Commit-ID: 059053a275b56eff1db11605c68988a6e9818561
Gitweb: https://git.kernel.org/tip/059053a275b56eff1db11605c68988a6e9818561
Author: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
AuthorDate: Wed, 20 Jun 2018 01:10:27 +0900
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 21 Jun 2018 12:33:12 +0200
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@xxxxxxxxxx>
Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: linux-arch@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/lkml/152942462686.15209.6324404940493598980.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
Documentation/kprobes.txt | 2 +-
kernel/kprobes.c | 39 +++++----------------------------------
2 files changed, 6 insertions(+), 35 deletions(-)
diff --git a/Documentation/kprobes.txt b/Documentation/kprobes.txt
index 33dd6a81fb64..ab2c7307f123 100644
--- a/Documentation/kprobes.txt
+++ b/Documentation/kprobes.txt
@@ -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
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 69de130595f7..536ab451e96d 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -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);
}
/*
--
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