diff options
| author | Oleg Nesterov <oleg@tv-sign.ru> | 2006-10-28 10:38:49 -0700 |
|---|---|---|
| committer | Chris Wright <chrisw@sous-sol.org> | 2006-11-03 17:33:50 -0800 |
| commit | e17f8851e194c759c35e058d9692e81a3eec8a1e (patch) | |
| tree | 308514d3cb389ee235360ac35d22d275768871aa | |
| parent | 1406fd4e987bd05a22827e8f0aa01f3335550e01 (diff) | |
[PATCH] fill_tgid: fix task_struct leak and possible oops
1. fill_tgid() forgets to do put_task_struct(first).
2. release_task(first) can happen after fill_tgid() drops tasklist_lock,
it is unsafe to dereference first->signal.
This is a temporary fix, imho the locking should be reworked.
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>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
| -rw-r--r-- | kernel/taskstats.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/kernel/taskstats.c b/kernel/taskstats.c index e7818765733..b90b2a7ef60 100644 --- a/kernel/taskstats.c +++ b/kernel/taskstats.c @@ -229,14 +229,17 @@ static int fill_tgid(pid_t tgid, struct task_struct *tgidtsk, } else get_task_struct(first); - /* Start with stats from dead tasks */ - spin_lock_irqsave(&first->signal->stats_lock, flags); - if (first->signal->stats) - memcpy(stats, first->signal->stats, sizeof(*stats)); - spin_unlock_irqrestore(&first->signal->stats_lock, flags); tsk = first; read_lock(&tasklist_lock); + /* Start with stats from dead tasks */ + if (first->signal) { + spin_lock_irqsave(&first->signal->stats_lock, flags); + if (first->signal->stats) + memcpy(stats, first->signal->stats, sizeof(*stats)); + spin_unlock_irqrestore(&first->signal->stats_lock, flags); + } + do { if (tsk->exit_state == EXIT_ZOMBIE && thread_group_leader(tsk)) continue; @@ -256,7 +259,7 @@ static int fill_tgid(pid_t tgid, struct task_struct *tgidtsk, * Accounting subsytems can also add calls here to modify * fields of taskstats. */ - + put_task_struct(first); return 0; } |