From 7ecfbee3b9c38f263e64c06aac5ca861ac57362a Mon Sep 17 00:00:00 2001 From: Mikhail Malygin Date: Thu, 16 Jul 2020 22:03:41 +0300 Subject: [PATCH] RDMA/rxe: Prevent access to wr->next ptr afrer wr is posted to send queue [ Upstream commit 5f0b2a6093a4d9aab093964c65083fe801ef1e58 ] rxe_post_send_kernel() iterates over linked list of wr's, until the wr->next ptr is NULL. However if we've got an interrupt after last wr is posted, control may be returned to the code after send completion callback is executed and wr memory is freed. As a result, wr->next pointer may contain incorrect value leading to panic. Store the wr->next on the stack before posting it. Fixes: 8700e3e7c485 ("Soft RoCE driver") Link: https://lore.kernel.org/r/20200716190340.23453-1-m.malygin@yadro.com Signed-off-by: Mikhail Malygin Signed-off-by: Sergey Kojushev Signed-off-by: Jason Gunthorpe Signed-off-by: Sasha Levin --- drivers/infiniband/sw/rxe/rxe_verbs.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.c b/drivers/infiniband/sw/rxe/rxe_verbs.c index 623129f27f5a..71358b0b8910 100644 --- a/drivers/infiniband/sw/rxe/rxe_verbs.c +++ b/drivers/infiniband/sw/rxe/rxe_verbs.c @@ -679,6 +679,7 @@ static int rxe_post_send_kernel(struct rxe_qp *qp, const struct ib_send_wr *wr, unsigned int mask; unsigned int length = 0; int i; + struct ib_send_wr *next; while (wr) { mask = wr_opcode_mask(wr->opcode, qp); @@ -695,6 +696,8 @@ static int rxe_post_send_kernel(struct rxe_qp *qp, const struct ib_send_wr *wr, break; } + next = wr->next; + length = 0; for (i = 0; i < wr->num_sge; i++) length += wr->sg_list[i].length; @@ -705,7 +708,7 @@ static int rxe_post_send_kernel(struct rxe_qp *qp, const struct ib_send_wr *wr, *bad_wr = wr; break; } - wr = wr->next; + wr = next; } rxe_run_task(&qp->req.task, 1);