Commit 6308191f authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Ingo Molnar
Browse files

tracing, sched, vfs: Fix 'old_pid' usage in trace_sched_process_exec() 



1. TRACE_EVENT(sched_process_exec) forgets to actually use the
   old pid argument, it sets ->old_pid = p->pid.

2. search_binary_handler() uses the wrong pid number. tracepoint
   needs the global pid_t from the root namespace, while old_pid
   is the virtual pid number as it seen by the tracer/parent.

With this patch we have two pid_t's in search_binary_handler(),
not really nice. Perhaps we should switch to "struct pid*", but
in this case it would be better to cleanup the current code
first and move the "depth == 0" code outside.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Cc: David Smith <dsmith@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Link: http://lkml.kernel.org/r/20120330162636.GA4857@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 8ebfdf2b

fs/exec.c

+4 −3
Original line number Original line Diff line number Diff line
@@ -1370,7 +1370,7 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) 
	unsigned int depth = bprm->recursion_depth;

	unsigned int depth = bprm->recursion_depth;

	int try,retval;

	int try,retval;

	struct linux_binfmt *fmt;

	struct linux_binfmt *fmt;

	pid_t old_pid;

	pid_t old_pid, old_vpid;





	retval = security_bprm_check(bprm);

	retval = security_bprm_check(bprm);

	if (retval)

	if (retval)
@@ -1381,8 +1381,9 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) 
		return retval;

		return retval;





	/* Need to fetch pid before load_binary changes it */

	/* Need to fetch pid before load_binary changes it */

	old_pid = current->pid;

	rcu_read_lock();

	rcu_read_lock();

	old_pid = task_pid_nr_ns(current, task_active_pid_ns(current->parent));

	old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent));

	rcu_read_unlock();

	rcu_read_unlock();





	retval = -ENOENT;

	retval = -ENOENT;
@@ -1405,7 +1406,7 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) 
			if (retval >= 0) {

			if (retval >= 0) {

				if (depth == 0) {

				if (depth == 0) {

					trace_sched_process_exec(current, old_pid, bprm);

					trace_sched_process_exec(current, old_pid, bprm);

					ptrace_event(PTRACE_EVENT_EXEC, old_pid);

					ptrace_event(PTRACE_EVENT_EXEC, old_vpid);

				}

				}

				put_binfmt(fmt);

				put_binfmt(fmt);

				allow_write_access(bprm->file);

				allow_write_access(bprm->file);

include/trace/events/sched.h

+1 −1
Original line number Original line Diff line number Diff line
@@ -295,7 +295,7 @@ TRACE_EVENT(sched_process_exec, 
	TP_fast_assign(

	TP_fast_assign(

		__assign_str(filename, bprm->filename);

		__assign_str(filename, bprm->filename);

		__entry->pid		= p->pid;

		__entry->pid		= p->pid;

		__entry->old_pid	= p->pid;

		__entry->old_pid	= old_pid;

	),

	),





	TP_printk("filename=%s pid=%d old_pid=%d", __get_str(filename),

	TP_printk("filename=%s pid=%d old_pid=%d", __get_str(filename),

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