Messages in this thread | | | Subject | Re: [PATCH] bpf: mark get_entry_ip as __maybe_unused | From | Daniel Borkmann <> | Date | Sat, 5 Nov 2022 00:03:28 +0100 |
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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@cs.fau.de> >> --- >> 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 >>
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