| Message ID | 20220202030904.GA9742@altlinux.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | c86d86131ab75696fc52d98571148842e067d620 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Partially revert "net/smc: Add netlink net namespace support" | expand |
On 02/02/2022 04:09, Dmitry V. Levin wrote: > The change of sizeof(struct smc_diag_linkinfo) by commit 79d39fc503b4 > ("net/smc: Add netlink net namespace support") introduced an ABI > regression: since struct smc_diag_lgrinfo contains an object of > type "struct smc_diag_linkinfo", offset of all subsequent members > of struct smc_diag_lgrinfo was changed by that change. > > As result, applications compiled with the old version > of struct smc_diag_linkinfo will receive garbage in > struct smc_diag_lgrinfo.role if the kernel implements > this new version of struct smc_diag_linkinfo. > > Fix this regression by reverting the part of commit 79d39fc503b4 that > changes struct smc_diag_linkinfo. After all, there is SMC_GEN_NETLINK > interface which is good enough, so there is probably no need to touch > the smc_diag ABI in the first place. Reviewed-by: Karsten Graul <kgraul@linux.ibm.com> Thank you Dmitry.
On Wed, Feb 02, 2022 at 06:09:04AM +0300, Dmitry V. Levin wrote: > The change of sizeof(struct smc_diag_linkinfo) by commit 79d39fc503b4 > ("net/smc: Add netlink net namespace support") introduced an ABI > regression: since struct smc_diag_lgrinfo contains an object of > type "struct smc_diag_linkinfo", offset of all subsequent members > of struct smc_diag_lgrinfo was changed by that change. > > As result, applications compiled with the old version > of struct smc_diag_linkinfo will receive garbage in > struct smc_diag_lgrinfo.role if the kernel implements > this new version of struct smc_diag_linkinfo. > > Fix this regression by reverting the part of commit 79d39fc503b4 that > changes struct smc_diag_linkinfo. After all, there is SMC_GEN_NETLINK > interface which is good enough, so there is probably no need to touch > the smc_diag ABI in the first place. > > Fixes: 79d39fc503b4 ("net/smc: Add netlink net namespace support") > Signed-off-by: Dmitry V. Levin <ldv@altlinux.org> Thank you and Karsten. It was my negligence that caused the ABI incompatibility issue. I will consider to fix it completely. And we are starting to build smc-tools and other userspace test for potential ABI modifications. Best regards, Tony Lu
diff --git a/include/uapi/linux/smc_diag.h b/include/uapi/linux/smc_diag.h index c7008d87f1a4..8cb3a6fef553 100644 --- a/include/uapi/linux/smc_diag.h +++ b/include/uapi/linux/smc_diag.h @@ -84,12 +84,11 @@ struct smc_diag_conninfo { /* SMC_DIAG_LINKINFO */ struct smc_diag_linkinfo { - __u8 link_id; /* link identifier */ - __u8 ibname[IB_DEVICE_NAME_MAX]; /* name of the RDMA device */ - __u8 ibport; /* RDMA device port number */ - __u8 gid[40]; /* local GID */ - __u8 peer_gid[40]; /* peer GID */ - __aligned_u64 net_cookie; /* RDMA device net namespace */ + __u8 link_id; /* link identifier */ + __u8 ibname[IB_DEVICE_NAME_MAX]; /* name of the RDMA device */ + __u8 ibport; /* RDMA device port number */ + __u8 gid[40]; /* local GID */ + __u8 peer_gid[40]; /* peer GID */ }; struct smc_diag_lgrinfo { diff --git a/net/smc/smc_diag.c b/net/smc/smc_diag.c index b8898c787d23..1fca2f90a9c7 100644 --- a/net/smc/smc_diag.c +++ b/net/smc/smc_diag.c @@ -146,13 +146,11 @@ static int __smc_diag_dump(struct sock *sk, struct sk_buff *skb, (req->diag_ext & (1 << (SMC_DIAG_LGRINFO - 1))) && !list_empty(&smc->conn.lgr->list)) { struct smc_link *link = smc->conn.lnk; - struct net *net = read_pnet(&link->smcibdev->ibdev->coredev.rdma_net); struct smc_diag_lgrinfo linfo = { .role = smc->conn.lgr->role, .lnk[0].ibport = link->ibport, .lnk[0].link_id = link->link_id, - .lnk[0].net_cookie = net->net_cookie, }; memcpy(linfo.lnk[0].ibname,
The change of sizeof(struct smc_diag_linkinfo) by commit 79d39fc503b4 ("net/smc: Add netlink net namespace support") introduced an ABI regression: since struct smc_diag_lgrinfo contains an object of type "struct smc_diag_linkinfo", offset of all subsequent members of struct smc_diag_lgrinfo was changed by that change. As result, applications compiled with the old version of struct smc_diag_linkinfo will receive garbage in struct smc_diag_lgrinfo.role if the kernel implements this new version of struct smc_diag_linkinfo. Fix this regression by reverting the part of commit 79d39fc503b4 that changes struct smc_diag_linkinfo. After all, there is SMC_GEN_NETLINK interface which is good enough, so there is probably no need to touch the smc_diag ABI in the first place. Fixes: 79d39fc503b4 ("net/smc: Add netlink net namespace support") Signed-off-by: Dmitry V. Levin <ldv@altlinux.org> --- include/uapi/linux/smc_diag.h | 11 +++++------ net/smc/smc_diag.c | 2 -- 2 files changed, 5 insertions(+), 8 deletions(-)