hi, Andrii reported an issue with optimized uprobes [1] that can clobber redzone area with call instruction storing return address on stack where user code may keep temporary data without adjusting rsp.
Fixing this by moving the optimized uprobes on top of 10-bytes nop instruction, so we can squeeze another instruction to escape the redzone area before doing the call. Note we need upstream update first for patch 3 (github.com/libbpf/usdt), if we decide to take this change. thanks, jirka v1: https://lore.kernel.org/bpf/[email protected]/ v2 changes: - several selftest fixes [sashiko] - consolidate is_lea_insn and is_call_insn insto single check [Jakub Sitnicki] - use proper mm_struct object in __in_uprobe_trampoline check [sashiko] - allow to copy uprobe trampolines vma objects on fork [sashiko] - change uprobe syscall detection error from -ENXIO to -EPROTO [Andrii] - added fork/clone tests - I kept the selftest changes and nop5->nop10 changes in separate commits for easier review, we can squash them later if we want to keep bisect working properly [1] https://lore.kernel.org/bpf/[email protected]/ --- Andrii Nakryiko (1): selftests/bpf: Add tests for uprobe nop10 red zone clobbering Jiri Olsa (10): uprobes/x86: Use proper mm_struct in __in_uprobe_trampoline uprobes/x86: Allow to copy uprobe trampolines on fork uprobes/x86: Move optimized uprobe from nop5 to nop10 libbpf: Change has_nop_combo to work on top of nop10 libbpf: Detect uprobe syscall with new error selftests/bpf: Emit nop,nop10 instructions combo for x86_64 arch selftests/bpf: Change uprobe syscall tests to use nop10 selftests/bpf: Change uprobe/usdt trigger bench code to use nop10 selftests/bpf: Add reattach tests for uprobe syscall selftests/bpf: Add tests for forked/cloned optimized uprobes arch/x86/kernel/uprobes.c | 144 ++++++++++++++++++++++------------ tools/lib/bpf/features.c | 4 +- tools/lib/bpf/usdt.c | 16 ++-- tools/testing/selftests/bpf/bench.c | 20 ++--- tools/testing/selftests/bpf/benchs/bench_trigger.c | 38 ++++----- tools/testing/selftests/bpf/benchs/run_bench_uprobes.sh | 2 +- tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c | 307 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------ tools/testing/selftests/bpf/prog_tests/usdt.c | 74 +++++++++++++++--- tools/testing/selftests/bpf/progs/test_usdt.c | 25 ++++++ tools/testing/selftests/bpf/usdt.h | 2 +- tools/testing/selftests/bpf/usdt_2.c | 15 +++- 11 files changed, 524 insertions(+), 123 deletions(-)
