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author | Alan Wu <XrXr@users.noreply.github.com> | 2023-11-29 18:10:13 -0500 |
---|---|---|
committer | Alan Wu <XrXr@users.noreply.github.com> | 2023-11-30 11:59:32 -0500 |
commit | 85092ecd6f5c4d12d0cb1d6dfa7040337a4f558b (patch) | |
tree | 5a0a74b7f7fdb437db1014320eb62016181cfc1b /vm.c | |
parent | d048bae96b4108104cd0e77aad44962a39a5796f (diff) | |
download | ruby-85092ecd6f5c4d12d0cb1d6dfa7040337a4f558b.tar.gz |
Fix imemo_env corruption under auto compaction
Previously, vm_make_env_each() did:
1. ALLOC env_body
2. Copy locals into env_body
3. Allocate imemo_env
4. Set up imemo_env with env_body
If compaction runs during (3), locals copied to env_body could be
moved and the imemo_env could end up with invalid references.
Move (2) down so it reads references after potential movement.
Diffstat (limited to 'vm.c')
-rw-r--r-- | vm.c | 27 |
1 files changed, 17 insertions, 10 deletions
@@ -918,8 +918,6 @@ static VALUE vm_make_env_each(const rb_execution_context_t * const ec, rb_control_frame_t *const cfp) { const VALUE * const ep = cfp->ep; - const rb_env_t *env; - const rb_iseq_t *env_iseq; VALUE *env_body, *env_ep; int local_size, env_size; @@ -971,9 +969,26 @@ vm_make_env_each(const rb_execution_context_t * const ec, rb_control_frame_t *co env_size = local_size + 1 /* envval */; + + // Careful with order in the following sequence. Each allocation can move objects. env_body = ALLOC_N(VALUE, env_size); + rb_env_t *env = (rb_env_t *)rb_imemo_new(imemo_env, 0, 0, 0, 0); + + // Set up env without WB since it's brand new (similar to newobj_init(), newobj_fill()) MEMCPY(env_body, ep - (local_size - 1 /* specval */), VALUE, local_size); + env_ep = &env_body[local_size - 1 /* specval */]; + env_ep[VM_ENV_DATA_INDEX_ENV] = (VALUE)env; + + env->iseq = (rb_iseq_t *)(VM_FRAME_RUBYFRAME_P(cfp) ? cfp->iseq : NULL); + env->ep = env_ep; + env->env = env_body; + env->env_size = env_size; + + cfp->ep = env_ep; + VM_ENV_FLAGS_SET(env_ep, VM_ENV_FLAG_ESCAPED | VM_ENV_FLAG_WB_REQUIRED); + VM_STACK_ENV_WRITE(ep, 0, (VALUE)env); /* GC mark */ + #if 0 for (i = 0; i < local_size; i++) { if (VM_FRAME_RUBYFRAME_P(cfp)) { @@ -983,14 +998,6 @@ vm_make_env_each(const rb_execution_context_t * const ec, rb_control_frame_t *co } #endif - env_iseq = VM_FRAME_RUBYFRAME_P(cfp) ? cfp->iseq : NULL; - env_ep = &env_body[local_size - 1 /* specval */]; - - env = vm_env_new(env_ep, env_body, env_size, env_iseq); - - cfp->ep = env_ep; - VM_ENV_FLAGS_SET(env_ep, VM_ENV_FLAG_ESCAPED | VM_ENV_FLAG_WB_REQUIRED); - VM_STACK_ENV_WRITE(ep, 0, (VALUE)env); /* GC mark */ return (VALUE)env; } |