From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: akpm@linux-foundation.org
Cc: david@redhat.com, lenb@kernel.org, mhocko@suse.com,
mm-commits@vger.kernel.org, osalvador@suse.de,
Linux ACPI <linux-acpi@vger.kernel.org>
Subject: Re: + acpi-scan-acquire-device_hotplug_lock-in-acpi_scan_init.patch added to -mm tree
Date: Thu, 25 Jul 2019 11:10:25 +0200 [thread overview]
Message-ID: <5199522.mxBJLoqJZG@kreacher> (raw)
In-Reply-To: <20190725000620.lggHICHUI%akpm@linux-foundation.org>
On Thursday, July 25, 2019 2:06:20 AM CEST akpm@linux-foundation.org wrote:
>
> The patch titled
> Subject: drivers/acpi/scan.c: acquire device_hotplug_lock in acpi_scan_init()
> has been added to the -mm tree. Its filename is
> acpi-scan-acquire-device_hotplug_lock-in-acpi_scan_init.patch
>
> This patch should soon appear at
> http://ozlabs.org/~akpm/mmots/broken-out/acpi-scan-acquire-device_hotplug_lock-in-acpi_scan_init.patch
> and later at
> http://ozlabs.org/~akpm/mmotm/broken-out/acpi-scan-acquire-device_hotplug_lock-in-acpi_scan_init.patch
>
> Before you just go and hit "reply", please:
> a) Consider who else should be cc'ed
> b) Prefer to cc a suitable mailing list as well
> c) Ideally: find the original patch on the mailing list and do a
> reply-to-all to that, adding suitable additional cc's
>
> *** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
>
> The -mm tree is included into linux-next and is updated
> there every 3-4 working days
>
> ------------------------------------------------------
> From: David Hildenbrand <david@redhat.com>
> Subject: drivers/acpi/scan.c: acquire device_hotplug_lock in acpi_scan_init()
>
> We end up calling __add_memory() without the device hotplug lock held. (I
> used a local patch to assert in __add_memory() that the
> device_hotplug_lock is held - I might upstream that as well soon)
>
> [ 26.771684] create_memory_block_devices+0xa4/0x140
> [ 26.772952] add_memory_resource+0xde/0x200
> [ 26.773987] __add_memory+0x6e/0xa0
> [ 26.775161] acpi_memory_device_add+0x149/0x2b0
> [ 26.776263] acpi_bus_attach+0xf1/0x1f0
> [ 26.777247] acpi_bus_attach+0x66/0x1f0
> [ 26.778268] acpi_bus_attach+0x66/0x1f0
> [ 26.779073] acpi_bus_attach+0x66/0x1f0
> [ 26.780143] acpi_bus_scan+0x3e/0x90
> [ 26.780844] acpi_scan_init+0x109/0x257
> [ 26.781638] acpi_init+0x2ab/0x30d
> [ 26.782248] do_one_initcall+0x58/0x2cf
> [ 26.783181] kernel_init_freeable+0x1bd/0x247
> [ 26.784345] kernel_init+0x5/0xf1
> [ 26.785314] ret_from_fork+0x3a/0x50
>
> So perform the locking just like in acpi_device_hotplug().
>
> Link: http://lkml.kernel.org/r/20190724143017.12841-1-david@redhat.com
> Signed-off-by: David Hildenbrand <david@redhat.com>
> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> Cc: Len Brown <lenb@kernel.org
> Cc: Oscar Salvador <osalvador@suse.de>
> Cc: Michal Hocko <mhocko@suse.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
>
> drivers/acpi/scan.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> --- a/drivers/acpi/scan.c~acpi-scan-acquire-device_hotplug_lock-in-acpi_scan_init
> +++ a/drivers/acpi/scan.c
> @@ -2204,7 +2204,9 @@ int __init acpi_scan_init(void)
> acpi_gpe_apply_masked_gpes();
> acpi_update_all_gpes();
>
> + lock_device_hotplug();
> mutex_lock(&acpi_scan_lock);
> +
> /*
> * Enumerate devices in the ACPI namespace.
> */
> @@ -2232,6 +2234,7 @@ int __init acpi_scan_init(void)
>
> out:
> mutex_unlock(&acpi_scan_lock);
> + unlock_device_hotplug();
> return result;
> }
>
> _
>
> Patches currently in -mm which might be from david@redhat.com are
>
> acpi-scan-acquire-device_hotplug_lock-in-acpi_scan_init.patch
> drivers-base-nodec-simplify-unregister_memory_block_under_nodes.patch
>
>
parent reply other threads:[~2019-07-25 9:10 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <20190725000620.lggHICHUI%akpm@linux-foundation.org>]
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