From 1524b12a6e02a85264af4ed208b034a2239ef374 Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Thu, 24 Oct 2019 23:49:13 +0000 Subject: [PATCH] RDMA/mlx5: Use irq xarray locking for mkey_table The mkey_table xarray is touched by the reg_mr_callback() function which is called from a hard irq. Thus all other uses of xa_lock must use the _irq variants. WARNING: inconsistent lock state 5.4.0-rc1 #12 Not tainted -------------------------------- inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. python3/343 [HC0[0]:SC0[0]:HE1:SE1] takes: ffff888182be1d40 (&(&xa->xa_lock)->rlock#3){?.-.}, at: xa_erase+0x12/0x30 {IN-HARDIRQ-W} state was registered at: lock_acquire+0xe1/0x200 _raw_spin_lock_irqsave+0x35/0x50 reg_mr_callback+0x2dd/0x450 [mlx5_ib] mlx5_cmd_exec_cb_handler+0x2c/0x70 [mlx5_core] mlx5_cmd_comp_handler+0x355/0x840 [mlx5_core] [..] Possible unsafe locking scenario: CPU0 ---- lock(&(&xa->xa_lock)->rlock#3); lock(&(&xa->xa_lock)->rlock#3); *** DEADLOCK *** 2 locks held by python3/343: #0: ffff88818eb4bd38 (&uverbs_dev->disassociate_srcu){....}, at: ib_uverbs_ioctl+0xe5/0x1e0 [ib_uverbs] #1: ffff888176c76d38 (&file->hw_destroy_rwsem){++++}, at: uobj_destroy+0x2d/0x90 [ib_uverbs] stack backtrace: CPU: 3 PID: 343 Comm: python3 Not tainted 5.4.0-rc1 #12 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014 Call Trace: dump_stack+0x86/0xca print_usage_bug.cold.50+0x2e5/0x355 mark_lock+0x871/0xb50 ? match_held_lock+0x20/0x250 ? check_usage_forwards+0x240/0x240 __lock_acquire+0x7de/0x23a0 ? __kasan_check_read+0x11/0x20 ? mark_lock+0xae/0xb50 ? mark_held_locks+0xb0/0xb0 ? find_held_lock+0xca/0xf0 lock_acquire+0xe1/0x200 ? xa_erase+0x12/0x30 _raw_spin_lock+0x2a/0x40 ? xa_erase+0x12/0x30 xa_erase+0x12/0x30 mlx5_ib_dealloc_mw+0x55/0xa0 [mlx5_ib] uverbs_dealloc_mw+0x3c/0x70 [ib_uverbs] uverbs_free_mw+0x1a/0x20 [ib_uverbs] destroy_hw_idr_uobject+0x49/0xa0 [ib_uverbs] [..] Fixes: 0417791536ae ("RDMA/mlx5: Add missing synchronize_srcu() for MW cases") Link: https://lore.kernel.org/r/20191024234910.GA9038@ziepe.ca Acked-by: Leon Romanovsky Signed-off-by: Jason Gunthorpe --- drivers/infiniband/hw/mlx5/mr.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c index 630599311586..7019c12005f4 100644 --- a/drivers/infiniband/hw/mlx5/mr.c +++ b/drivers/infiniband/hw/mlx5/mr.c @@ -1967,8 +1967,8 @@ int mlx5_ib_dealloc_mw(struct ib_mw *mw) int err; if (IS_ENABLED(CONFIG_INFINIBAND_ON_DEMAND_PAGING)) { - xa_erase(&dev->mdev->priv.mkey_table, - mlx5_base_mkey(mmw->mmkey.key)); + xa_erase_irq(&dev->mdev->priv.mkey_table, + mlx5_base_mkey(mmw->mmkey.key)); /* * pagefault_single_data_segment() may be accessing mmw under * SRCU if the user bound an ODP MR to this MW.