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Hennadii Stepanov ff26406b2b
Merge bitcoin-core/gui#693: Fix segfault when shutdown during wallet open 
9a1d73fdff Fix segfault when shutdown during wallet open (John Moffett)

Pull request description:

  Fixes #689

  ## Summary

  If you open a wallet and send a shutdown signal during that process, you'll get a segfault when the wallet finishes opening. That's because the `WalletController` object gets deleted manually in bitcoin.cpp during shutdown, but copies of the pointer (and pointers to child objects) are dangling in various places and are accessed in queued events after the deletion.

  ## Details

  The issue in #689 is caused by the following sequence of events:

  1. Wallet open modal dialog is shown and worker thread does the actual work.
  2. Every 200ms, the main event loop checks to see if a shutdown has been requested, but only if a modal is not being shown.
  3. Request a shutdown while the modal window is shown.
  4. The wallet open process completes, the modal window is dismissed, and various `finish` signals are sent.
  5. During handling of one of the `finish` signals, `qApp->processEvents()` is [called](e9262ea32a/src/qt/sendcoinsdialog.cpp (L603)), which causes the main event loop to detect the shutdown (now that the modal window has been dismissed). The `WalletController` and all the `WalletModel`s are [deleted](65de8eeeca/src/qt/bitcoin.cpp (L394-L401)).
  6. Control returns to the `finish` method, which eventually tries to send a [signal](e9262ea32a/src/qt/sendcoinsdialog.cpp (L167)) from a wallet model, but it's been deleted already (and the signal is sent from a now-[dangling](d8bdee0fc8/src/qt/walletview.cpp (L65)) pointer).

  The simplest fix for that is to change the `qApp->processEvents()` into a `QueuedConnection` call. (The `qApp->processEvents() was a [workaround](https://github.com/bitcoin/bitcoin/pull/593#issuecomment-3050699) to get the GUI to scroll to the last item in a list that just got added, and this is just a safer way of doing that).

  However, once that segfault is fixed, another segfault occurs due to some queued wallet events happening after the wallet controller object is deleted here:

  65de8eeeca/src/qt/bitcoin.cpp (L394-L401)

  Since `m_wallet_controller` is a copy of that pointer in `bitcoingui.cpp`, it's now dangling and `if(null)` checks won't work correctly. For instance, this line:

  65de8eeeca/src/qt/bitcoingui.cpp (L413)

  sets up a `QueuedConnection` to `setCurrentWallet`, but by the time control reaches that method (one event cycle after shutdown deleted `m_wallet_controller` in `bitcoin.cpp`), the underlying objects have been destroyed (but the pointers are still dangling).

  Ideally, we'd use a `QPointer` or `std::shared_ptr / std::weak_ptr`s for these, but the changes would be more involved.

  This is a minimal fix for the issues. Just set `m_wallet_controller` to `nullptr` in `bitcoingui.cpp`, check its value in a couple places, and avoid a use of `qApp->processEvents`.

ACKs for top commit:
  hebasto:
    ACK 9a1d73fdff, I have reviewed the code and it looks OK.
  furszy:
    ACK 9a1d73fdff

Tree-SHA512: a1b94676eb2fcb7606e68fab443b1565b4122aab93c35382b561842a049f4b43fecc459535370d67a64d6ebc4bcec0ebcda981fff633ebd41bdba6f7093ea540
 		2023-03-27 15:53:42 +01:00
.github github: Switch to yaml issue templates 2023-02-21 11:31:16 +00:00
.tx qt: Bump Transifex slug for 25.x 2023-02-27 14:01:14 +00:00
build-aux/m4 build: remove Boost lib detection from ax_boost_base 2023-01-13 10:41:33 +00:00
build_msvc Merge bitcoin/bitcoin#26691: Update secp256k1 subtree to libsecp256k1 version 0.2.0 2023-01-13 09:40:57 +00:00
ci ci: Cache more stuff in the ci images: msan, iwyu, pip, sdks 2023-03-24 10:19:25 +01:00
contrib Merge bitcoin/bitcoin#27326: guix: combine and document `enable_werror` 2023-03-27 14:55:27 +01:00
depends Merge bitcoin/bitcoin#27314: build, qt: Fix handling of `CXX=clang++` when building `qt` package 2023-03-27 15:24:33 +01:00
doc Merge bitcoin/bitcoin#26899: p2p: set `-dnsseed` and `-listen` false if `maxconnections=0` 2023-03-20 12:49:10 -04:00
share Modernize rpcauth.py and its tests 2023-02-13 17:11:15 -05:00
src Merge bitcoin-core/gui#693: Fix segfault when shutdown during wallet open 2023-03-27 15:53:42 +01:00
test Merge bitcoin/bitcoin#27269: test: Support decoding segwit address in address_to_scriptpubkey() 2023-03-24 12:17:38 +00:00
.cirrus.yml ci: Use clang-15 in "tidy" task 2023-03-22 15:21:39 +00:00
.editorconfig ci: Drop AppVeyor CI integration 2021-09-07 06:12:53 +03:00
.gitattributes Separate protocol versioning from clientversion 2014-10-29 00:24:40 -04:00
.gitignore refactor: cleanups post unsubtree'ing univalue 2022-06-15 12:56:44 +01:00
.python-version Bump minimum python version to 3.7 2023-01-18 12:59:11 +01:00
.style.yapf test: .style.yapf: Set column_limit=160 2019-03-04 18:28:13 -05:00
CONTRIBUTING.md doc: Explain squashing with merge commits 2022-05-24 08:17:41 +02:00
COPYING doc: Update license year range to 2023 2022-12-24 11:40:16 +01:00
INSTALL.md doc: Added hyperlink for doc/build 2021-09-09 19:53:12 +05:30
Makefile.am build: package test_bitcoin in Windows installer 2022-08-09 09:13:23 +01:00
README.md doc: Explain Bitcoin Core in README.md 2022-05-10 07:49:09 +02:00
SECURITY.md doc: Add my key to SECURITY.md 2022-08-23 16:57:46 -04:00
autogen.sh scripted-diff: Bump copyright of files changed in 2019 2019-12-30 10:42:20 +13:00
configure.ac Merge bitcoin/bitcoin#25696: build: Re-enable external signer on Windows 2023-03-08 21:01:53 -05:00
libbitcoinconsensus.pc.in build: remove libcrypto as internal dependency in libbitcoinconsensus.pc 2019-11-19 15:03:44 +01:00

README.md

Bitcoin Core integration/staging tree

https://bitcoincore.org

For an immediately usable, binary version of the Bitcoin Core software, see https://bitcoincore.org/en/download/.

What is Bitcoin Core?

Bitcoin Core connects to the Bitcoin peer-to-peer network to download and fully validate blocks and transactions. It also includes a wallet and graphical user interface, which can be optionally built.

Further information about Bitcoin Core is available in the doc folder.

License

Bitcoin Core is released under the terms of the MIT license. See COPYING for more information or see https://opensource.org/licenses/MIT.

Development Process

The master branch is regularly built (see doc/build-*.md for instructions) and tested, but it is not guaranteed to be completely stable. Tags are created regularly from release branches to indicate new official, stable release versions of Bitcoin Core.

The https://github.com/bitcoin-core/gui repository is used exclusively for the development of the GUI. Its master branch is identical in all monotree repositories. Release branches and tags do not exist, so please do not fork that repository unless it is for development reasons.

The contribution workflow is described in CONTRIBUTING.md and useful hints for developers can be found in doc/developer-notes.md.

Testing

Testing and code review is the bottleneck for development; we get more pull requests than we can review and test on short notice. Please be patient and help out by testing other people's pull requests, and remember this is a security-critical project where any mistake might cost people lots of money.

Automated Testing

Developers are strongly encouraged to write unit tests for new code, and to submit new unit tests for old code. Unit tests can be compiled and run (assuming they weren't disabled in configure) with: make check. Further details on running and extending unit tests can be found in /src/test/README.md.

There are also regression and integration tests, written in Python. These tests can be run (if the test dependencies are installed) with: test/functional/test_runner.py

The CI (Continuous Integration) systems make sure that every pull request is built for Windows, Linux, and macOS, and that unit/sanity tests are run automatically.

Manual Quality Assurance (QA) Testing

Changes should be tested by somebody other than the developer who wrote the code. This is especially important for large or high-risk changes. It is useful to add a test plan to the pull request description if testing the changes is not straightforward.

Translations

Changes to translations as well as new translations can be submitted to Bitcoin Core's Transifex page.

Translations are periodically pulled from Transifex and merged into the git repository. See the translation process for details on how this works.

Important: We do not accept translation changes as GitHub pull requests because the next pull from Transifex would automatically overwrite them again.