2022-08-26 23:27:32

by Dave Jiang

Subject: Re: [PATCH] tracepoint: Allow trace events in modules with TAINT_TEST

On 8/26/2022 3:35 PM, [email protected] wrote:
> From: Alison Schofield <[email protected]>
>
> Commit 2852ca7fba9f ("panic: Taint kernel if tests are run")
> introduced a new taint type, TAINT_TEST, to signal that an
> in-kernel test has been run.

has been loaded?

>
> TAINT_TEST taint type defaults into a 'bad_taint' list for
> kernel tracing and blocks the creation of trace events. This
> causes a problem for CXL testing where loading the cxl_test
> module makes all CXL modules out-of-tree, blocking any trace
> events.
>
> Trace events are in development for CXL at the moment and this
> issue was found in test with v6.0-rc1.
>
> Reported-by: Ira Weiny <[email protected]>
> Suggested-by: Dan Williams <[email protected]>
> Signed-off-by: Alison Schofield <[email protected]>
> ---
> kernel/tracepoint.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
> index 64ea283f2f86..5f17378c9dc2 100644
> --- a/kernel/tracepoint.c
> +++ b/kernel/tracepoint.c
> @@ -571,7 +571,8 @@ static void for_each_tracepoint_range(
> bool trace_module_has_bad_taint(struct module *mod)
> {
> return mod->taints & ~((1 << TAINT_OOT_MODULE) | (1 << TAINT_CRAP) |
> - (1 << TAINT_UNSIGNED_MODULE));
> + (1 << TAINT_UNSIGNED_MODULE) |
> + (1 << TAINT_TEST));
> }
>
> static BLOCKING_NOTIFIER_HEAD(tracepoint_notify_list);
>
> base-commit: 4c612826bec1441214816827979b62f84a097e91

2022-08-27 00:03:39

by Alison Schofield

Subject: Re: [PATCH] tracepoint: Allow trace events in modules with TAINT_TEST

On Fri, Aug 26, 2022 at 03:48:42PM -0700, Dave Jiang wrote:
>
> On 8/26/2022 3:35 PM, [email protected] wrote:
> > From: Alison Schofield <[email protected]>
> >
> > Commit 2852ca7fba9f ("panic: Taint kernel if tests are run")
> > introduced a new taint type, TAINT_TEST, to signal that an
> > in-kernel test has been run.
>
> has been loaded?
>

I took that explanation directly from the mentioned commit, where
it seems that 'run' was the intended word when referring to KUnit
tests. Reviewer feedback led the submitter to make the taint per
module to handle 'longer lasting' modules.

> >
> > TAINT_TEST taint type defaults into a 'bad_taint' list for
> > kernel tracing and blocks the creation of trace events. This
> > causes a problem for CXL testing where loading the cxl_test
> > module makes all CXL modules out-of-tree, blocking any trace
> > events.
> >
> > Trace events are in development for CXL at the moment and this
> > issue was found in test with v6.0-rc1.
> >
> > Reported-by: Ira Weiny <[email protected]>
> > Suggested-by: Dan Williams <[email protected]>
> > Signed-off-by: Alison Schofield <[email protected]>
> > ---
> > kernel/tracepoint.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
> > index 64ea283f2f86..5f17378c9dc2 100644
> > --- a/kernel/tracepoint.c
> > +++ b/kernel/tracepoint.c
> > @@ -571,7 +571,8 @@ static void for_each_tracepoint_range(
> > bool trace_module_has_bad_taint(struct module *mod)
> > {
> > return mod->taints & ~((1 << TAINT_OOT_MODULE) | (1 << TAINT_CRAP) |
> > - (1 << TAINT_UNSIGNED_MODULE));
> > + (1 << TAINT_UNSIGNED_MODULE) |
> > + (1 << TAINT_TEST));
> > }
> > static BLOCKING_NOTIFIER_HEAD(tracepoint_notify_list);
> >
> > base-commit: 4c612826bec1441214816827979b62f84a097e91