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| author | Oleg Nesterov <oleg@redhat.com> | 2014-04-13 20:59:38 +0200 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2014-06-21 00:15:26 -0400 |
| commit | ea73c79e33c45e1fa0071e216f06fd5682314490 (patch) | |
| tree | d1159b8993d462f28d8862e8839f3572d8f66e9a | |
| parent | 8063e41d2ffc0b0ce974ea802158be35902072f3 (diff) | |
| download | talos-obmc-linux-ea73c79e33c45e1fa0071e216f06fd5682314490.tar.gz talos-obmc-linux-ea73c79e33c45e1fa0071e216f06fd5682314490.zip | |
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.c | 4 |
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); } |
