From: Patrisious Haddad <phaddad@xxxxxxxxxx> Previously when destroying a DCT, if the firmware function for the destruction failed, the common resource would have been destroyed either way, since it was destroyed before the firmware object. Which leads to kernel warning "refcount_t: underflow" which indicates possible use-after-free. Which is triggered when we try to destroy the common resource for the second time and execute refcount_dec_and_test(&common->refcount). So, currently before destroying the common resource we check its refcount and continue with the destruction only if it isn't zero. refcount_t: underflow; use-after-free. WARNING: CPU: 8 PID: 1002 at lib/refcount.c:28 refcount_warn_saturate+0xd8/0xe0 Modules linked in: xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xt_addrtype iptable_nat nf_nat br_netfilter rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm mlx5_ib ib_uverbs ib_core overlay mlx5_core fuse CPU: 8 PID: 1002 Comm: python3 Not tainted 5.16.0-rc5+ #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 RIP: 0010:refcount_warn_saturate+0xd8/0xe0 Code: ff 48 c7 c7 18 f5 23 82 c6 05 60 70 ff 00 01 e8 d0 0a 45 00 0f 0b c3 48 c7 c7 c0 f4 23 82 c6 05 4c 70 ff 00 01 e8 ba 0a 45 00 <0f> 0b c3 0f 1f 44 00 00 8b 07 3d 00 00 00 c0 74 12 83 f8 01 74 13 RSP: 0018:ffff8881221d3aa8 EFLAGS: 00010286 RAX: 0000000000000000 RBX: ffff8881313e8d40 RCX: ffff88852cc1b5c8 RDX: 00000000ffffffd8 RSI: 0000000000000027 RDI: ffff88852cc1b5c0 RBP: ffff888100f70000 R08: ffff88853ffd1ba8 R09: 0000000000000003 R10: 00000000fffff000 R11: 3fffffffffffffff R12: 0000000000000246 R13: ffff888100f71fa0 R14: ffff8881221d3c68 R15: 0000000000000020 FS: 00007efebbb13740(0000) GS:ffff88852cc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005611aac29f80 CR3: 00000001313de004 CR4: 0000000000370ea0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> destroy_resource_common+0x6e/0x95 [mlx5_ib] mlx5_core_destroy_rq_tracked+0x38/0xbe [mlx5_ib] mlx5_ib_destroy_wq+0x22/0x80 [mlx5_ib] ib_destroy_wq_user+0x1f/0x40 [ib_core] uverbs_free_wq+0x19/0x40 [ib_uverbs] destroy_hw_idr_uobject+0x18/0x50 [ib_uverbs] uverbs_destroy_uobject+0x2f/0x190 [ib_uverbs] uobj_destroy+0x3c/0x80 [ib_uverbs] ib_uverbs_cmd_verbs+0x3e4/0xb80 [ib_uverbs] ? uverbs_free_wq+0x40/0x40 [ib_uverbs] ? ip_list_rcv+0xf7/0x120 ? netif_receive_skb_list_internal+0x1b6/0x2d0 ? task_tick_fair+0xbf/0x450 ? __handle_mm_fault+0x11fc/0x1450 ib_uverbs_ioctl+0xa4/0x110 [ib_uverbs] __x64_sys_ioctl+0x3e4/0x8e0 ? handle_mm_fault+0xb9/0x210 do_syscall_64+0x3d/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7efebc0be17b Code: 0f 1e fa 48 8b 05 1d ad 0c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ed ac 0c 00 f7 d8 64 89 01 48 RSP: 002b:00007ffe71813e78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ffe71813fb8 RCX: 00007efebc0be17b RDX: 00007ffe71813fa0 RSI: 00000000c0181b01 RDI: 0000000000000005 RBP: 00007ffe71813f80 R08: 00005611aae96020 R09: 000000000000004f R10: 00007efebbf9ffa0 R11: 0000000000000246 R12: 00007ffe71813f80 R13: 00007ffe71813f4c R14: 00005611aae2eca0 R15: 00007efeae6c89d0 </TASK> Signed-off-by: Patrisious Haddad <phaddad@xxxxxxxxxx> Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxx> --- drivers/infiniband/hw/mlx5/qpc.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/infiniband/hw/mlx5/qpc.c b/drivers/infiniband/hw/mlx5/qpc.c index bae0334d6e7f..43d87bdcaf9c 100644 --- a/drivers/infiniband/hw/mlx5/qpc.c +++ b/drivers/infiniband/hw/mlx5/qpc.c @@ -179,6 +179,9 @@ static void destroy_resource_common(struct mlx5_ib_dev *dev, struct mlx5_qp_table *table = &dev->qp_table; unsigned long flags; + if (refcount_read(&qp->common.refcount) == 0) + return; + spin_lock_irqsave(&table->lock, flags); radix_tree_delete(&table->tree, qp->qpn | (qp->common.res << MLX5_USER_INDEX_LEN)); -- 2.39.2
