[PATCH 6.1 0917/1146] devlink: hold region lock when flushing snapshots

Greg Kroah-Hartman
2022-12-28T16:42:39Z

From: Jakub Kicinski <kuba@kernel.org>

[ Upstream commit b4cafb3d2c740f8d1b1234b43ac4a60e5291c960 ]

Netdevsim triggers a splat on reload, when it destroys regions
with snapshots pending:

WARNING: CPU: 1 PID: 787 at net/core/devlink.c:6291 devlink_region_snapshot_del+0x12e/0x140
CPU: 1 PID: 787 Comm: devlink Not tainted 6.1.0-07460-g7ae9888d6e1c #580
RIP: 0010:devlink_region_snapshot_del+0x12e/0x140
Call Trace:
<TASK>
devl_region_destroy+0x70/0x140
nsim_dev_reload_down+0x2f/0x60 [netdevsim]
devlink_reload+0x1f7/0x360
devlink_nl_cmd_reload+0x6ce/0x860
genl_family_rcv_msg_doit.isra.0+0x145/0x1c0

This is the locking assert in devlink_region_snapshot_del(),
we're supposed to be holding the region->snapshot_lock here.

Fixes: 2dec18ad826f ("net: devlink: remove region snapshots list dependency on devlink->lock")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/core/devlink.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/net/core/devlink.c b/net/core/devlink.c
index 89baa7c0938b..e8f1af4231db 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -11435,8 +11435,10 @@ void devl_region_destroy(struct devlink_region *region)
devl_assert_locked(devlink);

/* Free all snapshots of region */
+ mutex_lock(&region->snapshot_lock);
list_for_each_entry_safe(snapshot, ts, &region->snapshot_list, list)
devlink_region_snapshot_del(region, snapshot);
+ mutex_unlock(&region->snapshot_lock);

list_del(&region->list);
mutex_destroy(&region->snapshot_lock);
--
2.35.1