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Wythe" , Tony Lu , Wen Gu , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman Cc: Shuah Khan , Anup Sharma , linux-s390@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20241109-fix-oops-__smc_diag_dump-v1-1-1c55a3e54ad4@iiitd.ac.in> Content-Language: en-US From: Wenjia Zhang In-Reply-To: <20241109-fix-oops-__smc_diag_dump-v1-1-1c55a3e54ad4@iiitd.ac.in> Content-Type: text/plain; charset=UTF-8; format=flowed X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 4C5mASve2whXvM_WL953xWdc_KxJU8lX X-Proofpoint-ORIG-GUID: Qxm2kzobVISdmhXTG2g3pw-7R_eySd5- Content-Transfer-Encoding: 7bit X-Proofpoint-UnRewURL: 0 URL was un-rewritten Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1051,Hydra:6.0.680,FMLib:17.12.62.30 definitions=2024-10-15_01,2024-10-11_01,2024-09-30_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=999 malwarescore=0 spamscore=0 suspectscore=0 bulkscore=0 impostorscore=0 mlxscore=0 priorityscore=1501 phishscore=0 clxscore=1011 adultscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2409260000 definitions=main-2411110116 On 09.11.24 07:28, Manas via B4 Relay wrote: > From: Manas > > The last parameter in __smc_diag_dump (struct nlattr *bc) is unused. > There is only one instance of this function being called and its passed > with a NULL value in place of bc. > > Signed-off-by: Manas > --- > The last parameter in __smc_diag_dump (struct nlattr *bc) is unused. > There is only one instance of this function being called and its passed > with a NULL value in place of bc. > > Though, the compiler (gcc) optimizes it. Looking at the object dump of > vmlinux (via `objdump -D vmlinux`), a new function clone > (__smc_diag_dump.constprop.0) is added which removes this parameter from > calling convention altogether. > > ffffffff8a701770 <__smc_diag_dump.constprop.0>: > ffffffff8a701770: 41 57 push %r15 > ffffffff8a701772: 41 56 push %r14 > ffffffff8a701774: 41 55 push %r13 > ffffffff8a701776: 41 54 push %r12 > > There are 5 parameters in original function, but in the cloned function > only 4. > > I believe this patch also fixes this oops bug[1], which arises in the > same function __smc_diag_dump. But I couldn't verify it further. Can > someone please test this? > > [1] https://syzkaller.appspot.com/bug?extid=271fed3ed6f24600c364 > --- > net/smc/smc_diag.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/net/smc/smc_diag.c b/net/smc/smc_diag.c > index 6fdb2d96777ad704c394709ec845f9ddef5e599a..8f7bd40f475945171a0afa5a2cce12d9aa2b1eb4 100644 > --- a/net/smc/smc_diag.c > +++ b/net/smc/smc_diag.c > @@ -71,8 +71,7 @@ static int smc_diag_msg_attrs_fill(struct sock *sk, struct sk_buff *skb, > > static int __smc_diag_dump(struct sock *sk, struct sk_buff *skb, > struct netlink_callback *cb, > - const struct smc_diag_req *req, > - struct nlattr *bc) > + const struct smc_diag_req *req) > { > struct smc_sock *smc = smc_sk(sk); > struct smc_diag_fallback fallback; > @@ -199,7 +198,6 @@ static int smc_diag_dump_proto(struct proto *prot, struct sk_buff *skb, > struct smc_diag_dump_ctx *cb_ctx = smc_dump_context(cb); > struct net *net = sock_net(skb->sk); > int snum = cb_ctx->pos[p_type]; > - struct nlattr *bc = NULL; > struct hlist_head *head; > int rc = 0, num = 0; > struct sock *sk; > @@ -214,7 +212,7 @@ static int smc_diag_dump_proto(struct proto *prot, struct sk_buff *skb, > continue; > if (num < snum) > goto next; > - rc = __smc_diag_dump(sk, skb, cb, nlmsg_data(cb->nlh), bc); > + rc = __smc_diag_dump(sk, skb, cb, nlmsg_data(cb->nlh)); > if (rc < 0) > goto out; > next: > > --- > base-commit: 59b723cd2adbac2a34fc8e12c74ae26ae45bf230 > change-id: 20241109-fix-oops-__smc_diag_dump-06ab3e9d39f4 > > Best regards, That's true that the last parameter is not used. And the patch you suggested as a cleanup patch looks good to me. However, it should not fix the bug[1], because it does not match what the bug[1] described. Thank you, Jeongjun, for testing it! That verified that it indeed didn't fix the issue. I think the root cause is on handling idiag_sport. I'll look into it. [1] https://syzkaller.appspot.com/bug?extid=271fed3ed6f24600c364 Thanks, Wenjia