From: Lukas Wunner <lukas@wunner.de>
To: Hans de Goede <hdegoede@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>, linux-pci@vger.kernel.org
Subject: Re: Lockdep warning in PCI-e hotplug code
Date: Sun, 9 Aug 2020 20:40:52 +0200 [thread overview]
Message-ID: <20200809184052.evq42lngznypxi4f@wunner.de> (raw)
In-Reply-To: <b469d86a-7567-db43-23d1-e499b32cb449@redhat.com>
On Sun, Aug 09, 2020 at 08:23:20PM +0200, Hans de Goede wrote:
> [ 139.759255] ============================================
> [ 139.759257] WARNING: possible recursive locking detected
> [ 139.759259] 5.8.0+ #16 Tainted: G E
> [ 139.759260] --------------------------------------------
> [ 139.759261] irq/125-pciehp/143 is trying to acquire lock:
> [ 139.759263] ffff95ee9f3d1f38 (&ctrl->reset_lock){.+.+}-{3:3}, at: pciehp_check_presence+0x23/0x80
> [ 139.759269]
> but task is already holding lock:
> [ 139.759270] ffff95eee497e738 (&ctrl->reset_lock){.+.+}-{3:3}, at: pciehp_ist+0xdf/0x120
False positive, the reset_lock is per-controller and multiple
instances of the lock are held concurrently because pciehp
controllers are nested with Thunderbolt.
This was already reported by Theodore T'so:
https://lore.kernel.org/linux-pci/20190402021933.GA2966@mit.edu/
So the issue is on my radar and I have some ideas how to fix it.
Let me get back to you with a solution later. In the meantime,
thank you for the report.
Lukas
prev parent reply other threads:[~2020-08-09 18:40 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-09 18:23 Lockdep warning in PCI-e hotplug code Hans de Goede
2020-08-09 18:40 ` Lukas Wunner [this message]
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