[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] question about SIGSEGV in datacopier_readable in libxl_aoutil.c [and 1 more messages]
Ian Campbell writes ("Re: [Xen-devel] question about SIGSEGV in datacopier_readable in libxl_aoutil.c"): > On Tue, 2013-09-03 at 15:01 +0800, Chunyan Liu wrote: > > if (!buf || buf->used >= sizeof(buf->buf)) { > > buf = malloc(sizeof(*buf)); ... > > ==7510== Syscall param read(buf) points to unaddressable byte(s) ... > > ==7510== Address 0x18a409ec is 0 bytes after a block of size 28 alloc'd > > ==7510== at 0x4C26FFB: calloc (in > > /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so) > > ==7510== by 0x14AAECB6: libxl__zalloc (libxl_internal.c:83) > > ==7510== by 0x14AB33B0: libxl__datacopier_prefixdata (libxl_aoutils.c:92) I think this is my fault. Please try this patch. Thanks, Ian. commit 25cd65c97b733d5892b62c3ffae0887f426398ec Author: Ian Jackson <ian.jackson@xxxxxxxxxxxxx> Date: Tue Sep 3 13:41:46 2013 +0100 libxl: Do not generate short block in libxl__datacopier_prefixdata libxl__datacopier_prefixdata would prepend a deliberately short block (not just a half-full one, but one with a short buffer) to the dc->bufs queue. However, this is wrong because datacopier_readable will find it and try to continue to fill it up. Instead, allocate a full-sized buffer. Signed-off-by: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx> diff --git a/tools/libxl/libxl_aoutils.c b/tools/libxl/libxl_aoutils.c index 983a60a..b4eb6e5 100644 --- a/tools/libxl/libxl_aoutils.c +++ b/tools/libxl/libxl_aoutils.c @@ -89,7 +89,7 @@ void libxl__datacopier_prefixdata(libxl__egc *egc, libxl__datacopier_state *dc, assert(len < dc->maxsz - dc->used); - buf = libxl__zalloc(NOGC, sizeof(*buf) - sizeof(buf->buf) + len); + buf = libxl__zalloc(NOGC, sizeof(*buf)); buf->used = len; memcpy(buf->buf, data, len); _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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