Now that we have an extension to handle images, use it.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Allow TTL propagation from IP packets to MPLS packets to be
configured. Add a new optional LWT attribute, MPLS_IPTUNNEL_TTL, which
allows the TTL to be set in the resulting MPLS packet, with the value
of 0 having the semantics of enabling propagation of the TTL from the
IP header (i.e. non-zero values disable propagation).
Also allow the configuration to be overridden globally by reusing the
same sysctl to control whether the TTL is propagated from IP packets
into the MPLS header. If the per-LWT attribute is set then it
overrides the global configuration. If the TTL isn't propagated then a
default TTL value is used which can be configured via a new sysctl,
"net.mpls.default_ttl". This is kept separate from the configuration
of whether IP TTL propagation is enabled as it can be used in the
future when non-IP payloads are supported (i.e. where there is no
payload TTL that can be propagated).
Signed-off-by: Robert Shearman <rshearma@brocade.com>
Acked-by: David Ahern <dsa@cumulusnetworks.com>
Tested-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Provide the ability to control on a per-route basis whether the TTL
value from an MPLS packet is propagated to an IPv4/IPv6 packet when
the last label is popped as per the theoretical model in RFC 3443
through a new route attribute, RTA_TTL_PROPAGATE which can be 0 to
mean disable propagation and 1 to mean enable propagation.
In order to provide the ability to change the behaviour for packets
arriving with IPv4/IPv6 Explicit Null labels and to provide an easy
way for a user to change the behaviour for all existing routes without
having to reprogram them, a global knob is provided. This is done
through the addition of a new per-namespace sysctl,
"net.mpls.ip_ttl_propagate", which defaults to enabled. If the
per-route attribute is set (either enabled or disabled) then it
overrides the global configuration.
Signed-off-by: Robert Shearman <rshearma@brocade.com>
Acked-by: David Ahern <dsa@cumulusnetworks.com>
Tested-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for PF0200 coin cell/super capacitor charger which works as
a current limited voltage source via the LICELL pin. When VIN goes below
a certain threshold LICELL is used to provide power for VSNVS which is
usually used to hold up secure non-volatile storage and the real-time
clock on the SoC.
Signed-off-by: George McCollister <george.mccollister@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Add a binding for setting how the I2S pins are driven in unused slots,
currently the chip will just use the default of drive 0, however
this causes issues when multiple devices are attached to the same bus.
Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: Brian Austin <brian.austin@cirrus.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Add documentation for the bindings of the high speed SPI controller found
on newer bcm63xx SoCs.
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
This patch adds the configuration of the AVB Credit-Based Shaper.
Signed-off-by: Joao Pinto <jpinto@synopsys.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds the multiple queues configuration in the Device Tree.
It was also created a set of structures to keep the RX and TX queues
configurations to be used in the driver.
Signed-off-by: Joao Pinto <jpinto@synopsys.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It wasn't clear if the 'forwarding' setting needs to be enabled on the
interface that packets are received from, or on the interface that
packets are forwarded to, or both.
In fact (according to my code reading) the setting is relevant on the
interface that packets are received from, so this change updates the doc
to say that.
Signed-off-by: Neil Jerram <neil@tigera.io>
Signed-off-by: David S. Miller <davem@davemloft.net>
This adds the necessary data for handling io voltage domains on the rk3328.
As interesting tidbit, the rk3328 only contains one iodomain area in the
regular General Register Files (GRF).
Signed-off-by: David Wu <david.wu@rock-chips.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Pull irq fixes from Thomas Gleixner:
- a workaround for a GIC erratum
- a missing stub function for CONFIG_IRQDOMAIN=n
- fixes for a couple of type inconsistencies
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/crossbar: Fix incorrect type of register size
irqchip/gicv3-its: Add workaround for QDF2400 ITS erratum 0065
irqdomain: Add empty irq_domain_check_msi_remap
irqchip/crossbar: Fix incorrect type of local variables
Pull KVM fixes from Radim Krčmář:
"ARM updates from Marc Zyngier:
- vgic updates:
- Honour disabling the ITS
- Don't deadlock when deactivating own interrupts via MMIO
- Correctly expose the lact of IRQ/FIQ bypass on GICv3
- I/O virtualization:
- Make KVM_CAP_NR_MEMSLOTS big enough for large guests with many
PCIe devices
- General bug fixes:
- Gracefully handle exception generated with syndroms that the host
doesn't understand
- Properly invalidate TLBs on VHE systems
x86:
- improvements in emulation of VMCLEAR, VMX MSR bitmaps, and VCPU
reset
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: nVMX: do not warn when MSR bitmap address is not backed
KVM: arm64: Increase number of user memslots to 512
KVM: arm/arm64: Remove KVM_PRIVATE_MEM_SLOTS definition that are unused
KVM: arm/arm64: Enable KVM_CAP_NR_MEMSLOTS on arm/arm64
KVM: Add documentation for KVM_CAP_NR_MEMSLOTS
KVM: arm/arm64: VGIC: Fix command handling while ITS being disabled
arm64: KVM: Survive unknown traps from guests
arm: KVM: Survive unknown traps from guests
KVM: arm/arm64: Let vcpu thread modify its own active state
KVM: nVMX: reset nested_run_pending if the vCPU is going to be reset
kvm: nVMX: VMCLEAR should not cause the vCPU to shut down
KVM: arm/arm64: vgic-v3: Don't pretend to support IRQ/FIQ bypass
arm64: KVM: VHE: Clear HCR_TGE when invalidating guest TLBs
Merge Laurent's drm_platform removal code. Only conflict is with the
drm_pci.h extraction, which allows me to fix up the misplayed
drm_platform_init fumble that 0day and Stephen Rothwell reported.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Pull USB fixes from Greg KH:
"Here is a number of different USB fixes for 4.11-rc2.
Seems like there were a lot of unresolved issues that people have been
finding for this subsystem, and a bunch of good security auditing
happening as well from Johan Hovold. There's the usual batch of gadget
driver fixes and xhci issues resolved as well.
All of these have been in linux-next with no reported issues"
* tag 'usb-4.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (35 commits)
usb: host: xhci-plat: Fix timeout on removal of hot pluggable xhci controllers
usb: host: xhci-dbg: HCIVERSION should be a binary number
usb: xhci: remove dummy extra_priv_size for size of xhci_hcd struct
usb: xhci-mtk: check hcc_params after adding primary hcd
USB: serial: digi_acceleport: fix OOB-event processing
MAINTAINERS: usb251xb: remove reference inexistent file
doc: dt-bindings: usb251xb: mark reg as required
usb: usb251xb: dt: add unit suffix to oc-delay and power-on-time
usb: usb251xb: remove max_{power,current}_{sp,bp} properties
usb-storage: Add ignore-residue quirk for Initio INIC-3619
USB: iowarrior: fix NULL-deref in write
USB: iowarrior: fix NULL-deref at probe
usb: phy: isp1301: Add OF device ID table
usb: ohci-at91: Do not drop unhandled USB suspend control requests
USB: serial: safe_serial: fix information leak in completion handler
USB: serial: io_ti: fix information leak in completion handler
USB: serial: omninet: drop open callback
USB: serial: omninet: fix reference leaks at open
USB: serial: io_ti: fix NULL-deref in interrupt callback
usb: dwc3: gadget: make to increment req->remaining in all cases
...
Merge fixes from Andrew Morton:
"26 fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (26 commits)
userfaultfd: remove wrong comment from userfaultfd_ctx_get()
fat: fix using uninitialized fields of fat_inode/fsinfo_inode
sh: cayman: IDE support fix
kasan: fix races in quarantine_remove_cache()
kasan: resched in quarantine_remove_cache()
mm: do not call mem_cgroup_free() from within mem_cgroup_alloc()
thp: fix another corner case of munlock() vs. THPs
rmap: fix NULL-pointer dereference on THP munlocking
mm/memblock.c: fix memblock_next_valid_pfn()
userfaultfd: selftest: vm: allow to build in vm/ directory
userfaultfd: non-cooperative: userfaultfd_remove revalidate vma in MADV_DONTNEED
userfaultfd: non-cooperative: fix fork fctx->new memleak
mm/cgroup: avoid panic when init with low memory
drivers/md/bcache/util.h: remove duplicate inclusion of blkdev.h
mm/vmstats: add thp_split_pud event for clarity
include/linux/fs.h: fix unsigned enum warning with gcc-4.2
userfaultfd: non-cooperative: release all ctx in dup_userfaultfd_complete
userfaultfd: non-cooperative: robustness check
userfaultfd: non-cooperative: rollback userfaultfd_exit
x86, mm: unify exit paths in gup_pte_range()
...
Patch series "userfaultfd non-cooperative further update for 4.11 merge
window".
Unfortunately I noticed one relevant bug in userfaultfd_exit while doing
more testing. I've been doing testing before and this was also tested
by kbuild bot and exercised by the selftest, but this bug never
reproduced before.
I dropped userfaultfd_exit as result. I dropped it because of
implementation difficulty in receiving signals in __mmput and because I
think -ENOSPC as result from the background UFFDIO_COPY should be enough
already.
Before I decided to remove userfaultfd_exit, I noticed userfaultfd_exit
wasn't exercised by the selftest and when I tried to exercise it, after
moving it to a more correct place in __mmput where it would make more
sense and where the vma list is stable, it resulted in the
event_wait_completion in D state. So then I added the second patch to
be sure even if we call userfaultfd_event_wait_completion too late
during task exit(), we won't risk to generate tasks in D state. The
same check exists in handle_userfault() for the same reason, except it
makes a difference there, while here is just a robustness check and it's
run under WARN_ON_ONCE.
While looking at the userfaultfd_event_wait_completion() function I
looked back at its callers too while at it and I think it's not ok to
stop executing dup_fctx on the fcs list because we relay on
userfaultfd_event_wait_completion to execute
userfaultfd_ctx_put(fctx->orig) which is paired against
userfaultfd_ctx_get(fctx->orig) in dup_userfault just before
list_add(fcs). This change only takes care of fctx->orig but this area
also needs further review looking for similar problems in fctx->new.
The only patch that is urgent is the first because it's an use after
free during a SMP race condition that affects all processes if
CONFIG_USERFAULTFD=y. Very hard to reproduce though and probably
impossible without SLUB poisoning enabled.
This patch (of 3):
I once reproduced this oops with the userfaultfd selftest, it's not
easily reproducible and it requires SLUB poisoning to reproduce.
general protection fault: 0000 [#1] SMP
Modules linked in:
CPU: 2 PID: 18421 Comm: userfaultfd Tainted: G ------------ T 3.10.0+ #15
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.1-0-g8891697-prebuilt.qemu-project.org 04/01/2014
task: ffff8801f83b9440 ti: ffff8801f833c000 task.ti: ffff8801f833c000
RIP: 0010:[<ffffffff81451299>] [<ffffffff81451299>] userfaultfd_exit+0x29/0xa0
RSP: 0018:ffff8801f833fe80 EFLAGS: 00010202
RAX: ffff8801f833ffd8 RBX: 6b6b6b6b6b6b6b6b RCX: ffff8801f83b9440
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8800baf18600
RBP: ffff8801f833fee8 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: ffffffff8127ceb3 R12: 0000000000000000
R13: ffff8800baf186b0 R14: ffff8801f83b99f8 R15: 00007faed746c700
FS: 0000000000000000(0000) GS:ffff88023fc80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00007faf0966f028 CR3: 0000000001bc6000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
do_exit+0x297/0xd10
SyS_exit+0x17/0x20
tracesys+0xdd/0xe2
Code: 00 00 66 66 66 66 90 55 48 89 e5 41 54 53 48 83 ec 58 48 8b 1f 48 85 db 75 11 eb 73 66 0f 1f 44 00 00 48 8b 5b 10 48 85 db 74 64 <4c> 8b a3 b8 00 00 00 4d 85 e4 74 eb 41 f6 84 24 2c 01 00 00 80
RIP [<ffffffff81451299>] userfaultfd_exit+0x29/0xa0
RSP <ffff8801f833fe80>
---[ end trace 9fecd6dcb442846a ]---
In the debugger I located the "mm" pointer in the stack and walking
mm->mmap->vm_next through the end shows the vma->vm_next list is fully
consistent and it is null terminated list as expected. So this has to
be an SMP race condition where userfaultfd_exit was running while the
vma list was being modified by another CPU.
When userfaultfd_exit() run one of the ->vm_next pointers pointed to
SLAB_POISON (RBX is the vma pointer and is 0x6b6b..).
The reason is that it's not running in __mmput but while there are still
other threads running and it's not holding the mmap_sem (it can't as it
has to wait the even to be received by the manager). So this is an use
after free that was happening for all processes.
One more implementation problem aside from the race condition:
userfaultfd_exit has really to check a flag in mm->flags before walking
the vma or it's going to slowdown the exit() path for regular tasks.
One more implementation problem: at that point signals can't be
delivered so it would also create a task in D state if the manager
doesn't read the event.
The major design issue: it overall looks superfluous as the manager can
check for -ENOSPC in the background transfer:
if (mmget_not_zero(ctx->mm)) {
[..]
} else {
return -ENOSPC;
}
It's safer to roll it back and re-introduce it later if at all.
[rppt@linux.vnet.ibm.com: documentation fixup after removal of UFFD_EVENT_EXIT]
Link: http://lkml.kernel.org/r/1488345437-4364-1-git-send-email-rppt@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/20170224181957.19736-2-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull power management fixes from Rafael Wysocki:
"These fix several issues in the intel_pstate driver and one issue in
the schedutil cpufreq governor, clean up that governor a bit and hook
up existing code for disabling cpufreq to a new kernel command line
option.
Specifics:
- Three fixes for intel_pstate problems related to the passive mode
(in which it acts as a regular cpufreq scaling driver), two for the
handling of global P-state limits and one for the handling of the
cpu_frequency tracepoint in that mode (Rafael Wysocki).
- Three fixes for the handling of P-state limits in intel_pstate in
the active mode (Rafael Wysocki).
- Introduction of a new cpufreq.off=1 kernel command line argument
that will disable cpufreq entirely if passed to the kernel and is
simply hooked up to the existing code used by Xen (Len Brown).
- Fix for the schedutil cpufreq governor to prevent it from using
stale raw frequency values in configurations with mutiple CPUs
sharing one policy object and a cleanup for it reducing its
overhead slightly (Viresh Kumar)"
* tag 'pm-4.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpufreq: intel_pstate: Do not reinit performance limits in ->setpolicy
cpufreq: intel_pstate: Fix intel_pstate_verify_policy()
cpufreq: intel_pstate: Fix global settings in active mode
cpufreq: Add the "cpufreq.off=1" cmdline option
cpufreq: schedutil: Pass sg_policy to get_next_freq()
cpufreq: schedutil: move cached_raw_freq to struct sugov_policy
cpufreq: intel_pstate: Avoid triggering cpu_frequency tracepoint unnecessarily
cpufreq: intel_pstate: Fix intel_cpufreq_verify_policy()
cpufreq: intel_pstate: Do not use performance_limits in passive mode
The Marvell PPv2 Device Tree binding was so far only used to describe
the PPv2.1 network controller, used in the Marvell Armada 375.
A new version of this IP block, PPv2.2 is used in the Marvell Armada
7K/8K processor. This commit extends the existing binding so that it can
also be used to describe PPv2.2 hardware.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Initial patch for generic TEE subsystem.
This subsystem provides:
* Registration/un-registration of TEE drivers.
* Shared memory between normal world and secure world.
* Ioctl interface for interaction with user space.
* Sysfs implementation_id of TEE driver
A TEE (Trusted Execution Environment) driver is a driver that interfaces
with a trusted OS running in some secure environment, for example,
TrustZone on ARM cpus, or a separate secure co-processor etc.
The TEE subsystem can serve a TEE driver for a Global Platform compliant
TEE, but it's not limited to only Global Platform TEEs.
This patch builds on other similar implementations trying to solve
the same problem:
* "optee_linuxdriver" by among others
Jean-michel DELORME<jean-michel.delorme@st.com> and
Emmanuel MICHEL <emmanuel.michel@st.com>
* "Generic TrustZone Driver" by Javier González <javier@javigon.com>
Acked-by: Andreas Dannenberg <dannenberg@ti.com>
Tested-by: Jerome Forissier <jerome.forissier@linaro.org> (HiKey)
Tested-by: Volodymyr Babchuk <vlad.babchuk@gmail.com> (RCAR H3)
Tested-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Javier González <javier@javigon.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
* pm-cpufreq:
cpufreq: intel_pstate: Do not reinit performance limits in ->setpolicy
cpufreq: intel_pstate: Fix intel_pstate_verify_policy()
cpufreq: intel_pstate: Fix global settings in active mode
cpufreq: Add the "cpufreq.off=1" cmdline option
cpufreq: intel_pstate: Avoid triggering cpu_frequency tracepoint unnecessarily
cpufreq: intel_pstate: Fix intel_cpufreq_verify_policy()
cpufreq: intel_pstate: Do not use performance_limits in passive mode
This reverts commit c8ca631f94 ("dt-bindings: phy: Add documentation
for NSP USB3 PHY") to match reverting commit adding the new PHY driver.
Please note we revert this commit before it reached stable release.
If new compatible string is needed it should be added to the existing
bcm-ns-usb3-phy.txt which already describes this PHY.
Acked-by: Jon Mason <jon.mason@broadcom.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
We're still pretty far away from anything like a consensus, but
there's clearly a lot of people who prefer an as-light as possible
approach to converting existing .txt files to .rst. Make sure this is
properly taken into account and clear.
Motivated by discussions with Peter and Christoph and others.
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Mark the reg property as required and furthermore fix some typos and
spellings in the documentation.
Signed-off-by: Richard Leitner <richard.leitner@skidata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Remove the max_{power,current}_{sp,bp} properties of the usb251xb driver
from devicetree. This is done to simplify the dt bindings as requested
by Rob Herring in https://lkml.org/lkml/2017/2/15/1283. If those
properties are ever needed by somebody they can be enabled again easily.
Signed-off-by: Richard Leitner <richard.leitner@skidata.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The patch replaces 'the the' with 'the' in the documentation.
Signed-off-by: sayli karnik <karniksayli1995@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The patch replaces 'the the' with 'the' in the documantation.
Signed-off-by: sayli karnik <karniksayli1995@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Motorola was involved in semiconductor and mobile phone business.
The "motorola," prefix is already used by a couple of bindings:
* rtc/rtc-cmos.txt
* mfd/motorola-cpcap.txt
* regulator/cpcap-regulator.txt
Apart from that it is used in the DT file for the Droid 4 mobile
phone.
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
This patch adds the missing devicetree binding documentation for I2SE's
Duckbill and Duckbill 2 series boards.
Signed-off-by: Michael Heimpold <mhei@heimpold.de>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
This adds a new binding for the Freescale i.MX GPC block, which allows
to describe multiple power domains in a more natural way. The driver
will continue to support the old binding for existing DTBs, but new
features like the additional domains present on i.MX6SX will only be
usable with the new binding.
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Previously the coreclk binding for the 98dx3236 SoC was inherited from
the armada-370/xp. This block is present in as much as it is possible to
read from the register location without causing any harm. However the
actual sampled at reset values are reflected in the DFX block.
Moving the binding to the DFX block enables support for different clock
strapping options in hardware.
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Rather than having a separate node for the dfx server add a reg property
to the parent node. This give some compatibility with the Marvell
supplied SDK.
As no upstream driver currently exists for this block and support for
this SoC is still quite fresh in the kernel it should not be necessary
to retain a backwards compatible binding.
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Currently we do not allow patch module to unload since there is no
method to determine if a task is still running in the patched code.
The consistency model gives us the way because when the unpatching
finishes we know that all tasks were marked as safe to call an original
function. Thus every new call to the function calls the original code
and at the same time no task can be somewhere in the patched code,
because it had to leave that code to be marked as safe.
We can safely let the patch module go after that.
Completion is used for synchronization between module removal and sysfs
infrastructure in a similar way to commit 942e443127 ("module: Fix
mod->mkobj.kobj potentially freed too early").
Note that we still do not allow the removal for immediate model, that is
no consistency model. The module refcount may increase in this case if
somebody disables and enables the patch several times. This should not
cause any harm.
With this change a call to try_module_get() is moved to
__klp_enable_patch from klp_register_patch to make module reference
counting symmetric (module_put() is in a patch disable path) and to
allow to take a new reference to a disabled module when being enabled.
Finally, we need to be very careful about possible races between
klp_unregister_patch(), kobject_put() functions and operations
on the related sysfs files.
kobject_put(&patch->kobj) must be called without klp_mutex. Otherwise,
it might be blocked by enabled_store() that needs the mutex as well.
In addition, enabled_store() must check if the patch was not
unregisted in the meantime.
There is no need to do the same for other kobject_put() callsites
at the moment. Their sysfs operations neither take the lock nor
they access any data that might be freed in the meantime.
There was an attempt to use kobjects the right way and prevent these
races by design. But it made the patch definition more complicated
and opened another can of worms. See
https://lkml.kernel.org/r/1464018848-4303-1-git-send-email-pmladek@suse.com
[Thanks to Petr Mladek for improving the commit message.]
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
