Enclose return probes implementation, introduce ->ret_handler() and update
existing code to rely on ->handler() *and* ->ret_handler() for uprobe and
uretprobe respectively.
v1 changes:
* add bp_vaddr argument to ->ret_handler()
RFCv5 changes:
* don't remove uprobe in case there are no uprobe consumer(handler),
see handler_chain() changes.
RFCv3 changes: (the patch is introduced in v3)
* check whether at least one of the consumer's handlers were set.
* a 'TODO' cap that will be removed once return probes be implemented.
* introduce ->ret_handler().
Signed-off-by: Anton Arapov <an...@redhat.com>
---
include/linux/uprobes.h | 3 +++
kernel/events/uprobes.c | 17 ++++++++++++++---
2 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index 02b83db..4042cad 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -46,6 +46,9 @@ enum uprobe_filter_ctx {
struct uprobe_consumer {
int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs);
+ int (*ret_handler)(struct uprobe_consumer *self,
+ unsigned long func,
+ struct pt_regs *regs);
bool (*filter)(struct uprobe_consumer *self,
enum uprobe_filter_ctx ctx,
struct mm_struct *mm);
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 21d8a65..27c964b 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -815,6 +815,14 @@ int uprobe_register(struct inode *inode, loff_t offset,
struct uprobe_consumer *
struct uprobe *uprobe;
int ret;
+ /* Uprobe must have at least one set consumer */
+ if (!uc->handler && !uc->ret_handler)
+ return -EINVAL;
+
+ /* TODO: Implement return probes */
+ if (uc->ret_handler)
+ return -ENOSYS;
+
/* Racy, just to catch the obvious mistakes */
if (offset > i_size_read(inode))
return -EINVAL;
@@ -1473,10 +1481,13 @@ static void handler_chain(struct uprobe *uprobe, struct
pt_regs *regs)
down_read(&uprobe->register_rwsem);
for (uc = uprobe->consumers; uc; uc = uc->next) {
- int rc = uc->handler(uc, regs);
+ int rc = 0;
- WARN(rc & ~UPROBE_HANDLER_MASK,
- "bad rc=0x%x from %pf()\n", rc, uc->handler);
+ if (uc->handler) {
+ rc = uc->handler(uc, regs);
+ WARN(rc & ~UPROBE_HANDLER_MASK,
+ "bad rc=0x%x from %pf()\n", rc, uc->handler);
+ }
remove &= rc;
}
--
1.8.1.4
--
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