Previously, I fixed a tailcall infinite loop issue caused by trampoline[0].
At this time, I fix a tailcall infinite loop issue caused by tailcall and
freplace combination by preventing updating extended prog to prog_array map
and preventing extending tail callee prog with freplace.
v2 -> v3:
* Address comments from Alexei:
* Stop hacking JIT.
* Prevent the specific use case at attach/update time.
v1 -> v2:
* Address comment from Eduard:
* Explain why nop5 and xor/nop3 are swapped at prologue.
* Address comment from Alexei:
* Disallow attaching tail_call_reachable freplace prog to
not-tail_call_reachable target in verifier.
* Update "bpf, arm64: Fix tailcall infinite loop caused by freplace" with
latest arm64 JIT code.
Links:
[0] https://lore.kernel.org/bpf/20230912150442.2009-1-hffilwlqm@xxxxxxxxx/
Leon Hwang (4):
bpf: Prevent updating extended prog to prog_array map
bpf: Prevent extending tail callee prog with freplace
selftests/bpf: Add a test case to confirm a tailcall infinite loop
issue has been prevented
selftests/bpf: Add cases to test tailcall in freplace
include/linux/bpf.h | 2 +
kernel/bpf/arraymap.c | 13 +-
kernel/bpf/syscall.c | 19 +-
.../selftests/bpf/prog_tests/tailcalls.c | 196 +++++++++++++++++-
.../tailcall_bpf2bpf_hierarchy_freplace.c | 30 +++
.../testing/selftests/bpf/progs/tc_bpf2bpf.c | 37 +++-
6 files changed, 290 insertions(+), 7 deletions(-)
create mode 100644 tools/testing/selftests/bpf/progs/tailcall_bpf2bpf_hierarchy_freplace.c
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2.44.0
