Adjust conditions for dumping the memory around a register.
Previously, we would do a simple bounds check before deciding
whether to dump the memory around a register. On 64-bit platforms,
the register's value was required to be less than (4 << 60). However,
after stripping tags on AArch64 as part of r.android.com/1365229, all
pointer values became less than (4 << 60), so the check became useless
for filtering out invalid pointers. As a result, we would attempt to
dump memory for all registers, which for a register not containing
a valid pointer would typically consist of 16 lines of dashes.
One possible fix may be to replace the constant (4 << 60) with the
process's actual address space limit (known as TASK_SIZE inside the
kernel; typically 39 bits on AArch64 and 48 bits on x86_64), but the
kernel provides no API for retrieving a process's TASK_SIZE value. We
could guess it by looking at for example the highest bit set in the
value of getauxval(AT_EXECFN), which points to an address on the stack
which typically is mapped at the end of the address space on program
startup, but at least on AArch64 it is possible to dynamically extend
TASK_SIZE at runtime by providing a hint to mmap(), so this is not
always sufficient.
Instead, it seems best to remove most of the early bounds check, and
simply issue ptrace() calls for each register value, bailing out of
the entire output if none of the calls ended up succeeding. This also
has the nice side effect of avoiding 16 lines of noise per register
whose value looks like a pointer but actually points to unmapped
memory. We still retain part of the bounds check in order to avoid
integer overflow during the dump (including overflows into the tag
part of the address on architectures that support tagging).
Bug: 154272452
Change-Id: I94e4b7124b7735b92fd83a49c80ebded3483cd4e
diff --git a/debuggerd/libdebuggerd/test/dump_memory_test.cpp b/debuggerd/libdebuggerd/test/dump_memory_test.cpp
index be39582..254be38 100644
--- a/debuggerd/libdebuggerd/test/dump_memory_test.cpp
+++ b/debuggerd/libdebuggerd/test/dump_memory_test.cpp
@@ -112,7 +112,10 @@
if (last_read_addr_ > 0) {
offset = addr - last_read_addr_;
}
- size_t bytes_available = buffer_.size() - offset;
+ size_t bytes_available = 0;
+ if (offset < buffer_.size()) {
+ bytes_available = buffer_.size() - offset;
+ }
if (partial_read_) {
bytes = std::min(bytes, bytes_partial_read_);
@@ -258,44 +261,7 @@
std::string tombstone_contents;
ASSERT_TRUE(lseek(log_.tfd, 0, SEEK_SET) == 0);
ASSERT_TRUE(android::base::ReadFdToString(log_.tfd, &tombstone_contents));
- const char* expected_dump = \
-"\nmemory near pc:\n"
-#if defined(__LP64__)
-" 00000000a2345658 ---------------- ---------------- ................\n"
-" 00000000a2345668 ---------------- ---------------- ................\n"
-" 00000000a2345678 ---------------- ---------------- ................\n"
-" 00000000a2345688 ---------------- ---------------- ................\n"
-" 00000000a2345698 ---------------- ---------------- ................\n"
-" 00000000a23456a8 ---------------- ---------------- ................\n"
-" 00000000a23456b8 ---------------- ---------------- ................\n"
-" 00000000a23456c8 ---------------- ---------------- ................\n"
-" 00000000a23456d8 ---------------- ---------------- ................\n"
-" 00000000a23456e8 ---------------- ---------------- ................\n"
-" 00000000a23456f8 ---------------- ---------------- ................\n"
-" 00000000a2345708 ---------------- ---------------- ................\n"
-" 00000000a2345718 ---------------- ---------------- ................\n"
-" 00000000a2345728 ---------------- ---------------- ................\n"
-" 00000000a2345738 ---------------- ---------------- ................\n"
-" 00000000a2345748 ---------------- ---------------- ................\n";
-#else
-" a2345658 -------- -------- -------- -------- ................\n"
-" a2345668 -------- -------- -------- -------- ................\n"
-" a2345678 -------- -------- -------- -------- ................\n"
-" a2345688 -------- -------- -------- -------- ................\n"
-" a2345698 -------- -------- -------- -------- ................\n"
-" a23456a8 -------- -------- -------- -------- ................\n"
-" a23456b8 -------- -------- -------- -------- ................\n"
-" a23456c8 -------- -------- -------- -------- ................\n"
-" a23456d8 -------- -------- -------- -------- ................\n"
-" a23456e8 -------- -------- -------- -------- ................\n"
-" a23456f8 -------- -------- -------- -------- ................\n"
-" a2345708 -------- -------- -------- -------- ................\n"
-" a2345718 -------- -------- -------- -------- ................\n"
-" a2345728 -------- -------- -------- -------- ................\n"
-" a2345738 -------- -------- -------- -------- ................\n"
-" a2345748 -------- -------- -------- -------- ................\n";
-#endif
- ASSERT_STREQ(expected_dump, tombstone_contents.c_str());
+ ASSERT_STREQ("", tombstone_contents.c_str());
// Verify that the log buf is empty, and no error messages.
ASSERT_STREQ("", getFakeLogBuf().c_str());
@@ -429,57 +395,17 @@
ASSERT_STREQ("", getFakeLogPrint().c_str());
}
-TEST_F(DumpMemoryTest, memory_address_too_low) {
- uint8_t buffer[256];
- memset(buffer, 0, sizeof(buffer));
- memory_mock_->SetReadData(buffer, sizeof(buffer));
-
- dump_memory(&log_, memory_mock_.get(), 0, "memory near r1");
-
- std::string tombstone_contents;
- ASSERT_TRUE(lseek(log_.tfd, 0, SEEK_SET) == 0);
- ASSERT_TRUE(android::base::ReadFdToString(log_.tfd, &tombstone_contents));
- ASSERT_STREQ("", tombstone_contents.c_str());
-
- // Verify that the log buf is empty, and no error messages.
- ASSERT_STREQ("", getFakeLogBuf().c_str());
- ASSERT_STREQ("", getFakeLogPrint().c_str());
-}
-
TEST_F(DumpMemoryTest, memory_address_too_high) {
uint8_t buffer[256];
memset(buffer, 0, sizeof(buffer));
memory_mock_->SetReadData(buffer, sizeof(buffer));
#if defined(__LP64__)
- dump_memory(&log_, memory_mock_.get(), 0x4000000000000000UL, "memory near r1");
- dump_memory(&log_, memory_mock_.get(), 0x4000000000000000UL - 32, "memory near r1");
- dump_memory(&log_, memory_mock_.get(), 0x4000000000000000UL - 216, "memory near r1");
+ dump_memory(&log_, memory_mock_.get(), -32, "memory near r1");
+ dump_memory(&log_, memory_mock_.get(), -208, "memory near r1");
#else
- dump_memory(&log_, memory_mock_.get(), 0xffff0000, "memory near r1");
- dump_memory(&log_, memory_mock_.get(), 0xffff0000 - 32, "memory near r1");
- dump_memory(&log_, memory_mock_.get(), 0xffff0000 - 220, "memory near r1");
-#endif
-
- std::string tombstone_contents;
- ASSERT_TRUE(lseek(log_.tfd, 0, SEEK_SET) == 0);
- ASSERT_TRUE(android::base::ReadFdToString(log_.tfd, &tombstone_contents));
- ASSERT_STREQ("", tombstone_contents.c_str());
-
- // Verify that the log buf is empty, and no error messages.
- ASSERT_STREQ("", getFakeLogBuf().c_str());
- ASSERT_STREQ("", getFakeLogPrint().c_str());
-}
-
-TEST_F(DumpMemoryTest, memory_address_would_overflow) {
- uint8_t buffer[256];
- memset(buffer, 0, sizeof(buffer));
- memory_mock_->SetReadData(buffer, sizeof(buffer));
-
-#if defined(__LP64__)
- dump_memory(&log_, memory_mock_.get(), 0xfffffffffffffff0, "memory near r1");
-#else
- dump_memory(&log_, memory_mock_.get(), 0xfffffff0, "memory near r1");
+ dump_memory(&log_, memory_mock_.get(), 0x100000000 - 32, "memory near r1");
+ dump_memory(&log_, memory_mock_.get(), 0x100000000 - 208, "memory near r1");
#endif
std::string tombstone_contents;
@@ -500,9 +426,9 @@
memory_mock_->SetReadData(buffer, sizeof(buffer));
#if defined(__LP64__)
- dump_memory(&log_, memory_mock_.get(), 0x4000000000000000UL - 224, "memory near r4");
+ dump_memory(&log_, memory_mock_.get(), -224, "memory near r4");
#else
- dump_memory(&log_, memory_mock_.get(), 0xffff0000 - 224, "memory near r4");
+ dump_memory(&log_, memory_mock_.get(), 0x100000000 - 224, "memory near r4");
#endif
std::string tombstone_contents;
@@ -510,40 +436,57 @@
ASSERT_TRUE(android::base::ReadFdToString(log_.tfd, &tombstone_contents));
const char* expected_dump = \
"\nmemory near r4:\n"
-#if defined(__LP64__)
-" 3fffffffffffff00 0706050403020100 0f0e0d0c0b0a0908 ................\n"
-" 3fffffffffffff10 1716151413121110 1f1e1d1c1b1a1918 ................\n"
-" 3fffffffffffff20 2726252423222120 2f2e2d2c2b2a2928 !\"#$%&'()*+,-./\n"
-" 3fffffffffffff30 3736353433323130 3f3e3d3c3b3a3938 0123456789:;<=>?\n"
-" 3fffffffffffff40 4746454443424140 4f4e4d4c4b4a4948 @ABCDEFGHIJKLMNO\n"
-" 3fffffffffffff50 5756555453525150 5f5e5d5c5b5a5958 PQRSTUVWXYZ[\\]^_\n"
-" 3fffffffffffff60 6766656463626160 6f6e6d6c6b6a6968 `abcdefghijklmno\n"
-" 3fffffffffffff70 7776757473727170 7f7e7d7c7b7a7978 pqrstuvwxyz{|}~.\n"
-" 3fffffffffffff80 8786858483828180 8f8e8d8c8b8a8988 ................\n"
-" 3fffffffffffff90 9796959493929190 9f9e9d9c9b9a9998 ................\n"
-" 3fffffffffffffa0 a7a6a5a4a3a2a1a0 afaeadacabaaa9a8 ................\n"
-" 3fffffffffffffb0 b7b6b5b4b3b2b1b0 bfbebdbcbbbab9b8 ................\n"
-" 3fffffffffffffc0 c7c6c5c4c3c2c1c0 cfcecdcccbcac9c8 ................\n"
-" 3fffffffffffffd0 d7d6d5d4d3d2d1d0 dfdedddcdbdad9d8 ................\n"
-" 3fffffffffffffe0 e7e6e5e4e3e2e1e0 efeeedecebeae9e8 ................\n"
-" 3ffffffffffffff0 f7f6f5f4f3f2f1f0 fffefdfcfbfaf9f8 ................\n";
+#if defined(__aarch64__)
+" 00ffffffffffff00 0706050403020100 0f0e0d0c0b0a0908 ................\n"
+" 00ffffffffffff10 1716151413121110 1f1e1d1c1b1a1918 ................\n"
+" 00ffffffffffff20 2726252423222120 2f2e2d2c2b2a2928 !\"#$%&'()*+,-./\n"
+" 00ffffffffffff30 3736353433323130 3f3e3d3c3b3a3938 0123456789:;<=>?\n"
+" 00ffffffffffff40 4746454443424140 4f4e4d4c4b4a4948 @ABCDEFGHIJKLMNO\n"
+" 00ffffffffffff50 5756555453525150 5f5e5d5c5b5a5958 PQRSTUVWXYZ[\\]^_\n"
+" 00ffffffffffff60 6766656463626160 6f6e6d6c6b6a6968 `abcdefghijklmno\n"
+" 00ffffffffffff70 7776757473727170 7f7e7d7c7b7a7978 pqrstuvwxyz{|}~.\n"
+" 00ffffffffffff80 8786858483828180 8f8e8d8c8b8a8988 ................\n"
+" 00ffffffffffff90 9796959493929190 9f9e9d9c9b9a9998 ................\n"
+" 00ffffffffffffa0 a7a6a5a4a3a2a1a0 afaeadacabaaa9a8 ................\n"
+" 00ffffffffffffb0 b7b6b5b4b3b2b1b0 bfbebdbcbbbab9b8 ................\n"
+" 00ffffffffffffc0 c7c6c5c4c3c2c1c0 cfcecdcccbcac9c8 ................\n"
+" 00ffffffffffffd0 d7d6d5d4d3d2d1d0 dfdedddcdbdad9d8 ................\n"
+" 00ffffffffffffe0 e7e6e5e4e3e2e1e0 efeeedecebeae9e8 ................\n"
+" 00fffffffffffff0 f7f6f5f4f3f2f1f0 fffefdfcfbfaf9f8 ................\n";
+#elif defined(__LP64__)
+" ffffffffffffff00 0706050403020100 0f0e0d0c0b0a0908 ................\n"
+" ffffffffffffff10 1716151413121110 1f1e1d1c1b1a1918 ................\n"
+" ffffffffffffff20 2726252423222120 2f2e2d2c2b2a2928 !\"#$%&'()*+,-./\n"
+" ffffffffffffff30 3736353433323130 3f3e3d3c3b3a3938 0123456789:;<=>?\n"
+" ffffffffffffff40 4746454443424140 4f4e4d4c4b4a4948 @ABCDEFGHIJKLMNO\n"
+" ffffffffffffff50 5756555453525150 5f5e5d5c5b5a5958 PQRSTUVWXYZ[\\]^_\n"
+" ffffffffffffff60 6766656463626160 6f6e6d6c6b6a6968 `abcdefghijklmno\n"
+" ffffffffffffff70 7776757473727170 7f7e7d7c7b7a7978 pqrstuvwxyz{|}~.\n"
+" ffffffffffffff80 8786858483828180 8f8e8d8c8b8a8988 ................\n"
+" ffffffffffffff90 9796959493929190 9f9e9d9c9b9a9998 ................\n"
+" ffffffffffffffa0 a7a6a5a4a3a2a1a0 afaeadacabaaa9a8 ................\n"
+" ffffffffffffffb0 b7b6b5b4b3b2b1b0 bfbebdbcbbbab9b8 ................\n"
+" ffffffffffffffc0 c7c6c5c4c3c2c1c0 cfcecdcccbcac9c8 ................\n"
+" ffffffffffffffd0 d7d6d5d4d3d2d1d0 dfdedddcdbdad9d8 ................\n"
+" ffffffffffffffe0 e7e6e5e4e3e2e1e0 efeeedecebeae9e8 ................\n"
+" fffffffffffffff0 f7f6f5f4f3f2f1f0 fffefdfcfbfaf9f8 ................\n";
#else
-" fffeff00 03020100 07060504 0b0a0908 0f0e0d0c ................\n"
-" fffeff10 13121110 17161514 1b1a1918 1f1e1d1c ................\n"
-" fffeff20 23222120 27262524 2b2a2928 2f2e2d2c !\"#$%&'()*+,-./\n"
-" fffeff30 33323130 37363534 3b3a3938 3f3e3d3c 0123456789:;<=>?\n"
-" fffeff40 43424140 47464544 4b4a4948 4f4e4d4c @ABCDEFGHIJKLMNO\n"
-" fffeff50 53525150 57565554 5b5a5958 5f5e5d5c PQRSTUVWXYZ[\\]^_\n"
-" fffeff60 63626160 67666564 6b6a6968 6f6e6d6c `abcdefghijklmno\n"
-" fffeff70 73727170 77767574 7b7a7978 7f7e7d7c pqrstuvwxyz{|}~.\n"
-" fffeff80 83828180 87868584 8b8a8988 8f8e8d8c ................\n"
-" fffeff90 93929190 97969594 9b9a9998 9f9e9d9c ................\n"
-" fffeffa0 a3a2a1a0 a7a6a5a4 abaaa9a8 afaeadac ................\n"
-" fffeffb0 b3b2b1b0 b7b6b5b4 bbbab9b8 bfbebdbc ................\n"
-" fffeffc0 c3c2c1c0 c7c6c5c4 cbcac9c8 cfcecdcc ................\n"
-" fffeffd0 d3d2d1d0 d7d6d5d4 dbdad9d8 dfdedddc ................\n"
-" fffeffe0 e3e2e1e0 e7e6e5e4 ebeae9e8 efeeedec ................\n"
-" fffefff0 f3f2f1f0 f7f6f5f4 fbfaf9f8 fffefdfc ................\n";
+" ffffff00 03020100 07060504 0b0a0908 0f0e0d0c ................\n"
+" ffffff10 13121110 17161514 1b1a1918 1f1e1d1c ................\n"
+" ffffff20 23222120 27262524 2b2a2928 2f2e2d2c !\"#$%&'()*+,-./\n"
+" ffffff30 33323130 37363534 3b3a3938 3f3e3d3c 0123456789:;<=>?\n"
+" ffffff40 43424140 47464544 4b4a4948 4f4e4d4c @ABCDEFGHIJKLMNO\n"
+" ffffff50 53525150 57565554 5b5a5958 5f5e5d5c PQRSTUVWXYZ[\\]^_\n"
+" ffffff60 63626160 67666564 6b6a6968 6f6e6d6c `abcdefghijklmno\n"
+" ffffff70 73727170 77767574 7b7a7978 7f7e7d7c pqrstuvwxyz{|}~.\n"
+" ffffff80 83828180 87868584 8b8a8988 8f8e8d8c ................\n"
+" ffffff90 93929190 97969594 9b9a9998 9f9e9d9c ................\n"
+" ffffffa0 a3a2a1a0 a7a6a5a4 abaaa9a8 afaeadac ................\n"
+" ffffffb0 b3b2b1b0 b7b6b5b4 bbbab9b8 bfbebdbc ................\n"
+" ffffffc0 c3c2c1c0 c7c6c5c4 cbcac9c8 cfcecdcc ................\n"
+" ffffffd0 d3d2d1d0 d7d6d5d4 dbdad9d8 dfdedddc ................\n"
+" ffffffe0 e3e2e1e0 e7e6e5e4 ebeae9e8 efeeedec ................\n"
+" fffffff0 f3f2f1f0 f7f6f5f4 fbfaf9f8 fffefdfc ................\n";
#endif
ASSERT_STREQ(expected_dump, tombstone_contents.c_str());
@@ -684,44 +627,7 @@
std::string tombstone_contents;
ASSERT_TRUE(lseek(log_.tfd, 0, SEEK_SET) == 0);
ASSERT_TRUE(android::base::ReadFdToString(log_.tfd, &tombstone_contents));
- const char* expected_dump = \
-"\nmemory near r4:\n"
-#if defined(__LP64__)
-" 0000000010000000 ---------------- ---------------- ................\n"
-" 0000000010000010 ---------------- ---------------- ................\n"
-" 0000000010000020 ---------------- ---------------- ................\n"
-" 0000000010000030 ---------------- ---------------- ................\n"
-" 0000000010000040 ---------------- ---------------- ................\n"
-" 0000000010000050 ---------------- ---------------- ................\n"
-" 0000000010000060 ---------------- ---------------- ................\n"
-" 0000000010000070 ---------------- ---------------- ................\n"
-" 0000000010000080 ---------------- ---------------- ................\n"
-" 0000000010000090 ---------------- ---------------- ................\n"
-" 00000000100000a0 ---------------- ---------------- ................\n"
-" 00000000100000b0 ---------------- ---------------- ................\n"
-" 00000000100000c0 ---------------- ---------------- ................\n"
-" 00000000100000d0 ---------------- ---------------- ................\n"
-" 00000000100000e0 ---------------- ---------------- ................\n"
-" 00000000100000f0 ---------------- ---------------- ................\n";
-#else
-" 10000000 -------- -------- -------- -------- ................\n"
-" 10000010 -------- -------- -------- -------- ................\n"
-" 10000020 -------- -------- -------- -------- ................\n"
-" 10000030 -------- -------- -------- -------- ................\n"
-" 10000040 -------- -------- -------- -------- ................\n"
-" 10000050 -------- -------- -------- -------- ................\n"
-" 10000060 -------- -------- -------- -------- ................\n"
-" 10000070 -------- -------- -------- -------- ................\n"
-" 10000080 -------- -------- -------- -------- ................\n"
-" 10000090 -------- -------- -------- -------- ................\n"
-" 100000a0 -------- -------- -------- -------- ................\n"
-" 100000b0 -------- -------- -------- -------- ................\n"
-" 100000c0 -------- -------- -------- -------- ................\n"
-" 100000d0 -------- -------- -------- -------- ................\n"
-" 100000e0 -------- -------- -------- -------- ................\n"
-" 100000f0 -------- -------- -------- -------- ................\n";
-#endif
- ASSERT_STREQ(expected_dump, tombstone_contents.c_str());
+ ASSERT_STREQ("", tombstone_contents.c_str());
// Verify that the log buf is empty, and no error messages.
ASSERT_STREQ("", getFakeLogBuf().c_str());
@@ -744,44 +650,7 @@
std::string tombstone_contents;
ASSERT_TRUE(lseek(log_.tfd, 0, SEEK_SET) == 0);
ASSERT_TRUE(android::base::ReadFdToString(log_.tfd, &tombstone_contents));
- const char* expected_dump = \
-"\nmemory near r4:\n"
-#if defined(__LP64__)
-" 0000000010000f00 ---------------- ---------------- ................\n"
-" 0000000010000f10 ---------------- ---------------- ................\n"
-" 0000000010000f20 ---------------- ---------------- ................\n"
-" 0000000010000f30 ---------------- ---------------- ................\n"
-" 0000000010000f40 ---------------- ---------------- ................\n"
-" 0000000010000f50 ---------------- ---------------- ................\n"
-" 0000000010000f60 ---------------- ---------------- ................\n"
-" 0000000010000f70 ---------------- ---------------- ................\n"
-" 0000000010000f80 ---------------- ---------------- ................\n"
-" 0000000010000f90 ---------------- ---------------- ................\n"
-" 0000000010000fa0 ---------------- ---------------- ................\n"
-" 0000000010000fb0 ---------------- ---------------- ................\n"
-" 0000000010000fc0 ---------------- ---------------- ................\n"
-" 0000000010000fd0 ---------------- ---------------- ................\n"
-" 0000000010000fe0 ---------------- ---------------- ................\n"
-" 0000000010000ff0 ---------------- ---------------- ................\n";
-#else
-" 10000f00 -------- -------- -------- -------- ................\n"
-" 10000f10 -------- -------- -------- -------- ................\n"
-" 10000f20 -------- -------- -------- -------- ................\n"
-" 10000f30 -------- -------- -------- -------- ................\n"
-" 10000f40 -------- -------- -------- -------- ................\n"
-" 10000f50 -------- -------- -------- -------- ................\n"
-" 10000f60 -------- -------- -------- -------- ................\n"
-" 10000f70 -------- -------- -------- -------- ................\n"
-" 10000f80 -------- -------- -------- -------- ................\n"
-" 10000f90 -------- -------- -------- -------- ................\n"
-" 10000fa0 -------- -------- -------- -------- ................\n"
-" 10000fb0 -------- -------- -------- -------- ................\n"
-" 10000fc0 -------- -------- -------- -------- ................\n"
-" 10000fd0 -------- -------- -------- -------- ................\n"
-" 10000fe0 -------- -------- -------- -------- ................\n"
-" 10000ff0 -------- -------- -------- -------- ................\n";
-#endif
- ASSERT_STREQ(expected_dump, tombstone_contents.c_str());
+ ASSERT_STREQ("", tombstone_contents.c_str());
// Verify that the log buf is empty, and no error messages.
ASSERT_STREQ("", getFakeLogBuf().c_str());
diff --git a/debuggerd/libdebuggerd/utility.cpp b/debuggerd/libdebuggerd/utility.cpp
index 0a491bb..d2554ae 100644
--- a/debuggerd/libdebuggerd/utility.cpp
+++ b/debuggerd/libdebuggerd/utility.cpp
@@ -135,22 +135,16 @@
addr -= 32;
}
- // We don't want the address tag to interfere with the bounds check below or appear in the
- // addresses in the memory dump.
+ // We don't want the address tag to appear in the addresses in the memory dump.
addr = untag_address(addr);
- // Don't bother if the address looks too low, or looks too high.
- if (addr < 4096 ||
-#if defined(__LP64__)
- addr > 0x4000000000000000UL - MEMORY_BYTES_TO_DUMP) {
-#else
- addr > 0xffff0000 - MEMORY_BYTES_TO_DUMP) {
-#endif
+ // Don't bother if the address would overflow, taking tag bits into account. Note that
+ // untag_address truncates to 32 bits on 32-bit platforms as a side effect of returning a
+ // uintptr_t, so this also checks for 32-bit overflow.
+ if (untag_address(addr + MEMORY_BYTES_TO_DUMP - 1) < addr) {
return;
}
- _LOG(log, logtype::MEMORY, "\n%s:\n", label.c_str());
-
// Dump 256 bytes
uintptr_t data[MEMORY_BYTES_TO_DUMP/sizeof(uintptr_t)];
memset(data, 0, MEMORY_BYTES_TO_DUMP);
@@ -191,6 +185,15 @@
}
}
+ // If we were unable to read anything, it probably means that the register doesn't contain a
+ // valid pointer. In that case, skip the output for this register entirely rather than emitting 16
+ // lines of dashes.
+ if (bytes == 0) {
+ return;
+ }
+
+ _LOG(log, logtype::MEMORY, "\n%s:\n", label.c_str());
+
// Dump the code around memory as:
// addr contents ascii
// 0000000000008d34 ef000000e8bd0090 e1b00000512fff1e ............../Q