From: Vinod Koul <vkoul@kernel.org>
To: Rex Zhang <rex.zhang@intel.com>
Cc: dmaengine@vger.kernel.org, dave.jiang@intel.com,
fenghua.yu@intel.com, lijun.pan@intel.com
Subject: Re: [PATCH v2] dmaengine: idxd: Convert spinlock to mutex to lock evl workqueue
Date: Mon, 22 Jan 2024 17:03:58 +0530 [thread overview]
Message-ID: <Za5Spr6FjjL-XN2i@matsya> (raw)
In-Reply-To: <20231223060642.979483-1-rex.zhang@intel.com>
On 23-12-23, 14:06, Rex Zhang wrote:
> The drain_workqueue() is not in a locked context. In the multi-task case,
> it's possible to call queue_work() when drain_workqueue() is ongoing, then
> it can cause Call Trace due to pushing a work into a draining workqueue:
> 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 original lock for event log was spinlock, drain_workqueue() can't
> be in a spinlocked context because it may cause task rescheduling. The
> spinlock was called in thread and irq thread context, the current usages
> does not require a spinlock for event log, so it's feasible to convert
> spinlock to mutex.
> For putting drain_workqueue() into a locked context, convert the spinlock
> to mutex, then lock drain_workqueue() by mutex.
This fails to apply for me, pls rebase
--
~Vinod
next prev parent reply other threads:[~2024-01-22 11:34 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-23 6:06 [PATCH v2] dmaengine: idxd: Convert spinlock to mutex to lock evl workqueue Rex Zhang
2024-01-22 11:33 ` Vinod Koul [this message]
2024-04-07 16:38 ` Vinod Koul
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