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d5638de8 |
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04-Apr-2024 |
Rex Zhang <rex.zhang@intel.com> |
dmaengine: idxd: Convert spinlock to mutex to lock evl workqueue drain_workqueue() cannot be called safely in a spinlocked context due to possible task rescheduling. In the multi-task scenario, calling queue_work() while drain_workqueue() will lead to a Call Trace as pushing a work on a draining workqueue is not permitted in spinlocked context. Call Trace: <TASK> ? __warn+0x7d/0x140 ? __queue_work+0x2b2/0x440 ? report_bug+0x1f8/0x200 ? handle_bug+0x3c/0x70 ? exc_invalid_op+0x18/0x70 ? asm_exc_invalid_op+0x1a/0x20 ? __queue_work+0x2b2/0x440 queue_work_on+0x28/0x30 idxd_misc_thread+0x303/0x5a0 [idxd] ? __schedule+0x369/0xb40 ? __pfx_irq_thread_fn+0x10/0x10 ? irq_thread+0xbc/0x1b0 irq_thread_fn+0x21/0x70 irq_thread+0x102/0x1b0 ? preempt_count_add+0x74/0xa0 ? __pfx_irq_thread_dtor+0x10/0x10 ? __pfx_irq_thread+0x10/0x10 kthread+0x103/0x140 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x31/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1b/0x30 </TASK> The current implementation uses a spinlock to protect event log workqueue and will lead to the Call Trace due to potential task rescheduling. To address the locking issue, convert the spinlock to mutex, allowing the drain_workqueue() to be called in a safe mutex-locked context. This change ensures proper synchronization when accessing the event log workqueue, preventing potential Call Trace and improving the overall robustness of the code. Fixes: c40bd7d9737b ("dmaengine: idxd: process user page faults for completion record") Signed-off-by: Rex Zhang <rex.zhang@intel.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Fenghua Yu <fenghua.yu@intel.com> Reviewed-by: Lijun Pan <lijun.pan@intel.com> Link: https://lore.kernel.org/r/20240404223949.2885604-1-fenghua.yu@intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org>
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ecec7c9f |
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14-Feb-2024 |
Fenghua Yu <fenghua.yu@intel.com> |
dmaengine: idxd: Remove shadow Event Log head stored in idxd head is defined in idxd->evl as a shadow of head in the EVLSTATUS register. There are two issues related to the shadow head: 1. Mismatch between the shadow head and the state of the EVLSTATUS register: If Event Log is supported, upon completion of the Enable Device command, the Event Log head in the variable idxd->evl->head should be cleared to match the state of the EVLSTATUS register. But the variable is not reset currently, leading mismatch between the variable and the register state. The mismatch causes incorrect processing of Event Log entries. 2. Unnecessary shadow head definition: The shadow head is unnecessary as head can be read directly from the EVLSTATUS register. Reading head from the register incurs no additional cost because event log head and tail are always read together and tail is already read directly from the register as required by hardware. Remove the shadow Event Log head stored in idxd->evl to address the mentioned issues. Fixes: 244da66cda35 ("dmaengine: idxd: setup event log configuration") Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/20240215024931.1739621-1-fenghua.yu@intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org>
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