Author: Wu Yingcong Date: 2025-09-01T09:15:52+08:00 New Revision: e57f0e928d7b92f536a646d8ba1c26916b09e67e
URL: https://github.com/llvm/llvm-project/commit/e57f0e928d7b92f536a646d8ba1c26916b09e67e DIFF: https://github.com/llvm/llvm-project/commit/e57f0e928d7b92f536a646d8ba1c26916b09e67e.diff LOG: [libunwind] fix pc range condition check bug (#154902) There is an off-by-one error with current condition check for PC fallen into the range or not. There is another check within libunwind that use the correct checks in https://github.com/llvm/llvm-project/blob/5050da7ba18fc876f80fbeaaca3564d3b4483bb8/libunwind/src/UnwindCursor.hpp#L2757 ``` if ((fdeInfo.pcStart <= pc) && (pc < fdeInfo.pcEnd)) ``` Added: libunwind/test/eh_frame_fde_pc_range.pass.cpp Modified: libunwind/src/DwarfParser.hpp Removed: ################################################################################ diff --git a/libunwind/src/DwarfParser.hpp b/libunwind/src/DwarfParser.hpp index 7e85025dd054d..25250e0810987 100644 --- a/libunwind/src/DwarfParser.hpp +++ b/libunwind/src/DwarfParser.hpp @@ -273,7 +273,7 @@ bool CFI_Parser<A>::findFDE(A &addressSpace, pint_t pc, pint_t ehSectionStart, pint_t pcRange = addressSpace.getEncodedP( p, nextCFI, cieInfo->pointerEncoding & 0x0F); // Test if pc is within the function this FDE covers. - if ((pcStart < pc) && (pc <= pcStart + pcRange)) { + if ((pcStart <= pc) && (pc < pcStart + pcRange)) { // parse rest of info fdeInfo->lsda = 0; // check for augmentation length diff --git a/libunwind/test/eh_frame_fde_pc_range.pass.cpp b/libunwind/test/eh_frame_fde_pc_range.pass.cpp new file mode 100644 index 0000000000000..d8bcb3939913c --- /dev/null +++ b/libunwind/test/eh_frame_fde_pc_range.pass.cpp @@ -0,0 +1,58 @@ +// -*- C++ -*- +//===----------------------------------------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +// Manually marking the .eh_frame_hdr as DW_EH_PE_omit to make libunwind to do +// the linear search. +// Assuming the begining of the function is at the start of the FDE range. + +// clang-format off + +// REQUIRES: linux + +// TODO: Figure out why this fails with Memory Sanitizer. +// XFAIL: msan + +// RUN: %{build} +// RUN: objcopy --dump-section .eh_frame_hdr=%t_ehf_hdr.bin %t.exe +// RUN: echo -ne '\xFF' | dd of=%t_ehf_hdr.bin bs=1 seek=2 count=2 conv=notrunc status=none +// RUN: objcopy --update-section .eh_frame_hdr=%t_ehf_hdr.bin %t.exe +// RUN: %{exec} %t.exe + +// clang-format on + +#include <assert.h> +#include <libunwind.h> +#include <stdint.h> +#include <stdio.h> +#include <unwind.h> + +void f() { + printf("123\n"); + void *pc = __builtin_return_address(0); + void *fpc = (void *)&f; + void *fpc1 = (void *)((uintptr_t)fpc + 1); + + struct dwarf_eh_bases bases; + const void *fde_pc = _Unwind_Find_FDE(pc, &bases); + const void *fde_fpc = _Unwind_Find_FDE(fpc, &bases); + const void *fde_fpc1 = _Unwind_Find_FDE(fpc1, &bases); + printf("fde_pc = %p\n", fde_pc); + printf("fde_fpc = %p\n", fde_fpc); + printf("fde_fpc1 = %p\n", fde_fpc1); + fflush(stdout); + assert(fde_pc != NULL); + assert(fde_fpc != NULL); + assert(fde_fpc1 != NULL); + assert(fde_fpc == fde_fpc1); +} + +int main() { + f(); + return 0; +} _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
