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author | Samuel Williams <samuel.williams@oriontransfer.co.nz> | 2019-06-20 11:31:22 +1200 |
---|---|---|
committer | Samuel Williams <samuel.williams@oriontransfer.co.nz> | 2019-06-20 16:44:50 +1200 |
commit | e4cafa393f8fd4aa207f20b1d122884b4de99cf1 (patch) | |
tree | 78e6a286bcb55b6dd180153b1be9508090c25090 /thread.c | |
parent | c26c51449461e3c8ee9bb4e1800933fb3d3caf67 (diff) | |
download | ruby-e4cafa393f8fd4aa207f20b1d122884b4de99cf1.tar.gz |
Ensure that vm_stack is cleared in `thread_cleanup_func_before_exec`.
If `vm_stack` is left dangling in a forked process, the gc attempts to scan
it, but it is invalid and will cause a segfault. Therefore, we clear it
before forking.
In order to simplify this, `rb_ec_clear_vm_stack` was introduced.
Diffstat (limited to 'thread.c')
-rw-r--r-- | thread.c | 16 |
1 files changed, 12 insertions, 4 deletions
@@ -596,7 +596,11 @@ thread_cleanup_func_before_exec(void *th_ptr) { rb_thread_t *th = th_ptr; th->status = THREAD_KILLED; + // The thread stack doesn't exist in the forked process: th->ec->machine.stack_start = th->ec->machine.stack_end = NULL; + + // The vm_stack is `alloca`ed on the thread stack, so it's gone too: + rb_ec_clear_vm_stack(th->ec); } static void @@ -713,19 +717,19 @@ thread_start_func_2(rb_thread_t *th, VALUE *stack_start) rb_bug("thread_start_func_2 must not be used for main thread"); } + thread_debug("thread start: %p\n", (void *)th); + VM_ASSERT((size * sizeof(VALUE)) <= th->ec->machine.stack_maxsize); + vm_stack = alloca(size * sizeof(VALUE)); VM_ASSERT(vm_stack); gvl_acquire(th->vm, th); rb_ec_initialize_vm_stack(th->ec, vm_stack, size); - - ruby_thread_set_native(th); - th->ec->machine.stack_start = STACK_DIR_UPPER(vm_stack + size, vm_stack); th->ec->machine.stack_maxsize -= size * sizeof(VALUE); - thread_debug("thread start: %p\n", (void *)th); + ruby_thread_set_native(th); { thread_debug("thread start (get lock): %p\n", (void *)th); @@ -806,7 +810,10 @@ thread_start_func_2(rb_thread_t *th, VALUE *stack_start) rb_fiber_close(th->ec->fiber_ptr); } + thread_cleanup_func(th, FALSE); + VM_ASSERT(th->ec->vm_stack == NULL); + gvl_release(th->vm); return 0; @@ -2253,6 +2260,7 @@ rb_threadptr_execute_interrupts(rb_thread_t *th, int blocking_timing) if (th->status == THREAD_RUNNABLE) th->running_time_us += TIME_QUANTUM_USEC; + VM_ASSERT(th->ec->cfp); EXEC_EVENT_HOOK(th->ec, RUBY_INTERNAL_EVENT_SWITCH, th->ec->cfp->self, 0, 0, 0, Qundef); |