The value 0 for devs_max means to spread the allocated chunks over all
available devices, eg. stripe for RAID0 or RAID5. This got mistakenly
copied to the RAID1C3/4 profiles. The intention is to have exactly 3 and
4 copies respectively.
Fixes: 47e6f7423b ("btrfs: add support for 3-copy replication (raid1c3)")
Fixes: 8d6fac0087 ("btrfs: add support for 4-copy replication (raid1c4)")
Signed-off-by: David Sterba <dsterba@suse.com>
Argument BTRFS_FILE_EXTENT_INLINE_DATA_START is defined as offsetof(),
which returns type size_t, so we need %zu instead of %lu.
This fixes a build warning on 32-bit ARM:
../fs/btrfs/tree-checker.c: In function 'check_extent_data_item':
../fs/btrfs/tree-checker.c:230:43: warning: format '%lu' expects argument of type 'long unsigned int', but argument 5 has type 'unsigned int' [-Wformat=]
230 | "invalid item size, have %u expect [%lu, %u)",
| ~~^
| long unsigned int
| %u
Fixes: 153a6d2999 ("btrfs: tree-checker: Check item size before reading file extent type")
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andreas Färber <afaerber@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If we're rename exchanging two subvols we'll try to lock this lock
twice, which is bad. Just lock once if either of the ino's are subvols.
Fixes: cdd1fedf82 ("btrfs: add support for RENAME_EXCHANGE and RENAME_WHITEOUT")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have a BUG_ON(ret < 0) in find_free_extent from
btrfs_cache_block_group. If we fail to allocate our ctl we'll just
panic, which is not good. Instead just go on to another block group.
If we fail to find a block group we don't want to return ENOSPC, because
really we got a ENOMEM and that's the root of the problem. Save our
return from btrfs_cache_block_group(), and then if we still fail to make
our allocation return that ret so we get the right error back.
Tested with inject-error.py from bcc.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Testing with the new fsstress uncovered a pretty nasty deadlock with
lookup and snapshot deletion.
Process A
unlink
-> final iput
-> inode_tree_del
-> synchronize_srcu(subvol_srcu)
Process B
btrfs_lookup <- srcu_read_lock() acquired here
-> btrfs_iget
-> find inode that has I_FREEING set
-> __wait_on_freeing_inode()
We're holding the srcu_read_lock() while doing the iget in order to make
sure our fs root doesn't go away, and then we are waiting for the inode
to finish freeing. However because the free'ing process is doing a
synchronize_srcu() we deadlock.
Fix this by dropping the synchronize_srcu() in inode_tree_del(). We
don't need people to stop accessing the fs root at this point, we're
only adding our empty root to the dead roots list.
A larger much more invasive fix is forthcoming to address how we deal
with fs roots, but this fixes the immediate problem.
Fixes: 76dda93c6a ("Btrfs: add snapshot/subvolume destroy ioctl")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since commit 0e4a459f56 ("tracing: Remove unnecessary DEBUG_FS
dependency"), CONFIG_DEBUG_FS is no longer auto-enabled. This breaks
booting Debian 9, as systemd needs debugfs:
[FAILED] Failed to mount /sys/kernel/debug.
See 'systemctl status sys-kernel-debug.mount' for details.
[DEPEND] Dependency failed for Local File Systems.
...
You are in emergGive root password for maintenance
(or press Control-D to continue):
Fix this by enabling CONFIG_DEBUG_FS explicitly.
See also commit 18977008f4 ("ARM: multi_v7_defconfig: Restore
debugfs support").
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://lore.kernel.org/r/20191209101327.26571-1-geert+renesas@glider.be
When using the NO_HOLES feature if we clone a range that contains a hole
and a temporary ENOSPC happens while dropping extents from the target
inode's range, we can end up failing and aborting the transaction with
-EEXIST or with a corrupt file extent item, that has a length greater
than it should and overlaps with other extents. For example when cloning
the following range from inode A to inode B:
Inode A:
extent A1 extent A2
[ ----------- ] [ hole, implicit, 4MB length ] [ ------------- ]
0 1MB 5MB 6MB
Range to clone: [1MB, 6MB)
Inode B:
extent B1 extent B2 extent B3 extent B4
[ ---------- ] [ --------- ] [ ---------- ] [ ---------- ]
0 1MB 1MB 2MB 2MB 5MB 5MB 6MB
Target range: [1MB, 6MB) (same as source, to make it easier to explain)
The following can happen:
1) btrfs_punch_hole_range() gets -ENOSPC from __btrfs_drop_extents();
2) At that point, 'cur_offset' is set to 1MB and __btrfs_drop_extents()
set 'drop_end' to 2MB, meaning it was able to drop only extent B2;
3) We then compute 'clone_len' as 'drop_end' - 'cur_offset' = 2MB - 1MB =
1MB;
4) We then attempt to insert a file extent item at inode B with a file
offset of 5MB, which is the value of clone_info->file_offset. This
fails with error -EEXIST because there's already an extent at that
offset (extent B4);
5) We abort the current transaction with -EEXIST and return that error
to user space as well.
Another example, for extent corruption:
Inode A:
extent A1 extent A2
[ ----------- ] [ hole, implicit, 10MB length ] [ ------------- ]
0 1MB 11MB 12MB
Inode B:
extent B1 extent B2
[ ----------- ] [ --------- ] [ ----------------------------- ]
0 1MB 1MB 5MB 5MB 12MB
Target range: [1MB, 12MB) (same as source, to make it easier to explain)
1) btrfs_punch_hole_range() gets -ENOSPC from __btrfs_drop_extents();
2) At that point, 'cur_offset' is set to 1MB and __btrfs_drop_extents()
set 'drop_end' to 5MB, meaning it was able to drop only extent B2;
3) We then compute 'clone_len' as 'drop_end' - 'cur_offset' = 5MB - 1MB =
4MB;
4) We then insert a file extent item at inode B with a file offset of 11MB
which is the value of clone_info->file_offset, and a length of 4MB (the
value of 'clone_len'). So we get 2 extents items with ranges that
overlap and an extent length of 4MB, larger then the extent A2 from
inode A (1MB length);
5) After that we end the transaction, balance the btree dirty pages and
then start another or join the previous transaction. It might happen
that the transaction which inserted the incorrect extent was committed
by another task so we end up with extent corruption if a power failure
happens.
So fix this by making sure we attempt to insert the extent to clone at
the destination inode only if we are past dropping the sub-range that
corresponds to a hole.
Fixes: 690a5dbfc5 ("Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The branch of qgroup_rescan_init which is executed from the mount
path prints wrong errors messages. The textual print out in case
BTRFS_QGROUP_STATUS_FLAG_RESCAN/BTRFS_QGROUP_STATUS_FLAG_ON are not
set are transposed. Fix it by exchanging their place.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Some powerpc platforms (e.g. 85xx) limit DMA-able memory way below 4G.
If a system has more physical memory than this limit, the swiotlb
buffer is not addressable because it is allocated from memblock using
top-down mode.
Force memblock to bottom-up mode before calling swiotlb_init() to
ensure that the swiotlb buffer is DMA-able.
Reported-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191204123524.22919-1-rppt@kernel.org
intel-pinctrl for v5.5-2
* Fix Baytrail silicon issue by using a global lock
* Fix North community pin names that user will assume their functions
* Convert Cherryview and Baytrail to pass IRQ chip along with GPIO one
The following is an automated git shortlog grouped by driver:
baytrail:
- Pass irqchip when adding gpiochip
- Add GPIO <-> pin mapping ranges via callback
- Update North Community pin list
- Really serialize all register accesses
cherryview:
- Pass irqchip when adding gpiochip
- Add GPIO <-> pin mapping ranges via callback
- Split out irq hw-init into a separate helper function
Instead of just having an airtime flag in debugfs, turn AQL into a proper
NL80211_EXT_FEATURE, so drivers can turn it on when they are ready, and so
we also expose the presence of the feature to userspace.
This also has the effect of flipping the default, so drivers have to opt in
to using AQL instead of getting it by default with TXQs. To keep
functionality the same as pre-patch, we set this feature for ath10k (which
is where it is needed the most).
While we're at it, split out the debugfs interface so AQL gets its own
per-station debugfs file instead of using the 'airtime' file.
[Johannes:]
This effectively disables AQL for iwlwifi, where it fixes a number of
issues:
* TSO in iwlwifi is causing underflows and associated warnings in AQL
* HE (802.11ax) rates aren't reported properly so at HE rates, AQL could
never have a valid estimate (it'd use 6 Mbps instead of up to 2400!)
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20191212111437.224294-1-toke@redhat.com
Fixes: 3ace10f5b5 ("mac80211: Implement Airtime-based Queue Limit (AQL)")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
* pm-cpuidle:
cpuidle: Drop unnecessary type cast in cpuidle_poll_time()
cpuidle: Fix cpuidle_driver_state_disabled()
cpuidle: use first valid target residency as poll time
* acpi-pm:
ACPI: PM: Avoid attaching ACPI PM domain to certain devices
Fix overwriting of the qos_ctrl.tid field for encrypted frames injected on
a monitor interface. While qos_ctrl.tid is not encrypted, it's used as an
input into the encryption algorithm so it's protected, and thus cannot be
modified after encryption. For injected frames, the encryption may already
have been done in userspace, so we cannot change any fields.
Before passing the frame to the driver, the qos_ctrl.tid field is updated
from skb->priority. Prior to dbd50a851c skb->priority was updated in
ieee80211_select_queue_80211(), but this function is no longer always
called.
Update skb->priority in ieee80211_monitor_start_xmit() so that the value
is stored, and when later code 'modifies' the TID it really sets it to
the same value as before, preserving the encryption.
Fixes: dbd50a851c ("mac80211: only allocate one queue when using iTXQs")
Signed-off-by: Fredrik Olofsson <fredrik.olofsson@anyfinetworks.com>
Link: https://lore.kernel.org/r/20191119133451.14711-1-fredrik.olofsson@anyfinetworks.com
[rewrite commit message based on our discussion]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
When CONFIG_XEN_BALLOON_MEMORY_HOTPLUG is not defined
reserve_additional_memory() will set balloon_stats.target_pages to a
wrong value in case there are still some ballooned pages allocated via
alloc_xenballooned_pages().
This will result in balloon_process() no longer be triggered when
ballooned pages are freed in batches.
Reported-by: Nicholas Tsirakis <niko.tsirakis@gmail.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Objects allocated by xen_blkif_alloc come from the 'blkif_cache' kmem
cache. This cache is destoyed when xen-blkif is unloaded so it is
necessary to wait for the deferred free routine used for such objects to
complete. This necessity was missed in commit 14855954f6 "xen-blkback:
allow module to be cleanly unloaded". This patch fixes the problem by
taking/releasing extra module references in xen_blkif_alloc/free()
respectively.
Signed-off-by: Paul Durrant <pdurrant@amazon.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
SMB2_tdis() checks if a root handle is valid in order to decide
whether it needs to close the handle or not. However if another
thread has reference for the handle, it may end up with putting
the reference twice. The extra reference that we want to put
during the tree disconnect is the reference that has a directory
lease. So, track the fact that we have a directory lease and
close the handle only in that case.
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Ran into an intermittent crash in
SMB2_open_init+0x2f6/0x970
due to oparms.cifs_sb not being initialized when called from:
smb2_compound_op+0x45d/0x1690
Zero the whole oparms struct in the compounding path before setting up the
oparms so we don't risk any uninitialized fields.
Fixes: fdef665ba4 ("smb3: fix mode passed in on create for modetosid mount option")
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Pull i.MX clk fixes from Shawn Guo:
- Add missing lock to divider in the composite driver for exclusive
register access
- Add missing sentinel for ulp_div_table in clk-imx7ulp driver
- Fix clk_pll14xx_wait_lock() function which calls into
readl_poll_timeout() with incorrect parameter
* tag 'imx-clk-fixes-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux:
clk: imx: pll14xx: fix clk_pll14xx_wait_lock
clk: imx: clk-imx7ulp: Add missing sentinel of ulp_div_table
clk: imx: clk-composite-8m: add lock to gate/mux
So far, we walked the orphan list every time a new clock was registered
in CCF. This was fine since the clocks were only referenced by name.
Now that the clock can be referenced through DT, it is not enough:
* Controller A register first a reference clocks from controller B
through DT.
* Controller B register all its clocks then register the provider.
Each time controller B registers a new clock, the orphan list is walked
but it can't match since the provider is registered yet. When the
provider is finally registered, the orphan list is not walked unless
another clock is registered afterward.
This can lead to situation where some clocks remain orphaned even if
the parent is available.
Walking the orphan list on provider registration solves the problem.
Reported-by: Jian Hu <jian.hu@amlogic.com>
Fixes: fc0c209c14 ("clk: Allow parents to be specified without string names")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lkml.kernel.org/r/20191203080805.104628-1-jbrunet@baylibre.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Commit 5e6669387e ("of/platform: Pause/resume sync state during init
and of_platform_populate()") paused/resumed sync state during init only
if Linux had parsed and populated a devicetree.
However, the check for that (of_have_populated_dt()) can change after
of_platform_default_populate_init() executes. One example of this is
when devicetree unittests are enabled. This causes an unmatched
pause/resume of sync state. To avoid this, just unconditionally
pause/resume sync state during init.
Fixes: 5e6669387e ("of/platform: Pause/resume sync state during init and of_platform_populate()")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Reviewed-by: Frank Rowand <frowand.list@gmail.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Json-schema requires a $ref to be under an 'allOf' if there are
additional constraints otherwise the additional constraints are
ignored. (Note that this behavior will be changed in draft8.)
Fixes: 641262f5e1 ("dt-bindings: memory: Add binding for NVIDIA Tegra30 External Memory Controller")
Fixes: 785685b7a1 ("dt-bindings: memory: Add binding for NVIDIA Tegra30 Memory Controller")
Fixes: 8da65c377b ("dt-bindings: memory: tegra30: Convert to Tegra124 YAML")
Cc: Thierry Reding <treding@nvidia.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: linux-tegra@vger.kernel.org
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Rob Herring <robh@kernel.org>
While my email address has changed for a while, all the schemas I
contributed still have the old one unfortunately. Update it.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: Rob Herring <robh@kernel.org>
Fix device memory flows so that only once there will be no live mmaped
VA to a given allocation the matching object will be destroyed.
This prevents a potential scenario that existing VA that was mmaped by
one process might still be used post its deallocation despite that it's
owned now by other process.
The above is achieved by integrating with IB core APIs to manage
mmap/munmap. Only once the refcount will become 0 the DM object and its
underlay area will be freed.
Fixes: 3b113a1ec3 ("IB/mlx5: Support device memory type attribute")
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Link: https://lore.kernel.org/r/20191212100237.330654-3-leon@kernel.org
Signed-off-by: Doug Ledford <dledford@redhat.com>
KEYS_COMPAT now always takes the value of COMPAT && KEYS. But the
security/keys/ directory is only compiled if KEYS is enabled, so in
practice KEYS_COMPAT is the same as COMPAT. Therefore, remove the
unnecessary KEYS_COMPAT and just use COMPAT directly.
(Also remove an outdated comment from compat.c.)
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
It may fail to load guest driver in round 2 when using invalidate
semaphore for SRIOV. So it needs to avoid using invalidate semaphore
for SRIOV.
Signed-off-by: changzhu <Changfeng.Zhu@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
It may fail to load guest driver in round 2 or cause Xstart problem
when using invalidate semaphore for SRIOV or picasso. So it needs avoid
using invalidate semaphore for SRIOV and picasso.
Signed-off-by: changzhu <Changfeng.Zhu@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Current code device add sequence is:
ib_register_device()
ib_mad_init()
init_sriov_init()
register_netdev_notifier()
Therefore, the remove sequence should be,
unregister_netdev_notifier()
close_sriov()
mad_cleanup()
ib_unregister_device()
However it is not above.
Hence, make do above remove sequence.
Fixes: fa417f7b52 ("IB/mlx4: Add support for IBoE")
Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Link: https://lore.kernel.org/r/20191212091214.315005-3-leon@kernel.org
Signed-off-by: Doug Ledford <dledford@redhat.com>
Driver doesn't accommodate the configuration for max number
of multicast mac addresses, in such particular case it leaves
the device with improper/invalid multicast configuration state,
causing connectivity issues (in lacp bonding like scenarios).
Signed-off-by: Manish Chopra <manishc@marvell.com>
Signed-off-by: Ariel Elior <aelior@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Lan78xx driver accesses the PHY registers through MDIO bus over USB
connection. When performing a suspend/resume, the PHY registers can be
accessed before the USB connection is resumed. This will generate an
error and will prevent the device to resume correctly.
This patch adds the dependency between the MDIO bus and USB device to
allow correct handling of suspend/resume.
Fixes: ce85e13ad6 ("lan78xx: Update to use phylib instead of mii_if_info.")
Signed-off-by: Cristian Birsan <cristian.birsan@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull ceph fixes from Ilya Dryomov:
"A fix to avoid a corner case when scheduling cap reclaim in batches
from Xiubo, a patch to add some observability into cap waiters from
Jeff and a couple of cleanups"
* tag 'ceph-for-5.5-rc2' of git://github.com/ceph/ceph-client:
ceph: add more debug info when decoding mdsmap
ceph: switch to global cap helper
ceph: trigger the reclaim work once there has enough pending caps
ceph: show tasks waiting on caps in debugfs caps file
ceph: convert int fields in ceph_mount_options to unsigned int
ksys_dup() is used only at one place in the kernel, namely to duplicate
fd 0 of /dev/console to stdout and stderr. The same functionality can be
achieved by using functions already available within the kernel namespace.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
i.MX fixes for 5.5:
- Add missing jedec,spi-nor compatible for imx6ul-14x14-evk board,
so that SPI NOR device can be probed.
- Fix power button of E60K02 board by removing LDORTC2 regulator.
- A couple of fixes on serial number support of i.MX6ULL/ULZ SoCs to
remove the boot regression caused by 8267ff89b7 ("ARM: imx: Add
serial number support for i.MX6/7 SoCs").
- A couple of fixes on LS1028A SoC TMU regarding to calibration data
and reboot register configuration.
- Fix a regression seen on imx6ul-evk board by marking always-on for
the regulator that is shared by many peripherals.
- Explicitly restore CONFIG_DEBUG_FS in imx_v6_v7_defconfig.
* tag 'imx-fixes-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux:
ARM: imx: Fix boot crash if ocotp is not found
ARM: imx_v6_v7_defconfig: Explicitly restore CONFIG_DEBUG_FS
ARM: dts: imx6ul-evk: Fix peripheral regulator
arm64: dts: ls1028a: fix reboot node
arm64: dts: ls1028a: fix typo in TMU calibration data
ARM: imx: Correct ocotp id for serial number support of i.MX6ULL/ULZ SoCs
ARM: dts: e60k02: fix power button
ARM: dts: imx6ul: imx6ul-14x14-evk.dtsi: Fix SPI NOR probing
Link: https://lore.kernel.org/r/20191212122427.GK15858@dragon
Signed-off-by: Olof Johansson <olof@lixom.net>
The scheduler code calling cpufreq_update_util() may run during CPU
offline on the target CPU after the IRQ work lists have been flushed
for it, so the target CPU should be prevented from running code that
may queue up an IRQ work item on it at that point.
Unfortunately, that may not be the case if dvfs_possible_from_any_cpu
is set for at least one cpufreq policy in the system, because that
allows the CPU going offline to run the utilization update callback
of the cpufreq governor on behalf of another (online) CPU in some
cases.
If that happens, the cpufreq governor callback may queue up an IRQ
work on the CPU running it, which is going offline, and the IRQ work
may not be flushed after that point. Moreover, that IRQ work cannot
be flushed until the "offlining" CPU goes back online, so if any
other CPU calls irq_work_sync() to wait for the completion of that
IRQ work, it will have to wait until the "offlining" CPU is back
online and that may not happen forever. In particular, a system-wide
deadlock may occur during CPU online as a result of that.
The failing scenario is as follows. CPU0 is the boot CPU, so it
creates a cpufreq policy and becomes the "leader" of it
(policy->cpu). It cannot go offline, because it is the boot CPU.
Next, other CPUs join the cpufreq policy as they go online and they
leave it when they go offline. The last CPU to go offline, say CPU3,
may queue up an IRQ work while running the governor callback on
behalf of CPU0 after leaving the cpufreq policy because of the
dvfs_possible_from_any_cpu effect described above. Then, CPU0 is
the only online CPU in the system and the stale IRQ work is still
queued on CPU3. When, say, CPU1 goes back online, it will run
irq_work_sync() to wait for that IRQ work to complete and so it
will wait for CPU3 to go back online (which may never happen even
in principle), but (worse yet) CPU0 is waiting for CPU1 at that
point too and a system-wide deadlock occurs.
To address this problem notice that CPUs which cannot run cpufreq
utilization update code for themselves (for example, because they
have left the cpufreq policies that they belonged to), should also
be prevented from running that code on behalf of the other CPUs that
belong to a cpufreq policy with dvfs_possible_from_any_cpu set and so
in that case the cpufreq_update_util_data pointer of the CPU running
the code must not be NULL as well as for the CPU which is the target
of the cpufreq utilization update in progress.
Accordingly, change cpufreq_this_cpu_can_update() into a regular
function in kernel/sched/cpufreq.c (instead of a static inline in a
header file) and make it check the cpufreq_update_util_data pointer
of the local CPU if dvfs_possible_from_any_cpu is set for the target
cpufreq policy.
Also update the schedutil governor to do the
cpufreq_this_cpu_can_update() check in the non-fast-switch
case too to avoid the stale IRQ work issues.
Fixes: 99d14d0e16 ("cpufreq: Process remote callbacks from any CPU if the platform permits")
Link: https://lore.kernel.org/linux-pm/20191121093557.bycvdo4xyinbc5cb@vireshk-i7/
Reported-by: Anson Huang <anson.huang@nxp.com>
Tested-by: Anson Huang <anson.huang@nxp.com>
Cc: 4.14+ <stable@vger.kernel.org> # 4.14+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Peng Fan <peng.fan@nxp.com> (i.MX8QXP-MEK)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
