David Vernet 8b7b0e5fe4 bpf: Load vmlinux btf for any struct_ops map ... In libbpf, when determining whether we need to load vmlinux btf, we're currently (among other things) checking whether there is any struct_ops program present in the object. This works for most realistic struct_ops maps, as a struct_ops map is of course typically composed of one or more struct_ops programs. However, that technically need not be the case. A struct_ops interface could be defined which allows a map to be specified which one or more non-prog fields, and which provides default behavior if no struct_ops progs is actually provided otherwise. For sched_ext, for example, you technically only need to specify the name of the scheduler in the struct_ops map, with the core scheduler logic providing default behavior if no prog is actually specified. If we were to define and try to load such a struct_ops map, we would crash in libbpf when initializing it as obj->btf_vmlinux will be NULL: Reading symbols from minimal... (gdb) r Starting program: minimal_example [Thread debugging using libthread_db enabled] Using host libthread_db library "/usr/lib/libthread_db.so.1". Program received signal SIGSEGV, Segmentation fault. 0x000055555558308c in btf__type_cnt (btf=0x0) at btf.c:612 612 return btf->start_id + btf->nr_types; (gdb) bt type_name=0x5555555d99e3 "sched_ext_ops", kind=4) at btf.c:914 kind=4) at btf.c:942 type=0x7fffffffe558, type_id=0x7fffffffe548, ... data_member=0x7fffffffe568) at libbpf.c:948 kern_btf=0x0) at libbpf.c:1017 at libbpf.c:8059 So as to account for such bare-bones struct_ops maps, let's update obj_needs_vmlinux_btf() to also iterate over an obj's maps and check whether any of them are struct_ops maps. Signed-off-by: David Vernet <void@manifault.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Link: https://lore.kernel.org/bpf/20231208061704.400463-1-void@manifault.com		2023-12-08 09:38:59 -08:00
..
api	tools api: Avoid potential double free	2023-10-12 10:01:57 -07:00
bpf	bpf: Load vmlinux btf for any struct_ops map	2023-12-08 09:38:59 -08:00
perf	libperf rc_check: Add RC_CHK_EQUAL	2023-10-25 13:37:22 -07:00
subcmd	libsubcmd: Avoid SEGV/use-after-free when commands aren't excluded	2023-07-11 16:44:12 -03:00
symbol	tools lib symbol: Add dependency test to install_headers	2022-12-14 11:16:12 -03:00
thermal	tools/lib/thermal: Fix include path for libnl3 in pkg-config file.	2023-02-15 17:29:40 +01:00
argv_split.c
bitmap.c	Bitmap patches for v6.0-rc1	2022-08-07 17:52:35 -07:00
ctype.c
find_bit.c	tools: sync find_bit() implementation	2022-09-21 12:21:44 -07:00
hweight.c
list_sort.c	tools lib: Adopt list_sort() from the kernel sources	2021-10-20 10:30:59 -03:00
rbtree.c
slab.c	tools: Move gfp.h and slab.h from radix-tree to lib	2022-02-20 08:44:37 +02:00
str_error_r.c
string.c
vsprintf.c
zalloc.c