From 341ba0df4c69269cac839ddbacb2a0ca641a856d Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Tue, 25 Sep 2018 17:19:24 +0100 Subject: [PATCH] migration/ram.c: Avoid taking address of fields in packed MultiFDInit_t struct MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Taking the address of a field in a packed struct is a bad idea, because it might not be actually aligned enough for that pointer type (and thus cause a crash on dereference on some host architectures). Newer versions of clang warn about this: migration/ram.c:651:19: warning: taking address of packed member 'magic' of class or structure 'MultiFDInit_t' may result in an unaligned pointer value [-Waddress-of-packed-member] migration/ram.c:652:19: warning: taking address of packed member 'version' of class or structure 'MultiFDInit_t' may result in an unaligned pointer value [-Waddress-of-packed-member] migration/ram.c:737:19: warning: taking address of packed member 'magic' of class or structure 'MultiFDPacket_t' may result in an unaligned pointer value [-Waddress-of-packed-member] migration/ram.c:745:19: warning: taking address of packed member 'version' of class or structure 'MultiFDPacket_t' may result in an unaligned pointer value [-Waddress-of-packed-member] migration/ram.c:755:19: warning: taking address of packed member 'size' of class or structure 'MultiFDPacket_t' may result in an unaligned pointer value [-Waddress-of-packed-member] Avoid the bug by not using the "modify in place" byteswapping functions. Signed-off-by: Peter Maydell Message-Id: <20180925161924.7832-1-peter.maydell@linaro.org> Reviewed-by: Marc-André Lureau Signed-off-by: Dr. David Alan Gilbert --- migration/ram.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/migration/ram.c b/migration/ram.c index 408d237700..bc38d98cc3 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -651,8 +651,8 @@ static int multifd_recv_initial_packet(QIOChannel *c, Error **errp) return -1; } - be32_to_cpus(&msg.magic); - be32_to_cpus(&msg.version); + msg.magic = be32_to_cpu(msg.magic); + msg.version = be32_to_cpu(msg.version); if (msg.magic != MULTIFD_MAGIC) { error_setg(errp, "multifd: received packet magic %x " @@ -737,7 +737,7 @@ static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp) RAMBlock *block; int i; - be32_to_cpus(&packet->magic); + packet->magic = be32_to_cpu(packet->magic); if (packet->magic != MULTIFD_MAGIC) { error_setg(errp, "multifd: received packet " "magic %x and expected magic %x", @@ -745,7 +745,7 @@ static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp) return -1; } - be32_to_cpus(&packet->version); + packet->version = be32_to_cpu(packet->version); if (packet->version != MULTIFD_VERSION) { error_setg(errp, "multifd: received packet " "version %d and expected version %d", @@ -755,7 +755,7 @@ static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp) p->flags = be32_to_cpu(packet->flags); - be32_to_cpus(&packet->size); + packet->size = be32_to_cpu(packet->size); if (packet->size > migrate_multifd_page_count()) { error_setg(errp, "multifd: received packet " "with size %d and expected maximum size %d",