diff options
| author | Oleg Nesterov <oleg@tv-sign.ru> | 2006-10-29 22:46:43 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-10-30 12:08:41 -0800 |
| commit | f0ec1aaf54caddd21c259aea8b2ecfbde4ee4fb9 (patch) | |
| tree | 61202a09a030d659064df65e127b9be1c571c48c /kernel | |
| parent | d45e44d4be60ef508579001792f33753b5cb6d36 (diff) | |
| download | lwn-f0ec1aaf54caddd21c259aea8b2ecfbde4ee4fb9.tar.gz lwn-f0ec1aaf54caddd21c259aea8b2ecfbde4ee4fb9.zip | |
[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')
| -rw-r--r-- | kernel/tsacct.c | 10 |
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; |