On Sun, Nov 28, 2021 at 01:48:05PM -0500, Steven Rostedt wrote: > On Sun, 28 Nov 2021 12:44:01 +0100 > <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > > The patch below does not apply to the 5.10-stable tree. > > If someone wants it applied there, or to any other stable or longterm > > tree, then please email the backport, including the original git commit > > id to <stable@xxxxxxxxxxxxxxx>. > > This is a funny case, where I actually found the bug in the 5.15 kernel > that I was using to do my cut and paste screen shots for the upcoming > Embedded Fest conference I'll be giving a talk at on Friday. > > I wrote this fix for 5.15 first (to continue working on my > presentation), and since stable requires upstream to have the fix, I > forward ported it to 5.16-rc. As 5.16 introduced changes in this code, > the forward port had to do things differently, and my forward port > added a bug which the fix has just been added: > > https://git.kernel.org/torvalds/c/f8132d62a2deedca1b7558028cfe72f93ad5ba2d > > That fix does not need to be backported, as the origin 5.15 patch did > not have that bug. > > This is the original 5.15 patch I used to create the 5.16 version with, > and it should also fix 5.10. Kernels before 5.7 will need a different > patch, as it did not have the "no_pid" feature yet. I'll send out the > fix for those kernels later. > > -- Steve > > Upstream commit: 6cb206508b621a9a0a2c35b60540e399225c8243 > > From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx> > Subject: [PATCH] tracing: Check pid filtering when creating events > > When pid filtering is activated in an instance, all of the events trace > files for that instance has the PID_FILTER flag set. This determines > whether or not pid filtering needs to be done on the event, otherwise the > event is executed as normal. > > If pid filtering is enabled when an event is created (via a dynamic event > or modules), its flag is not updated to reflect the current state, and the > events are not filtered properly. > > Cc: stable@xxxxxxxxxxxxxxx > Fixes: 3fdaf80f4a836 ("tracing: Implement event pid filtering") > Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> > --- > kernel/trace/trace_events.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c > index 830b3b9940f4..e760e078c733 100644 > --- a/kernel/trace/trace_events.c > +++ b/kernel/trace/trace_events.c > @@ -2677,12 +2677,23 @@ static struct trace_event_file * > trace_create_new_event(struct trace_event_call *call, > struct trace_array *tr) > { > + struct trace_pid_list *no_pid_list; > + struct trace_pid_list *pid_list; > struct trace_event_file *file; > + unsigned int first; > > file = kmem_cache_alloc(file_cachep, GFP_TRACE); > if (!file) > return NULL; > > + pid_list = rcu_dereference_protected(tr->filtered_pids, > + lockdep_is_held(&event_mutex)); > + no_pid_list = rcu_dereference_protected(tr->filtered_no_pids, > + lockdep_is_held(&event_mutex)); > + > + if (pid_list || no_pid_list) > + file->flags |= EVENT_FILE_FL_PID_FILTER; > + > file->event_call = call; > file->tr = tr; > atomic_set(&file->sm_ref, 0); > -- > 2.33.0 Why did you add the first variable here? I get the build failure: kernel/trace/trace_events.c: In function ‘trace_create_new_event’: kernel/trace/trace_events.c:2684:22: error: unused variable ‘first’ [-Werror=unused-variable] 2684 | unsigned int first; | ^~~~~ cc1: all warnings being treated as errors because of that. I'll go remove that line, but please, test-build your patches at the very least :) thanks, greg k-h
