build: indefinite mpgen hang on Ubuntu 22.04 #33176

issue fanquake opened this issue on August 12, 2025
  1. fanquake commented at 8:52 AM on August 12, 2025: member

    Noticed this while looking at #31802, but the same happens on master (273e600e65c2e31a6e9a0bd72b40672aaa503b08).

    # podman run -it ubuntu:22.04 /bin/bash

apt update && apt upgrade -y && apt install build-essential cmake pkgconf python3 git libevent-dev libboost-dev libsqlite3-dev libcapnp-dev capnproto -y

git clone https://github.com/bitcoin/bitcoin

cd bitcoin
cmake -B build -DENABLE_IPC=ON
cmake --build build

    The build never completes. It hangs indefinitely doing capnp generation:

    cmake --build build -j10
[  1%] Built target crc32c
[  1%] Generating bitcoin-build-info.h
[  1%] Built target secp256k1_precomputed
[  1%] Built target mputil
[  2%] Built target univalue
[  4%] Built target bitcoin_consensus
[  7%] Built target bitcoin_crypto
[ 10%] Built target minisketch
[ 10%] Built target bitcoin_cli
[ 10%] Built target exhaustive_tests
[ 16%] Built target leveldb
[ 26%] Built target unitester
[ 26%] Built target mpgen
[ 26%] Built target object
[ 27%] Built target multiprocess
[ 28%] Built target secp256k1
[ 28%] Built target noverify_tests
[ 28%] Generating capnp/mining.capnp.c++, capnp/mining.capnp.h, capnp/mining.capnp.proxy-client.c++, capnp/mining.capnp.proxy-types.h, capnp/mining.capnp.proxy-server.c++, capnp/mining.capnp.proxy-types.c++, capnp/mining.capnp.proxy.h
[ 28%] Generating capnp/init.capnp.c++, capnp/init.capnp.h, capnp/init.capnp.proxy-client.c++, capnp/init.capnp.proxy-types.h, capnp/init.capnp.proxy-server.c++, capnp/init.capnp.proxy-types.c++, capnp/init.capnp.proxy.h
[ 28%] Generating capnp/echo.capnp.c++, capnp/echo.capnp.h, capnp/echo.capnp.proxy-client.c++, capnp/echo.capnp.proxy-types.h, capnp/echo.capnp.proxy-server.c++, capnp/echo.capnp.proxy-types.c++, capnp/echo.capnp.proxy.h
[ 28%] Generating capnp/common.capnp.c++, capnp/common.capnp.h, capnp/common.capnp.proxy-client.c++, capnp/common.capnp.proxy-types.h, capnp/common.capnp.proxy-server.c++, capnp/common.capnp.proxy-types.c++, capnp/common.capnp.proxy.h
[ 28%] Generating mp/test/foo.capnp.c++, mp/test/foo.capnp.h, mp/test/foo.capnp.proxy-client.c++, mp/test/foo.capnp.proxy-types.h, mp/test/foo.capnp.proxy-server.c++, mp/test/foo.capnp.proxy-types.c++, mp/test/foo.capnp.proxy.h
[ 28%] Built target tests
[ 28%] Generating capnp/echo.capnp.c++, capnp/echo.capnp.h, capnp/echo.capnp.proxy-client.c++, capnp/echo.capnp.proxy-types.h, capnp/echo.capnp.proxy-server.c++, capnp/echo.capnp.proxy-types.c++, capnp/echo.capnp.proxy.h
[ 28%] Generating capnp/common.capnp.c++, capnp/common.capnp.h, capnp/common.capnp.proxy-client.c++, capnp/common.capnp.proxy-types.h, capnp/common.capnp.proxy-server.c++, capnp/common.capnp.proxy-types.c++, capnp/common.capnp.proxy.h
[ 32%] Built target test_util
[ 32%] Generating capnp/init.capnp.c++, capnp/init.capnp.h, capnp/init.capnp.proxy-client.c++, capnp/init.capnp.proxy-types.h, capnp/init.capnp.proxy-server.c++, capnp/init.capnp.proxy-types.c++, capnp/init.capnp.proxy.h
[ 32%] Generating capnp/mining.capnp.c++, capnp/mining.capnp.h, capnp/mining.capnp.proxy-client.c++, capnp/mining.capnp.proxy-types.h, capnp/mining.capnp.proxy-server.c++, capnp/mining.capnp.proxy-types.c++, capnp/mining.capnp.proxy.h
[ 32%] Built target generate_build_info
[ 37%] Built target bitcoin_wallet
[ 37%] Built target bitcoin_clientversion
[ 46%] Built target bitcoin_common
[ 52%] Built target bitcoin_util
[ 67%] Built target bitcoin_node
[ 67%] Built target bitcoin-cli
[ 67%] Built target bitcoin-tx
[ 67%] Built target bitcoin-util
[ 68%] Built target bitcoin-wallet
[ 68%] Built target bitcoin
[ 68%] Built target bitcoind
  2. fanquake added the label Build system on Aug 12, 2025
  3. willcl-ark commented at 10:11 AM on August 12, 2025: member

    I also see the sameinfinite hang:

    [ 33%] Generating mp/test/foo.capnp.c++, mp/test/foo.capnp.h, mp/test/foo.capnp.proxy-client.c++, mp/test/foo.capnp.proxy-types.h, mp/test/foo.capnp.proxy-server.c++, mp/test/foo.capnp.proxy-types.c++, mp/test/foo.capnp.proxy.h
[ 33%] Generating capnp/mining.capnp.c++, capnp/mining.capnp.h, capnp/mining.capnp.proxy-client.c++, capnp/mining.capnp.proxy-types.h, capnp/mining.capnp.proxy-server.c++, capnp/mining.capnp.proxy-types.c++, capnp/mining.capnp.proxy.h
[ 33%] Generating capnp/echo.capnp.c++, capnp/echo.capnp.h, capnp/echo.capnp.proxy-client.c++, capnp/echo.capnp.proxy-types.h, capnp/echo.capnp.proxy-server.c++, capnp/echo.capnp.proxy-types.c++, capnp/echo.capnp.proxy.h
[ 33%] Generating capnp/common.capnp.c++, capnp/common.capnp.h, capnp/common.capnp.proxy-client.c++, capnp/common.capnp.proxy-types.h, capnp/common.capnp.proxy-server.c++, capnp/common.capnp.proxy-types.c++, capnp/common.capnp.proxy.h
[ 33%] Generating capnp/init.capnp.c++, capnp/init.capnp.h, capnp/init.capnp.proxy-client.c++, capnp/init.capnp.proxy-types.h, capnp/init.capnp.proxy-server.c++, capnp/init.capnp.proxy-types.c++, capnp/init.capnp.proxy.h
[ 33%] Generating capnp/mining.capnp.c++, capnp/mining.capnp.h, capnp/mining.capnp.proxy-client.c++, capnp/mining.capnp.proxy-types.h, capnp/mining.capnp.proxy-server.c++, capnp/mining.capnp.proxy-types.c++, capnp/mining.capnp.proxy.h
[ 33%] Built target generate_build_info
Consolidate compiler generated dependencies of target bitcoin_clientversion
Consolidate compiler generated dependencies of target bitcoin_util
[ 33%] Built target bitcoin_clientversion
Consolidate compiler generated dependencies of target bitcoin_common
Consolidate compiler generated dependencies of target bitcoin_wallet
[ 38%] Built target bitcoin_util
Consolidate compiler generated dependencies of target bitcoin_node
Consolidate compiler generated dependencies of target bitcoin
[ 38%] Built target bitcoin
[ 47%] Built target bitcoin_common
[ 47%] Building CXX object src/CMakeFiles/bitcoin-cli.dir/bitcoin-cli.cpp.o
[ 47%] Building CXX object src/CMakeFiles/bitcoin-util.dir/bitcoin-util.cpp.o
[ 47%] Building CXX object src/CMakeFiles/bitcoin-tx.dir/bitcoin-tx.cpp.o
[ 52%] Built target bitcoin_wallet
[ 52%] Building CXX object src/CMakeFiles/bitcoin-wallet.dir/bitcoin-wallet.cpp.o
[ 67%] Built target bitcoin_node
[ 67%] Building CXX object src/CMakeFiles/bitcoin-wallet.dir/init/bitcoin-wallet.cpp.o
[ 67%] Linking CXX executable ../bin/bitcoin-util
[ 67%] Building CXX object src/CMakeFiles/bitcoind.dir/bitcoind.cpp.o
[ 67%] Built target bitcoin-util
[ 68%] Building CXX object src/CMakeFiles/bitcoin-wallet.dir/wallet/wallettool.cpp.o
[ 70%] Building CXX object src/CMakeFiles/bitcoind.dir/init/bitcoind.cpp.o
[ 70%] Linking CXX executable ../bin/bitcoin-cli
[ 70%] Linking CXX executable ../bin/bitcoin-tx
[ 70%] Built target bitcoin-cli
[ 70%] Linking CXX executable ../bin/bitcoind
[ 70%] Built target bitcoin-tx
[ 70%] Linking CXX executable ../bin/bitcoin-wallet
[ 70%] Built target bitcoind
[ 70%] Built target bitcoin-wallet
^Cgmake[2]: *** [src/ipc/CMakeFiles/bitcoin_ipc.dir/build.make:96: src/ipc/capnp/echo.capnp.c++] Interrupt
gmake[2]: *** [src/ipc/CMakeFiles/bitcoin_ipc_headers.dir/build.make:98: src/ipc/capnp/echo.capnp.c++] Interrupt
gmake[2]: *** [src/ipc/CMakeFiles/bitcoin_ipc_headers.dir/build.make:120: src/ipc/capnp/init.capnp.c++] Interrupt
gmake[2]: *** [src/ipc/CMakeFiles/bitcoin_ipc.dir/build.make:74: src/ipc/capnp/common.capnp.c++] Interrupt
gmake[2]: *** [src/ipc/CMakeFiles/bitcoin_ipc_headers.dir/build.make:76: src/ipc/capnp/common.capnp.c++] Interrupt
gmake[2]: *** [src/ipc/CMakeFiles/bitcoin_ipc.dir/build.make:140: src/ipc/capnp/mining.capnp.c++] Interrupt
gmake[2]: *** [src/ipc/CMakeFiles/bitcoin_ipc_headers.dir/build.make:142: src/ipc/capnp/mining.capnp.c++] Interrupt
gmake[2]: *** [src/ipc/libmultiprocess/test/CMakeFiles/mptest.dir/build.make:74: src/ipc/libmultiprocess/test/mp/test/foo.capnp.c++] Interrupt
gmake[2]: *** [src/ipc/CMakeFiles/bitcoin_ipc.dir/build.make:118: src/ipc/capnp/init.capnp.c++] Interrupt
gmake[1]: *** [CMakeFiles/Makefile2:1502: src/ipc/libmultiprocess/test/CMakeFiles/mptest.dir/all] Interrupt
gmake[1]: *** [CMakeFiles/Makefile2:1737: src/ipc/CMakeFiles/bitcoin_ipc.dir/all] Interrupt
gmake[1]: *** [CMakeFiles/Makefile2:1764: src/ipc/CMakeFiles/bitcoin_ipc_headers.dir/all] Interrupt
gmake: *** [Makefile:146: all] Interrupt
  4. ryanofsky commented at 2:04 PM on August 12, 2025: contributor

    Thanks, instructions make this very easy to reproduce. Error is strange. If I attach with gdb it shows program is hung in a self-loop instruction:

    => 0x0000563e5f583f7f <+1103>:	jmp    0x563e5f583f7f <main(int, char**)+1103>

    Some more context is:

       0x0000563e5f583f6b <+1083>:	call   0x563e5f584450 <_ZN2kj3OwnIKNS_17ReadableDirectoryEE7disposeEv>
   0x0000563e5f583f70 <+1088>:	add    $0x8,%r13
   0x0000563e5f583f74 <+1092>:	cmp    %r13,0x8(%rsp)
   0x0000563e5f583f79 <+1097>:	jne    0x563e5f583e6d <main(int, char**)+829>
=> 0x0000563e5f583f7f <+1103>:	jmp    0x563e5f583f7f <main(int, char**)+1103>
   0x0000563e5f583f81 <+1105>:	nopl   0x0(%rax)
   0x0000563e5f583f88 <+1112>:	lea    0x70(%rsp),%r15
   0x0000563e5f583f8d <+1117>:	lea    0xd0(%rsp),%rdi
   0x0000563e5f583f95 <+1125>:	mov    %r15,%rdx
   0x0000563e5f583f98 <+1128>:	call   0x563e5f584690 <_ZNSt6vectorIN2kj3OwnIKNS0_17ReadableDirectoryEEESaIS4_EE17_M_realloc_insertIJS4_EEEvN9__gnu_cxx17__normal_iteratorIPS4_S6_EEDpOT_>

    GDB says corresponding source code is

    (gdb) info line *$pc
Line 669 of "./ipc/libmultiprocess/src/mp/gen.cpp" starts at address 0x563e5f583f74 <main(int, char**)+1092> and ends at 0x563e5f583f88 <main(int, char**)+1112>.
(gdb) info line *$pc
Line 669 of "./ipc/libmultiprocess/src/mp/gen.cpp" starts at address 0x563e5f583f74 <main(int, char**)+1092> and ends at 0x563e5f583f88 <main(int, char**)+1112>.
(gdb) list
664	            import_dirs.emplace_back(kj::mv(*dir));
665	        } else {
666	            throw std::runtime_error(std::string("Failed to open import directory: ") + argv[i]);
667	        }
668	    }
669	    for (const char* path : {CMAKE_INSTALL_PREFIX "/include", capnp_PREFIX "/include"}) {
670	        KJ_IF_MAYBE(dir, fs->getRoot().tryOpenSubdir(cwd.evalNative(path))) {
671	            import_paths.emplace_back(path);
672	            import_dirs.emplace_back(kj::mv(*dir));
673	        }

    But I'm not sure I trust assembly to source mapping because if I add std::cerr prints, program seems to be hanging at a later point ( 146 if (src_prefix == ".") { in Generate()

    This is very confusing and I'm not sure what is causing it. I haven't encountered a jmp instruction just looping to itself before but I guess a compiler might output one as a trap for unreachable code or something like that. Looking at the code, I don't think I can identify any bugs, so I wonder if cause might be that program is being compiled with bad flags or something like that. Will look into this more.

  5. ryanofsky commented at 2:46 PM on August 12, 2025: contributor

    Found the problem, and a workaround below. The bug is kind of crazy. Ubuntu 22.04 installs capnproto 0.8.0 which defines

    inline bool operator==(const char* a, const StringPtr& b) { return b == a; }

    Which seems to call itself recursively when compiled with c++20. This doesn't happen with newer versions of capnproto because they include a change https://github.com/capnproto/capnproto/pull/1170 https://github.com/capnproto/capnproto/pull/1235/commits/4db91df614be91db82833ec1b7cef18ef97711cb dropping it when a newer c++ version is used.

    Following change seems to successfully work around the problem though need to test more.

    <details><summary>diff</summary> <p>

    --- a/src/ipc/libmultiprocess/src/mp/gen.cpp
+++ b/src/ipc/libmultiprocess/src/mp/gen.cpp
@@ -143,7 +143,7 @@ static void Generate(kj::StringPtr src_prefix,
     const std::vector<kj::Own<const kj::ReadableDirectory>>& import_dirs)
 {
     std::string output_path;
-    if (src_prefix == ".") {
+    if (src_prefix == kj::StringPtr{"."}) {
         output_path = src_file;
     } else if (!src_file.startsWith(src_prefix) || src_file.size() <= src_prefix.size() ||
                src_file[src_prefix.size()] != '/') {
@@ -153,7 +153,7 @@ static void Generate(kj::StringPtr src_prefix,
     }
 
     std::string include_path;
-    if (include_prefix == ".") {
+    if (include_prefix == kj::StringPtr{"."}) {
         include_path = src_file;
     } else if (!src_file.startsWith(include_prefix) || src_file.size() <= include_prefix.size() ||
                src_file[include_prefix.size()] != '/') {
@@ -394,8 +394,8 @@ static void Generate(kj::StringPtr src_prefix,
 
                 const std::string method_prefix = Format() << message_namespace << "::" << method_interface.getShortDisplayName()
                                                            << "::" << Cap(method_name);
-                const bool is_construct = method_name == "construct";
-                const bool is_destroy = method_name == "destroy";
+                const bool is_construct = method_name == kj::StringPtr{"construct"};
+                const bool is_destroy = method_name == kj::StringPtr{"destroy"};
 
                 struct Field
                 {
@@ -434,7 +434,7 @@ static void Generate(kj::StringPtr src_prefix,
                         field.result_is_set = true;
                     }
 
-                    if (!param && field_name == "result") {
+                    if (!param && field_name == kj::StringPtr{"result"}) {
                         field.retval = true;
                         has_result = true;
                     }

    </p> </details>

  6. ryanofsky commented at 4:37 PM on August 12, 2025: contributor

    IPC functionality seems to work fine on ubuntu 22.04 apart from this bug, so I guess I will create a PR with the workaround from #33176 (comment).

    I posted a comment about this upstream https://github.com/capnproto/capnproto/pull/1170#discussion_r2270385770.

    This issue does not occur with Cap'n Proto 0.9.0 and later due to the changes in that PR which added c++20 support. In theory a fix could be backported, but ubuntu 22.04 is still using 0.8.0, not even 0.8.1 which fixes a CVE, so it seems best not to rely on ubuntu packaging.

  7. 1BitcoinBoWP1FZ4xwTNkq6XksKidmgYYw commented at 5:41 PM on August 12, 2025: none

    @ryanofsky

    This issue does not occur with Cap'n Proto 0.9.0 and later

    I oppose merging any workaround for this issue since:

    • The root cause has been resolved upstream (no need for Bitcoin-specific fixes)
    • We should instead implement a targeted warning advising users to upgrade their Ubuntu distribution

    Any additional workaround would:

    • Unnecessarily complicate the codebase
    • Provide no benefit for modern Ubuntu versions
    • Introduce maintenance burden without solving core issues

    Let's keep Bitcoin Core clean by only merging changes that:

    • Address actual problems (not upstream-fixed issues)
    • Provide clear benefits across environments
    • Avoid version-specific pollution
  8. Sjors commented at 6:22 PM on August 12, 2025: member

    I'm not sure if we should bother with a workaround for a version that also has a CVE. The compiler failure might be a "feature" here.

  9. ryanofsky commented at 8:40 PM on August 12, 2025: contributor

    I guess it seems ok to drop support for old versions, but this also seems like an easy problem to fix so I went ahead and implemented a fix in https://github.com/bitcoin-core/libmultiprocess/pull/194 along with a CI job that tests for compatibility.

    I'm not sure if we should bother with a workaround for a version that also has a CVE. The compiler failure might be a "feature" here.

    To be sure, the fact that the stable ubuntu package might have a CVE is eyebrow raising, but I'm not it actually does. I don't know very much about ubuntu and debian packaging and I just looked at the tarballs and patches at the bottom of https://packages.ubuntu.com/source/jammy/capnproto and noticed they seemed to be using an unpatched 0.8.0. The fix in https://github.com/bitcoin-core/libmultiprocess/pull/194 also lets mpgen work with 0.8.1 and 0.7.1 and is not specifically targeted at 0.8.0.

  10. 1BitcoinBoWP1FZ4xwTNkq6XksKidmgYYw commented at 9:05 PM on August 12, 2025: none

    @ryanofsky,

    Regarding the Cap'n Proto dependency, the correct source link is:
    https://launchpad.net/ubuntu/+source/capnproto

    After reviewing PR #194 (https://github.com/bitcoin-core/libmultiprocess/pull/194), I have some concerns:

    1. Maintenance Policy:
      We generally shouldn't maintain patches for older OS versions unless there's a compelling security reason. Supporting outdated systems creates long-term maintenance burden.

    2. Code Origin:
      Some changes appear to be copied directly from upstream.

    3. Better Alternatives:
      Users running older systems should either:

      • Upgrade their OS to supported versions
      • Build dependencies from source

    Or, download and install binaries directly from https://launchpad.net/ubuntu/+source/capnproto:

    <img width="1920" height="1285" alt="Image" src="https://github.com/user-attachments/assets/622e0e73-6c27-4754-bf1b-06c25e6570e7" />

  11. ryanofsky commented at 10:06 PM on August 12, 2025: contributor

    Regarding the Cap'n Proto dependency, the correct source link is: https://launchpad.net/ubuntu/+source/capnproto

    Thanks! If I follow that link to https://launchpad.net/ubuntu/+source/capnproto/0.8.0-2ubuntu2 I see same tarballs that I checked previously at https://packages.ubuntu.com/source/jammy/capnproto, so this may be additional confirmation.

    Re your concerns:

    1. **Maintenance Policy**:

    To be sure https://github.com/bitcoin-core/libmultiprocess/pull/194 isn't adding a patch that needs to be maintained, it's just comparing strings in a different way that's more verbose but more backwards compatible. I don't think the changes there will create a maintenance burden. I actually think to the contrary, the CI improvements there will help with long term maintenance, by making it easier to swap capnproto versions for testing and by catching any changes that are unintentionally backwards compatible.

    2. **Code Origin**:
   Some changes appear to be copied directly from upstream.

    I don't think this is true, but I'd welcome you to review the PR and point out any problems there that I might be missing.

    3. **Better Alternatives**:

    I do agree updating the OS or building cap'nproto from source could be good alternatives if anyone runs across this bug. Setting -DENABLE_IPC=off could be another good alternative in many cases. I still think fixing the bug has merits though so would welcome review in the PR.

  12. Sjors commented at 9:13 AM on August 13, 2025: member

    The fix in https://github.com/bitcoin-core/libmultiprocess/pull/194 also lets mpgen work with 0.8.1 and 0.7.1 and is not specifically targeted at 0.8.0.

    Ok, that seems a good enough reason, because we might want to support those versions (even if not immediately). @1BitcoinBoWP1FZ4xwTNkq6XksKidmgYYw wrote:

    We generally shouldn't maintain patches for older OS versions unless there's a compelling security reason.

    Bitcoin Core generally supports fairly old OS versions. There's pros and cons to that (and it's certainly a pain), but that's a more general discussion.

  13. ryanofsky commented at 12:23 PM on August 13, 2025: contributor

    Latest version of https://github.com/bitcoin-core/libmultiprocess/pull/194 should trigger an error on ubuntu 22.04 instead of hanging:

    CMake Error at CMakeLists.txt:32 (message):
  Cap'n Proto 0.8.0 is affected by CVE-2022-46149.

  Please install an updated package.

  Details: https://github.com/advisories/GHSA-qqff-4vw4-f6hx
  14. ryanofsky commented at 12:37 AM on August 18, 2025: contributor

    I didn't dig into this but it seems like the root cause of infinite recursion might be a gcc bug https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53499 so using clang could be another workaround for this. The gcc bug is also fixed in gcc 14 according the issue. Ubuntu 22.04 uses gcc 11.4.0.

    (I stumbled across this seeing a headline about a gcc bug https://osec.io/blog/2025-08-11-compiler-bug-causes-compiler-bug https://news.ycombinator.com/item?id=44872584)

  15. fanquake commented at 12:39 PM on August 21, 2025: member

    Put on the v30.0 milestone.

  16. fanquake added this to the milestone 30.0 on Aug 21, 2025
  17. ryanofsky referenced this in commit 1b8d4a6f1e on Aug 22, 2025
  18. achow101 referenced this in commit 6ca6f3b37b on Aug 25, 2025
  19. maflcko commented at 8:08 AM on August 26, 2025: member

    On current master this will now fail configure:

    ...
cmake -B build -DENABLE_IPC=ON
...
-- Checking for module 'capnp'
--   Found capnp, version 0.8.0
-- Checking for module 'capnp-rpc'
--   Found capnp-rpc, version 0.8.0
-- Checking for module 'capnp-json'
--   Found capnp-json, version 0.8.0
-- Checking for module 'kj'
--   Found kj, version 0.8.0
-- Checking for module 'kj-async'
--   Found kj-async, version 0.8.0
-- Checking for module 'kj-http'
--   Found kj-http, version 0.8.0
-- Checking for module 'kj-gzip'
--   Found kj-gzip, version 0.8.0
-- Checking for module 'kj-tls'
--   Found kj-tls, version 0.8.0
-- Checking for module 'kj-test'
--   Found kj-test, version 0.8.0
CMake Error at src/ipc/libmultiprocess/CMakeLists.txt:32 (message):
  Cap'n Proto 0.8.0 is affected by CVE-2022-46149.

  Please install an updated package.

  Details: https://github.com/advisories/GHSA-qqff-4vw4-f6hx

    Not sure if this can be closed, or if something else may be better. C.f. https://github.com/bitcoin-core/libmultiprocess/pull/194#discussion_r2285528868

  20. Sjors commented at 9:03 AM on August 26, 2025: member

    I'm still investigating whether Ubuntu can be pursuaded to bump this. I received some replies on https://answers.launchpad.net/ubuntu/+source/capnproto/+question/822317 but haven't gotten around to studying those.

  21. maflcko commented at 9:25 AM on August 26, 2025: member

    The current IPC interface is trusted, and I don't think this is going to change after feature-freeze. Also, https://ubuntu.com/security/CVE-2022-46149 specifically says "low priority" and ignored for jammy, so I don't think Ubuntu is going to change the package.

    Not sure how common Ubuntu Jammy is and how many people compile from source, but https://snapcraft.io/bitcoin-core lists (by frequency):

    Ubuntu 24.04 Ubuntu 22.04 Ubuntu 20.04 Ubuntu 25.04

  22. ryanofsky commented at 10:48 AM on August 26, 2025: contributor

    From https://ubuntu.com/security/CVE-2022-46149 it seems to say ubuntu has looked at the issue and ignoring it in LTS releases ("Ignored" value in Status table), because the fix changes changes the ABI and could maybe break applications compiled against the 0.8.0 version of the headers but using the 0.8.1 runtime library (IIUC, I'm not exactly sure what they mean by changing the ABI). It seems like we have a few options here. Maybe we could update the documentation to recommend disabling ENABLE_IPC on Ubuntu 0.8.0, or installing cap'nproto from source, or as Marco is suggesting, just warn about 0.8.0 instead of erroring assuming we don't care about the CVE.

  24. fanquake commented at 9:06 AM on September 8, 2025: member

    Closing this with #33322. If there are new / more issues, lets open new issues.

  25. fanquake closed this on Sep 8, 2025
  26. ryanofsky commented at 9:42 AM on September 8, 2025: contributor

    Makes sense to close. Since #33241 which includes https://github.com/bitcoin-core/libmultiprocess/pull/194, the build hang using old versions of GCC with v0.8.0 and v0.8.1 was fixed, but a cmake error was added warning about a CVE in v0.8.0, which means that Ubuntu 22.04 triggers this error. Ubuntu security team evaluated the CVE and opted not to fix it based on the severity and fact that is fix is in a library, so could cause other packages to need to be recompiled. #33322 improves the situation by making error message clearer about potential workarounds (updating capnproto or setting -DENABLE_IPC=off)

Contributors
fanquakewillcl-arkryanofsky1BitcoinBoWP1FZ4xwTNkq6XksKidmgYYwSjorsmaflcko
Labels
Build system

Milestone
30.0

Linked (view graph)
#28722 Multiprocess tracking issue#31802 Add bitcoin-{node,gui} to release binaries for IPC#33241 Update libmultiprocess subtree to fix build issues
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