[PULL 2/5] accel/tcg: Fix uninitialized hostp in get_page_addr_code_hostp

Richard Henderson posted 5 patches 3 days, 18 hours ago
Maintainers: Richard Henderson <richard.henderson@linaro.org>, Paolo Bonzini <pbonzini@redhat.com>, Riku Voipio <riku.voipio@iki.fi>, Laurent Vivier <laurent@vivier.eu>, Pierrick Bouvier <pierrick.bouvier@linaro.org>
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[PULL 2/5] accel/tcg: Fix uninitialized hostp in get_page_addr_code_hostp
Posted by Richard Henderson 3 days, 18 hours ago
This uninitialized value violates the contract in the
documentation comment, and may lead to a SEGV during
translaton with -d in_asm.

Change the documentation to disallow hostp NULL.
Pass hostp to probe_access_internal directly.

Reported-by: Panda Jiang <3160104094@zju.edu.cn>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 accel/tcg/internal-common.h | 2 +-
 accel/tcg/cputlb.c          | 8 ++++----
 accel/tcg/user-exec.c       | 4 +---
 3 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/accel/tcg/internal-common.h b/accel/tcg/internal-common.h
index 0ca13750f9..9e7be2d78d 100644
--- a/accel/tcg/internal-common.h
+++ b/accel/tcg/internal-common.h
@@ -82,7 +82,7 @@ void tb_check_watchpoint(CPUState *cpu, uintptr_t retaddr);
  * See get_page_addr_code() (full-system version) for documentation on the
  * return value.
  *
- * Sets *@hostp (when @hostp is non-NULL) as follows.
+ * Sets *@hostp as follows.
  * If the return value is -1, sets *@hostp to NULL. Otherwise, sets *@hostp
  * to the host address where @addr's content is kept.
  *
diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
index 76546c6651..3d75abbe68 100644
--- a/accel/tcg/cputlb.c
+++ b/accel/tcg/cputlb.c
@@ -1545,18 +1545,18 @@ tb_page_addr_t get_page_addr_code_hostp(CPUArchState *env, vaddr addr,
 
     (void)probe_access_internal(env_cpu(env), addr, 1, MMU_INST_FETCH,
                                 cpu_mmu_index(env_cpu(env), true), false,
-                                &p, &full, 0, false);
+                                hostp, &full, 0, false);
+
+    p = *hostp;
     if (p == NULL) {
         return -1;
     }
 
     if (full->lg_page_size < TARGET_PAGE_BITS) {
+        *hostp = NULL;
         return -1;
     }
 
-    if (hostp) {
-        *hostp = p;
-    }
     return qemu_ram_addr_from_host_nofail(p);
 }
 
diff --git a/accel/tcg/user-exec.c b/accel/tcg/user-exec.c
index ddbdc0432d..f8b4a26711 100644
--- a/accel/tcg/user-exec.c
+++ b/accel/tcg/user-exec.c
@@ -822,9 +822,7 @@ tb_page_addr_t get_page_addr_code_hostp(CPUArchState *env, vaddr addr,
     flags = probe_access_internal(env, addr, 1, MMU_INST_FETCH, false, 0);
     g_assert(flags == 0);
 
-    if (hostp) {
-        *hostp = g2h_untagged(addr);
-    }
+    *hostp = g2h_untagged(addr);
     return addr;
 }
 
-- 
2.43.0