From: Moshe Shemesh moshe@mellanox.com
[ Upstream commit 17d00e839d3b592da9659c1977d45f85b77f986a ]
When FW response to commands is very slow and all command entries in use are waiting for completion we can have a race where commands can get timeout before they get out of the queue and handled. Timeout completion on uninitialized command will cause releasing command's buffers before accessing it for initialization and then we will get NULL pointer exception while trying access it. It may also cause releasing buffers of another command since we may have timeout completion before even allocating entry index for this command. Add entry handling completion to avoid this race.
Fixes: e126ba97dba9 ("mlx5: Add driver for Mellanox Connect-IB adapters") Signed-off-by: Moshe Shemesh moshe@mellanox.com Signed-off-by: Eran Ben Elisha eranbe@mellanox.com Signed-off-by: Saeed Mahameed saeedm@mellanox.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/mellanox/mlx5/core/cmd.c | 14 ++++++++++++++ include/linux/mlx5/driver.h | 1 + 2 files changed, 15 insertions(+)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c index 08048a2d7259..b6a3370068f1 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c @@ -861,6 +861,7 @@ static void cmd_work_handler(struct work_struct *work) int alloc_ret; int cmd_mode;
+ complete(&ent->handling); sem = ent->page_queue ? &cmd->pages_sem : &cmd->sem; down(sem); if (!ent->page_queue) { @@ -978,6 +979,11 @@ static int wait_func(struct mlx5_core_dev *dev, struct mlx5_cmd_work_ent *ent) struct mlx5_cmd *cmd = &dev->cmd; int err;
+ if (!wait_for_completion_timeout(&ent->handling, timeout) && + cancel_work_sync(&ent->work)) { + ent->ret = -ECANCELED; + goto out_err; + } if (cmd->mode == CMD_MODE_POLLING || ent->polling) { wait_for_completion(&ent->done); } else if (!wait_for_completion_timeout(&ent->done, timeout)) { @@ -985,12 +991,17 @@ static int wait_func(struct mlx5_core_dev *dev, struct mlx5_cmd_work_ent *ent) mlx5_cmd_comp_handler(dev, 1UL << ent->idx, true); }
+out_err: err = ent->ret;
if (err == -ETIMEDOUT) { mlx5_core_warn(dev, "%s(0x%x) timeout. Will cause a leak of a command resource\n", mlx5_command_str(msg_to_opcode(ent->in)), msg_to_opcode(ent->in)); + } else if (err == -ECANCELED) { + mlx5_core_warn(dev, "%s(0x%x) canceled on out of queue timeout.\n", + mlx5_command_str(msg_to_opcode(ent->in)), + msg_to_opcode(ent->in)); } mlx5_core_dbg(dev, "err %d, delivery status %s(%d)\n", err, deliv_status_to_str(ent->status), ent->status); @@ -1026,6 +1037,7 @@ static int mlx5_cmd_invoke(struct mlx5_core_dev *dev, struct mlx5_cmd_msg *in, ent->token = token; ent->polling = force_polling;
+ init_completion(&ent->handling); if (!callback) init_completion(&ent->done);
@@ -1045,6 +1057,8 @@ static int mlx5_cmd_invoke(struct mlx5_core_dev *dev, struct mlx5_cmd_msg *in, err = wait_func(dev, ent); if (err == -ETIMEDOUT) goto out; + if (err == -ECANCELED) + goto out_free;
ds = ent->ts2 - ent->ts1; op = MLX5_GET(mbox_in, in->first.data, opcode); diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h index 3e80f03a387f..897829651204 100644 --- a/include/linux/mlx5/driver.h +++ b/include/linux/mlx5/driver.h @@ -756,6 +756,7 @@ struct mlx5_cmd_work_ent { struct delayed_work cb_timeout_work; void *context; int idx; + struct completion handling; struct completion done; struct mlx5_cmd *cmd; struct work_struct work;