On Mon, Apr 17, 2023 at 04:44:49PM +0800, songrui.771 wrote: > The introduced header file linux/version.h in libbpf_probes.c may have a > wrong macro KERNEL_VERSION for calculating LINUX_VERSION_CODE in some old > kernel (Debian9, 10). Below is a version info example from Debian 10. > > release: 4.19.0-22-amd64 > version: #1 SMP Debian 4.19.260-1 (2022-09-29) > > The macro KERNEL_VERSION is defined to (((a) << 16) + ((b) << 8)) + (c)), > which a, b, and c stand for major, minor and patch version. So in example here, > the major is 4, minor is 19, patch is 260, the LINUX_VERSION(4, 19, 260) which > is 267268 should be matched to LINUX_VERSION_CODE. However, the KERNEL_VERSION_CODE > in linux/version.h is defined to 267263. > > I noticed that the macro KERNEL_VERSION in linux/version.h of some new kernel is > defined to (((a) << 16) + ((b) << 8) + ((c) > 255 ? 255 : (c))). And > KERNEL_VERSION(4, 19, 260) is equal to 267263 which is the right LINUX_VERSION_CODE. > > The mismatched LINUX_VERSION_CODE which will cause failing to load kprobe BPF > programs in the version check of BPF syscall. > > The return value of get_kernel_version in libbpf_probes.c should be matched to > LINUX_VERSION_CODE by correcting the macro KERNEL_VERSION. > > Signed-off-by: songrui.771 <songrui.771@xxxxxxxxxxxxx> This needs to be your name, not your email alias (do you use ".771" as a name to sign things with?) > --- > tools/lib/bpf/libbpf_probes.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c > index 4f3bc968ff8e..5b22a880c7e7 100644 > --- a/tools/lib/bpf/libbpf_probes.c > +++ b/tools/lib/bpf/libbpf_probes.c > @@ -18,6 +18,10 @@ > #include "libbpf.h" > #include "libbpf_internal.h" > > +#ifndef LIBBPF_KERNEL_VERSION > +#define LIBBPF_KERNEL_VERSION(a, b, c) (((a) << 16) + ((b) << 8) + ((c) > 255 ? 255 : (c))) > +#endif What is wrong with using the KERNEL_VERSION() macro, it should be fixed to work properly here, right? Did we not get this resolved in the main portion of the kernel already? thanks, greg k-h
