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Commit 5838e53b authored by Christopher Ferris's avatar Christopher Ferris
Browse files

Fix handling of PT_GNU_EH_FRAME. 

The bias for the PT_GNU_EH_FRAME was using the paddr instead of vaddr.
This doesn't match the way the load bias is calculated, which always
use vaddr - offset, so change to use vaddr.

Found on an old x86 device that has a vdso that sets vaddr differently
from paddr.

Add a new offline test to catch this case and update the elf interface
unit tests.

Also, fix a small bug in the unwind_for_offline tool.

Bug: 142365899

Test: Unit tests pass.
Change-Id: I5f0bf062dd8ee45aa8553189ba493ec962e0b059
parent d1a6d75d

libunwindstack/Android.bp

+1 −0
Original line number Diff line number Diff line
@@ -239,6 +239,7 @@ cc_defaults { 
        "tests/files/offline/bad_eh_frame_hdr_arm64/*",

        "tests/files/offline/debug_frame_first_x86/*",

        "tests/files/offline/debug_frame_load_bias_arm/*",

        "tests/files/offline/eh_frame_bias_x86/*",

        "tests/files/offline/eh_frame_hdr_begin_x86_64/*",

        "tests/files/offline/invalid_elf_offset_arm/*",

        "tests/files/offline/jit_debug_arm/*",

libunwindstack/ElfInterface.cpp

+1 −1
Original line number Diff line number Diff line
@@ -228,7 +228,7 @@ void ElfInterface::ReadProgramHeaders(const EhdrType& ehdr, int64_t* load_bias) 
    case PT_GNU_EH_FRAME:

      // This is really the pointer to the .eh_frame_hdr section.

      eh_frame_hdr_offset_ = phdr.p_offset;

      eh_frame_hdr_section_bias_ = static_cast<uint64_t>(phdr.p_paddr) - phdr.p_offset;

      eh_frame_hdr_section_bias_ = static_cast<uint64_t>(phdr.p_vaddr) - phdr.p_offset;

      eh_frame_hdr_size_ = phdr.p_memsz;

      break;

libunwindstack/tests/ElfInterfaceTest.cpp

+1 −1
Original line number Diff line number Diff line
@@ -1310,7 +1310,7 @@ void ElfInterfaceTest::CheckGnuEhFrame(uint64_t addr, uint64_t offset, int64_t e 


  memset(&phdr, 0, sizeof(phdr));

  phdr.p_type = PT_GNU_EH_FRAME;

  phdr.p_paddr = addr;

  phdr.p_vaddr = addr;

  phdr.p_offset = offset;

  memory_.SetMemory(phdr_offset, &phdr, sizeof(phdr));

libunwindstack/tests/UnwindOfflineTest.cpp

+46 −0
Original line number Diff line number Diff line
@@ -1583,4 +1583,50 @@ TEST_F(UnwindOfflineTest, load_bias_different_section_bias_arm64) { 
  EXPECT_EQ(0x7fdd4a4170ULL, unwinder.frames()[11].sp);

}



TEST_F(UnwindOfflineTest, eh_frame_bias_x86) {

  ASSERT_NO_FATAL_FAILURE(Init("eh_frame_bias_x86/", ARCH_X86));



  Unwinder unwinder(128, maps_.get(), regs_.get(), process_memory_);

  unwinder.Unwind();



  std::string frame_info(DumpFrames(unwinder));

  ASSERT_EQ(11U, unwinder.NumFrames()) << "Unwind:\n" << frame_info;

  EXPECT_EQ(

      "  #00 pc ffffe430  vdso.so (__kernel_vsyscall+16)\n"

      "  #01 pc 00082a4b  libc.so (__epoll_pwait+43)\n"

      "  #02 pc 000303a3  libc.so (epoll_pwait+115)\n"

      "  #03 pc 000303ed  libc.so (epoll_wait+45)\n"

      "  #04 pc 00010ea2  tombstoned (epoll_dispatch+226)\n"

      "  #05 pc 0000c5e7  tombstoned (event_base_loop+1095)\n"

      "  #06 pc 0000c193  tombstoned (event_base_dispatch+35)\n"

      "  #07 pc 00005c77  tombstoned (main+884)\n"

      "  #08 pc 00015f66  libc.so (__libc_init+102)\n"

      "  #09 pc 0000360e  tombstoned (_start+98)\n"

      "  #10 pc 00000001  <unknown>\n",

      frame_info);



  EXPECT_EQ(0xffffe430ULL, unwinder.frames()[0].pc);

  EXPECT_EQ(0xfffe1a30ULL, unwinder.frames()[0].sp);

  EXPECT_EQ(0xeb585a4bULL, unwinder.frames()[1].pc);

  EXPECT_EQ(0xfffe1a40ULL, unwinder.frames()[1].sp);

  EXPECT_EQ(0xeb5333a3ULL, unwinder.frames()[2].pc);

  EXPECT_EQ(0xfffe1a60ULL, unwinder.frames()[2].sp);

  EXPECT_EQ(0xeb5333edULL, unwinder.frames()[3].pc);

  EXPECT_EQ(0xfffe1ab0ULL, unwinder.frames()[3].sp);

  EXPECT_EQ(0xeb841ea2ULL, unwinder.frames()[4].pc);

  EXPECT_EQ(0xfffe1ae0ULL, unwinder.frames()[4].sp);

  EXPECT_EQ(0xeb83d5e7ULL, unwinder.frames()[5].pc);

  EXPECT_EQ(0xfffe1b30ULL, unwinder.frames()[5].sp);

  EXPECT_EQ(0xeb83d193ULL, unwinder.frames()[6].pc);

  EXPECT_EQ(0xfffe1bd0ULL, unwinder.frames()[6].sp);

  EXPECT_EQ(0xeb836c77ULL, unwinder.frames()[7].pc);

  EXPECT_EQ(0xfffe1c00ULL, unwinder.frames()[7].sp);

  EXPECT_EQ(0xeb518f66ULL, unwinder.frames()[8].pc);

  EXPECT_EQ(0xfffe1d00ULL, unwinder.frames()[8].sp);

  EXPECT_EQ(0xeb83460eULL, unwinder.frames()[9].pc);

  EXPECT_EQ(0xfffe1d40ULL, unwinder.frames()[9].sp);

  EXPECT_EQ(0x00000001ULL, unwinder.frames()[10].pc);

  EXPECT_EQ(0xfffe1d74ULL, unwinder.frames()[10].sp);

}



}  // namespace unwindstack

libunwindstack/tests/files/offline/eh_frame_bias_x86/libc.so

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+1.05 MiB

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