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authorOleg Nesterov <oleg@redhat.com>2014-04-13 20:59:38 +0200
committerSteven Rostedt <rostedt@goodmis.org>2014-06-21 00:15:26 -0400
commitea73c79e33c45e1fa0071e216f06fd5682314490 (patch)
treed1159b8993d462f28d8862e8839f3572d8f66e9a
parent8063e41d2ffc0b0ce974ea802158be35902072f3 (diff)
tracing: syscall_regfunc() should not skip kernel threads
syscall_regfunc() ignores the kernel threads because "it has no effect", see cc3b13c1 "Don't trace kernel thread syscalls" which added this check. However, this means that a user-space task spawned by call_usermodehelper() will run without TIF_SYSCALL_TRACEPOINT if sys_tracepoint_refcount != 0. Remove this check. The unnecessary report from ret_from_fork path mentioned by cc3b13c1 is no longer possible, see See commit fb45550d76bb5 "make sure that kernel_thread() callbacks call do_exit() themselves". A kernel_thread() callback can only return and take the int_ret_from_sys_call path after do_execve() succeeds, otherwise the kernel will crash. But in this case it is no longer a kernel thread and thus is needs TIF_SYSCALL_TRACEPOINT. Link: http://lkml.kernel.org/p/20140413185938.GD20668@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
-rw-r--r--kernel/tracepoint.c4
1 files changed, 1 insertions, 3 deletions
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 9cf12640de5a..3490407dc7b7 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -497,9 +497,7 @@ void syscall_regfunc(void)
if (!sys_tracepoint_refcount) {
read_lock(&tasklist_lock);
for_each_process_thread(p, t) {
- /* Skip kernel threads. */
- if (!(t->flags & PF_KTHREAD))
- set_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT);
+ set_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT);
}
read_unlock(&tasklist_lock);
}

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