YJIT: Add integrity checks for blockid

Verify that the iseq idx pair for the block is valid in
invalidate_block_version(). While we are at it, bound loop
iterating over instructions to `iseq_body->iseq_size`.

1 files changed, 11 insertions, 0 deletions

diff --git a/yjit_core.c b/yjit_core.c
index 00905e7f24..d420f0fcab 100644
--- a/yjit_core.c
+++ b/yjit_core.c
@@ -1205,6 +1205,15 @@ block_array_remove(rb_yjit_block_array_t block_array, block_t *block)
     RUBY_ASSERT(false);
 }
 
+// Some runtime checks for integrity of a program location
+static void
+verify_blockid(const blockid_t blockid)
+{
+    const rb_iseq_t *const iseq = blockid.iseq;
+    RUBY_ASSERT_ALWAYS(IMEMO_TYPE_P(iseq, imemo_iseq));
+    RUBY_ASSERT_ALWAYS(blockid.idx < iseq->body->iseq_size);
+}
+
 // Invalidate one specific block version
 static void
 invalidate_block_version(block_t *block)
@@ -1214,6 +1223,8 @@ invalidate_block_version(block_t *block)
     // TODO: want to assert that all other ractors are stopped here. Can't patch
     // machine code that some other thread is running.
 
+    verify_blockid(block->blockid);
+
     const rb_iseq_t *iseq = block->blockid.iseq;
 
     //fprintf(stderr, "invalidating block (%p, %d)\n", block->blockid.iseq, block->blockid.idx);