[PULL 5/5] linux-user: fix Coverity CID 1464101

[Laurent Vivier <laurent@vivier.eu>]

target_mmap() can fail and return -1, but we don't check for that and
instead assume it's always valid.

Fixes: db2af69d6ba8 ("linux-user: Add infrastructure for a signal trampoline page")
Cc: richard.henderson@linaro.org
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211121151711.331653-1-laurent@vivier.eu>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 linux-user/elfload.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 5da8c02d0822..767f54c76dc5 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -3254,9 +3254,13 @@ int load_elf_binary(struct linux_binprm *bprm, struct image_info *info)
      * Otherwise, allocate a private page to hold them.
      */
     if (TARGET_ARCH_HAS_SIGTRAMP_PAGE) {
-        abi_ulong tramp_page = target_mmap(0, TARGET_PAGE_SIZE,
-                                           PROT_READ | PROT_WRITE,
-                                           MAP_PRIVATE | MAP_ANON, -1, 0);
+        abi_long tramp_page = target_mmap(0, TARGET_PAGE_SIZE,
+                                          PROT_READ | PROT_WRITE,
+                                          MAP_PRIVATE | MAP_ANON, -1, 0);
+        if (tramp_page == -1) {
+            return -errno;
+        }
+
         setup_sigtramp(tramp_page);
         target_mprotect(tramp_page, TARGET_PAGE_SIZE, PROT_READ | PROT_EXEC);
     }
-- 
2.31.1