Re: [PATCH] tracepoint: Do not fail unregistering a probe due to memory allocation

2020-11-17 Thread Steven Rostedt
On Tue, 17 Nov 2020 18:08:19 -0500 (EST) Mathieu Desnoyers wrote: > Because of this end-of-loop condition ^ > which is also testing for a NULL func. So if we reach a stub, we end up > stopping > iteration and not firing the following tracepoint probes. Ah right. OK, since it's looking like

Re: [PATCH] tracepoint: Do not fail unregistering a probe due to memory allocation

2020-11-17 Thread Mathieu Desnoyers
- On Nov 17, 2020, at 5:19 PM, rostedt rost...@goodmis.org wrote: > On Tue, 17 Nov 2020 13:33:42 -0800 > Kees Cook wrote: > >> As I think got discussed in the thread, what you had here wouldn't work >> in a CFI build if the function prototype of the call site and the >> function don't

Re: [PATCH] tracepoint: Do not fail unregistering a probe due to memory allocation

2020-11-17 Thread Mathieu Desnoyers
- On Nov 17, 2020, at 5:16 PM, rostedt rost...@goodmis.org wrote: > On Tue, 17 Nov 2020 16:22:23 -0500 (EST) > Mathieu Desnoyers wrote: > >> If we don't call the stub, then there is no point in having the stub at >> all, and we should just compare to a constant value, e.g. 0x1UL. As far >>

Re: [PATCH] tracepoint: Do not fail unregistering a probe due to memory allocation

2020-11-17 Thread Steven Rostedt
On Tue, 17 Nov 2020 13:33:42 -0800 Kees Cook wrote: > As I think got discussed in the thread, what you had here wouldn't work > in a CFI build if the function prototype of the call site and the > function don't match. (Though I can't tell if .func() is ever called?) > > i.e. .func's prototype

Re: [PATCH] tracepoint: Do not fail unregistering a probe due to memory allocation

2020-11-17 Thread Steven Rostedt
On Tue, 17 Nov 2020 16:22:23 -0500 (EST) Mathieu Desnoyers wrote: > If we don't call the stub, then there is no point in having the stub at > all, and we should just compare to a constant value, e.g. 0x1UL. As far > as I can recall, comparing with a small immediate constant is more efficient >

Re: [PATCH] tracepoint: Do not fail unregistering a probe due to memory allocation

2020-11-17 Thread Kees Cook
On Mon, Nov 16, 2020 at 05:51:07PM -0500, Steven Rostedt wrote: > [ Kees, I added you because you tend to know about these things. > Is it OK to assign a void func(void) that doesn't do anything and returns > nothing to a function pointer that could be call with parameters? We need > to add

Re: [PATCH] tracepoint: Do not fail unregistering a probe due to memory allocation

2020-11-17 Thread Mathieu Desnoyers
- On Nov 17, 2020, at 3:58 PM, rostedt rost...@goodmis.org wrote: > On Tue, 17 Nov 2020 15:34:51 -0500 > Steven Rostedt wrote: [...] > If it comes down to not trusting calling a stub, I'll still keep the stub > logic in, and just add the following: If we don't call the stub, then there is

Re: [PATCH] tracepoint: Do not fail unregistering a probe due to memory allocation

2020-11-17 Thread Mathieu Desnoyers
- On Nov 17, 2020, at 3:34 PM, rostedt rost...@goodmis.org wrote: > On Tue, 17 Nov 2020 14:47:20 -0500 (EST) > Mathieu Desnoyers wrote: > >> There seems to be more effect on the data size: adding the "stub_func" field >> in struct tracepoint adds 8320 bytes of data to my vmlinux. But

Re: [PATCH] tracepoint: Do not fail unregistering a probe due to memory allocation

2020-11-17 Thread Steven Rostedt
On Tue, 17 Nov 2020 15:34:51 -0500 Steven Rostedt wrote: > On Tue, 17 Nov 2020 14:47:20 -0500 (EST) > Mathieu Desnoyers wrote: > > > There seems to be more effect on the data size: adding the "stub_func" field > > in struct tracepoint adds 8320 bytes of data to my vmlinux. But considering > >

Re: [PATCH] tracepoint: Do not fail unregistering a probe due to memory allocation

2020-11-17 Thread Steven Rostedt
On Tue, 17 Nov 2020 14:47:20 -0500 (EST) Mathieu Desnoyers wrote: > There seems to be more effect on the data size: adding the "stub_func" field > in struct tracepoint adds 8320 bytes of data to my vmlinux. But considering > the layout of struct tracepoint: > > struct tracepoint { >

Re: [PATCH] tracepoint: Do not fail unregistering a probe due to memory allocation

2020-11-17 Thread Mathieu Desnoyers
- On Nov 17, 2020, at 2:21 PM, rostedt rost...@goodmis.org wrote: > On Tue, 17 Nov 2020 14:15:10 -0500 (EST) > Mathieu Desnoyers wrote: > > >> diff --git a/include/linux/tracepoint-defs.h >> b/include/linux/tracepoint-defs.h >> index e7c2276be33e..e0351bb0b140 100644 >> ---

Re: [PATCH] tracepoint: Do not fail unregistering a probe due to memory allocation

2020-11-17 Thread Steven Rostedt
On Tue, 17 Nov 2020 14:15:10 -0500 (EST) Mathieu Desnoyers wrote: > diff --git a/include/linux/tracepoint-defs.h b/include/linux/tracepoint-defs.h > index e7c2276be33e..e0351bb0b140 100644 > --- a/include/linux/tracepoint-defs.h > +++ b/include/linux/tracepoint-defs.h > @@ -38,6 +38,7 @@ struct

Re: [PATCH] tracepoint: Do not fail unregistering a probe due to memory allocation

2020-11-17 Thread Mathieu Desnoyers
- On Nov 16, 2020, at 5:51 PM, rostedt rost...@goodmis.org wrote: > [ Kees, I added you because you tend to know about these things. > Is it OK to assign a void func(void) that doesn't do anything and returns > nothing to a function pointer that could be call with parameters? We need > to

Re: [PATCH] tracepoint: Do not fail unregistering a probe due to memory allocation

2020-11-16 Thread Steven Rostedt
On Mon, 16 Nov 2020 17:51:07 -0500 Steven Rostedt wrote: > [ Kees, I added you because you tend to know about these things. > Is it OK to assign a void func(void) that doesn't do anything and returns > nothing to a function pointer that could be call with parameters? We need > to add stubs

[PATCH] tracepoint: Do not fail unregistering a probe due to memory allocation

2020-11-16 Thread Steven Rostedt
[ Kees, I added you because you tend to know about these things. Is it OK to assign a void func(void) that doesn't do anything and returns nothing to a function pointer that could be call with parameters? We need to add stubs for tracepoints when we fail to allocate a new array on