--- a/kernel/tsacct.c
+++ b/kernel/tsacct.c
@@ -80,13 +80,17 @@ void bacct_add_tsk(struct taskstats *stats, struct task_struct *tsk)
*/
void xacct_add_tsk(struct taskstats *stats, struct task_struct *p)
{
+ struct mm_struct *mm;
+
/* convert pages-jiffies to Mbyte-usec */
stats->coremem = jiffies_to_usecs(p->acct_rss_mem1) * PAGE_SIZE / MB;
stats->virtmem = jiffies_to_usecs(p->acct_vm_mem1) * PAGE_SIZE / MB;
- if (p->mm) {
+ mm = get_task_mm(p);
+ if (mm) {
/* adjust to KB unit */
- stats->hiwater_rss = p->mm->hiwater_rss * PAGE_SIZE / KB;
- stats->hiwater_vm = p->mm->hiwater_vm * PAGE_SIZE / KB;
+ stats->hiwater_rss = mm->hiwater_rss * PAGE_SIZE / KB;
+ stats->hiwater_vm = mm->hiwater_vm * PAGE_SIZE / KB;
+ mmput(mm);
}
stats->read_char = p->rchar;
stats->write_char = p->wchar;