diff options
Diffstat (limited to 'kernel/bpf/log.c')
| -rw-r--r-- | kernel/bpf/log.c | 65 |
1 files changed, 55 insertions, 10 deletions
diff --git a/kernel/bpf/log.c b/kernel/bpf/log.c index 594a234f12..2a243cf37c 100644 --- a/kernel/bpf/log.c +++ b/kernel/bpf/log.c @@ -9,6 +9,7 @@ #include <linux/bpf.h> #include <linux/bpf_verifier.h> #include <linux/math64.h> +#include <linux/string.h> #define verbose(env, fmt, args...) bpf_verifier_log_write(env, fmt, ##args) @@ -333,7 +334,8 @@ find_linfo(const struct bpf_verifier_env *env, u32 insn_off) { const struct bpf_line_info *linfo; const struct bpf_prog *prog; - u32 i, nr_linfo; + u32 nr_linfo; + int l, r, m; prog = env->prog; nr_linfo = prog->aux->nr_linfo; @@ -342,11 +344,30 @@ find_linfo(const struct bpf_verifier_env *env, u32 insn_off) return NULL; linfo = prog->aux->linfo; - for (i = 1; i < nr_linfo; i++) - if (insn_off < linfo[i].insn_off) - break; + /* Loop invariant: linfo[l].insn_off <= insns_off. + * linfo[0].insn_off == 0 which always satisfies above condition. + * Binary search is searching for rightmost linfo entry that satisfies + * the above invariant, giving us the desired record that covers given + * instruction offset. + */ + l = 0; + r = nr_linfo - 1; + while (l < r) { + /* (r - l + 1) / 2 means we break a tie to the right, so if: + * l=1, r=2, linfo[l].insn_off <= insn_off, linfo[r].insn_off > insn_off, + * then m=2, we see that linfo[m].insn_off > insn_off, and so + * r becomes 1 and we exit the loop with correct l==1. + * If the tie was broken to the left, m=1 would end us up in + * an endless loop where l and m stay at 1 and r stays at 2. + */ + m = l + (r - l + 1) / 2; + if (linfo[m].insn_off <= insn_off) + l = m; + else + r = m - 1; + } - return &linfo[i - 1]; + return &linfo[l]; } static const char *ltrim(const char *s) @@ -361,13 +382,28 @@ __printf(3, 4) void verbose_linfo(struct bpf_verifier_env *env, u32 insn_off, const char *prefix_fmt, ...) { - const struct bpf_line_info *linfo; + const struct bpf_line_info *linfo, *prev_linfo; + const struct btf *btf; + const char *s, *fname; if (!bpf_verifier_log_needed(&env->log)) return; + prev_linfo = env->prev_linfo; linfo = find_linfo(env, insn_off); - if (!linfo || linfo == env->prev_linfo) + if (!linfo || linfo == prev_linfo) + return; + + /* It often happens that two separate linfo records point to the same + * source code line, but have differing column numbers. Given verifier + * log doesn't emit column information, from user perspective we just + * end up emitting the same source code line twice unnecessarily. + * So instead check that previous and current linfo record point to + * the same file (file_name_offs match) and the same line number, and + * avoid emitting duplicated source code line in such case. + */ + if (prev_linfo && linfo->file_name_off == prev_linfo->file_name_off && + BPF_LINE_INFO_LINE_NUM(linfo->line_col) == BPF_LINE_INFO_LINE_NUM(prev_linfo->line_col)) return; if (prefix_fmt) { @@ -378,9 +414,15 @@ __printf(3, 4) void verbose_linfo(struct bpf_verifier_env *env, va_end(args); } - verbose(env, "%s\n", - ltrim(btf_name_by_offset(env->prog->aux->btf, - linfo->line_off))); + btf = env->prog->aux->btf; + s = ltrim(btf_name_by_offset(btf, linfo->line_off)); + verbose(env, "%s", s); /* source code line */ + + s = btf_name_by_offset(btf, linfo->file_name_off); + /* leave only file name */ + fname = strrchr(s, '/'); + fname = fname ? fname + 1 : s; + verbose(env, " @ %s:%u\n", fname, BPF_LINE_INFO_LINE_NUM(linfo->line_col)); env->prev_linfo = linfo; } @@ -416,6 +458,7 @@ const char *reg_type_str(struct bpf_verifier_env *env, enum bpf_reg_type type) [PTR_TO_XDP_SOCK] = "xdp_sock", [PTR_TO_BTF_ID] = "ptr_", [PTR_TO_MEM] = "mem", + [PTR_TO_ARENA] = "arena", [PTR_TO_BUF] = "buf", [PTR_TO_FUNC] = "func", [PTR_TO_MAP_KEY] = "map_key", @@ -651,6 +694,8 @@ static void print_reg_state(struct bpf_verifier_env *env, } verbose(env, "%s", reg_type_str(env, t)); + if (t == PTR_TO_ARENA) + return; if (t == PTR_TO_STACK) { if (state->frameno != reg->frameno) verbose(env, "[%d]", reg->frameno); |