From 3282a549cf9b300e2d1b007925ed007ab24e4131 Mon Sep 17 00:00:00 2001
From: Daisuke Matsuda <matsuda-daisuke@fujitsu.com>
Date: Fri, 9 Dec 2022 13:59:26 +0900
Subject: [PATCH 1/1] RDMA/rxe: Fix oops with zero length reads
Git-commit: 3282a549cf9b300e2d1b007925ed007ab24e4131
Patch-mainline: v6.2-rc1
References: git-fixes
The commit 686d348476ee ("RDMA/rxe: Remove unnecessary mr testing") causes
a kernel crash. If responder get a zero-byte RDMA Read request,
qp->resp.mr is not set in check_rkey() (see IBA C9-88). The mr is NULL in
this case, and a NULL pointer dereference occurs as shown below.
BUG: kernel NULL pointer dereference, address: 0000000000000010
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 0 P4D 0
Oops: 0002 [#1] PREEMPT SMP PTI
CPU: 2 PID: 3622 Comm: python3 Kdump: loaded Not tainted 6.1.0-rc3+ #34
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:__rxe_put+0xc/0x60 [rdma_rxe]
Code: cc cc cc 31 f6 e8 64 36 1b d3 41 b8 01 00 00 00 44 89 c0 c3 cc cc cc cc 41 89 c0 eb c1 90 0f 1f 44 00 00 41 54 b8 ff ff ff ff <f0> 0f c1 47 10 83 f8 01 74 11 45 31 e4 85 c0 7e 20 44 89 e0 41 5c
RSP: 0018:ffffb27bc012ce78 EFLAGS: 00010246
RAX: 00000000ffffffff RBX: ffff9790857b0580 RCX: 0000000000000000
RDX: ffff979080fe145a RSI: 000055560e3e0000 RDI: 0000000000000000
RBP: ffff97909c7dd800 R08: 0000000000000001 R09: e7ce43d97f7bed0f
R10: ffff97908b29c300 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffff97908b29c300 R15: 0000000000000000
FS: 00007f276f7bd740(0000) GS:ffff9792b5c80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000010 CR3: 0000000114230002 CR4: 0000000000060ee0
Call Trace:
<IRQ>
read_reply+0xda/0x310 [rdma_rxe]
rxe_responder+0x82d/0xe50 [rdma_rxe]
do_task+0x84/0x170 [rdma_rxe]
tasklet_action_common.constprop.0+0xa7/0x120
__do_softirq+0xcb/0x2ac
do_softirq+0x63/0x90
</IRQ>
Support a NULL mr during read_reply()
Fixes: 686d348476ee ("RDMA/rxe: Remove unnecessary mr testing")
Fixes: b5f9a01fae42 ("RDMA/rxe: Fix mr leak in RESPST_ERR_RNR")
Link: https://lore.kernel.org/r/20221209045926.531689-1-matsuda-daisuke@fujitsu.com
Link: https://lore.kernel.org/r/20221202145713.13152-1-lizhijian@fujitsu.com
Signed-off-by: Daisuke Matsuda <matsuda-daisuke@fujitsu.com>
Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Nicolas Morey <nmorey@suse.com>
---
drivers/infiniband/sw/rxe/rxe_resp.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c
index 12eb85e8d415..0c8bec281937 100644
--- a/drivers/infiniband/sw/rxe/rxe_resp.c
+++ b/drivers/infiniband/sw/rxe/rxe_resp.c
@@ -460,7 +460,7 @@ static enum resp_states check_rkey(struct rxe_qp *qp,
return RESPST_EXECUTE;
}
- /* A zero-byte op is not required to set an addr or rkey. */
+ /* A zero-byte op is not required to set an addr or rkey. See C9-88 */
if ((pkt->mask & RXE_READ_OR_WRITE_MASK) &&
(pkt->mask & RXE_RETH_MASK) &&
reth_len(pkt) == 0) {
@@ -880,7 +880,8 @@ static enum resp_states read_reply(struct rxe_qp *qp,
skb = prepare_ack_packet(qp, &ack_pkt, opcode, payload,
res->cur_psn, AETH_ACK_UNLIMITED);
if (!skb) {
- rxe_put(mr);
+ if (mr)
+ rxe_put(mr);
return RESPST_ERR_RNR;
}
--
2.38.0.1.gee35aeee4b76