[PATCH bpf-next v2 0/2] Fix global subprog verification context

[Kumar Kartikeya Dwivedi <memxor@gmail.com>]

Global subprogs can be invoked in both sleepable and non-sleepable
contexts, but are verified based on context assumptions for the program
type as a whole and not the precise context in which they are invoked.
Nicholas identified that this can violate verifier safety assumptions.
Verify global subprogs once for each observed sleepability context and add
selftests covering workqueue and task-work callbacks.

Changelog:
----------
v1 -> v2
v1: https://lore.kernel.org/bpf/20260905034018.2095649-1-memxor@gmail.com

 * Preserve the harmless global subprog calls in the positive test with
   barrier() so LLVM cannot eliminate the intended coverage.
 * Return zero explicitly from workqueue callbacks after global subprog calls.
 * Document cumulative instruction accounting across verification contexts.
 * Fix BPF multi-line comment formatting.

Kumar Kartikeya Dwivedi (2):
  bpf: Verify global subprogs in each sleepability context
  selftests/bpf: Test global subprog callback contexts

 include/linux/bpf.h                           |   5 +-
 kernel/bpf/verifier.c                         |  77 ++++++----
 .../bpf/progs/verifier_async_cb_context.c     | 132 ++++++++++++++++++
 3 files changed, 182 insertions(+), 32 deletions(-)


base-commit: 3ccdb07813829ba9487273e75d1cb238cfa774c1
-- 
2.53.0