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 [1] https://lore.kernel.org/bpf/[email protected]/ --- Andrii Nakryiko (1): selftests/bpf: Add tests for uprobe nop10 red zone clobbering Jiri Olsa (6): uprobes/x86: Move optimized uprobe from nop5 to nop10 libbpf: Change has_nop_combo to work on top of nop10 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 arch/x86/kernel/uprobes.c | 121 ++++++++++++++++++++++++++++------------ 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 | 217 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-------- 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 ++++- 10 files changed, 423 insertions(+), 107 deletions(-)
