On Tue, Oct 22, 2024 at 10:06 AM Simon Horman <horms@xxxxxxxxxx> wrote:
>
> On Mon, Oct 21, 2024 at 12:12:33PM -0700, Li Li wrote:
> > + * @pid: the target process
> > + * @flags: the flags to set
> > + *
> > + * If pid is 0, the flags are applied to the whole binder context.
> > + * Otherwise, the flags are applied to the specific process only.
> > + */
> > +static int binder_genl_set_report(struct binder_context *context, u32 pid, u32 flags)
>
> ...
>
> > static int __init init_binder_device(const char *name)
> > {
> > int ret;
> > @@ -6920,6 +7196,11 @@ static int __init init_binder_device(const char *name)
>
> The code above this hunk looks like this:
>
>
> ret = misc_register(&binder_device->miscdev);
> if (ret < 0) {
> kfree(binder_device);
> return ret;
> }
>
> >
> > hlist_add_head(&binder_device->hlist, &binder_devices);
> >
> > + binder_device->context.report_seq = (atomic_t)ATOMIC_INIT(0);
> > + ret = binder_genl_init(&binder_device->context.genl_family, name);
> > + if (ret < 0)
> > + kfree(binder_device);
>
> So I think that binder_device->miscdev needs to be misc_deregister'ed
> if we hit this error condition.
>
> > +
> > return ret;
>
> Probably adding an unwind ladder like this makes sense (completely untested!):
>
> ret = misc_register(&binder_device->miscdev);
> if (ret < 0)
> goto err_misc_deregister;
>
> hlist_add_head(&binder_device->hlist, &binder_devices);
>
> binder_device->context.report_seq = (atomic_t)ATOMIC_INIT(0);
> ret = binder_genl_init(&binder_device->context.genl_family, name);
> if (ret < 0);
> goto err_misc_deregister;
>
> return 0;
>
> err_misc_deregister:
> misc_deregister(&binder_device->miscdev);
> err_free_dev:
> kfree(binder_device);
> return ret;
>
Good catch! Will fix it in the next revision.
> ...
>
> > diff --git a/drivers/android/binder_genl.h b/drivers/android/binder_genl.h
>
> Perhaps it is because of a different version of net-next,
> but with this patch applied on top of the current head commit
> 13feb6074a9f ("binder: report txn errors via generic netlink (genl)")
> I see:
>
> $ ./tools/net/ynl/ynl-regen.sh -f
> $ git diff
>
> diff --git a/include/uapi/linux/android/binder_genl.h b/include/uapi/linux/android/binder_genl.h
> index ef5289133be5..93e58b370420 100644
> --- a/include/uapi/linux/android/binder_genl.h
> +++ b/include/uapi/linux/android/binder_genl.h
> @@ -3,12 +3,17 @@
> /* Documentation/netlink/specs/binder_genl.yaml */
> /* YNL-GEN uapi header */
>
> -#ifndef _UAPI_LINUX_BINDER_GENL_H
> -#define _UAPI_LINUX_BINDER_GENL_H
> +#ifndef _UAPI_LINUX_ANDROID/BINDER_GENL_H
> +#define _UAPI_LINUX_ANDROID/BINDER_GENL_H
>
> #define BINDER_GENL_FAMILY_NAME "binder_genl"
> #define BINDER_GENL_FAMILY_VERSION 1
>
> +/**
> + * enum binder_genl_flag - Used with "set" and "reply" command below, defining
> + * what kind \ of binder transactions should be reported to the user space \
> + * administration process.
> + */
> enum binder_genl_flag {
> BINDER_GENL_FLAG_FAILED = 1,
> BINDER_GENL_FLAG_DELAYED = 2,
> @@ -34,4 +39,4 @@ enum {
> BINDER_GENL_CMD_MAX = (__BINDER_GENL_CMD_MAX - 1)
> };
>
> -#endif /* _UAPI_LINUX_BINDER_GENL_H */
> +#endif /* _UAPI_LINUX_ANDROID/BINDER_GENL_H */
The patch was based on the top of Linus's tree instead of net-next.
I'll investigate this difference.
