From: Steven Rostedt <rostedt@goodmis.org>
To: Mark Rutland <mark.rutland@arm.com>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>
Subject: Re: [for-next][PATCH 12/16] kprobes: Initialize kprobes at postcore_initcall
Date: Wed, 3 Jul 2019 10:02:05 -0400 [thread overview]
Message-ID: <20190703100205.0b58f3bf@gandalf.local.home> (raw)
In-Reply-To: <20190702165008.GC34718@lakrids.cambridge.arm.com>
On Tue, 2 Jul 2019 17:50:09 +0100
Mark Rutland <mark.rutland@arm.com> wrote:
> On Sun, May 26, 2019 at 03:18:40PM -0400, Steven Rostedt wrote:
> > From: Masami Hiramatsu <mhiramat@kernel.org>
> >
> > Initialize kprobes at postcore_initcall level instead of module_init
> > since kprobes is not a module, and it depends on only subsystems
> > initialized in core_initcall.
> > This will allow ftrace kprobe event to add new events when it is
> > initializing because ftrace kprobe event is initialized at
> > later initcall level.
> >
> > Link: http://lkml.kernel.org/r/155851394736.15728.13626739508905120098.stgit@devnote2
> >
> > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> > Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> > ---
> > kernel/kprobes.c | 3 +--
> > 1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> > index b1ea30a5540e..54aaaad00a47 100644
> > --- a/kernel/kprobes.c
> > +++ b/kernel/kprobes.c
> > @@ -2289,6 +2289,7 @@ static int __init init_kprobes(void)
> > init_test_probes();
> > return err;
> > }
> > +postcore_initcall(init_kprobes);
>
> As a heads-up, this is causing boot-time failures on arm64.
Thanks for the report.
>
> On arm64 kprobes depends on the BRK handler we register in
> debug_traps_init(), which is an arch_initcall.
>
> As of this change, init_krprobes() calls init_test_probes() before
> that's registered, so we end up hitting a BRK before we can handle it.
>
Would something like this help?
-- Steve
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 5471efbeb937..0ca6f53c8505 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2235,6 +2235,8 @@ static struct notifier_block kprobe_module_nb = {
extern unsigned long __start_kprobe_blacklist[];
extern unsigned long __stop_kprobe_blacklist[];
+static bool run_kprobe_tests __initdata;
+
static int __init init_kprobes(void)
{
int i, err = 0;
@@ -2286,11 +2288,18 @@ static int __init init_kprobes(void)
kprobes_initialized = (err == 0);
if (!err)
- init_test_probes();
+ run_kprobe_tests = true;
return err;
}
subsys_initcall(init_kprobes);
+static int __init run_init_test_probes(void)
+{
+ if (run_kprobe_tests)
+ init_test_probes();
+}
+module_init(run_init_test_probes);
+
#ifdef CONFIG_DEBUG_FS
static void report_probe(struct seq_file *pi, struct kprobe *p,
const char *sym, int offset, char *modname, struct kprobe *pp)
next prev parent reply other threads:[~2019-07-03 14:02 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-26 19:18 [for-next][PATCH 00/16] tracing: Updates for the next merge window Steven Rostedt
2019-05-26 19:18 ` [for-next][PATCH 01/16] ftrace: Make enable and update parameters bool when applicable Steven Rostedt
2019-05-26 19:18 ` [for-next][PATCH 02/16] x86/ftrace: Make enable parameter bool where applicable Steven Rostedt
2019-05-26 19:18 ` [for-next][PATCH 03/16] x86/uaccess: Allow access_ok() in irq context if pagefault_disabled Steven Rostedt
2019-05-26 19:18 ` [for-next][PATCH 04/16] uaccess: Add non-pagefault user-space read functions Steven Rostedt
2019-05-26 19:18 ` [for-next][PATCH 05/16] tracing/probe: Add ustring type for user-space string Steven Rostedt
2019-05-26 19:18 ` [for-next][PATCH 06/16] tracing/probe: Support user-space dereference Steven Rostedt
2019-05-26 19:18 ` [for-next][PATCH 07/16] selftests/ftrace: Add user-memory access syntax testcase Steven Rostedt
2019-05-26 19:18 ` [for-next][PATCH 08/16] perf-probe: Add user memory access attribute support Steven Rostedt
2019-05-26 19:18 ` [for-next][PATCH 09/16] tracing: Use correct function name in trace_filter_add_remove_task() comment Steven Rostedt
2019-05-26 19:18 ` [for-next][PATCH 10/16] uaccess: Add a prototype of non-static __probe_user_read() Steven Rostedt
2019-05-26 19:18 ` [for-next][PATCH 11/16] tracing/kprobe: Cast user-space address correctly Steven Rostedt
2019-05-26 19:18 ` [for-next][PATCH 12/16] kprobes: Initialize kprobes at postcore_initcall Steven Rostedt
2019-07-02 16:50 ` Mark Rutland
2019-07-03 13:50 ` Catalin Marinas
2019-07-03 14:02 ` Steven Rostedt [this message]
2019-07-03 14:08 ` Catalin Marinas
2019-07-03 14:24 ` Steven Rostedt
2019-07-03 14:25 ` Steven Rostedt
2019-07-03 14:37 ` Steven Rostedt
2019-07-09 12:51 ` Masami Hiramatsu
2019-07-09 15:18 ` Steven Rostedt
2019-07-09 15:15 ` Steven Rostedt
2019-07-22 12:42 ` Catalin Marinas
2019-07-22 15:00 ` Steven Rostedt
2019-07-22 16:01 ` Catalin Marinas
2019-07-09 12:30 ` Masami Hiramatsu
2019-07-22 12:34 ` Catalin Marinas
2019-05-26 19:18 ` [for-next][PATCH 13/16] tracing/kprobe: Add kprobe_event= boot parameter Steven Rostedt
2019-05-26 19:18 ` [for-next][PATCH 14/16] tracing: Make a separate config for trace event self tests Steven Rostedt
2019-05-26 19:18 ` [for-next][PATCH 15/16] tracing/kprobe: Do not run kprobe boot tests if kprobe_event is on cmdline Steven Rostedt
2019-05-26 19:18 ` [for-next][PATCH 16/16] ftrace: Enable trampoline when rec count returns back to one Steven Rostedt
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