[PATCH 1/3] bpf: use 'error_xxx' tags in bpf_kprobe_multi_link_attach

From: Wan Jiabing
Date: Thu May 12 2022 - 10:17:50 EST


Use 'error_addrs', 'error_cookies' and 'error_link' tags to make error
handling more efficient.

Signed-off-by: Wan Jiabing <wanjiabing@xxxxxxxx>
---
kernel/trace/bpf_trace.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 2eaac094caf8..3a8b69ef9a0d 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2467,20 +2467,20 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
if (uaddrs) {
if (copy_from_user(addrs, uaddrs, size)) {
err = -EFAULT;
- goto error;
+ goto error_addrs;
}
} else {
struct user_syms us;

err = copy_user_syms(&us, usyms, cnt);
if (err)
- goto error;
+ goto error_addrs;

sort(us.syms, cnt, sizeof(*us.syms), symbols_cmp, NULL);
err = ftrace_lookup_symbols(us.syms, cnt, addrs);
free_user_syms(&us);
if (err)
- goto error;
+ goto error_addrs;
}

ucookies = u64_to_user_ptr(attr->link_create.kprobe_multi.cookies);
@@ -2488,18 +2488,18 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
cookies = kvmalloc(size, GFP_KERNEL);
if (!cookies) {
err = -ENOMEM;
- goto error;
+ goto error_addrs;
}
if (copy_from_user(cookies, ucookies, size)) {
err = -EFAULT;
- goto error;
+ goto error_cookies;
}
}

link = kzalloc(sizeof(*link), GFP_KERNEL);
if (!link) {
err = -ENOMEM;
- goto error;
+ goto error_cookies;
}

bpf_link_init(&link->link, BPF_LINK_TYPE_KPROBE_MULTI,
@@ -2507,7 +2507,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr

err = bpf_link_prime(&link->link, &link_primer);
if (err)
- goto error;
+ goto error_link;

if (flags & BPF_F_KPROBE_MULTI_RETURN)
link->fp.exit_handler = kprobe_multi_link_handler;
@@ -2539,10 +2539,12 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr

return bpf_link_settle(&link_primer);

-error:
+error_link:
kfree(link);
- kvfree(addrs);
+error_cookies:
kvfree(cookies);
+error_addrs:
+ kvfree(addrs);
return err;
}
#else /* !CONFIG_FPROBE */
--
2.35.1