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kprobes: Disable booster when CONFIG_PREEMPT=y

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Disable kprobe booster when CONFIG_PREEMPT=y at this time,
because it can't ensure that all kernel threads preempted on
kprobe's boosted slot run out from the slot even using
freeze_processes().

The booster on preemptive kernel will be resumed if
synchronize_tasks() or something like that is introduced.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20100202214904.4694.24330.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Masami Hiramatsu
2010-02-02 16:49:04 -05:00
committed by Ingo Molnar
parent 57d818895f
commit 615d0ebbc7
3 changed files with 4 additions and 29 deletions
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2
arch/ia64/kernel/kprobes.c
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@ -870,7 +870,7 @@ static int __kprobes pre_kprobes_handler(struct die_args *args)
return 1;
ss_probe:
#if !defined(CONFIG_PREEMPT) || defined(CONFIG_FREEZER)
#if !defined(CONFIG_PREEMPT)
if (p->ainsn.inst_flag == INST_FLAG_BOOSTABLE && !p->post_handler) {
/* Boost up -- we can execute copied instructions directly */
ia64_psr(regs)->ri = p->ainsn.slot;