From: Daisuke Matsuda Date: Fri, 9 Dec 2022 04:59:26 +0000 (+0900) Subject: RDMA/rxe: Fix oops with zero length reads X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=3282a549cf9b300e2d1b007925ed007ab24e4131;p=linux.git RDMA/rxe: Fix oops with zero length reads 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 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: 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 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 Signed-off-by: Li Zhijian Reviewed-by: Li Zhijian Signed-off-by: Jason Gunthorpe --- diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c index 12eb85e8d4154..0c8bec2819376 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) { @@ -880,13 +880,15 @@ 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; } err = rxe_mr_copy(mr, res->read.va, payload_addr(&ack_pkt), payload, RXE_FROM_MR_OBJ); - rxe_put(mr); + if (mr) + rxe_put(mr); if (err) { kfree_skb(skb); return RESPST_ERR_RKEY_VIOLATION;