github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-11-06 21:58:01 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

bpf: Print 32-bit SCEV bounds as 32-bit numbers

Browse Source 
- Print large 32-bit bounds without sign extension.
- Omit 32-bit bounds when they coincide with 64-bit bounds.

Before:
  loop header at ..., widening r0 to 0x80000000..0xffffffff (s32 0xffffffff80000000..-1) step 1
  loop header at ..., widening r0 to 0..3 (s32 0..3) step 1

After:
  loop header at ..., widening r0 to 0x80000000..0xffffffff (s32 0x80000000..-1) step 1
  loop header at ..., widening r0 to 0..3 step 1

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://patch.msgid.link/20261026-scev-simpler-clamp-v2-6-f373aec9825f@gmail.com
This commit is contained in:
Eduard Zingerman 2026-10-26 16:38:26 -07:00 committed by Alexei Starovoitov
parent abc9a76a88
commit 899cbaae6e
No known key found for this signature in database
4 changed files with 15 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/linux/bpf_verifier.h
View File

@ -1280,6 +1280,7 @@ __printf(3, 4) void verbose_linfo(struct bpf_verifier_env *env,
u32 insn_off,
const char *prefix_fmt, ...);
void bpf_verbose_snum(struct bpf_verifier_env *env, s64 num);
void bpf_verbose_snum32(struct bpf_verifier_env *env, s32 num);
#define verifier_bug_if(cond, env, fmt, args...) \
({ \

8
kernel/bpf/log.c
View File

@ -535,6 +535,14 @@ void bpf_verbose_snum(struct bpf_verifier_env *env, s64 num)
verbose(env, "%#llx", num);
}
void bpf_verbose_snum32(struct bpf_verifier_env *env, s32 num)
{
if (is_snum_decimal(num))
verbose(env, "%d", num);
else
verbose(env, "%#x", (u32)num);
}
int tnum_strn(char *str, size_t size, struct tnum a)
{
/* print as a constant, if tnum is fully known */

8
kernel/bpf/scev.c
View File

@ -2456,11 +2456,13 @@ static void log_bounds(struct bpf_verifier_env *env, const struct bounds *bounds
bpf_verbose_snum(env, cnum64_smin(bounds->r64));
bpf_log(log, "..");
bpf_verbose_snum(env, cnum64_smax(bounds->r64));
if (bounds->r32.size < U32_MAX) {
if (bounds->r32.size < U32_MAX &&
(cnum32_smin(bounds->r32) != cnum64_smin(bounds->r64) ||
cnum32_smax(bounds->r32) != cnum64_smax(bounds->r64))) {
bpf_log(log, " (s32 ");
bpf_verbose_snum(env, cnum32_smin(bounds->r32));
bpf_verbose_snum32(env, cnum32_smin(bounds->r32));
bpf_log(log, "..");
bpf_verbose_snum(env, cnum32_smax(bounds->r32));
bpf_verbose_snum32(env, cnum32_smax(bounds->r32));
bpf_log(log, ")");
}
bpf_log(log, " step %u", bounds->step);

2
tools/testing/selftests/bpf/progs/verifier_scev.c
View File

@ -1771,7 +1771,7 @@ __success
__log_level(2)
__flag(BPF_F_TEST_STATE_FREQ)
__msg("loop header at 1, header_count is 4")
__msg("loop header at 1, widening r0 to 0..3 (s32 0..3) step 1")
__msg("loop header at 1, widening r0 to 0..3 step 1")
__msg("loop header at 1, clamping r0")
__msg("4: R0=3")
__naked void pre_cond_je32(void)