fix: Dynamorio crash in rseq_clear_tls_pointer during thread exit

patches/dynamorio-10.0.patch

@@ -694,6 +694,31 @@ index d5133bf16..e9273a08b 100644
          if (ksynch_get_value(&ostd->suspended) == 0) {
              /* If it still has to wait, give up the cpu. */
              os_thread_yield();
+diff --git a/core/unix/rseq_linux.c b/core/unix/rseq_linux.c
+index 4d3b9e60f..4ce713450 100644
+--- a/core/unix/rseq_linux.c
++++ b/core/unix/rseq_linux.c
+@@ -253,12 +253,14 @@ rseq_clear_tls_ptr(dcontext_t *dcontext)
+ {
+     ASSERT(rseq_tls_offset != 0);
+     byte *base = get_app_segment_base(LIB_SEG_TLS);
+-    struct rseq *app_rseq = (struct rseq *)(base + rseq_tls_offset);
+-    /* We're directly writing this in the cache, so we do not bother with safe_read
+-     * or safe_write here either.  We already cannot handle rseq adversarial cases.
+-     */
+-    if (is_dynamo_address((byte *)(ptr_uint_t)app_rseq->rseq_cs))
+-        app_rseq->rseq_cs = 0;
++    if (base > 0) {
++        struct rseq *app_rseq = (struct rseq *)(base + rseq_tls_offset);
++        /* We're directly writing this in the cache, so we do not bother with safe_read
++         * or safe_write here either.  We already cannot handle rseq adversarial cases.
++         */
++        if (is_dynamo_address((byte *)(ptr_uint_t)app_rseq->rseq_cs))
++            app_rseq->rseq_cs = 0;
++    }
+ }
+
+ int
 diff --git a/core/unix/signal.c b/core/unix/signal.c
 index 0cbc94337..4d32e4610 100644
 --- a/core/unix/signal.c