Commit b0fafc11 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

proc: task_state: move the main seq_printf() outside of rcu_read_lock() 



task_state() does seq_printf() under rcu_read_lock(), but this is only
needed for task_tgid_nr_ns() and task_numa_group_id().  We can calculate
tgid/ngid and drop rcu lock.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
Cc: Sterling Alexander <stalexan@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roland McGrath <roland@hack.frob.com>
Reviewed-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0f4a0d53

fs/proc/array.c

+6 −6
Original line number Diff line number Diff line
@@ -158,7 +158,7 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns, 
	struct group_info *group_info;

	int g;

	const struct cred *cred;

	pid_t ppid, tpid;

	pid_t ppid, tpid, tgid, ngid;

	unsigned int max_fds = 0;



	rcu_read_lock();
@@ -170,12 +170,16 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns, 
		if (tracer)

			tpid = task_pid_nr_ns(tracer, ns);

	}



	tgid = task_tgid_nr_ns(p, ns);

	ngid = task_numa_group_id(p);

	cred = get_task_cred(p);



	task_lock(p);

	if (p->files)

		max_fds = files_fdtable(p->files)->max_fds;

	task_unlock(p);

	rcu_read_unlock();



	seq_printf(m,

		"State:\t%s\n"
@@ -188,10 +192,7 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns, 
		"Gid:\t%d\t%d\t%d\t%d\n"

		"FDSize:\t%d\nGroups:\t",

		get_task_state(p),

		task_tgid_nr_ns(p, ns),

		task_numa_group_id(p),

		pid_nr_ns(pid, ns),

		ppid, tpid,

		tgid, ngid, pid_nr_ns(pid, ns), ppid, tpid,

		from_kuid_munged(user_ns, cred->uid),

		from_kuid_munged(user_ns, cred->euid),

		from_kuid_munged(user_ns, cred->suid),
@@ -201,7 +202,6 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns, 
		from_kgid_munged(user_ns, cred->sgid),

		from_kgid_munged(user_ns, cred->fsgid),

		max_fds);

	rcu_read_unlock();



	group_info = cred->group_info;

	for (g = 0; g < group_info->ngroups; g++)

CRA Git | Maintained and supported by SUSTech CRA and CCSE