| Message ID | 1437566873-28782-1-git-send-email-rjones@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Wed, Jul 22, 2015 at 01:07:53PM +0100, Richard W.M. Jones wrote: > On some (but not all) systems: > > $ qemu-img create -f qcow2 overlay -b ssh://xen/ > Segmentation fault > > It turns out this happens when inet_connect returns NULL in the > following code, but errno is not set (0). Bleah .. not NULL, -1. I'm going to send an updated v2 patch which will just fix the message. Rich. > s->sock = inet_connect(s->hostport, errp); > if (s->sock < 0) { > ret = -errno; > goto err; > } > > In the case above, 'xen' doesn't exist so getaddrinfo fails. On > Fedora 22, getaddrinfo happens to set errno = ENOENT (although it is > _not_ documented to do that), so it doesn't segfault. > > On RHEL 7, errno is not set by the failing getaddrinfo, so ret == 0, > so the caller doesn't know there was an error and continues with a > half-initialized BDRVSSHState struct, and everything goes south from > there. > > Fix this by setting errno to EINVAL. The real error is saved in the > Error** errp struct, so it is printed correctly: > > $ ./qemu-img create -f qcow2 overlay -b ssh://xen/ > qemu-img: overlay: address resolution failed for xen:22: No address associated with hostname > > BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1147343 > Signed-off-by: Richard W.M. Jones <rjones@redhat.com> > --- > block/ssh.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/block/ssh.c b/block/ssh.c > index aebb18c..8d4dc2a 100644 > --- a/block/ssh.c > +++ b/block/ssh.c > @@ -563,7 +563,7 @@ static int connect_to_ssh(BDRVSSHState *s, QDict *options, > /* Open the socket and connect. */ > s->sock = inet_connect(s->hostport, errp); > if (s->sock < 0) { > - ret = -errno; > + ret = -EINVAL; > goto err; > } > > -- > 2.4.3 >
diff --git a/block/ssh.c b/block/ssh.c index aebb18c..8d4dc2a 100644 --- a/block/ssh.c +++ b/block/ssh.c @@ -563,7 +563,7 @@ static int connect_to_ssh(BDRVSSHState *s, QDict *options, /* Open the socket and connect. */ s->sock = inet_connect(s->hostport, errp); if (s->sock < 0) { - ret = -errno; + ret = -EINVAL; goto err; }
On some (but not all) systems: $ qemu-img create -f qcow2 overlay -b ssh://xen/ Segmentation fault It turns out this happens when inet_connect returns NULL in the following code, but errno is not set (0). s->sock = inet_connect(s->hostport, errp); if (s->sock < 0) { ret = -errno; goto err; } In the case above, 'xen' doesn't exist so getaddrinfo fails. On Fedora 22, getaddrinfo happens to set errno = ENOENT (although it is _not_ documented to do that), so it doesn't segfault. On RHEL 7, errno is not set by the failing getaddrinfo, so ret == 0, so the caller doesn't know there was an error and continues with a half-initialized BDRVSSHState struct, and everything goes south from there. Fix this by setting errno to EINVAL. The real error is saved in the Error** errp struct, so it is printed correctly: $ ./qemu-img create -f qcow2 overlay -b ssh://xen/ qemu-img: overlay: address resolution failed for xen:22: No address associated with hostname BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1147343 Signed-off-by: Richard W.M. Jones <rjones@redhat.com> --- block/ssh.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)