[bpf-next,v2,2/2] selftests/bpf: Fix error linking uprobe_multi on mips

Commit Message

Tony Ambardar July 23, 2024, 12:13 a.m. UTC

From: Tony Ambardar <[e-mail]>

Linking uprobe_multi.c on mips64el fails due to relocation overflows, when
the GOT entries required exceeds the default maximum. Add a specific CFLAGS
(-mxgot) for uprobe_multi.c on MIPS that allows using a larger GOT and
avoids errors such as:

  /tmp/ccBTNQzv.o: in function `bench':
  uprobe_multi.c:49:(.text+0x1d7720): relocation truncated to fit: R_MIPS_GOT_DISP against `uprobe_multi_func_08188'
  uprobe_multi.c:49:(.text+0x1d7730): relocation truncated to fit: R_MIPS_GOT_DISP against `uprobe_multi_func_08189'
  ...
  collect2: error: ld returned 1 exit status

Fixes: 519dfeaf5119 ("selftests/bpf: Add uprobe_multi test program")
Signed-off-by: Tony Ambardar <[e-mail]>
---
 tools/testing/selftests/bpf/Makefile | 2 ++
 1 file changed, 2 insertions(+)

Comments

[e-mail] July 23, 2024, 12:34 a.m. UTC | #1

Dear patch submitter,

CI has tested the following submission:
Status:     SUCCESS
Name:       [bpf-next,v2,2/2] selftests/bpf: Fix error linking uprobe_multi on mips
Patchwork:  https://patchwork.kernel.org/project/netdevbpf/list/?series=873092&state=*
Matrix:     https://github.com/kernel-patches/bpf/actions/runs/10050383298

No further action is necessary on your part.


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[e-mail] July 23, 2024, 1:39 a.m. UTC | #2

Dear patch submitter,

CI has tested the following submission:
Status:     FAILURE
Name:       [bpf-next,v2,2/2] selftests/bpf: Fix error linking uprobe_multi on mips
Patchwork:  https://patchwork.kernel.org/project/netdevbpf/list/?series=873092&state=*
Matrix:     https://github.com/kernel-patches/bpf/actions/runs/10050686380

Failed jobs:
test_progs_no_alu32-aarch64-gcc: https://github.com/kernel-patches/bpf/actions/runs/10050686380/job/27779204312
test_progs_no_alu32-s390x-gcc: https://github.com/kernel-patches/bpf/actions/runs/10050686380/job/27779282003
test_progs_no_alu32-x86_64-gcc: https://github.com/kernel-patches/bpf/actions/runs/10050686380/job/27779242545
test_progs_no_alu32-x86_64-llvm-17: https://github.com/kernel-patches/bpf/actions/runs/10050686380/job/27779265515
test_progs_no_alu32-x86_64-llvm-18: https://github.com/kernel-patches/bpf/actions/runs/10050686380/job/27779280320

First test_progs failure (test_progs_no_alu32-aarch64-gcc):
#134 libbpf_get_fd_by_id_opts
libbpf: prog 'check_access': BPF program load failed: Invalid argument
libbpf: prog 'check_access': -- BEGIN PROG LOAD LOG --
0: R1=ctx() R10=fp0
; int BPF_PROG(check_access, struct bpf_map *map, fmode_t fmode) @ test_libbpf_get_fd_by_id_opts.c:27
0: (b7) r0 = 0                        ; R0_w=0
1: (79) r2 = *(u64 *)(r1 +0)
func 'bpf_lsm_bpf_map' arg0 has btf_id 2072 type STRUCT 'bpf_map'
2: R1=ctx() R2_w=trusted_ptr_bpf_map()
; if (map != (struct bpf_map *)&data_input) @ test_libbpf_get_fd_by_id_opts.c:29
2: (18) r3 = 0xffff0000c4890c00       ; R3_w=map_ptr(map=data_input,ks=4,vs=4)
4: (5d) if r2 != r3 goto pc+4         ; R2_w=trusted_ptr_bpf_map() R3_w=map_ptr(map=data_input,ks=4,vs=4)
; int BPF_PROG(check_access, struct bpf_map *map, fmode_t fmode) @ test_libbpf_get_fd_by_id_opts.c:27
5: (79) r0 = *(u64 *)(r1 +8)          ; R0_w=scalar() R1=ctx()
; if (fmode & FMODE_WRITE) @ test_libbpf_get_fd_by_id_opts.c:32
6: (67) r0 <<= 62                     ; R0_w=scalar(smax=0x4000000000000000,umax=0xc000000000000000,smin32=0,smax32=umax32=0,var_off=(0x0; 0xc000000000000000))
7: (c7) r0 s>>= 63                    ; R0_w=scalar(smin=smin32=-1,smax=smax32=0)
;  @ test_libbpf_get_fd_by_id_opts.c:0
8: (57) r0 &= -13                     ; R0_w=scalar(smax=0x7ffffffffffffff3,umax=0xfffffffffffffff3,smax32=0x7ffffff3,umax32=0xfffffff3,var_off=(0x0; 0xfffffffffffffff3))
; int BPF_PROG(check_access, struct bpf_map *map, fmode_t fmode) @ test_libbpf_get_fd_by_id_opts.c:27
9: (95) exit
At program exit the register R0 has smax=9223372036854775795 should have been in [-4095, 0]
processed 9 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0
-- END PROG LOAD LOG --
libbpf: prog 'check_access': failed to load: -22
libbpf: failed to load object 'test_libbpf_get_fd_by_id_opts'
libbpf: failed to load BPF skeleton 'test_libbpf_get_fd_by_id_opts': -22
test_libbpf_get_fd_by_id_opts:FAIL:test_libbpf_get_fd_by_id_opts__open_and_load unexpected error: -22


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[e-mail] July 23, 2024, 2:32 a.m. UTC | #3

Dear patch submitter,

CI has tested the following submission:
Status:     SUCCESS
Name:       [bpf-next,v2,2/2] selftests/bpf: Fix error linking uprobe_multi on mips
Patchwork:  https://patchwork.kernel.org/project/netdevbpf/list/?series=873092&state=*
Matrix:     https://github.com/kernel-patches/bpf/actions/runs/10051521603

No further action is necessary on your part.


Please note: this email is coming from an unmonitored mailbox. If you have
questions or feedback, please reach out to the Meta Kernel CI team at
[e-mail].

Patch

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 11fdf126cb7c..60a07605a162 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -785,6 +785,8 @@  $(OUTPUT)/veristat: $(OUTPUT)/veristat.o
 	$(call msg,BINARY,,$@)
 	$(Q)$(CC) $(CFLAGS) $(LDFLAGS) $(filter %.a %.o,$^) $(LDLIBS) -o $@
 
+# Linking uprobe_multi can fail due to relocation overflows on mips.
+$(OUTPUT)/uprobe_multi: CFLAGS += $(if $(filter mips, $(ARCH)),-mxgot)
 $(OUTPUT)/uprobe_multi: uprobe_multi.c
 	$(call msg,BINARY,,$@)
 	$(Q)$(CC) $(CFLAGS) -O0 $(LDFLAGS) $^ $(LDLIBS) -o $@