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kernel/user_mutex: Let single-threaded applications sleep on mutexes.

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It seems some single-threaded applications do use them, which doesn't
result in a deadlock because they use timeouts (or maybe wait on
signals, too.)
This commit is contained in:
Augustin Cavalier
2026-03-05 12:46:31 -05:00
parent 02683a08de
commit 585ac6895e
1 changed files with 11 additions and 4 deletions
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src/system/kernel/locks/user_mutex.cpp
+11 -4
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@@ -223,7 +223,8 @@ status_t
allocate_team_user_mutex_context(Team* team) allocate_team_user_mutex_context(Team* team)
{ {
team->AssertLocked(); team->AssertLocked();
ASSERT(team->user_mutex_context == NULL); if (team->user_mutex_context != NULL)
return B_OK;
struct user_mutex_context* context = new(std::nothrow) user_mutex_context; struct user_mutex_context* context = new(std::nothrow) user_mutex_context;
if (context == NULL) if (context == NULL)
@@ -465,9 +466,15 @@ struct UserMutexContextFetcher {
if (!fShared) { if (!fShared) {
fContext = thread_get_current_thread()->team->user_mutex_context; fContext = thread_get_current_thread()->team->user_mutex_context;
if (fContext == NULL) { if (fContext == NULL) {
_user_debugger("single-threaded team attempted mutex operation"); // This should only happen for single-threaded applications (some
fInitStatus = EDEADLK; // appear to use mutexes as a sleep mechanism), as the context gets
return; // allocated on the creation of a second thread.
Team* team = thread_get_current_thread()->team;
team->Lock();
fInitStatus = allocate_team_user_mutex_context(team);
team->Unlock();
if (fInitStatus != B_OK)
return;
} }
fAddress = (addr_t)mutex; fAddress = (addr_t)mutex;