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Merge pull request #34402 from keszybz/notes-readme
Add examples not package/dlopen notes
This commit is contained in:
Luca Boccassi
GitHub
commit
a7af35f1d4
2
TODO
2
TODO
@ -1501,6 +1501,8 @@ Features:
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* systemd-analyze netif that explains predictable interface (or networkctl)
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* systemd-analyze inspect-elf should show other notes too, at least build-id.
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* Figure out naming of verbs in systemd-analyze: we have (singular) capability,
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exit-status, but (plural) filesystems, architectures.
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@ -87,3 +87,90 @@ of the libraries they specify in order to be enabled.
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| required | Core functionality needs the dependency, the binary will not work if it cannot be found |
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| recommended | Important functionality needs the dependency, the binary will work but in most cases the dependency should be provided |
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| suggested | Secondary functionality needs the dependency, the binary will work and the dependency is only needed for full-featured installations |
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### Displaying `dlopen()` notes
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The raw ELF section can be extracted using `objdump`:
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```console
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$ objdump -j .note.dlopen -s /usr/lib64/systemd/libsystemd-shared-257.so
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/usr/lib64/systemd/libsystemd-shared-257.so: file format elf64-x86-64
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Contents of section .note.dlopen:
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0334 04000000 8e000000 0a0c7c40 46444f00 ..........|@FDO.
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0344 5b7b2266 65617475 7265223a 22627066 [{"feature":"bpf
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0354 222c2264 65736372 69707469 6f6e223a ","description":
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0364 22537570 706f7274 20666972 6577616c "Support firewal
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0374 6c696e67 20616e64 2073616e 64626f78 ling and sandbox
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0384 696e6720 77697468 20425046 222c2270 ing with BPF","p
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0394 72696f72 69747922 3a227375 67676573 riority":"sugges
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03a4 74656422 2c22736f 6e616d65 223a5b22 ted","soname":["
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03b4 6c696262 70662e73 6f2e3122 2c226c69 libbpf.so.1","li
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03c4 62627066 2e736f2e 30225d7d 5d000000 bbpf.so.0"]}]...
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03d4 04000000 9e000000 0a0c7c40 46444f00 ..........|@FDO.
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...
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```
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It is more convenient to use a higher level tool:
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```console
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$ dlopen-notes /usr/lib64/systemd/libsystemd-shared-257.so
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# /usr/lib64/systemd/libsystemd-shared-257.so
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[
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{
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"feature": "archive",
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"description": "Support for decompressing archive files",
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"priority": "suggested",
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"soname": [
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"libarchive.so.13"
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]
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},
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{
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"feature": "bpf",
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"description": "Support firewalling and sandboxing with BPF",
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"priority": "suggested",
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"soname": [
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"libbpf.so.1",
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"libbpf.so.0"
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]
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},
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...
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```
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`dlopen-notes` can display the notes grouped in a few different ways.
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One option is to filter the libraries by "feature". This answers the
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question "what libraries are needed to provide specified features":
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```console
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$ dlopen-notes.py -f archive,bpf /usr/lib64/systemd/libsystemd-shared-257.so
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# grouped by feature
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{
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"bpf": {
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"description": "Support firewalling and sandboxing with BPF",
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"sonames": {
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"libbpf.so.1": "suggested",
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"libbpf.so.0": "suggested"
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}
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},
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"archive": {
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"description": "Support for decompressing archive files",
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"sonames": {
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"libarchive.so.13": "suggested"
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}
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}
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}
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The format that is used when building `deb` packages:
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```console
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$ dlopen-notes -s /usr/lib64/systemd/libsystemd-shared-257.so
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libarchive.so.13 suggested
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libbpf.so.0 suggested
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libbpf.so.1 suggested
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...
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```
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The format that can be useful when building `rpm` packages:
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```console
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$ dlopen-notes --rpm-requires archive --rpm-recommends bpf /usr/lib64/systemd/libsystemd-shared-257.so
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Requires: libarchive.so.13()(64bit)
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Recommends: libbpf.so.1()(64bit)
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```
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@ -103,3 +103,97 @@ A set of well-known keys is defined here, and hopefully shared among all vendors
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| architecture | The binary package architecture | arm32 |
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| osCpe | A CPE name for the OS, typically corresponding to CPE_NAME in os-release | cpe:/o:fedoraproject:fedora:33 |
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| debugInfoUrl | The debuginfod server url, if available | https://debuginfod.fedoraproject.org/ |
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### Displaying package notes
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The raw ELF section can be extracted using `objdump`:
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```console
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$ objdump -j .note.package -s /usr/bin/ls
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/usr/bin/ls: file format elf64-x86-64
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Contents of section .note.package:
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03cc 04000000 7c000000 7e1afeca 46444f00 ....|...~...FDO.
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03dc 7b227479 7065223a 2272706d 222c226e {"type":"rpm","n
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03ec 616d6522 3a22636f 72657574 696c7322 ame":"coreutils"
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03fc 2c227665 7273696f 6e223a22 392e342d ,"version":"9.4-
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040c 372e6663 3430222c 22617263 68697465 7.fc40","archite
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041c 63747572 65223a22 7838365f 3634222c cture":"x86_64",
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042c 226f7343 7065223a 22637065 3a2f6f3a "osCpe":"cpe:/o:
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043c 6665646f 72617072 6f6a6563 743a6665 fedoraproject:fe
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044c 646f7261 3a343022 7d000000 dora:40"}...
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```
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It is more convenient to use a higher level tool:
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```console
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$ readelf --notes /usr/bin/ls
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...
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Displaying notes found in: .note.gnu.build-id
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Owner Data size Description
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GNU 0x00000014 NT_GNU_BUILD_ID (unique build ID bitstring)
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Build ID: 40e5a1570a9d97fc48f5c61cfb7690fec0f872b2
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Displaying notes found in: .note.ABI-tag
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Owner Data size Description
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GNU 0x00000010 NT_GNU_ABI_TAG (ABI version tag)
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OS: Linux, ABI: 3.2.0
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Displaying notes found in: .note.package
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Owner Data size Description
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FDO 0x0000007c FDO_PACKAGING_METADATA
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Packaging Metadata: {"type":"rpm","name":"coreutils","version":"9.4-7.fc40","architecture":"x86_64","osCpe":"cpe:/o:fedoraproject:fedora:40"}
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...
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$ systemd-analyze inspect-elf /usr/bin/ls
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path: /usr/bin/ls
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elfType: executable
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elfArchitecture: AMD x86-64
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type: rpm
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name: coreutils
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version: 9.4-7.fc40
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architecture: x86_64
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osCpe: cpe:/o:fedoraproject:fedora:40
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buildId: 40e5a1570a9d97fc48f5c61cfb7690fec0f872b2
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```
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If the binary crashes, `systemd-coredump` will display the combined information
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from the crashing binary and any shared libraries it links to:
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```console
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$ coredumpctl info
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PID: 3987823 (ls)
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Signal: 11 (SEGV)
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Command Line: ls --color=tty -lR /
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Executable: /usr/bin/ls
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...
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Storage: /var/lib/systemd/coredump/core.ls.1000.88dea1b9831c420dbb398f9d2ad9b41e.3987823.1726230641000000.zst (present)
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Size on Disk: 194.4K
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Package: coreutils/9.4-7.fc40
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build-id: 40e5a1570a9d97fc48f5c61cfb7690fec0f872b2
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Message: Process 3987823 (ls) of user 1000 dumped core.
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Module /usr/bin/ls from rpm coreutils-9.4-7.fc40.x86_64
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Module libz.so.1 from rpm zlib-ng-2.1.7-1.fc40.x86_64
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Module libcrypto.so.3 from rpm openssl-3.2.2-3.fc40.x86_64
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Module libmount.so.1 from rpm util-linux-2.40.1-1.fc40.x86_64
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Module libcrypt.so.2 from rpm libxcrypt-4.4.36-5.fc40.x86_64
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Module libblkid.so.1 from rpm util-linux-2.40.1-1.fc40.x86_64
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Module libnss_sss.so.2 from rpm sssd-2.9.5-1.fc40.x86_64
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Module libpcre2-8.so.0 from rpm pcre2-10.44-1.fc40.x86_64
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Module libcap.so.2 from rpm libcap-2.69-8.fc40.x86_64
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Module libselinux.so.1 from rpm libselinux-3.6-4.fc40.x86_64
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Stack trace of thread 3987823:
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#0 0x00007f19331c3f7e lgetxattr (libc.so.6 + 0x116f7e)
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#1 0x00007f19332be4c0 lgetfilecon_raw (libselinux.so.1 + 0x134c0)
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#2 0x00007f19332c3bd9 lgetfilecon (libselinux.so.1 + 0x18bd9)
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#3 0x000056038273ad55 gobble_file.constprop.0 (/usr/bin/ls + 0x17d55)
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#4 0x0000560382733c55 print_dir (/usr/bin/ls + 0x10c55)
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#5 0x0000560382727c35 main (/usr/bin/ls + 0x4c35)
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#6 0x00007f19330d7088 __libc_start_call_main (libc.so.6 + 0x2a088)
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#7 0x00007f19330d714b __libc_start_main@@GLIBC_2.34 (libc.so.6 + 0x2a14b)
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#8 0x0000560382728f15 _start (/usr/bin/ls + 0x5f15)
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ELF object binary architecture: AMD x86-64
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```
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(This is just a simulation. `ls` is not prone to crashing with a segmentation violation.)
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