[PATCH 5.4 09/71] RDMA/core: Dont access cm_id after its destruction

Greg Kroah-Hartman
2021-05-24T15:54:01Z

From: Shay Drory <shayd@nvidia.com>

[ Upstream commit 889d916b6f8a48b8c9489fffcad3b78eedd01a51 ]

restrack should only be attached to a cm_id while the ID has a valid
device pointer. It is set up when the device is first loaded, but not
cleared when the device is removed. There is also two copies of the device
pointer, one private and one in the public API, and these were left out of
sync.

Make everything go to NULL together and manipulate restrack right around
the device assignments.

Found by syzcaller:
BUG: KASAN: wild-memory-access in __list_del include/linux/list.h:112 [inline]
BUG: KASAN: wild-memory-access in __list_del_entry include/linux/list.h:135 [inline]
BUG: KASAN: wild-memory-access in list_del include/linux/list.h:146 [inline]
BUG: KASAN: wild-memory-access in cma_cancel_listens drivers/infiniband/core/cma.c:1767 [inline]
BUG: KASAN: wild-memory-access in cma_cancel_operation drivers/infiniband/core/cma.c:1795 [inline]
BUG: KASAN: wild-memory-access in cma_cancel_operation+0x1f4/0x4b0 drivers/infiniband/core/cma.c:1783
Write of size 8 at addr dead000000000108 by task syz-executor716/334

CPU: 0 PID: 334 Comm: syz-executor716 Not tainted 5.11.0+ #271
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0xbe/0xf9 lib/dump_stack.c:120
__kasan_report mm/kasan/report.c:400 [inline]
kasan_report.cold+0x5f/0xd5 mm/kasan/report.c:413
__list_del include/linux/list.h:112 [inline]
__list_del_entry include/linux/list.h:135 [inline]
list_del include/linux/list.h:146 [inline]
cma_cancel_listens drivers/infiniband/core/cma.c:1767 [inline]
cma_cancel_operation drivers/infiniband/core/cma.c:1795 [inline]
cma_cancel_operation+0x1f4/0x4b0 drivers/infiniband/core/cma.c:1783
_destroy_id+0x29/0x460 drivers/infiniband/core/cma.c:1862
ucma_close_id+0x36/0x50 drivers/infiniband/core/ucma.c:185
ucma_destroy_private_ctx+0x58d/0x5b0 drivers/infiniband/core/ucma.c:576
ucma_close+0x91/0xd0 drivers/infiniband/core/ucma.c:1797
__fput+0x169/0x540 fs/file_table.c:280
task_work_run+0xb7/0x100 kernel/task_work.c:140
exit_task_work include/linux/task_work.h:30 [inline]
do_exit+0x7da/0x17f0 kernel/exit.c:825
do_group_exit+0x9e/0x190 kernel/exit.c:922
__do_sys_exit_group kernel/exit.c:933 [inline]
__se_sys_exit_group kernel/exit.c:931 [inline]
__x64_sys_exit_group+0x2d/0x30 kernel/exit.c:931
do_syscall_64+0x2d/0x40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: 255d0c14b375 ("RDMA/cma: rdma_bind_addr() leaks a cma_dev reference count")
Link: https://lore.kernel.org/r/3352ee288fe34f2b44220457a29bfc0548686363.1620711734.git.leonro@nvidia.com
Signed-off-by: Shay Drory <shayd@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/infiniband/core/cma.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index ecac62a7b59e..92428990f0cc 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -530,6 +530,7 @@ static void cma_release_dev(struct rdma_id_private *id_priv)
list_del(&id_priv->list);
cma_deref_dev(id_priv->cma_dev);
id_priv->cma_dev = NULL;
+ id_priv->id.device = NULL;
if (id_priv->id.route.addr.dev_addr.sgid_attr) {
rdma_put_gid_attr(id_priv->id.route.addr.dev_addr.sgid_attr);
id_priv->id.route.addr.dev_addr.sgid_attr = NULL;
@@ -1871,6 +1872,7 @@ void rdma_destroy_id(struct rdma_cm_id *id)
iw_destroy_cm_id(id_priv->cm_id.iw);
}
cma_leave_mc_groups(id_priv);
+ rdma_restrack_del(&id_priv->res);
cma_release_dev(id_priv);
}

@@ -3580,7 +3582,7 @@ int rdma_listen(struct rdma_cm_id *id, int backlog)
}

id_priv->backlog = backlog;
- if (id->device) {
+ if (id_priv->cma_dev) {
if (rdma_cap_ib_cm(id->device, 1)) {
ret = cma_ib_listen(id_priv);
if (ret)
--
2.30.2