perf bpf_skel augmented_raw_syscalls: Cap the socklen parameter using &= sizeof(saddr) ...
This works with:
$ clang -v
clang version 14.0.5 (Fedora 14.0.5-2.fc36)
$
But not with:
$ clang -v
clang version 16.0.6 (Fedora 16.0.6-2.fc38)
$
[root@quaco ~]# perf trace -e connect*,sendto* ping -c 10 localhost
libbpf: prog 'sys_enter_sendto': BPF program load failed: Permission denied
libbpf: prog 'sys_enter_sendto': -- BEGIN PROG LOAD LOG --
reg type unsupported for arg#0 function sys_enter_sendto#59
0: R1=ctx(off=0,imm=0) R10=fp0
; int sys_enter_sendto(struct syscall_enter_args *args)
0: (bf) r6 = r1 ; R1=ctx(off=0,imm=0) R6_w=ctx(off=0,imm=0)
1: (b7) r1 = 0 ; R1_w=0
; int key = 0;
2: (63) *(u32 *)(r10 -4) = r1 ; R1_w=0 R10=fp0 fp-8=0000????
3: (bf) r2 = r10 ; R2_w=fp0 R10=fp0
;
4: (07) r2 += -4 ; R2_w=fp-4
; return bpf_map_lookup_elem(&augmented_args_tmp, &key);
5: (18) r1 = 0xffff8de5a5b8bc00 ; R1_w=map_ptr(off=0,ks=4,vs=8272,imm=0)
7: (85) call bpf_map_lookup_elem#1 ; R0_w=map_value_or_null(id=1,off=0,ks=4,vs=8272,imm=0)
8: (bf) r7 = r0 ; R0_w=map_value_or_null(id=1,off=0,ks=4,vs=8272,imm=0) R7_w=map_value_or_null(id=1,off=0,ks=4,vs=8272,imm=0)
9: (b7) r0 = 1 ; R0_w=1
; if (augmented_args == NULL)
10: (15) if r7 == 0x0 goto pc+25 ; R7_w=map_value(off=0,ks=4,vs=8272,imm=0)
; unsigned int socklen = args->args[5];
11: (79) r1 = *(u64 *)(r6 +56) ; R1_w=scalar() R6_w=ctx(off=0,imm=0)
;
12: (bf) r2 = r1 ; R1_w=scalar(id=2) R2_w=scalar(id=2)
13: (67) r2 <<= 32 ; R2_w=scalar(smax=9223372032559808512,umax=18446744069414584320,var_off=(0x0; 0xffffffff00000000),s32_min=0,s32_max=0,u32_max=0)
14: (77) r2 >>= 32 ; R2_w=scalar(umax=4294967295,var_off=(0x0; 0xffffffff))
15: (b7) r8 = 128 ; R8=128
; if (socklen > sizeof(augmented_args->saddr))
16: (25) if r2 > 0x80 goto pc+1 ; R2=scalar(umax=128,var_off=(0x0; 0xff))
17: (bf) r8 = r1 ; R1=scalar(id=2) R8_w=scalar(id=2)
; const void *sockaddr_arg = (const void *)args->args[4];
18: (79) r3 = *(u64 *)(r6 +48) ; R3_w=scalar() R6=ctx(off=0,imm=0)
; bpf_probe_read(&augmented_args->saddr, socklen, sockaddr_arg);
19: (bf) r1 = r7 ; R1_w=map_value(off=0,ks=4,vs=8272,imm=0) R7=map_value(off=0,ks=4,vs=8272,imm=0)
20: (07) r1 += 64 ; R1_w=map_value(off=64,ks=4,vs=8272,imm=0)
; bpf_probe_read(&augmented_args->saddr, socklen, sockaddr_arg);
21: (bf) r2 = r8 ; R2_w=scalar(id=2) R8_w=scalar(id=2)
22: (85) call bpf_probe_read#4
R2 min value is negative, either use unsigned or 'var &= const'
processed 22 insns (limit 1000000) max_states_per_insn 0 total_states 1 peak_states 1 mark_read 1
-- END PROG LOAD LOG --
libbpf: prog 'sys_enter_sendto': failed to load: -13
libbpf: failed to load object 'augmented_raw_syscalls_bpf'
libbpf: failed to load BPF skeleton 'augmented_raw_syscalls_bpf': -13
So use the suggested &= variant since sizeof(saddr) == 128 bytes.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
1836480429