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| author | Oleg Nesterov <oleg@tv-sign.ru> | 2007-11-28 16:21:24 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-11-29 09:24:52 -0800 |
| commit | c895078355b6b6e05c60aa205892526dd3390f0a (patch) | |
| tree | 922a0b9204b0cfcd5c59762f4d02e167d587ccd2 | |
| parent | c2319540cd7330fa9066e5b9b84d357a2c8631a2 (diff) | |
| download | linux-stable-c895078355b6b6e05c60aa205892526dd3390f0a.tar.gz linux-stable-c895078355b6b6e05c60aa205892526dd3390f0a.tar.bz2 linux-stable-c895078355b6b6e05c60aa205892526dd3390f0a.zip | |
wait_task_stopped(): don't use task_pid_nr_ns() lockless
wait_task_stopped(WNOWAIT) does task_pid_nr_ns() without tasklist/rcu lock,
we can read an already freed memory. Use the cached pid_t value.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Looks-good-to: Roland McGrath <roland@redhat.com>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | kernel/exit.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index cd0f1d4137a7..0a4a382ecf23 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1357,7 +1357,7 @@ static int wait_task_stopped(struct task_struct *p, int delayed_group_leader, int __user *stat_addr, struct rusage __user *ru) { int retval, exit_code; - struct pid_namespace *ns; + pid_t pid; if (!p->exit_code) return 0; @@ -1376,12 +1376,11 @@ static int wait_task_stopped(struct task_struct *p, int delayed_group_leader, * keep holding onto the tasklist_lock while we call getrusage and * possibly take page faults for user memory. */ - ns = current->nsproxy->pid_ns; + pid = task_pid_nr_ns(p, current->nsproxy->pid_ns); get_task_struct(p); read_unlock(&tasklist_lock); if (unlikely(noreap)) { - pid_t pid = task_pid_nr_ns(p, ns); uid_t uid = p->uid; int why = (p->ptrace & PT_PTRACED) ? CLD_TRAPPED : CLD_STOPPED; @@ -1451,11 +1450,11 @@ bail_ref: if (!retval && infop) retval = put_user(exit_code, &infop->si_status); if (!retval && infop) - retval = put_user(task_pid_nr_ns(p, ns), &infop->si_pid); + retval = put_user(pid, &infop->si_pid); if (!retval && infop) retval = put_user(p->uid, &infop->si_uid); if (!retval) - retval = task_pid_nr_ns(p, ns); + retval = pid; put_task_struct(p); BUG_ON(!retval); |