Enclose return probes implementation, introduce ->rp_handler() and update
existing code to rely on ->handler() *and* ->rp_handler() for uprobe and
uretprobe respectively.
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 ->rp_handler().
Signed-off-by: Anton Arapov <an...@redhat.com>
---
include/linux/uprobes.h | 1 +
kernel/events/uprobes.c | 14 +++++++++++++-
2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index 02b83db..a28bdee 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -46,6 +46,7 @@ enum uprobe_filter_ctx {
struct uprobe_consumer {
int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs);
+ int (*rp_handler)(struct uprobe_consumer *self, 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 26bc2e2..3205a2e 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -828,6 +828,14 @@ 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->rp_handler)
+ return -EINVAL;
+
+ /* TODO: Implement return probes */
+ if (uc->rp_handler)
+ return -ENOSYS;
+
/* Racy, just to catch the obvious mistakes */
if (offset > i_size_read(inode))
return -EINVAL;
@@ -1488,10 +1496,14 @@ static void handler_chain(struct uprobe *uprobe, struct
pt_regs *regs)
{
struct uprobe_consumer *uc;
int remove = UPROBE_HANDLER_REMOVE;
+ int rc = 0;
down_read(&uprobe->register_rwsem);
for (uc = uprobe->consumers; uc; uc = uc->next) {
- int rc = uc->handler(uc, regs);
+ if (uc->handler)
+ rc = uc->handler(uc, regs);
+ else
+ remove = 0;
WARN(rc & ~UPROBE_HANDLER_MASK,
"bad rc=0x%x from %pf()\n", rc, uc->handler);
--
1.8.1.4
--
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