[PATCH for-next v2] RDMA/rxe: Fix mr->map double free

[Li Zhijian]

rxe_mr_cleanup() which tries to free mr->map again will be called
when rxe_mr_init_user() fails.

[43895.939883] CPU: 0 PID: 4917 Comm: rdma_flush_serv Kdump: loaded Not tainted 6.1.0-rc1-roce-flush+ #25
[43895.942341] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
[43895.945208] Call Trace:
[43895.946130]  <TASK>
[43895.946931]  dump_stack_lvl+0x45/0x5d
[43895.948049]  panic+0x19e/0x349
[43895.949010]  ? panic_print_sys_info.part.0+0x77/0x77
[43895.950356]  ? asm_sysvec_apic_timer_interrupt+0x16/0x20
[43895.952589]  ? preempt_count_sub+0x14/0xc0
[43895.953809]  end_report.part.0+0x54/0x7c
[43895.954993]  ? rxe_mr_cleanup+0x9d/0xf0 [rdma_rxe]
[43895.956406]  kasan_report.cold+0xa/0xf
[43895.957668]  ? rxe_mr_cleanup+0x9d/0xf0 [rdma_rxe]
[43895.959090]  rxe_mr_cleanup+0x9d/0xf0 [rdma_rxe]
[43895.960502]  __rxe_cleanup+0x10a/0x1e0 [rdma_rxe]
[43895.961983]  rxe_reg_user_mr+0xb7/0xd0 [rdma_rxe]
[43895.963456]  ib_uverbs_reg_mr+0x26a/0x480 [ib_uverbs]
[43895.964921]  ? __lock_acquire+0x876/0x31e0
[43895.966182]  ? ib_uverbs_ex_create_wq+0x630/0x630 [ib_uverbs]
[43895.967739]  ? uverbs_fill_udata+0x1c6/0x330 [ib_uverbs]
[43895.969204]  ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0x1a2/0x250 [ib_uverbs]
[43895.971126]  ? ib_uverbs_handler_UVERBS_METHOD_QUERY_CONTEXT+0x1a0/0x1a0 [ib_uverbs]
[43895.973094]  ? ib_uverbs_handler_UVERBS_METHOD_QUERY_CONTEXT+0x1a0/0x1a0 [ib_uverbs]
[43895.975096]  ? uverbs_fill_udata+0x25f/0x330 [ib_uverbs]
[43895.976466]  ib_uverbs_cmd_verbs+0x1397/0x15a0 [ib_uverbs]
[43895.977930]  ? ib_uverbs_handler_UVERBS_METHOD_QUERY_CONTEXT+0x1a0/0x1a0 [ib_uverbs]
[43895.979937]  ? uverbs_fill_udata+0x330/0x330 [ib_uverbs]

This issue was fistrly exposed since
commit: b18c7da63fcb ("RDMA/rxe: Fix memory leak in error path code")
and then we fixed it in
commit: 8ff5f5d9d8cf ("RDMA/rxe: Prevent double freeing rxe_map_set()")
but this fix was reverted together at last by
commit: 1e75550648da (Revert "RDMA/rxe: Create duplicate mapping tables for FMRs")

Fixes: 1e75550648da (Revert "RDMA/rxe: Create duplicate mapping tables for FMRs")
Signed-off-by: Li Zhijian <lizhijian@xxxxxxxxxxx>
---
 drivers/infiniband/sw/rxe/rxe_mr.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
index d4f10c2d1aa7..7c99d1591580 100644
--- a/drivers/infiniband/sw/rxe/rxe_mr.c
+++ b/drivers/infiniband/sw/rxe/rxe_mr.c
@@ -99,6 +99,7 @@ static int rxe_mr_alloc(struct rxe_mr *mr, int num_buf)
 		kfree(mr->map[i]);
 
 	kfree(mr->map);
+	mr->map = NULL;
 err1:
 	return -ENOMEM;
 }
@@ -122,7 +123,6 @@ int rxe_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
 	int			num_buf;
 	void			*vaddr;
 	int err;
-	int i;
 
 	umem = ib_umem_get(&rxe->ib_dev, start, length, access);
 	if (IS_ERR(umem)) {
@@ -163,9 +163,8 @@ int rxe_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
 				pr_warn("%s: Unable to get virtual address\n",
 						__func__);
 				err = -ENOMEM;
-				goto err_cleanup_map;
+				goto err_release_umem;
 			}
-
 			buf->addr = (uintptr_t)vaddr;
 			buf->size = PAGE_SIZE;
 			num_buf++;
@@ -182,10 +181,6 @@ int rxe_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
 
 	return 0;
 
-err_cleanup_map:
-	for (i = 0; i < mr->num_map; i++)
-		kfree(mr->map[i]);
-	kfree(mr->map);
 err_release_umem:
 	ib_umem_release(umem);
 err_out:
-- 
1.8.3.1