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| author | Alexei Starovoitov <[email protected]> | 2024-07-22 19:08:15 -0700 |
|---|---|---|
| committer | Andrii Nakryiko <[email protected]> | 2024-07-29 15:04:55 -0700 |
| commit | aa8ebb270c66cea1f56a25d0f938036e91ad085a (patch) | |
| tree | 23bd75452bddaf6d1e9083c362b8a0e74b145149 | |
| parent | 02d9fe1c4d987c4b3d272b5217da53280ffa71f5 (diff) | |
selftests/bpf: Workaround strict bpf_lsm return value check.
test_progs-no_alu32 -t libbpf_get_fd_by_id_opts
is being rejected by the verifier with the following error
due to compiler optimization:
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]
Workaround by adding barrier().
Eventually the verifier will be able to recognize it.
Fixes: 5d99e198be27 ("bpf, lsm: Add check for BPF LSM return value")
Signed-off-by: Alexei Starovoitov <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
| -rw-r--r-- | tools/testing/selftests/bpf/progs/test_libbpf_get_fd_by_id_opts.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_libbpf_get_fd_by_id_opts.c b/tools/testing/selftests/bpf/progs/test_libbpf_get_fd_by_id_opts.c index f5ac5f3e8919..568816307f71 100644 --- a/tools/testing/selftests/bpf/progs/test_libbpf_get_fd_by_id_opts.c +++ b/tools/testing/selftests/bpf/progs/test_libbpf_get_fd_by_id_opts.c @@ -31,6 +31,7 @@ int BPF_PROG(check_access, struct bpf_map *map, fmode_t fmode) if (fmode & FMODE_WRITE) return -EACCES; + barrier(); return 0; } |