From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> To: Samuel Thibault <samuel.thibault@gnu.org> Cc: qemu-devel@nongnu.org, jan.kiszka@siemens.com Subject: Re: [Qemu-devel] [PATCH] slirp: Gcc 9 -O3 fix Date: Mon, 15 Apr 2019 13:02:36 +0100 [thread overview] Message-ID: <20190415120236.GJ2852@work-vm> (raw) In-Reply-To: <20190412211633.6pyn6cfm5dnwjzji@function> * Samuel Thibault (samuel.thibault@gnu.org) wrote: > Dr. David Alan Gilbert, le ven. 12 avril 2019 16:49:42 +0100, a ecrit: > > * Samuel Thibault (samuel.thibault@gnu.org) wrote: > > > Hello, > > > > > > Dr. David Alan Gilbert, le lun. 08 avril 2019 09:46:53 +0100, a ecrit: > > > > 'soread' has the comment: > > > > > > > > /* > > > > * No need to check if there's enough room to read. > > > > * soread wouldn't have been called if there weren't > > > > */ > > > > sopreprbuf(so, iov, &n); > > > > > > > > the compiler doesn't realise that, and is moaning about the case > > > > where the if (len <=0) return happens and the following > > > > code tries to use iov. > > > > > > I see. Perhaps we should make this an assert then? In case this isn't > > > true, i.e. soread() is called even if no room is available, returning 0 > > > would probably just let the caller just try again, and we should rather > > > just plainly crash than hang? > > > > Adding the assert in soread sorts that case out: > > assert(sopreprbuf(so, iov, &n) != 0); > > > > however, I also need to fix soreadbuf; is it legal to call that with > > a 0 size? > > It does not really make sense to, so an assert >0 should be fine. OK, replacement patch with just a couple of asserts sent. Dave > Samuel -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
WARNING: multiple messages have this Message-ID (diff)
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> To: Samuel Thibault <samuel.thibault@gnu.org> Cc: jan.kiszka@siemens.com, qemu-devel@nongnu.org Subject: Re: [Qemu-devel] [PATCH] slirp: Gcc 9 -O3 fix Date: Mon, 15 Apr 2019 13:02:36 +0100 [thread overview] Message-ID: <20190415120236.GJ2852@work-vm> (raw) Message-ID: <20190415120236.DbmK6xtV9FKYzGpsQ95lIjPOcYw6ZFFDwNlkdsaNgow@z> (raw) In-Reply-To: <20190412211633.6pyn6cfm5dnwjzji@function> * Samuel Thibault (samuel.thibault@gnu.org) wrote: > Dr. David Alan Gilbert, le ven. 12 avril 2019 16:49:42 +0100, a ecrit: > > * Samuel Thibault (samuel.thibault@gnu.org) wrote: > > > Hello, > > > > > > Dr. David Alan Gilbert, le lun. 08 avril 2019 09:46:53 +0100, a ecrit: > > > > 'soread' has the comment: > > > > > > > > /* > > > > * No need to check if there's enough room to read. > > > > * soread wouldn't have been called if there weren't > > > > */ > > > > sopreprbuf(so, iov, &n); > > > > > > > > the compiler doesn't realise that, and is moaning about the case > > > > where the if (len <=0) return happens and the following > > > > code tries to use iov. > > > > > > I see. Perhaps we should make this an assert then? In case this isn't > > > true, i.e. soread() is called even if no room is available, returning 0 > > > would probably just let the caller just try again, and we should rather > > > just plainly crash than hang? > > > > Adding the assert in soread sorts that case out: > > assert(sopreprbuf(so, iov, &n) != 0); > > > > however, I also need to fix soreadbuf; is it legal to call that with > > a 0 size? > > It does not really make sense to, so an assert >0 should be fine. OK, replacement patch with just a couple of asserts sent. Dave > Samuel -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
next prev parent reply other threads:[~2019-04-15 12:02 UTC|newest] Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-04-05 18:46 [Qemu-devel] [PATCH] slirp: Gcc 9 -O3 fix Dr. David Alan Gilbert (git) 2019-04-05 19:08 ` no-reply 2019-04-05 19:08 ` no-reply 2019-04-05 21:25 ` Samuel Thibault 2019-04-05 21:25 ` Samuel Thibault 2019-04-08 8:46 ` Dr. David Alan Gilbert 2019-04-08 8:46 ` Dr. David Alan Gilbert 2019-04-11 18:45 ` Samuel Thibault 2019-04-11 18:45 ` Samuel Thibault 2019-04-12 15:49 ` Dr. David Alan Gilbert 2019-04-12 15:49 ` Dr. David Alan Gilbert 2019-04-12 21:16 ` Samuel Thibault 2019-04-12 21:16 ` Samuel Thibault 2019-04-15 12:02 ` Dr. David Alan Gilbert [this message] 2019-04-15 12:02 ` Dr. David Alan Gilbert
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