From: Oleg Nesterov <oleg@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Aaron Tomlin <atomlin@redhat.com>,
Alexey Dobriyan <adobriyan@gmail.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Sterling Alexander <stalexan@redhat.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH 4/4] proc: task_state: ptrace_parent() doesn't need pid_alive() check
Date: Fri, 7 Nov 2014 21:14:54 +0100 [thread overview]
Message-ID: <20141107201454.GA22246@redhat.com> (raw)
In-Reply-To: <20141107201424.GA22209@redhat.com>
p->ptrace != 0 means that release_task(p) was not called, so pid_alive()
buys nothing and we can remove this check. Other callers already use it
directly without additional checks.
Note: with or without this patch ptrace_parent() can return the pointer
to the freed task, this will be explained/fixed later.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
fs/proc/array.c | 13 ++++++-------
1 files changed, 6 insertions(+), 7 deletions(-)
diff --git a/fs/proc/array.c b/fs/proc/array.c
index 800e30f..bd117d0 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -157,19 +157,18 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
struct user_namespace *user_ns = seq_user_ns(m);
struct group_info *group_info;
int g;
+ struct task_struct *tracer;
const struct cred *cred;
- pid_t ppid, tpid, tgid, ngid;
+ pid_t ppid, tpid = 0, tgid, ngid;
unsigned int max_fds = 0;
rcu_read_lock();
ppid = pid_alive(p) ?
task_tgid_nr_ns(rcu_dereference(p->real_parent), ns) : 0;
- tpid = 0;
- if (pid_alive(p)) {
- struct task_struct *tracer = ptrace_parent(p);
- if (tracer)
- tpid = task_pid_nr_ns(tracer, ns);
- }
+
+ tracer = ptrace_parent(p);
+ if (tracer)
+ tpid = task_pid_nr_ns(tracer, ns);
tgid = task_tgid_nr_ns(p, ns);
ngid = task_numa_group_id(p);
--
1.5.5.1
next prev parent reply other threads:[~2014-11-07 20:14 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-07 20:14 [PATCH 0/4] proc: deuglify task_state() Oleg Nesterov
2014-11-07 20:14 ` [PATCH 1/4] proc: task_state: read cred->group_info outside of task_lock() Oleg Nesterov
2014-11-07 20:14 ` [PATCH 2/4] proc: task_state: deuglify the max_fds calculation Oleg Nesterov
2014-11-07 20:14 ` [PATCH 3/4] proc: task_state: move the main seq_printf() outside of rcu_read_lock() Oleg Nesterov
2014-11-13 18:04 ` Paul E. McKenney
2014-11-07 20:14 ` Oleg Nesterov [this message]
2014-11-10 21:59 ` [PATCH 0/5] exit: reparent zombie fix + cleanups/optimizations Oleg Nesterov
2014-11-10 22:00 ` [PATCH 1/5] sched_show_task: fix unsafe usage of ->real_parent Oleg Nesterov
2014-11-11 10:39 ` Peter Zijlstra
2014-11-10 22:00 ` [PATCH 2/5] exit: reparent: use ->ptrace_entry rather than ->sibling for EXIT_DEAD tasks Oleg Nesterov
2014-11-10 22:00 ` [PATCH 3/5] exit: reparent: cleanup the changing of ->parent Oleg Nesterov
2014-11-10 22:00 ` [PATCH 4/5] exit: reparent: cleanup the usage of reparent_leader() Oleg Nesterov
2014-11-10 22:00 ` [PATCH 5/5] exit: ptrace: shift "reap dead" code from exit_ptrace() to forget_original_parent() Oleg Nesterov
2014-11-14 1:37 ` [PATCH 0/5] exit: more cleanups/optimizations Oleg Nesterov
2014-11-14 1:38 ` [PATCH 1/5] exit: wait: cleanup the ptrace_reparented() checks Oleg Nesterov
2014-11-14 1:38 ` [PATCH 2/5] exit: wait: don't use zombie->real_parent Oleg Nesterov
2014-11-14 1:38 ` [PATCH 3/5] exit: wait: drop tasklist_lock before psig->c* accounting Oleg Nesterov
2014-11-14 1:38 ` [PATCH 4/5] exit: release_task: fix the comment about group leader accounting Oleg Nesterov
2014-11-14 1:38 ` [PATCH 5/5] exit: proc: don't try to flush /proc/tgid/task/tgid Oleg Nesterov
2014-11-18 21:29 ` [PATCH 0/6] exit: find_new_reaper() fixes/cleanups Oleg Nesterov
2014-11-18 21:30 ` [PATCH 1/6] exit: reparent: fix the dead-parent PR_SET_CHILD_SUBREAPER reparenting Oleg Nesterov
2014-11-18 21:30 ` [PATCH 2/6] exit: reparent: fix the cross-namespace " Oleg Nesterov
2014-11-18 21:30 ` [PATCH 3/6] exit: reparent: s/while_each_thread/for_each_thread/ in find_new_reaper() Oleg Nesterov
2014-11-18 21:30 ` [PATCH 4/6] exit: reparent: document the ->has_child_subreaper checks Oleg Nesterov
2014-11-18 21:30 ` [PATCH 5/6] exit: reparent: introduce find_child_reaper() Oleg Nesterov
2014-11-18 21:30 ` [PATCH 6/6] exit: reparent: introduce find_alive_thread() Oleg Nesterov
2014-11-20 18:34 ` [PATCH 0/3] exit: avoid O(n ** 2) thread-list scan on group-exit if possible Oleg Nesterov
2014-11-20 18:34 ` [PATCH -mm 1/3] exit: reparent: avoid find_new_reaper() if no children Oleg Nesterov
2014-11-20 22:37 ` Andrew Morton
2014-11-21 20:01 ` Oleg Nesterov
2014-11-20 18:34 ` [PATCH -mm 2/3] exit: reparent: call forget_original_parent() under tasklist_lock Oleg Nesterov
2014-11-20 18:34 ` [PATCH -mm 3/3] exit: exit_notify: re-use "dead" list to autoreap current Oleg Nesterov
2014-11-24 20:06 ` [PATCH 0/2] exit/pid_ns: comments + simple fix Oleg Nesterov
2014-11-24 20:06 ` [PATCH 1/2] exit: reparent: fix/update the comments in zap_pid_ns_processes() Oleg Nesterov
2014-11-24 20:14 ` Oleg Nesterov
2014-11-24 22:07 ` Eric W. Biederman
2014-11-25 16:57 ` Oleg Nesterov
2014-11-25 17:17 ` Oleg Nesterov
2014-11-24 20:06 ` [PATCH 2/2] exit: pidns: alloc_pid() leaks pid_namespace if child_reaper is exiting Oleg Nesterov
2014-11-24 21:46 ` Eric W. Biederman
2014-11-25 17:07 ` Oleg Nesterov
2014-11-25 17:50 ` Eric W. Biederman
2014-11-25 18:15 ` Oleg Nesterov
2014-11-25 18:43 ` Eric W. Biederman
2014-11-25 18:59 ` Oleg Nesterov
2014-11-24 21:27 ` [PATCH 0/2] exit/pid_ns: comments + simple fix Eric W. Biederman
2014-11-24 21:38 ` Oleg Nesterov
2014-11-24 21:48 ` Eric W. Biederman
2014-11-25 16:57 ` Oleg Nesterov
2014-11-26 23:54 ` [PATCH v2 " Oleg Nesterov
2014-11-26 23:54 ` [PATCH v2 1/2] exit: pidns: alloc_pid() leaks pid_namespace if child_reaper is exiting Oleg Nesterov
2014-11-27 15:44 ` Eric W. Biederman
2014-11-26 23:54 ` [PATCH v2 2/2] exit: pidns: fix/update the comments in zap_pid_ns_processes() Oleg Nesterov
2014-12-01 22:39 ` Andrew Morton
2014-12-01 23:24 ` Oleg Nesterov
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