[PATCH] accel/tcg: test CPUJumpCache in tb_jmp_cache_clear_page()

[Eric Auger <eric.auger@redhat.com>]

After commit 4e4fa6c12d ("accel/tcg: Complete cpu initialization
before registration"), it looks the CPUJumpCache handle can be NULL.
This causes a SIGSEV when running debug-wp-migration kvm unit test.

At the first place it should be clarified why this TCG code is called
with KVM acceleration. This may hide another bug.

Fixes: 4e4fa6c12d ("accel/tcg: Complete cpu initialization before registration")
Signed-off-by: Eric Auger <eric.auger@redhat.com>
---
 accel/tcg/cputlb.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
index 4e040a1cb9..ac0245ee6c 100644
--- a/accel/tcg/cputlb.c
+++ b/accel/tcg/cputlb.c
@@ -103,6 +103,10 @@ static void tb_jmp_cache_clear_page(CPUState *cpu, target_ulong page_addr)
     int i, i0 = tb_jmp_cache_hash_page(page_addr);
     CPUJumpCache *jc = cpu->tb_jmp_cache;
 
+    if (!jc) {
+        return;
+    }
+
     for (i = 0; i < TB_JMP_PAGE_SIZE; i++) {
         qatomic_set(&jc->array[i0 + i].tb, NULL);
     }
-- 
2.37.3