Merge branch 'bpf-fixes-and-follow-ups-for-32-64-bit-scalar-evolution'

Eduard Zingerman says:

====================
bpf: fixes and follow-ups for 32-/64-bit scalar evolution

Fixes:
- bpf: avoid false infinite loop reports after changes in SCEV clamping
- bpf: do not intersect with current register range on clamp
- bpf: reject pointer operands for 32-bit recurrences/latches

Follow-ups:
- bpf: (zext32 (zext32 X)) -> (zext32 X) SCEV simplification rule
- bpf: check the iteration count before the predicted exit value

Note: this supersedes [1].

[1] bpf: reject pointer operands for 32-bit recurrences/latches
    https://lore.kernel.org/bpf/a7b9422e00b9a3f5438e996f01e97bef476040e0.camel@gmail.com/

There are some veristat improvements after clamping changes and new
zext32 simplification rule.

A: master; B: scev-simpler-clamp. Corpora: cilium, meta, scx, selftests.
Object exclusions: verifier_scev.bpf.o.
Histogram: selected programs, without the table filters.

Total progs: 8071
 -85 .. -75  %: 1
 -35 .. -25  %: 3
 -25 .. -20  %: 18
 -20 .. -10  %: 5
 -10 .. 0    %: 13
   0 .. 5    %: 8031

Tables: success in both runs; baseline Insns >= 5,000.
Ranked by percentage change, then instruction-count change, file, program.
Meta names are anonymized; numbered objects are distinct files.

Top wins
--------

File                       Program                            Insns (A)  Insns (B)      Insns (DIFF)
-------------------------  ---------------------------------  ---------  ---------  ----------------
profiler-06.bpf.o          on_perf_event                          94751      64595  -30156 (-31.83%)
profiler-19.bpf.o          sched_switch_offcpu                    21906      15726   -6180 (-28.21%)
profiler-12.bpf.o          sched_switch                           12105       9015   -3090 (-25.53%)
profiler-26.bpf.o          handle_cu_mem_address_reserve          12702       9738   -2964 (-23.33%)
profiler-26.bpf.o          handle_cu_mem_create                   12702       9738   -2964 (-23.33%)
profiler-26.bpf.o          handle_malloc                          12702       9738   -2964 (-23.33%)
profiler-26.bpf.o          handle_cu_mem_map                      12900       9936   -2964 (-22.98%)
profiler-09.bpf.o          on_custom_event_start                  12951       9987   -2964 (-22.89%)
profiler-09.bpf.o          trace_func_entry                       12951       9987   -2964 (-22.89%)
profiler-19.bpf.o          sched_waking                            6642       5160   -1482 (-22.31%)
profiler-27.bpf.o          handle_cuda_launch_exc                  6665       5183   -1482 (-22.24%)
profiler-27.bpf.o          handle_cuda_launch                      6678       5196   -1482 (-22.19%)
profiler-12.bpf.o          on_custom_event_begin                   6885       5403   -1482 (-21.53%)
profiler-12.bpf.o          on_custom_event_end                     6889       5407   -1482 (-21.51%)
profiler-26.bpf.o          handle_mtia_cached_alloc               13870      10906   -2964 (-21.37%)
profiler-26.bpf.o          handle_mtia_allocate_enter             13931      10967   -2964 (-21.28%)
profiler-26.bpf.o          handle_pytorch_malloc                  14223      11259   -2964 (-20.84%)
profiler-19.bpf.o          oncpu                                   7178       5696   -1482 (-20.65%)
profiler-12.bpf.o          on_task_enqueued                        7223       5741   -1482 (-20.52%)
profiler-12.bpf.o          sched_waking                            7258       5776   -1482 (-20.42%)
profiler-12.bpf.o          on_task_dequeued                        7398       5916   -1482 (-20.03%)
profiler-12.bpf.o          on_request_context_event                7489       6007   -1482 (-19.79%)
profiler-12.bpf.o          on_pytorch_event                        7490       6008   -1482 (-19.79%)
profiler-12.bpf.o          on_task_stats                           7572       6090   -1482 (-19.57%)
profiler-12.bpf.o          oncpu                                   7676       6194   -1482 (-19.31%)
profiler-12.bpf.o          get_crochet_walltime_stacks            22063      18973   -3090 (-14.01%)
profiler-24.bpf.o          get_task_stacks                        64928      61154    -3774 (-5.81%)

Changelog:
v1 -> v2:
- changed series target to bpf.
- change in the bpf_is_state_visited() to avoid infinite loop
  detection interference for terminating loops.

v1: https://lore.kernel.org/bpf/dc27fabc3f3c7d862c3f2ae583a3650a4d48804d.camel@gmail.com/T/47e07d3ab05
---
====================

Link: https://patch.msgid.link/20261026-scev-simpler-clamp-v2-0-f373aec9825f@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 5926f13ff43c..e51984cb3035 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -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...)						\
 	({											\