Simply remove UPROBE_RUN_HANDLER and the corresponding code.
It can only help if uprobe has a single consumer, and in fact
it is no longer needed after handler_chain() was changed to use
->register_rwsem, we simply can not race with uprobe_register().
Signed-off-by: Oleg Nesterov <o...@redhat.com>
---
kernel/events/uprobes.c | 23 +++++------------------
1 files changed, 5 insertions(+), 18 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 873c993..97c3874 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -83,10 +83,8 @@ static atomic_t uprobe_events = ATOMIC_INIT(0);
/* Have a copy of original instruction */
#define UPROBE_COPY_INSN 0
-/* Dont run handlers when first register/ last unregister in progress*/
-#define UPROBE_RUN_HANDLER 1
/* Can skip singlestep */
-#define UPROBE_SKIP_SSTEP 2
+#define UPROBE_SKIP_SSTEP 1
struct uprobe {
struct rb_node rb_node; /* node in the rb tree */
@@ -475,9 +473,6 @@ static void handler_chain(struct uprobe *uprobe, struct
pt_regs *regs)
{
struct uprobe_consumer *uc;
- if (!test_bit(UPROBE_RUN_HANDLER, &uprobe->flags))
- return;
-
down_read(&uprobe->register_rwsem);
for (uc = uprobe->consumers; uc; uc = uc->next)
uc->handler(uc, regs);
@@ -825,13 +820,8 @@ static int register_for_each_vma(struct uprobe *uprobe,
bool is_register)
static int __uprobe_register(struct uprobe *uprobe, struct uprobe_consumer *uc)
{
- int err;
-
consumer_add(uprobe, uc);
- err = register_for_each_vma(uprobe, true);
- if (!err) /* TODO: pointless unless the first consumer */
- set_bit(UPROBE_RUN_HANDLER, &uprobe->flags);
- return err;
+ return register_for_each_vma(uprobe, true);
}
static void __uprobe_unregister(struct uprobe *uprobe, struct uprobe_consumer
*uc)
@@ -842,12 +832,9 @@ static void __uprobe_unregister(struct uprobe *uprobe,
struct uprobe_consumer *u
return;
err = register_for_each_vma(uprobe, false);
- if (!uprobe->consumers) {
- clear_bit(UPROBE_RUN_HANDLER, &uprobe->flags);
- /* TODO : cant unregister? schedule a worker thread */
- if (!err)
- delete_uprobe(uprobe);
- }
+ /* TODO : cant unregister? schedule a worker thread */
+ if (!uprobe->consumers && !err)
+ delete_uprobe(uprobe);
}
/*
--
1.5.5.1
--
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