On Thu, Dec 08, 2022 at 11:14:39AM +0200, Leon Romanovsky wrote: > > __refcount_dec include/linux/refcount.h:344 [inline] > > refcount_dec include/linux/refcount.h:359 [inline] > > ref_tracker_free+0x539/0x6b0 lib/ref_tracker.c:118 > > netdev_tracker_free include/linux/netdevice.h:4039 [inline] > > netdev_put include/linux/netdevice.h:4056 [inline] > > dev_put include/linux/netdevice.h:4082 [inline] > > nldev_newlink+0x360/0x5d0 drivers/infiniband/core/nldev.c:1733 > > rdma_nl_rcv_msg+0x371/0x6a0 drivers/infiniband/core/netlink.c:195 > > rdma_nl_rcv_skb.constprop.0.isra.0+0x2fc/0x440 drivers/infiniband/core/netlink.c:239 > > netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline] > > netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1356 > > netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1932 > > sock_sendmsg_nosec net/socket.c:714 [inline] > > sock_sendmsg+0xd3/0x120 net/socket.c:734 > > ____sys_sendmsg+0x712/0x8c0 net/socket.c:2476 > > ___sys_sendmsg+0x110/0x1b0 net/socket.c:2530 > > __sys_sendmsg+0xf7/0x1c0 net/socket.c:2559 > > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > > do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 > > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > RIP: 0033:0x7fd5bc473699 > > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 > > RSP: 002b:00007ffed185aff8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e > > RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fd5bc473699 > > RDX: 0000000000000000 RSI: 0000000020000340 RDI: 0000000000000003 > > RBP: 0000000000000000 R08: 000000000000000d R09: 000000000000000d > > R10: 00007ffed185aa70 R11: 0000000000000246 R12: 00007ffed185b010 > > R13: 00000000000f4240 R14: 0000000000011fc1 R15: 00007ffed185b004 > > </TASK> > > > > > > --- > > This report is generated by a bot. It may contain errors. > > See https://goo.gl/tpsmEJ for more information about syzbot. > > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > > > syzbot will keep track of this issue. See: > > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > syzbot can test patches for this issue, for details see: > > https://goo.gl/tpsmEJ#testing-patches > > Jason, what do you think? No, the key to this report is that the refcount dec is inside the tracker: > > __refcount_dec include/linux/refcount.h:344 [inline] > > refcount_dec include/linux/refcount.h:359 [inline] > > ref_tracker_free+0x539/0x6b0 lib/ref_tracker.c:118 > > netdev_tracker_free include/linux/netdevice.h:4039 [inline] Which is not underflowing the refcount on the dev, it is actually trying to say the tracker has become unbalanced. Eg this put is not matched with a hold that specified the tracker. Probably this: diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c index ff35cebb25e265..115b77c5e9a146 100644 --- a/drivers/infiniband/core/device.c +++ b/drivers/infiniband/core/device.c @@ -2192,6 +2192,7 @@ static void free_netdevs(struct ib_device *ib_dev) if (ndev) { spin_lock(&ndev_hash_lock); hash_del_rcu(&pdata->ndev_hash_link); + netdev_tracker_free(ndev, &pdata->netdev_tracker); spin_unlock(&ndev_hash_lock); /* @@ -2201,7 +2202,7 @@ static void free_netdevs(struct ib_device *ib_dev) * comparisons after the put */ rcu_assign_pointer(pdata->netdev, NULL); - dev_put(ndev); + __dev_put(ndev); } spin_unlock_irqrestore(&pdata->netdev_lock, flags); }
