On Thursday, July 25, 2019 2:06:20 AM CEST akpm@xxxxxxxxxxxxxxxxxxxx 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@xxxxxxxxxx> > 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@xxxxxxxxxx > Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> > Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx> > Cc: Len Brown <lenb@xxxxxxxxxx > Cc: Oscar Salvador <osalvador@xxxxxxx> > Cc: Michal Hocko <mhocko@xxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > --- > > 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@xxxxxxxxxx are > > acpi-scan-acquire-device_hotplug_lock-in-acpi_scan_init.patch > drivers-base-nodec-simplify-unregister_memory_block_under_nodes.patch > >
