Thread (2 messages) 2 messages, 2 authors, 2021-07-21

Re: [PATCH net-next] bpf: fix pointer cast warning

From: Andrii Nakryiko <hidden>
Date: 2021-07-21 21:45:59
Also in: bpf, lkml

On Wed, Jul 21, 2021 at 2:20 PM Arnd Bergmann [off-list ref] wrote:
From: Arnd Bergmann <arnd@arndb.de>

kp->addr is a pointer, so it cannot be cast directly to a 'u64'
when it gets interpreted as an integer value:

kernel/trace/bpf_trace.c: In function '____bpf_get_func_ip_kprobe':
kernel/trace/bpf_trace.c:968:21: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]
  968 |         return kp ? (u64) kp->addr : 0;

Use the uintptr_t type instead.

Fixes: 9ffd9f3ff719 ("bpf: Add bpf_get_func_ip helper for kprobe programs")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
I'll take this through the bpf-next tree, if no one objects. Thanks for the fix!

quoted hunk ↗ jump to hunk
 kernel/trace/bpf_trace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 0de09f068697..a428d1ef0085 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -965,7 +965,7 @@ BPF_CALL_1(bpf_get_func_ip_kprobe, struct pt_regs *, regs)
 {
        struct kprobe *kp = kprobe_running();

-       return kp ? (u64) kp->addr : 0;
+       return kp ? (uintptr_t)kp->addr : 0;
 }

 static const struct bpf_func_proto bpf_get_func_ip_proto_kprobe = {
--
2.29.2
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