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llvm-project/lldb/test/Shell/Minidump/memory-region-from-module.yaml

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minidump: Create memory regions from the sections of loaded modules Summary: Not all minidumps contain information about memory permissions. However, it is still important to know which regions of memory contain potentially executable code. This is particularly important for unwinding on win32, as the default unwind method there relies on scanning the stack for things which "look like" code pointers. This patch enables ProcessMinidump to reconstruct the likely permissions of memory regions using the sections of loaded object files. It only does this if we don't have a better source (memory info list stream, or linux /proc/maps) for this information, and only if the information in the object files does not conflict with the information in the minidump. Theoretically that last bit could be improved, since the permissions obtained from the MemoryList streams is also only a very rough guess, but it did not seem worthwhile to complicate the implementation because of that because there will generally be no overlap in practice as the MemoryList will contain the stack contents and not any module data. The patch adds a test checking that the module section permissions are entered into the memory region list, and also a test which demonstrate that now the unwinder is able to correctly find return addresses even in minidumps without memory info list streams. There's one TODO left in this patch, which is that the "memory region" output does not give any indication about the "don't know" values of memory region permissions (it just prints them as if they permission bit was set). I address this in a follow up. Reviewers: amccarth, clayborg Subscribers: mgrang, lldb-commits Differential Revision: https://reviews.llvm.org/D69105
2019-10-16 16:38:10 +08:00
# Check that memory region parsing works correctly, with a particular emphasis
# on the boundary conditions.
# RUN: yaml2obj --docnum=1 %s > %t1.dmp
# RUN: yaml2obj --docnum=2 %s > %t2.dmp
# RUN: yaml2obj %S/Inputs/basic-elf.yaml >%T/memory-region-from-module.exe
# RUN: %lldb -b -c %t1.dmp %T/memory-region-from-module.exe \
# RUN: -o "memory region 0" -o "memory region 0x4000" \
# RUN: -o "memory region 0x5000" -o "memory region 0x6000" \
# RUN: | FileCheck --check-prefix=ALL --check-prefix=CHECK1 %s
# RUN: %lldb -b -c %t2.dmp %T/memory-region-from-module.exe \
# RUN: -o "memory region 0" -o "memory region 0x4000" \
# RUN: -o "memory region 0x5000" -o "memory region 0x6000" \
# RUN: | FileCheck --check-prefix=ALL --check-prefix=CHECK2 %s
# ALL-LABEL: (lldb) memory region 0
# ALL: [0x0000000000000000-0x0000000000004000) ---
# ALL-LABEL: (lldb) memory region 0x4000
# CHECK1: [0x0000000000004000-0x00000000000040b0) r-x {{.*}}memory-region-from-module.exe PT_LOAD[0]
MemoryRegion: Print "don't know" permission values as such Summary: The permissions in a memory region have ternary states (yes, no, don't know), but the memory region command only prints in binary, treating "don't know" as "yes", which is particularly confusing as for instance the unwinder will treat an unknown value as "no". This patch makes is so that we distinguish all three states when printing the values, using "?" to indicate the lack of information. It is implemented via a special argument to the format provider for the OptionalBool enumeration. Reviewers: clayborg, jingham Subscribers: lldb-commits Differential Revision: https://reviews.llvm.org/D69106
2019-10-16 21:29:20 +08:00
# CHECK2: [0x0000000000004000-0x0000000000004010) r??
minidump: Create memory regions from the sections of loaded modules Summary: Not all minidumps contain information about memory permissions. However, it is still important to know which regions of memory contain potentially executable code. This is particularly important for unwinding on win32, as the default unwind method there relies on scanning the stack for things which "look like" code pointers. This patch enables ProcessMinidump to reconstruct the likely permissions of memory regions using the sections of loaded object files. It only does this if we don't have a better source (memory info list stream, or linux /proc/maps) for this information, and only if the information in the object files does not conflict with the information in the minidump. Theoretically that last bit could be improved, since the permissions obtained from the MemoryList streams is also only a very rough guess, but it did not seem worthwhile to complicate the implementation because of that because there will generally be no overlap in practice as the MemoryList will contain the stack contents and not any module data. The patch adds a test checking that the module section permissions are entered into the memory region list, and also a test which demonstrate that now the unwinder is able to correctly find return addresses even in minidumps without memory info list streams. There's one TODO left in this patch, which is that the "memory region" output does not give any indication about the "don't know" values of memory region permissions (it just prints them as if they permission bit was set). I address this in a follow up. Reviewers: amccarth, clayborg Subscribers: mgrang, lldb-commits Differential Revision: https://reviews.llvm.org/D69105
2019-10-16 16:38:10 +08:00
# ALL-LABEL: (lldb) memory region 0x5000
# ALL: [0x0000000000005000-0x000000000000505c) rw- {{.*}}memory-region-from-module.exe PT_LOAD[1]
# ALL-LABEL: (lldb) memory region 0x6000
# ALL: [0x000000000000505c-0xffffffffffffffff) ---
--- !minidump
Streams:
- Type: ModuleList
Modules:
- Base of Image: 0x0000000000004000
Size of Image: 0x00002000
Module Name: 'memory-region-from-module.exe'
CodeView Record: 4C457042DEADBEEFBAADF00D
- Type: SystemInfo
Processor Arch: AMD64
Platform ID: Linux
CPU:
Vendor ID: GenuineIntel
Version Info: 0x00000000
Feature Info: 0x00000000
- Type: LinuxProcStatus
Text: |
Name: memory-region-from-module.exe
State: t (tracing stop)
Tgid: 29939
Ngid: 0
Pid: 29939
PPid: 29370
TracerPid: 29940
Uid: 1001 1001 1001 1001
Gid: 1001 1001 1001 1001
...
--- !minidump
Streams:
- Type: MemoryList
Memory Ranges:
- Start of Memory Range: 0x0000000000004000
Content: 30044000000000000000000000000000
- Type: ModuleList
Modules:
- Base of Image: 0x0000000000004000
Size of Image: 0x00002000
Module Name: 'memory-region-from-module.exe'
CodeView Record: 4C457042DEADBEEFBAADF00D
- Type: SystemInfo
Processor Arch: AMD64
Platform ID: Linux
CPU:
Vendor ID: GenuineIntel
Version Info: 0x00000000
Feature Info: 0x00000000
- Type: LinuxProcStatus
Text: |
Name: memory-region-from-module.exe
State: t (tracing stop)
Tgid: 29939
Ngid: 0
Pid: 29939
PPid: 29370
TracerPid: 29940
Uid: 1001 1001 1001 1001
Gid: 1001 1001 1001 1001
...