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kprobes: Don't check the ->break_handler() in generic kprobes code 

Don't check the ->break_handler() from the core kprobes code,
because it was only used by jprobes which got removed.

( In followup patches we'll remove the remaining calls in low level
  arch handlers as well and remove the callback altogether. )

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-arch@vger.kernel.org
Link: https://lore.kernel.org/lkml/152942462686.15209.6324404940493598980.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
hifive-unleashed-5.1
Masami Hiramatsu 2018-06-20 01:10:27 +09:00 committed by Ingo Molnar
parent e9bf11a5a6
commit 059053a275
2 changed files with 6 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Documentation/kprobes.txt
View File

@ -262,7 +262,7 @@ is optimized, that modification is ignored. Thus, if you want to
tweak the kernel's execution path, you need to suppress optimization,
using one of the following techniques:
- Specify an empty function for the kprobe's post_handler or break_handler.
- Specify an empty function for the kprobe's post_handler.
or

39
kernel/kprobes.c
View File

@ -627,8 +627,8 @@ static void optimize_kprobe(struct kprobe *p)
(kprobe_disabled(p) || kprobes_all_disarmed))
return;
/* Both of break_handler and post_handler are not supported. */
if (p->break_handler || p->post_handler)
/* kprobes with post_handler can not be optimized */
if (p->post_handler)
return;
op = container_of(p, struct optimized_kprobe, kp);
@ -1116,20 +1116,6 @@ static int aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
}
NOKPROBE_SYMBOL(aggr_fault_handler);
static int aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
{
struct kprobe *cur = __this_cpu_read(kprobe_instance);
int ret = 0;
if (cur && cur->break_handler) {
if (cur->break_handler(cur, regs))
ret = 1;
}
reset_kprobe_instance();
return ret;
}
NOKPROBE_SYMBOL(aggr_break_handler);
/* Walks the list and increments nmissed count for multiprobe case */
void kprobes_inc_nmissed_count(struct kprobe *p)
{
@ -1270,24 +1256,15 @@ static void cleanup_rp_inst(struct kretprobe *rp)
}
NOKPROBE_SYMBOL(cleanup_rp_inst);
/*
* Add the new probe to ap->list. Fail if this is the
* second break_handler at the address
*/
/* Add the new probe to ap->list */
static int add_new_kprobe(struct kprobe *ap, struct kprobe *p)
{
BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
if (p->break_handler || p->post_handler)
if (p->post_handler)
unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */
if (p->break_handler) {
if (ap->break_handler)
return -EEXIST;
list_add_tail_rcu(&p->list, &ap->list);
ap->break_handler = aggr_break_handler;
} else
list_add_rcu(&p->list, &ap->list);
list_add_rcu(&p->list, &ap->list);
if (p->post_handler && !ap->post_handler)
ap->post_handler = aggr_post_handler;
@ -1310,8 +1287,6 @@ static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
/* We don't care the kprobe which has gone. */
if (p->post_handler && !kprobe_gone(p))
ap->post_handler = aggr_post_handler;
if (p->break_handler && !kprobe_gone(p))
ap->break_handler = aggr_break_handler;
INIT_LIST_HEAD(&ap->list);
INIT_HLIST_NODE(&ap->hlist);
@ -1706,8 +1681,6 @@ static int __unregister_kprobe_top(struct kprobe *p)
goto disarmed;
else {
/* If disabling probe has special handlers, update aggrprobe */
if (p->break_handler && !kprobe_gone(p))
ap->break_handler = NULL;
if (p->post_handler && !kprobe_gone(p)) {
list_for_each_entry_rcu(list_p, &ap->list, list) {
if ((list_p != p) && (list_p->post_handler))
@ -1911,7 +1884,6 @@ int register_kretprobe(struct kretprobe *rp)
rp->kp.pre_handler = pre_handler_kretprobe;
rp->kp.post_handler = NULL;
rp->kp.fault_handler = NULL;
rp->kp.break_handler = NULL;
/* Pre-allocate memory for max kretprobe instances */
if (rp->maxactive <= 0) {
@ -2034,7 +2006,6 @@ static void kill_kprobe(struct kprobe *p)
list_for_each_entry_rcu(kp, &p->list, list)
kp->flags |= KPROBE_FLAG_GONE;
p->post_handler = NULL;
p->break_handler = NULL;
kill_optimized_kprobe(p);
}
/*