Merge branch 'bpf-consolidate-pointer-offset-tracking-in-var_off'

Eduard Zingerman says:

====================
bpf: consolidate pointer offset tracking in var_off

Consolidate static and varying pointer offset tracking logic in the
BPF verifier. All pointer offsets are now represented solely using
`reg->var_off` and min/max fields, simplifying pointer tracking code
and making it easier to widen pointer registers for loop convergence
checks.

Patch 1 is a preparatory refactoring of check_reg_sane_offset().
Patch 2 is the main change, moving pointer offsets from `reg->off`
  to `reg->var_off`.
Patch 3 removes references to `reg->off` in netronome code.
Patch 4 renames the now-repurposed `reg->off` field to `reg->delta`,
  reflecting its remaining role as a constant delta between linked
  scalar registers.

Note: netronome changes are compile-tested only!

Changelog:
v1 -> v2:
- put back WARN_ON_ONCE in mark_ptr_or_null_reg() (Alexei).
- references to `ptr->off` field are removed from netronome code
  (bot+bpf-ci, kernel test robot).
- fix for a comment referencing `ptr->off` in bpf_verifier.h
  (bot+bpf-ci).

v1: https://lore.kernel.org/bpf/20260211-ptrs-off-migration-v1-0-996c2a37b063@gmail.com/
---
====================

Link: https://patch.msgid.link/20260212-ptrs-off-migration-v2-0-00820e4d3438@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 4 insertions, 5 deletions

diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index ef8e45a362d9..c1e30096ea7b 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -38,10 +38,9 @@ struct bpf_reg_state {
 	/* Ordering of fields matters.  See states_equal() */
 	enum bpf_reg_type type;
 	/*
-	 * Fixed part of pointer offset, pointer types only.
-	 * Or constant delta between "linked" scalars with the same ID.
+	 * Constant delta between "linked" scalars with the same ID.
 	 */
-	s32 off;
+	s32 delta;
 	union {
 		/* valid when type == PTR_TO_PACKET */
 		int range;
@@ -146,9 +145,9 @@ struct bpf_reg_state {
 	 * Upper bit of ID is used to remember relationship between "linked"
 	 * registers. Example:
 	 * r1 = r2;    both will have r1->id == r2->id == N
-	 * r1 += 10;   r1->id == N | BPF_ADD_CONST and r1->off == 10
+	 * r1 += 10;   r1->id == N | BPF_ADD_CONST and r1->delta == 10
 	 * r3 = r2;    both will have r3->id == r2->id == N
-	 * w3 += 10;   r3->id == N | BPF_ADD_CONST32 and r3->off == 10
+	 * w3 += 10;   r3->id == N | BPF_ADD_CONST32 and r3->delta == 10
 	 */
 #define BPF_ADD_CONST64 (1U << 31)
 #define BPF_ADD_CONST32 (1U << 30)