On 11/3/22 4:32 PM, Jonas Rabenstein wrote:
Hi again,
after sending this out, I noticed this is only a problem in the stable
versions (starting from v6.0.3), as c09eb2e578eb1668bbc has been applied (as
03f148c159a250dd454) but not 0e253f7e558a3e250902 ("bpf: Return value in kprobe
get_func_ip only for entry address") which makes always use of get_entry_ip.
I therefore think, 0e253f7e558a3e250902 needs to be added to the stable v6.0
series as well as otherwise it can't be compiled with -Werror if
CONFIG_X6_KERNEL_IBT is set but CONFIG_FPROBE isn't.
Thanks for the info, Jonas. Added Greg wrt stable cherry-pick.
On Thu, Nov 03, 2022 at 04:03:03PM +0100, Jonas Rabenstein wrote:
Commit c09eb2e578eb1668bbc ("bpf: Adjust kprobe_multi entry_ip
for CONFIG_X86_KERNEL_IBT") introduced the get_entry_ip() function.
Depending on CONFIG_X86_KERNEL_IBT it is a static function or only
a macro definition. The only user of this symbol so far is in
kprobe_multi_link_handler() if CONFIG_FPROBE is enabled.
If CONFIG_FROBE is not set, the symbol is not used and - depending
on CONFIG_X86_KERNEL_IBT - a warning for get_entry_ip() is emitted.
To solve this, the function should be marked as __maybe_unused.
Signed-off-by: Jonas Rabenstein <rabenstein@xxxxxxxxx>
---
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 f2d8d070d024..19131aae0bc3 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1032,7 +1032,7 @@ static const struct bpf_func_proto bpf_get_func_ip_proto_tracing = {
};
#ifdef CONFIG_X86_KERNEL_IBT
-static unsigned long get_entry_ip(unsigned long fentry_ip)
+static unsigned long __maybe_unused get_entry_ip(unsigned long fentry_ip)
{
u32 instr;
--
2.37.4
