selftests/bpf: Add arena fault test for load-acquire

Add stream_arena_load_acquire_fault, which performs a load-acquire from an
unmapped arena address, next to the existing read and write fault tests.

The test covers both halves of the JIT bug that treated a load-acquire as
a store when populating its exception table entry:

  - the fault has to be reported as a READ, and at the address held by
    the source register, which __stderr() and test_address() check, and
  - the destination register has to be cleared by the fault handler,
    which the program checks by poisoning it before the load-acquire
    and returning it, so __retval(0) fails if it is left untouched

Note, load-acquire is open coded since linux/filter.h cannot be included
alongside vmlinux.h.

  # LDLIBS=-static PKG_CONFIG='pkg-config --static' ./vmtest.sh -- ./test_progs -t stream_arena_fault_address
  [...]
  #462/1   stream_arena_fault_address/read_fault:OK
  #462/2   stream_arena_fault_address/write_fault:OK
  #462/3   stream_arena_fault_address/load_acquire_fault:OK
  #462     stream_arena_fault_address:OK
  Summary: 1/3 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260806201047.333389-5-daniel@iogearbox.net
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

0 files changed, 0 insertions, 0 deletions