path: root/src
diff options
authorSamuel Holland <>2019-06-30 22:44:28 -0500
committerRich Felker <>2019-07-01 10:10:52 -0400
commit84ebec6ceea997568c1711e7d810ad6bb3a96346 (patch)
tree205112963e85f6d7e7db5a2d929da6e8131b8ff0 /src
parent3d178a7e2b75066593fbd5705742c5808395d90d (diff)
fix deadlock in synccall after threaded fork
synccall may be called by AS-safe functions such as setuid/setgid after fork. although fork() resets libc.threads_minus_one, causing synccall to take the single-threaded path, synccall still takes the thread list lock. This lock may be held by another thread if for example fork() races with pthread_create(). After fork(), the value of the lock is meaningless, so clear it. maintainer's note: commit 8f11e6127fe93093f81a52b15bb1537edc3fc8af and e4235d70672d9751d7718ddc2b52d0b426430768 introduced this regression. the state protected by this lock is the linked list, which is entirely replaced in the child path of fork (next=prev=self), so resetting it is semantically sound.
Diffstat (limited to 'src')
1 files changed, 1 insertions, 0 deletions
diff --git a/src/process/fork.c b/src/process/fork.c
index 11286ef4..fb42478a 100644
--- a/src/process/fork.c
+++ b/src/process/fork.c
@@ -28,6 +28,7 @@ pid_t fork(void)
self-> = 0;
self->robust_list.pending = 0;
self->next = self->prev = self;
+ __thread_list_lock = 0;
libc.threads_minus_1 = 0;