Re: [PATCH bpf-next v10 0/7] Generalizing bpf_local_storage

From: Alexei Starovoitov
Date: Tue Aug 25 2020 - 17:06:13 EST


On Tue, Aug 25, 2020 at 11:29 AM KP Singh <kpsingh@xxxxxxxxxxxx> wrote:
>
> From: KP Singh <kpsingh@xxxxxxxxxx>
>
> # v9 -> v10
>
> - Added NULL check for inode_storage_ptr before calling
> bpf_local_storage_update
> - Removed an extraneous include
> - Rebased and added Acks / Signoff.

Hmm. Though it looks good I cannot apply it, because
test_progs -t map_ptr
is broken:
2225: (18) r2 = 0xffffc900004e5004
2227: (b4) w1 = 58
2228: (63) *(u32 *)(r2 +0) = r1
R0=map_value(id=0,off=0,ks=4,vs=4,imm=0) R1_w=inv58
R2_w=map_value(id=0,off=4,ks=4,vs=8,imm=0) R3=inv49 R4=inv63
R5=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R6_w=inv0
R7=invP8 R8=map_ptr(id=0,off=0,ks=4,vs=4,imm=0) R10=?
; VERIFY_TYPE(BPF_MAP_TYPE_SK_STORAGE, check_sk_storage);
2229: (18) r1 = 0xffffc900004e5000
2231: (b4) w3 = 24
2232: (63) *(u32 *)(r1 +0) = r3
R0=map_value(id=0,off=0,ks=4,vs=4,imm=0)
R1_w=map_value(id=0,off=0,ks=4,vs=8,imm=0)
R2_w=map_value(id=0,off=4,ks=4,vs=8,imm=0) R3_w=inv24 R4=inv63
R5=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R6_w=inv0
R7=invP8 R8=map_pt?
2233: (18) r3 = 0xffff8881f03f7000
; VERIFY(indirect->map_type == direct->map_type);
2235: (85) call unknown#195896080
invalid func unknown#195896080
processed 4678 insns (limit 1000000) max_states_per_insn 9
total_states 240 peak_states 178 mark_read 11

libbpf: -- END LOG --
libbpf: failed to load program 'cgroup_skb/egress'
libbpf: failed to load object 'map_ptr_kern'
libbpf: failed to load BPF skeleton 'map_ptr_kern': -4007
test_map_ptr:FAIL:skel_open_load open_load failed
#43 map_ptr:FAIL

Above 'invalid func unknown#195896080' happens
when libbpf fails to do a relocation at runtime.
Please debug.
It's certainly caused by this set, but not sure why.