On Mon, Apr 24, 2023 at 06:04:28PM +0200, Jiri Olsa wrote:
> +
> +static int uprobe_prog_run(struct bpf_uprobe *uprobe,
> + unsigned long entry_ip,
> + struct pt_regs *regs)
> +{
> + struct bpf_uprobe_multi_link *link = uprobe->link;
> + struct bpf_uprobe_multi_run_ctx run_ctx = {
> + .entry_ip = entry_ip,
> + };
> + struct bpf_run_ctx *old_run_ctx;
> + int err;
> +
> + preempt_disable();
preempt_disable? Which year is this? :)
Let's allow sleepable from the start.
See bpf_prog_run_array_sleepable.
Other than this the set looks great.
> +
> + if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {
> + err = 0;
> + goto out;
> + }
> +
> + rcu_read_lock();
> + old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
> + err = bpf_prog_run(link->link.prog, regs);
> + bpf_reset_run_ctx(old_run_ctx);
> + rcu_read_unlock();
> +
> + out:
> + __this_cpu_dec(bpf_prog_active);
> + preempt_enable();
> + return err;
...
> + struct path path;
> + char *name;
> +
> + name = strndup_user(upath, PATH_MAX);
> + if (IS_ERR(name)) {
> + err = PTR_ERR(name);
> + goto error;
> + }
> + err = kern_path(name, LOOKUP_FOLLOW, &path);
> + kfree(name);
> + if (err)
> + goto error;
> + if (!d_is_reg(path.dentry)) {
> + err = -EINVAL;
> + path_put(&path);
> + goto error;
> + }
> + inode = d_real_inode(path.dentry);
> + path_put(&path);
inode won't disappear between here and its use in uprobe_register_refctr ?
> + }
> + old_upath = upath;
> +
> + uprobes[i].inode = inode;
> + uprobes[i].offset = offset;
> + uprobes[i].ref_ctr_offset = ref_ctr_offset;
> + uprobes[i].link = link;
> +
> + if (flags & BPF_F_UPROBE_MULTI_RETURN)
> + uprobes[i].consumer.ret_handler = uprobe_multi_link_ret_handler;
> + else
> + uprobes[i].consumer.handler = uprobe_multi_link_handler;
> + }
> +
> + link->cnt = cnt;
> + link->uprobes = uprobes;
> +
> + bpf_link_init(&link->link, BPF_LINK_TYPE_UPROBE_MULTI,
> + &bpf_uprobe_multi_link_lops, prog);
> +
> + err = bpf_link_prime(&link->link, &link_primer);
> + if (err)
> + goto error;
> +
> + for (i = 0; i < cnt; i++) {
> + err = uprobe_register_refctr(uprobes[i].inode, uprobes[i].offset,
> + uprobes[i].ref_ctr_offset,
> + &uprobes[i].consumer);
