The ALLOCA(3) man-page mentions its "use is discouraged".

Replace a g_alloca() call by a autofree g_malloc() one,
moving the allocation before the MUTEX guarded block.

Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 backends/tpm/tpm_emulator.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/backends/tpm/tpm_emulator.c b/backends/tpm/tpm_emulator.c
index a012adc1934..9553cdd891f 100644
--- a/backends/tpm/tpm_emulator.c
+++ b/backends/tpm/tpm_emulator.c
@@ -123,12 +123,11 @@ static int tpm_emulator_ctrlcmd(TPMEmulator *tpm, unsigned long cmd, void *msg,
     CharBackend *dev = &tpm->ctrl_chr;
     uint32_t cmd_no = cpu_to_be32(cmd);
     ssize_t n = sizeof(uint32_t) + msg_len_in;
-    uint8_t *buf = NULL;
+    g_autofree uint8_t *buf = g_malloc(n);
     int ret = -1;
 
     qemu_mutex_lock(&tpm->mutex);
 
-    buf = g_alloca(n);
     memcpy(buf, &cmd_no, sizeof(cmd_no));
     memcpy(buf + sizeof(cmd_no), msg, msg_len_in);
 
-- 
2.26.3