This is a note to let you know that I've just added the patch titled
net/smc: fix illegal rmb_desc access in SMC-D connection dump
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-smc-fix-illegal-rmb_desc-access-in-smc-d-connect.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f656bbfc246ac108ebed7f3b18e5bb9a6343cb20
Author: Wen Gu <guwen@xxxxxxxxxxxxxxxxx>
Date: Thu Jan 18 12:32:10 2024 +0800
net/smc: fix illegal rmb_desc access in SMC-D connection dump
[ Upstream commit dbc153fd3c142909e564bb256da087e13fbf239c ]
A crash was found when dumping SMC-D connections. It can be reproduced
by following steps:
- run nginx/wrk test:
smc_run nginx
smc_run wrk -t 16 -c 1000 -d <duration> -H 'Connection: Close' <URL>
- continuously dump SMC-D connections in parallel:
watch -n 1 'smcss -D'
BUG: kernel NULL pointer dereference, address: 0000000000000030
CPU: 2 PID: 7204 Comm: smcss Kdump: loaded Tainted: G E 6.7.0+ #55
RIP: 0010:__smc_diag_dump.constprop.0+0x5e5/0x620 [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+0x5e5/0x620 [smc_diag]
? __kmalloc_node_track_caller+0x35d/0x430
? __alloc_skb+0x77/0x170
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+0x1f8/0x420
__sock_sendmsg+0xb0/0xc0
____sys_sendmsg+0x24e/0x300
? copy_msghdr_from_user+0x62/0x80
___sys_sendmsg+0x7c/0xd0
? __do_fault+0x34/0x160
? do_read_fault+0x5f/0x100
? do_fault+0xb0/0x110
? __handle_mm_fault+0x2b0/0x6c0
__sys_sendmsg+0x4d/0x80
do_syscall_64+0x69/0x180
entry_SYSCALL_64_after_hwframe+0x6e/0x76
It is possible that the connection is in process of being established
when we dump it. Assumed that the connection has been registered in a
link group by smc_conn_create() but the rmb_desc has not yet been
initialized by smc_buf_create(), thus causing the illegal access to
conn->rmb_desc. So fix it by checking before dump.
Fixes: 4b1b7d3b30a6 ("net/smc: add SMC-D diag support")
Signed-off-by: Wen Gu <guwen@xxxxxxxxxxxxxxxxx>
Reviewed-by: Dust Li <dust.li@xxxxxxxxxxxxxxxxx>
Reviewed-by: Wenjia Zhang <wenjia@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/smc/smc_diag.c b/net/smc/smc_diag.c
index 801044e7d194..7a907186a33a 100644
--- a/net/smc/smc_diag.c
+++ b/net/smc/smc_diag.c
@@ -163,7 +163,7 @@ static int __smc_diag_dump(struct sock *sk, struct sk_buff *skb,
}
if (smc_conn_lgr_valid(&smc->conn) && smc->conn.lgr->is_smcd &&
(req->diag_ext & (1 << (SMC_DIAG_DMBINFO - 1))) &&
- !list_empty(&smc->conn.lgr->list)) {
+ !list_empty(&smc->conn.lgr->list) && smc->conn.rmb_desc) {
struct smc_connection *conn = &smc->conn;
struct smcd_diag_dmbinfo dinfo;
