* Anton Arapov <an...@redhat.com> [2013-04-03 18:00:31]:
> 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>
Acked-by: Srikar Dronamraju <sri...@linux.vnet.ibm.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
>
--
Thanks and Regards
Srikar Dronamraju
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