>From commit 65c93628599d ("bpftool: Add struct_ops support"),
a new type of command struct_ops has been added.
This command requires kernel CONFIG_DEBUG_INFO_BTF=y, and for retrieving
btf info, get_btf_vmlinux() is used.
When running this command on kernel without BTF debug info, this will
lead to 'btf_vmlinux' variable contains invalid(error) pointer. And by
this, btf_free() causes a segfault when executing 'bpftool struct_ops'.
This commit adds pointer validation with IS_ERR not to free invalid
pointer, and this will fix the segfault issue.
Signed-off-by: Daniel T. Lee <danieltimlee@xxxxxxxxx>
---
tools/bpf/bpftool/struct_ops.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/tools/bpf/bpftool/struct_ops.c b/tools/bpf/bpftool/struct_ops.c
index 2a7befbd11ad..0fe0d584c57e 100644
--- a/tools/bpf/bpftool/struct_ops.c
+++ b/tools/bpf/bpftool/struct_ops.c
@@ -591,6 +591,8 @@ int do_struct_ops(int argc, char **argv)
err = cmd_select(cmds, argc, argv, do_help);
- btf__free(btf_vmlinux);
+ if (!IS_ERR(btf_vmlinux))
+ btf__free(btf_vmlinux);
+
return err;
}
--
2.26.0
