| From 24c805210330b6e6e80d1ce54e5eceb90bf2e367 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Thu, 24 Oct 2019 22:08:11 +0800 |
| Subject: scsi: hisi_sas: Replace in_softirq() check in hisi_sas_task_exec() |
| |
| From: Xiang Chen <chenxiang66@hisilicon.com> |
| |
| [ Upstream commit 550c0d89d52d3bec5c299f69b4ed5d2ee6b8a9a6 ] |
| |
| For IOs from upper layer, preemption may be disabled as it may be called by |
| function __blk_mq_delay_run_hw_queue which will call get_cpu() (it disables |
| preemption). So if flags HISI_SAS_REJECT_CMD_BIT is set in function |
| hisi_sas_task_exec(), it may disable preempt twice after down() and up() |
| which will cause following call trace: |
| |
| BUG: scheduling while atomic: fio/60373/0x00000002 |
| Call trace: |
| dump_backtrace+0x0/0x150 |
| show_stack+0x24/0x30 |
| dump_stack+0xa0/0xc4 |
| __schedule_bug+0x68/0x88 |
| __schedule+0x4b8/0x548 |
| schedule+0x40/0xd0 |
| schedule_timeout+0x200/0x378 |
| __down+0x78/0xc8 |
| down+0x54/0x70 |
| hisi_sas_task_exec.isra.10+0x598/0x8d8 [hisi_sas_main] |
| hisi_sas_queue_command+0x28/0x38 [hisi_sas_main] |
| sas_queuecommand+0x168/0x1b0 [libsas] |
| scsi_queue_rq+0x2ac/0x980 |
| blk_mq_dispatch_rq_list+0xb0/0x550 |
| blk_mq_do_dispatch_sched+0x6c/0x110 |
| blk_mq_sched_dispatch_requests+0x114/0x1d8 |
| __blk_mq_run_hw_queue+0xb8/0x130 |
| __blk_mq_delay_run_hw_queue+0x1c0/0x220 |
| blk_mq_run_hw_queue+0xb0/0x128 |
| blk_mq_sched_insert_requests+0xdc/0x208 |
| blk_mq_flush_plug_list+0x1b4/0x3a0 |
| blk_flush_plug_list+0xdc/0x110 |
| blk_finish_plug+0x3c/0x50 |
| blkdev_direct_IO+0x404/0x550 |
| generic_file_read_iter+0x9c/0x848 |
| blkdev_read_iter+0x50/0x78 |
| aio_read+0xc8/0x170 |
| io_submit_one+0x1fc/0x8d8 |
| __arm64_sys_io_submit+0xdc/0x280 |
| el0_svc_common.constprop.0+0xe0/0x1e0 |
| el0_svc_handler+0x34/0x90 |
| el0_svc+0x10/0x14 |
| ... |
| |
| To solve the issue, check preemptible() to avoid disabling preempt multiple |
| when flag HISI_SAS_REJECT_CMD_BIT is set. |
| |
| Link: https://lore.kernel.org/r/1571926105-74636-5-git-send-email-john.garry@huawei.com |
| Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com> |
| Signed-off-by: John Garry <john.garry@huawei.com> |
| Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/scsi/hisi_sas/hisi_sas_main.c | 8 +++++++- |
| 1 file changed, 7 insertions(+), 1 deletion(-) |
| |
| diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c |
| index f35c56217694..33191673249c 100644 |
| --- a/drivers/scsi/hisi_sas/hisi_sas_main.c |
| +++ b/drivers/scsi/hisi_sas/hisi_sas_main.c |
| @@ -485,7 +485,13 @@ static int hisi_sas_task_exec(struct sas_task *task, gfp_t gfp_flags, |
| struct hisi_sas_dq *dq = NULL; |
| |
| if (unlikely(test_bit(HISI_SAS_REJECT_CMD_BIT, &hisi_hba->flags))) { |
| - if (in_softirq()) |
| + /* |
| + * For IOs from upper layer, it may already disable preempt |
| + * in the IO path, if disable preempt again in down(), |
| + * function schedule() will report schedule_bug(), so check |
| + * preemptible() before goto down(). |
| + */ |
| + if (!preemptible()) |
| return -EINVAL; |
| |
| down(&hisi_hba->sem); |
| -- |
| 2.20.1 |
| |