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[PULL,09/25] ivshmem: fix incorrect error handling in ivshmem_recv_msg()

Message ID b7b1e9dd6d56612d4656817b11e43d9fbefdc497.1501496349.git.mjt@msgid.tls.msk.ru (mailing list archive)
State New, archived
Headers show

Commit Message

Michael Tokarev July 31, 2017, 10:21 a.m. UTC 
From: Philippe Mathieu-Daudé <f4bug@amsat.org>

Screwed up in commit 3a55fc0f, v2.6.0.

If qemu_chr_fe_read_all() returns -EINTR the do {} statement continues and the
n accumulator used to complete reads upto sizeof(msg) is decremented by 4 (the
value of EINTR on Linux).
To avoid that, use simpler if() statements and continue if EINTR occured.

hw/misc/ivshmem.c:650:14: warning: Loss of sign in implicit conversion
    } while (n < sizeof(msg));
             ^

Reported-by: Clang Static Analyzer
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
---
 hw/misc/ivshmem.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
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Patch

diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index a58f9ee579..47a015f072 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -642,7 +642,10 @@  static int64_t ivshmem_recv_msg(IVShmemState *s, int *pfd, Error **errp)
     do {
         ret = qemu_chr_fe_read_all(&s->server_chr, (uint8_t *)&msg + n,
                                    sizeof(msg) - n);
-        if (ret < 0 && ret != -EINTR) {
+        if (ret < 0) {
+            if (ret == -EINTR) {
+                continue;
+            }
             error_setg_errno(errp, -ret, "read from server failed");
             return INT64_MIN;
         }