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With commit10e5e37581("scsi: ufs: Add clock ungating to a separate workqueue"), clock gating work was moved to a separate work queue with WQ_MEM_RECLAIM set, since clock gating could occur from a memory reclaim context. Unfortunately, clk_gating.gate_work was left queued via schedule_delayed_work, which is a system workqueue that does not have WQ_MEM_RECLAIM set. Because ufshcd_ungate_work attempts to cancel gate_work, the following warning appears: [ 14.174170] workqueue: WQ_MEM_RECLAIM ufs_clk_gating_0:ufshcd_ungate_work is flushing !WQ_MEM_RECLAIM events:ufshcd_gate_work [ 14.174179] WARNING: CPU: 4 PID: 173 at kernel/workqueue.c:2440 check_flush_dependency+0x110/0x118 [ 14.205725] CPU: 4 PID: 173 Comm: kworker/u16:3 Not tainted 4.14.68 #1 [ 14.212437] Hardware name: Google Cheza (rev1) (DT) [ 14.217459] Workqueue: ufs_clk_gating_0 ufshcd_ungate_work [ 14.223107] task: ffffffc0f6a40080 task.stack: ffffff800a490000 [ 14.229195] PC is at check_flush_dependency+0x110/0x118 [ 14.234569] LR is at check_flush_dependency+0x110/0x118 [ 14.239944] pc : [<ffffff80080cad14>] lr : [<ffffff80080cad14>] pstate: 60c001c9 [ 14.333050] Call trace: [ 14.427767] [<ffffff80080cad14>] check_flush_dependency+0x110/0x118 [ 14.434219] [<ffffff80080cafec>] start_flush_work+0xac/0x1fc [ 14.440046] [<ffffff80080caeec>] flush_work+0x40/0x94 [ 14.445246] [<ffffff80080cb288>] __cancel_work_timer+0x11c/0x1b8 [ 14.451433] [<ffffff80080cb4b8>] cancel_delayed_work_sync+0x20/0x30 [ 14.457886] [<ffffff80085b9294>] ufshcd_ungate_work+0x24/0xd0 [ 14.463800] [<ffffff80080cfb04>] process_one_work+0x32c/0x690 [ 14.469713] [<ffffff80080d0154>] worker_thread+0x218/0x338 [ 14.475361] [<ffffff80080d527c>] kthread+0x120/0x130 [ 14.480470] [<ffffff8008084814>] ret_from_fork+0x10/0x18 The simple solution is to put the gate_work on the same WQ_MEM_RECLAIM work queue as the ungate_work. Fixes:10e5e37581("scsi: ufs: Add clock ungating to a separate workqueue") Signed-off-by: Evan Green <evgreen@chromium.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Stephen Boyd <swboyd@chromium.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Linux kernel
============
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There are various text files in the Documentation/ subdirectory,
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See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
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