6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Wen Gu guwen@linux.alibaba.com
[ Upstream commit 9dbe086c69b8902c85cece394760ac212e9e4ccc ]
A crash was found when dumping SMC-R connections. It can be reproduced by following steps:
- environment: two RNICs on both sides. - run SMC-R between two sides, now a SMC_LGR_SYMMETRIC type link group will be created. - set the first RNIC down on either side and link group will turn to SMC_LGR_ASYMMETRIC_LOCAL then. - run 'smcss -R' and the crash will be triggered.
BUG: kernel NULL pointer dereference, address: 0000000000000010 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 8000000101fdd067 P4D 8000000101fdd067 PUD 10ce46067 PMD 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 3 PID: 1810 Comm: smcss Kdump: loaded Tainted: G W E 6.7.0-rc6+ #51 RIP: 0010:__smc_diag_dump.constprop.0+0x36e/0x620 [smc_diag] Call Trace: <TASK> ? __die+0x24/0x70 ? page_fault_oops+0x66/0x150 ? exc_page_fault+0x69/0x140 ? asm_exc_page_fault+0x26/0x30 ? __smc_diag_dump.constprop.0+0x36e/0x620 [smc_diag] smc_diag_dump_proto+0xd0/0xf0 [smc_diag] smc_diag_dump+0x26/0x60 [smc_diag] netlink_dump+0x19f/0x320 __netlink_dump_start+0x1dc/0x300 smc_diag_handler_dump+0x6a/0x80 [smc_diag] ? __pfx_smc_diag_dump+0x10/0x10 [smc_diag] sock_diag_rcv_msg+0x121/0x140 ? __pfx_sock_diag_rcv_msg+0x10/0x10 netlink_rcv_skb+0x5a/0x110 sock_diag_rcv+0x28/0x40 netlink_unicast+0x22a/0x330 netlink_sendmsg+0x240/0x4a0 __sock_sendmsg+0xb0/0xc0 ____sys_sendmsg+0x24e/0x300 ? copy_msghdr_from_user+0x62/0x80 ___sys_sendmsg+0x7c/0xd0 ? __do_fault+0x34/0x1a0 ? do_read_fault+0x5f/0x100 ? do_fault+0xb0/0x110 __sys_sendmsg+0x4d/0x80 do_syscall_64+0x45/0xf0 entry_SYSCALL_64_after_hwframe+0x6e/0x76
When the first RNIC is set down, the lgr->lnk[0] will be cleared and an asymmetric link will be allocated in lgr->link[SMC_LINKS_PER_LGR_MAX - 1] by smc_llc_alloc_alt_link(). Then when we try to dump SMC-R connections in __smc_diag_dump(), the invalid lgr->lnk[0] will be accessed, resulting in this issue. So fix it by accessing the right link.
Fixes: f16a7dd5cf27 ("smc: netlink interface for SMC sockets") Reported-by: henaumars henaumars@sina.com Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=7616 Signed-off-by: Wen Gu guwen@linux.alibaba.com Reviewed-by: Tony Lu tonylu@linux.alibaba.com Link: https://lore.kernel.org/r/1703662835-53416-1-git-send-email-guwen@linux.alib... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/smc/smc_diag.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/net/smc/smc_diag.c b/net/smc/smc_diag.c index 7ff2152971a5b..2c464d76b06ce 100644 --- a/net/smc/smc_diag.c +++ b/net/smc/smc_diag.c @@ -153,8 +153,7 @@ static int __smc_diag_dump(struct sock *sk, struct sk_buff *skb, .lnk[0].link_id = link->link_id, };
- memcpy(linfo.lnk[0].ibname, - smc->conn.lgr->lnk[0].smcibdev->ibdev->name, + memcpy(linfo.lnk[0].ibname, link->smcibdev->ibdev->name, sizeof(link->smcibdev->ibdev->name)); smc_gid_be16_convert(linfo.lnk[0].gid, link->gid); smc_gid_be16_convert(linfo.lnk[0].peer_gid, link->peer_gid);