To support the filtering uprobe_register() should do
register_for_each_vma(true) every time the new consumer comes,
we need to install the previously nacked breakpoints.
Note:
- uprobes_mutex[] should die, what is actually protects is
alloc_uprobe().
- UPROBE_RUN_HANDLER should die too, obviously it can't work
unless uprobe has a single consumer. The consumer should
serialize with _register/_unregister itself. Or this flag
should live in uprobe_consumer->state.
- Perhaps we can do some optimizations later. For example, if
filter_chain() never returns false uprobe can record this
fact and avoid the unnecessary register_for_each_vma().
Signed-off-by: Oleg Nesterov <o...@redhat.com>
---
kernel/events/uprobes.c | 31 +++++++++++++------------------
1 files changed, 13 insertions(+), 18 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 7c98671..c80507d 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -482,16 +482,12 @@ static void handler_chain(struct uprobe *uprobe, struct
pt_regs *regs)
up_read(&uprobe->consumer_rwsem);
}
-/* Returns the previous consumer */
-static struct uprobe_consumer *
-consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc)
+static void consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc)
{
down_write(&uprobe->consumer_rwsem);
uc->next = uprobe->consumers;
uprobe->consumers = uc;
up_write(&uprobe->consumer_rwsem);
-
- return uc->next;
}
/*
@@ -820,9 +816,15 @@ static int register_for_each_vma(struct uprobe *uprobe,
bool is_register)
return err;
}
-static int __uprobe_register(struct uprobe *uprobe)
+static int __uprobe_register(struct uprobe *uprobe, struct uprobe_consumer *uc)
{
- return register_for_each_vma(uprobe, true);
+ 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;
}
static void __uprobe_unregister(struct uprobe *uprobe, struct uprobe_consumer
*uc)
@@ -867,21 +869,14 @@ int uprobe_register(struct inode *inode, loff_t offset,
struct uprobe_consumer *
if (offset > i_size_read(inode))
return -EINVAL;
- ret = 0;
+ ret = -ENOMEM;
mutex_lock(uprobes_hash(inode));
uprobe = alloc_uprobe(inode, offset);
-
- if (!uprobe) {
- ret = -ENOMEM;
- } else if (!consumer_add(uprobe, uc)) {
- ret = __uprobe_register(uprobe);
- if (ret) {
+ if (uprobe) {
+ ret = __uprobe_register(uprobe, uc);
+ if (ret)
__uprobe_unregister(uprobe, uc);
- } else {
- set_bit(UPROBE_RUN_HANDLER, &uprobe->flags);
- }
}
-
mutex_unlock(uprobes_hash(inode));
if (uprobe)
put_uprobe(uprobe);
--
1.5.5.1
--
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