| Message ID | 20230528142027.5585-3-laoar.shao@gmail.com (mailing list archive) |
|---|---|
| State | RFC |
| Delegated to: | BPF |
| Headers | show |
| Series | bpf: Support ->show_fdinfo and ->fill_link_info for kprobe prog | expand |
On Sun, May 28, 2023 at 02:20:21PM +0000, Yafang Shao wrote: SNIP > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > index 0d84a7a..00a0009 100644 > --- a/kernel/trace/bpf_trace.c > +++ b/kernel/trace/bpf_trace.c > @@ -2564,10 +2564,41 @@ static void bpf_kprobe_multi_link_show_fdinfo(const struct bpf_link *link, > } > } > > +static int bpf_kprobe_multi_link_fill_link_info(const struct bpf_link *link, > + struct bpf_link_info *info) > +{ > + struct bpf_kprobe_multi_link *kmulti_link; > + u64 *uaddrs = u64_to_user_ptr(info->kprobe_multi.addrs); > + u32 ucount = info->kprobe_multi.count; > + int i; > + > + if (!uaddrs ^ !ucount) > + return -EINVAL; > + > + kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link); > + if (!uaddrs) { > + info->kprobe_multi.count = kmulti_link->cnt; > + return 0; > + } > + > + if (!ucount) > + return 0; > + > + if (ucount != kmulti_link->cnt) > + return -EINVAL; > + > + for (i = 0; i < ucount; i++) > + if (copy_to_user(uaddrs + i, kmulti_link->addrs + i, > + sizeof(u64))) > + return -EFAULT; let's use put_user instead copy_to_user? or even better why not copy that with single copy_to_user from kmulti_link->addrs jirka > + return 0; > +} > + > static const struct bpf_link_ops bpf_kprobe_multi_link_lops = { > .release = bpf_kprobe_multi_link_release, > .dealloc = bpf_kprobe_multi_link_dealloc, > .show_fdinfo = bpf_kprobe_multi_link_show_fdinfo, > + .fill_link_info = bpf_kprobe_multi_link_fill_link_info, > }; > > static void bpf_kprobe_multi_cookie_swap(void *a, void *b, int size, const void *priv) > diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h > index 9273c65..6be9b1d 100644 > --- a/tools/include/uapi/linux/bpf.h > +++ b/tools/include/uapi/linux/bpf.h > @@ -6434,6 +6434,10 @@ struct bpf_link_info { > __s32 priority; > __u32 flags; > } netfilter; > + struct { > + __aligned_u64 addrs; > + __u32 count; > + } kprobe_multi; > }; > } __attribute__((aligned(8))); > > -- > 1.8.3.1 >
On Mon, May 29, 2023 at 8:49 PM Jiri Olsa <olsajiri@gmail.com> wrote: > > On Sun, May 28, 2023 at 02:20:21PM +0000, Yafang Shao wrote: > > SNIP > > > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > > index 0d84a7a..00a0009 100644 > > --- a/kernel/trace/bpf_trace.c > > +++ b/kernel/trace/bpf_trace.c > > @@ -2564,10 +2564,41 @@ static void bpf_kprobe_multi_link_show_fdinfo(const struct bpf_link *link, > > } > > } > > > > +static int bpf_kprobe_multi_link_fill_link_info(const struct bpf_link *link, > > + struct bpf_link_info *info) > > +{ > > + struct bpf_kprobe_multi_link *kmulti_link; > > + u64 *uaddrs = u64_to_user_ptr(info->kprobe_multi.addrs); > > + u32 ucount = info->kprobe_multi.count; > > + int i; > > + > > + if (!uaddrs ^ !ucount) > > + return -EINVAL; > > + > > + kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link); > > + if (!uaddrs) { > > + info->kprobe_multi.count = kmulti_link->cnt; > > + return 0; > > + } > > + > > + if (!ucount) > > + return 0; > > + > > + if (ucount != kmulti_link->cnt) > > + return -EINVAL; > > + > > + for (i = 0; i < ucount; i++) > > + if (copy_to_user(uaddrs + i, kmulti_link->addrs + i, > > + sizeof(u64))) > > + return -EFAULT; > > let's use put_user instead copy_to_user? or even better why not > copy that with single copy_to_user from kmulti_link->addrs > Good point. I will utilize a single copy_to_user instead.
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 9273c65..6be9b1d 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -6434,6 +6434,10 @@ struct bpf_link_info { __s32 priority; __u32 flags; } netfilter; + struct { + __aligned_u64 addrs; + __u32 count; + } kprobe_multi; }; } __attribute__((aligned(8))); diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 0d84a7a..00a0009 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2564,10 +2564,41 @@ static void bpf_kprobe_multi_link_show_fdinfo(const struct bpf_link *link, } } +static int bpf_kprobe_multi_link_fill_link_info(const struct bpf_link *link, + struct bpf_link_info *info) +{ + struct bpf_kprobe_multi_link *kmulti_link; + u64 *uaddrs = u64_to_user_ptr(info->kprobe_multi.addrs); + u32 ucount = info->kprobe_multi.count; + int i; + + if (!uaddrs ^ !ucount) + return -EINVAL; + + kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link); + if (!uaddrs) { + info->kprobe_multi.count = kmulti_link->cnt; + return 0; + } + + if (!ucount) + return 0; + + if (ucount != kmulti_link->cnt) + return -EINVAL; + + for (i = 0; i < ucount; i++) + if (copy_to_user(uaddrs + i, kmulti_link->addrs + i, + sizeof(u64))) + return -EFAULT; + return 0; +} + static const struct bpf_link_ops bpf_kprobe_multi_link_lops = { .release = bpf_kprobe_multi_link_release, .dealloc = bpf_kprobe_multi_link_dealloc, .show_fdinfo = bpf_kprobe_multi_link_show_fdinfo, + .fill_link_info = bpf_kprobe_multi_link_fill_link_info, }; static void bpf_kprobe_multi_cookie_swap(void *a, void *b, int size, const void *priv) diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 9273c65..6be9b1d 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -6434,6 +6434,10 @@ struct bpf_link_info { __s32 priority; __u32 flags; } netfilter; + struct { + __aligned_u64 addrs; + __u32 count; + } kprobe_multi; }; } __attribute__((aligned(8)));
By adding support for ->fill_link_info to the kprobe_multi link, users will be able to inspect it using `bpftool link show`. This enhancement will expose both the count of probed functions and their respective addresses to the user. Signed-off-by: Yafang Shao <laoar.shao@gmail.com> --- include/uapi/linux/bpf.h | 4 ++++ kernel/trace/bpf_trace.c | 31 +++++++++++++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 4 ++++ 3 files changed, 39 insertions(+)