On Tue, Jul 02, 2019 at 05:50:09PM +0100, Mark Rutland wrote: > On Sun, May 26, 2019 at 03:18:40PM -0400, Steven Rostedt wrote: > > From: Masami Hiramatsu <mhira...@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 <mhira...@kernel.org> > > Signed-off-by: Steven Rostedt (VMware) <rost...@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. > > 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.
Thanks Mark for identifying this. So we either revert the above commit in -next or queue the one below together with the rest of the kprobes changes (I can queue it via the arm64 for-next/core assuming that the above commit id remains stable): --------------8<------------------------------------ >From de4f4d30bab3d77d6643a6fa9ba1deff73dac7f2 Mon Sep 17 00:00:00 2001 From: Catalin Marinas <catalin.mari...@arm.com> Date: Wed, 3 Jul 2019 14:44:23 +0100 Subject: [PATCH] arm64: Initialise the debug traps earlier Commit b5f8b32c93b2 ("kprobes: Initialize kprobes at postcore_initcall") makes init_kprobes() a postcore_initcall while the arm64 handling of the BRK instruction is initialised at arch_initcall level. Make the arm64 debug_traps_init() a core_initcall. Fixes: b5f8b32c93b2 ("kprobes: Initialize kprobes at postcore_initcall") Signed-off-by: Catalin Marinas <catalin.mari...@arm.com> --- arch/arm64/kernel/debug-monitors.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c index f8719bd30850..81770105cd8e 100644 --- a/arch/arm64/kernel/debug-monitors.c +++ b/arch/arm64/kernel/debug-monitors.c @@ -382,7 +382,7 @@ static int __init debug_traps_init(void) TRAP_BRKPT, "ptrace BRK handler"); return 0; } -arch_initcall(debug_traps_init); +core_initcall(debug_traps_init); /* Re-enable single step for syscall restarting. */ void user_rewind_single_step(struct task_struct *task)