Skip to content

gh-126688: Reinit import lock after fork #126692

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
colesbury merged 3 commits into from
Nov 12, 2024
Merged

gh-126688: Reinit import lock after fork #126692

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
5e86cca
gh-126688: Reinit import lock after fork
colesbury Nov 11, 2024
4bf74b8
Merge branch 'main' into gh-126688-import-lock
colesbury Nov 11, 2024
27d5db7
Only re-initialize thread id
colesbury Nov 11, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Next Next commit
gh-126688: Reinit import lock after fork 
The PyMutex implementation supports unlocking after fork because we
clear the list of watiers in parking_lot.c. This doesn't work as well
for _PyRecursiveMutex because on some systems, such as SerenityOS, the
thread id is not preserved across fork().
  • Loading branch information
@colesbury
colesbury committed Nov 11, 2024
commit 5e86cca8313575ab1cde8b01abee7f20d25df568
7 changes: 7 additions & 0 deletions Include/internal/pycore_lock.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -164,6 +164,13 @@ extern PyLockStatus _PyRecursiveMutex_LockTimed(_PyRecursiveMutex *m, PyTime_t t
PyAPI_FUNC(void) _PyRecursiveMutex_Unlock(_PyRecursiveMutex *m);
extern int _PyRecursiveMutex_TryUnlock(_PyRecursiveMutex *m);

static inline void
_PyRecursiveMutex_at_fork_reinit(_PyRecursiveMutex *m)
{
memset(m, 0, sizeof(*m));
}


// A readers-writer (RW) lock. The lock supports multiple concurrent readers or
// a single writer. The lock is write-preferring: if a writer is waiting while
// the lock is read-locked then, new readers will be blocked. This avoids
Expand Down
2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Core_and_Builtins/2024-11-11-17-02-48.gh-issue-126688.QiOXUi.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
Fix a crash when calling :func:`os.fork` on some operating systems,
including SerenityOS.
3 changes: 2 additions & 1 deletion Modules/posixmodule.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -678,7 +678,8 @@ PyOS_AfterFork_Child(void)
_PyEval_StartTheWorldAll(&_PyRuntime);
_PyThreadState_DeleteList(list);

_PyImport_ReleaseLock(tstate->interp);
// gh-126688: Reinit lock because thread id may differ in child process.
_PyRecursiveMutex_at_fork_reinit(&tstate->interp->imports.lock);

_PySignal_AfterFork();

Expand Down