[PATCH AUTOSEL 4.19 056/123] RDMA/bnxt_re: Avoid accessing the device structure after it is freed

Sasha Levin
2018-12-05T10:09:50Z

From: Selvin Xavier <selvin.xavier@broadcom.com>

[ Upstream commit a6c66d6a08b88cc10aca9d3f65cfae31e7652a99 ]

When bnxt_re_ib_reg returns failure, the device structure gets
freed. Driver tries to access the device pointer
after it is freed.

[ 4871.034744] Failed to register with netedev: 0xffffffa1
[ 4871.034765] infiniband (null): Failed to register with IB: 0xffffffea
[ 4871.046430] ==================================================================
[ 4871.046437] BUG: KASAN: use-after-free in bnxt_re_task+0x63/0x180 [bnxt_re]
[ 4871.046439] Write of size 4 at addr ffff880fa8406f48 by task kworker/u48:2/17813

[ 4871.046443] CPU: 20 PID: 17813 Comm: kworker/u48:2 Kdump: loaded Tainted: G B OE 4.20.0-rc1+ #42
[ 4871.046444] Hardware name: Dell Inc. PowerEdge R730/0599V5, BIOS 1.0.4 08/28/2014
[ 4871.046447] Workqueue: bnxt_re bnxt_re_task [bnxt_re]
[ 4871.046449] Call Trace:
[ 4871.046454] dump_stack+0x91/0xeb
[ 4871.046458] print_address_description+0x6a/0x2a0
[ 4871.046461] kasan_report+0x176/0x2d0
[ 4871.046463] ? bnxt_re_task+0x63/0x180 [bnxt_re]
[ 4871.046466] bnxt_re_task+0x63/0x180 [bnxt_re]
[ 4871.046470] process_one_work+0x216/0x5b0
[ 4871.046471] ? process_one_work+0x189/0x5b0
[ 4871.046475] worker_thread+0x4e/0x3d0
[ 4871.046479] kthread+0x10e/0x140
[ 4871.046480] ? process_one_work+0x5b0/0x5b0
[ 4871.046482] ? kthread_stop+0x220/0x220
[ 4871.046486] ret_from_fork+0x3a/0x50

[ 4871.046492] The buggy address belongs to the page:
[ 4871.046494] page:ffffea003ea10180 count:0 mapcount:0 mapping:0000000000000000 index:0x0
[ 4871.046495] flags: 0x57ffffc0000000()
[ 4871.046498] raw: 0057ffffc0000000 0000000000000000 ffffea003ea10188 0000000000000000
[ 4871.046500] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
[ 4871.046501] page dumped because: kasan: bad access detected

Avoid accessing the device structure once it is freed.

Fixes: 497158aa5f52 ("RDMA/bnxt_re: Fix the ib_reg failure cleanup")
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/infiniband/hw/bnxt_re/main.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/infiniband/hw/bnxt_re/main.c b/drivers/infiniband/hw/bnxt_re/main.c
index bb3f16273938..22bd9784fa2e 100644
--- a/drivers/infiniband/hw/bnxt_re/main.c
+++ b/drivers/infiniband/hw/bnxt_re/main.c
@@ -1462,6 +1462,7 @@ static void bnxt_re_task(struct work_struct *work)
"Failed to register with IB: %#x", rc);
bnxt_re_remove_one(rdev);
bnxt_re_dev_unreg(rdev);
+ goto exit;
}
break;
case NETDEV_UP:
@@ -1485,6 +1486,7 @@ static void bnxt_re_task(struct work_struct *work)
}
smp_mb__before_atomic();
atomic_dec(&rdev->sched_count);
+exit:
kfree(re_work);
}

--
2.17.1