On Mon, Dec 30, 2024 at 10:02 AM Jiri Olsa <olsajiri@xxxxxxxxx> wrote: > > On Mon, Dec 30, 2024 at 05:18:31PM +0000, Andrei Enache wrote: > > This patch enables use of non-executable memfds for bpf maps. [1] > > As this is a recent kernel feature, the code checks at runtime to make sure it is available. > > --- > > Changes in v3: > > - Check return value before checking errno > > - Update newline style > > - Link to v2: https://lore.kernel.org/bpf/Z3LHcCgqY7kHs08S@krava/T/ > > > > [1] https://lwn.net/Articles/918106/ > > > > Signed-off-by: Andrei Enache <andreien@xxxxxxxxx> > > --- > > tools/lib/bpf/libbpf.c | 13 ++++++++++++- > > 1 file changed, 12 insertions(+), 1 deletion(-) > > > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > > index 66173ddb5..3a30c094d 100644 > > --- a/tools/lib/bpf/libbpf.c > > +++ b/tools/lib/bpf/libbpf.c > > @@ -1732,11 +1732,22 @@ static int sys_memfd_create(const char *name, unsigned flags) > > #define MFD_CLOEXEC 0x0001U > > #endif > > > > +#ifndef MFD_NOEXEC_SEAL > > +#define MFD_NOEXEC_SEAL 0x0008U > > +#endif > > + > > static int create_placeholder_fd(void) > > { > > int fd; > > + int memfd; > > + > > + memfd = sys_memfd_create("libbpf-placeholder-fd", MFD_CLOEXEC); > > + > > + /* MFD_NOEXEC_SEAL is missing from older kernels */ > > + if (memfd < 0 && errno == EINVAL) > > + memfd = sys_memfd_create("libbpf-placeholder-fd", MFD_CLOEXEC | MFD_NOEXEC_SEAL); > > hum, you need to try 'MFD_CLOEXEC | MFD_NOEXEC_SEAL' first, right? > > jirka I think Daniel's fix is further along while this one is still buggy.
