From: Dan Carpenter <error27@gmail.com>
To: David Howells <dhowells@redhat.com>
Cc: Marc Dionne <marc.dionne@auristor.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
linux-afs@lists.infradead.org, netdev@vger.kernel.org,
kernel-janitors@vger.kernel.org
Subject: Re: [PATCH net-next] rxrpc: uninitialized variable in rxrpc_send_ack_packet()
Date: Thu, 17 Nov 2022 13:34:57 +0300 [thread overview]
Message-ID: <Y3YOUQM/ldDe/sgC@kadam> (raw)
In-Reply-To: <3475095.1668678264@warthog.procyon.org.uk>
On Thu, Nov 17, 2022 at 09:44:24AM +0000, David Howells wrote:
> Dan Carpenter <error27@gmail.com> wrote:
>
> > The "pkt" was supposed to have been deleted in a previous patch. It
> > leads to an uninitialized variable bug.
>
> Weird. I don't get a compiler warning and the kernel doesn't crash, despite
> transmitting millions of acks.
>
> If I disassemble the built code, I see:
>
> 0xffffffff81b09e89 <+723>: xor %edi,%edi
> 0xffffffff81b09e8b <+725>: call 0xffffffff811c0bc1 <kfree>
>
> I'm not sure why it's sticking 0 in EDI, though.
We disabled GCC's check for uninitialized variables. It could be that
you have the .config to automatically zero out stack variables.
CONFIG_CC_HAS_AUTO_VAR_INIT_PATTERN=y
CONFIG_CC_HAS_AUTO_VAR_INIT_ZERO_BARE=y
CONFIG_CC_HAS_AUTO_VAR_INIT_ZERO=y
regards,
dan carpenter
next prev parent reply other threads:[~2022-11-17 10:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-17 7:44 [PATCH net-next] rxrpc: uninitialized variable in rxrpc_send_ack_packet() Dan Carpenter
2022-11-17 9:44 ` David Howells
2022-11-17 10:34 ` Dan Carpenter [this message]
2022-11-17 11:59 ` David Howells
2022-11-17 13:35 ` Dan Carpenter
2022-11-17 12:04 ` David Howells
2022-11-18 12:10 ` patchwork-bot+netdevbpf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Y3YOUQM/ldDe/sgC@kadam \
--to=error27@gmail.com \
--cc=davem@davemloft.net \
--cc=dhowells@redhat.com \
--cc=edumazet@google.com \
--cc=kernel-janitors@vger.kernel.org \
--cc=kuba@kernel.org \
--cc=linux-afs@lists.infradead.org \
--cc=marc.dionne@auristor.com \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).