linux-stable.git/include/linux, branch linux-5.5.y

xarray: Fix early termination of xas_for_each_marked

2020-04-17T14:12:11+00:00

commit 7e934cf5ace1dceeb804f7493fa28bb697ed3c52 upstream.

xas_for_each_marked() is using entry == NULL as a termination condition
of the iteration. When xas_for_each_marked() is used protected only by
RCU, this can however race with xas_store(xas, NULL) in the following
way:

TASK1                                   TASK2
page_cache_delete()         	        find_get_pages_range_tag()
                                          xas_for_each_marked()
                                            xas_find_marked()
                                              off = xas_find_chunk()

  xas_store(&xas, NULL)
    xas_init_marks(&xas);
    ...
    rcu_assign_pointer(*slot, NULL);
                                              entry = xa_entry(off);

And thus xas_for_each_marked() terminates prematurely possibly leading
to missed entries in the iteration (translating to missing writeback of
some pages or a similar problem).

If we find a NULL entry that has been marked, skip it (unless we're trying
to allocate an entry).

Reported-by: Jan Kara 
CC: stable@vger.kernel.org
Fixes: ef8e5717db01 ("page cache: Convert delete_batch to XArray")
Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Greg Kroah-Hartman

signal: Extend exec_id to 64bits

2020-04-17T14:12:05+00:00

commit d1e7fd6462ca9fc76650fbe6ca800e35b24267da upstream.

Replace the 32bit exec_id with a 64bit exec_id to make it impossible
to wrap the exec_id counter.  With care an attacker can cause exec_id
wrap and send arbitrary signals to a newly exec'd parent.  This
bypasses the signal sending checks if the parent changes their
credentials during exec.

The severity of this problem can been seen that in my limited testing
of a 32bit exec_id it can take as little as 19s to exec 65536 times.
Which means that it can take as little as 14 days to wrap a 32bit
exec_id.  Adam Zabrocki has succeeded wrapping the self_exe_id in 7
days.  Even my slower timing is in the uptime of a typical server.
Which means self_exec_id is simply a speed bump today, and if exec
gets noticably faster self_exec_id won't even be a speed bump.

Extending self_exec_id to 64bits introduces a problem on 32bit
architectures where reading self_exec_id is no longer atomic and can
take two read instructions.  Which means that is is possible to hit
a window where the read value of exec_id does not match the written
value.  So with very lucky timing after this change this still
remains expoiltable.

I have updated the update of exec_id on exec to use WRITE_ONCE
and the read of exec_id in do_notify_parent to use READ_ONCE
to make it clear that there is no locking between these two
locations.

Link: https://lore.kernel.org/kernel-hardening/20200324215049.GA3710@pi3.com.pl
Fixes: 2.3.23pre2
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" 
Signed-off-by: Greg Kroah-Hartman

cpu/hotplug: Ignore pm_wakeup_pending() for disable_nonboot_cpus()

2020-04-17T14:12:03+00:00

commit e98eac6ff1b45e4e73f2e6031b37c256ccb5d36b upstream.

A recent change to freeze_secondary_cpus() which added an early abort if a
wakeup is pending missed the fact that the function is also invoked for
shutdown, reboot and kexec via disable_nonboot_cpus().

In case of disable_nonboot_cpus() the wakeup event needs to be ignored as
the purpose is to terminate the currently running kernel.

Add a 'suspend' argument which is only set when the freeze is in context of
a suspend operation. If not set then an eventually pending wakeup event is
ignored.

Fixes: a66d955e910a ("cpu/hotplug: Abort disabling secondary CPUs if wakeup is pending")
Reported-by: Boqun Feng 
Signed-off-by: Thomas Gleixner 
Cc: Pavankumar Kondeti 
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/874kuaxdiz.fsf@nanos.tec.linutronix.de
Signed-off-by: Greg Kroah-Hartman

PCI: endpoint: Fix for concurrent memory allocation in OB address region

2020-04-17T14:12:02+00:00

commit 04e046ca57ebed3943422dee10eec9e73aec081e upstream.

pci-epc-mem uses a bitmap to manage the Endpoint outbound (OB) address
region. This address region will be shared by multiple endpoint
functions (in the case of multi function endpoint) and it has to be
protected from concurrent access to avoid updating an inconsistent state.

Use a mutex to protect bitmap updates to prevent the memory
allocation API from returning incorrect addresses.

Signed-off-by: Kishon Vijay Abraham I 
Signed-off-by: Lorenzo Pieralisi 
Cc: stable@vger.kernel.org # v4.14+
Signed-off-by: Greg Kroah-Hartman

nvme-fc: Revert "add module to ops template to allow module references"

2020-04-17T14:12:02+00:00

commit 8c5c660529209a0e324c1c1a35ce3f83d67a2aa5 upstream.

The original patch was to resolve the lldd being able to be unloaded
while being used to talk to the boot device of the system. However, the
end result of the original patch is that any driver unload while a nvme
controller is live via the lldd is now being prohibited. Given the module
reference, the module teardown routine can't be called, thus there's no
way, other than manual actions to terminate the controllers.

Fixes: 863fbae929c7 ("nvme_fc: add module to ops template to allow module references")
Cc:  # v5.4+
Signed-off-by: James Smart 
Reviewed-by: Himanshu Madhani 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Greg Kroah-Hartman

thermal: devfreq_cooling: inline all stubs for CONFIG_DEVFREQ_THERMAL=n

2020-04-17T14:12:01+00:00

commit 3f5b9959041e0db6dacbea80bb833bff5900999f upstream.

When CONFIG_DEVFREQ_THERMAL is disabled all functions except
of_devfreq_cooling_register_power() were already inlined. Also inline
the last function to avoid compile errors when multiple drivers call
of_devfreq_cooling_register_power() when CONFIG_DEVFREQ_THERMAL is not
set. Compilation failed with the following message:
  multiple definition of `of_devfreq_cooling_register_power'
(which then lists all usages of of_devfreq_cooling_register_power())

Thomas Zimmermann reported this problem [0] on a kernel config with
CONFIG_DRM_LIMA={m,y}, CONFIG_DRM_PANFROST={m,y} and
CONFIG_DEVFREQ_THERMAL=n after both, the lima and panfrost drivers
gained devfreq cooling support.

[0] https://www.spinics.net/lists/dri-devel/msg252825.html

Fixes: a76caf55e5b356 ("thermal: Add devfreq cooling")
Cc: stable@vger.kernel.org
Reported-by: Thomas Zimmermann 
Signed-off-by: Martin Blumenstingl 
Tested-by: Thomas Zimmermann 
Signed-off-by: Daniel Lezcano 
Link: https://lore.kernel.org/r/20200403205133.1101808-1-martin.blumenstingl@googlemail.com
Signed-off-by: Greg Kroah-Hartman

block: Fix use-after-free issue accessing struct io_cq

2020-04-17T14:11:56+00:00

[ Upstream commit 30a2da7b7e225ef6c87a660419ea04d3cef3f6a7 ]

There is a potential race between ioc_release_fn() and
ioc_clear_queue() as shown below, due to which below kernel
crash is observed. It also can result into use-after-free
issue.

context#1:				context#2:
ioc_release_fn()			__ioc_clear_queue() gets the same icq
->spin_lock(&ioc->lock);		->spin_lock(&ioc->lock);
->ioc_destroy_icq(icq);
  ->list_del_init(&icq->q_node);
  ->call_rcu(&icq->__rcu_head,
  	icq_free_icq_rcu);
->spin_unlock(&ioc->lock);
					->ioc_destroy_icq(icq);
					  ->hlist_del_init(&icq->ioc_node);
					  This results into below crash as this memory
					  is now used by icq->__rcu_head in context#1.
					  There is a chance that icq could be free'd
					  as well.

22150.386550:   <6> Unable to handle kernel write to read-only memory
at virtual address ffffffaa8d31ca50
...
Call trace:
22150.607350:   <2>  ioc_destroy_icq+0x44/0x110
22150.611202:   <2>  ioc_clear_queue+0xac/0x148
22150.615056:   <2>  blk_cleanup_queue+0x11c/0x1a0
22150.619174:   <2>  __scsi_remove_device+0xdc/0x128
22150.623465:   <2>  scsi_forget_host+0x2c/0x78
22150.627315:   <2>  scsi_remove_host+0x7c/0x2a0
22150.631257:   <2>  usb_stor_disconnect+0x74/0xc8
22150.635371:   <2>  usb_unbind_interface+0xc8/0x278
22150.639665:   <2>  device_release_driver_internal+0x198/0x250
22150.644897:   <2>  device_release_driver+0x24/0x30
22150.649176:   <2>  bus_remove_device+0xec/0x140
22150.653204:   <2>  device_del+0x270/0x460
22150.656712:   <2>  usb_disable_device+0x120/0x390
22150.660918:   <2>  usb_disconnect+0xf4/0x2e0
22150.664684:   <2>  hub_event+0xd70/0x17e8
22150.668197:   <2>  process_one_work+0x210/0x480
22150.672222:   <2>  worker_thread+0x32c/0x4c8

Fix this by adding a new ICQ_DESTROYED flag in ioc_destroy_icq() to
indicate this icq is once marked as destroyed. Also, ensure
__ioc_clear_queue() is accessing icq within rcu_read_lock/unlock so
that icq doesn't get free'd up while it is still using it.

Signed-off-by: Sahitya Tummala 
Co-developed-by: Pradeep P V K 
Signed-off-by: Pradeep P V K 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

IB/mlx5: Replace tunnel mpls capability bits for tunnel_offloads

2020-04-13T11:16:41+00:00

commit 41e684ef3f37ce6e5eac3fb5b9c7c1853f4b0447 upstream.

Until now the flex parser capability was used in ib_query_device() to
indicate tunnel_offloads_caps support for mpls_over_gre/mpls_over_udp.

Newer devices and firmware will have configurations with the flexparser
but without mpls support.

Testing for the flex parser capability was a mistake, the tunnel_stateless
capability was intended for detecting mpls and was introduced at the same
time as the flex parser capability.

Otherwise userspace will be incorrectly informed that a future device
supports MPLS when it does not.

Link: https://lore.kernel.org/r/20200305123841.196086-1-leon@kernel.org
Cc:  # 4.17
Fixes: e818e255a58d ("IB/mlx5: Expose MPLS related tunneling offloads")
Signed-off-by: Alex Vesker 
Reviewed-by: Ariel Levkovich 
Signed-off-by: Leon Romanovsky 
Signed-off-by: Jason Gunthorpe 
Signed-off-by: Greg Kroah-Hartman

ACPI: PM: Add acpi_[un]register_wakeup_handler()

2020-04-13T11:16:39+00:00

commit ddfd9dcf270ce23ed1985b66fcfa163920e2e1b8 upstream.

Since commit fdde0ff8590b ("ACPI: PM: s2idle: Prevent spurious SCIs from
waking up the system") the SCI triggering without there being a wakeup
cause recognized by the ACPI sleep code will no longer wakeup the system.

This works as intended, but this is a problem for devices where the SCI
is shared with another device which is also a wakeup source.

In the past these, from the pov of the ACPI sleep code, spurious SCIs
would still cause a wakeup so the wakeup from the device sharing the
interrupt would actually wakeup the system. This now no longer works.

This is a problem on e.g. Bay Trail-T and Cherry Trail devices where
some peripherals (typically the XHCI controller) can signal a
Power Management Event (PME) to the Power Management Controller (PMC)
to wakeup the system, this uses the same interrupt as the SCI.
These wakeups are handled through a special INT0002 ACPI device which
checks for events in the GPE0a_STS for this and takes care of acking
the PME so that the shared interrupt stops triggering.

The change to the ACPI sleep code to ignore the spurious SCI, causes
the system to no longer wakeup on these PME events. To make things
worse this means that the INT0002 device driver interrupt handler will
no longer run, causing the PME to not get cleared and resulting in the
system hanging. Trying to wakeup the system after such a PME through e.g.
the power button no longer works.

Add an acpi_register_wakeup_handler() function which registers
a handler to be called from acpi_s2idle_wake() and when the handler
returns true, return true from acpi_s2idle_wake().

The INT0002 driver will use this mechanism to check the GPE0a_STS
register from acpi_s2idle_wake() and to tell the system to wakeup
if a PME is signaled in the register.

Fixes: fdde0ff8590b ("ACPI: PM: s2idle: Prevent spurious SCIs from waking up the system")
Cc: 5.4+  # 5.4+
Signed-off-by: Hans de Goede 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

uapi: rename ext2_swab() to swab() and share globally in swab.h

2020-04-13T11:16:34+00:00

commit d5767057c9a76a29f073dad66b7fa12a90e8c748 upstream.

ext2_swab() is defined locally in lib/find_bit.c However it is not
specific to ext2, neither to bitmaps.

There are many potential users of it, so rename it to just swab() and
move to include/uapi/linux/swab.h

ABI guarantees that size of unsigned long corresponds to BITS_PER_LONG,
therefore drop unneeded cast.

Link: http://lkml.kernel.org/r/20200103202846.21616-1-yury.norov@gmail.com
Signed-off-by: Yury Norov 
Cc: Allison Randal 
Cc: Joe Perches 
Cc: Thomas Gleixner 
Cc: William Breathitt Gray 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman