It can be useful to report dev->gso_max_segs and dev->gso_max_size
so that "ip -d link" can display them to help debugging.
For the moment, these attributes are read-only.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Petri Gynther <pgynther@google.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
vxlan_remcsum is called after iptunnel_pull_header and thus the skb has
vxlan header already pulled. Don't include vxlan header again in the
calculation.
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Sparse reports false positives for the header manipulation inlines. Annotate
them correctly.
Tested by sparse on a little endian and big endian machine.
Fixes: 54bfd872bf ("vxlan: keep flags and vni in network byte order")
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When the function dev_get_phys_port_name was added it missed a description
for it's len argument. Adding it.
Fixes: db24a9044e ("net: add support for phys_port_name")
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull cgroup namespace support from Tejun Heo:
"These are changes to implement namespace support for cgroup which has
been pending for quite some time now. It is very straight-forward and
only affects what part of cgroup hierarchies are visible.
After unsharing, mounting a cgroup fs will be scoped to the cgroups
the task belonged to at the time of unsharing and the cgroup paths
exposed to userland would be adjusted accordingly"
* 'for-4.6-ns' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: fix and restructure error handling in copy_cgroup_ns()
cgroup: fix alloc_cgroup_ns() error handling in copy_cgroup_ns()
Add FS_USERNS_FLAG to cgroup fs
cgroup: Add documentation for cgroup namespaces
cgroup: mount cgroupns-root when inside non-init cgroupns
kernfs: define kernfs_node_dentry
cgroup: cgroup namespace setns support
cgroup: introduce cgroup namespaces
sched: new clone flag CLONE_NEWCGROUP for cgroup namespace
kernfs: Add API to generate relative kernfs path
Only treat write goes up to the inode size as aligned request,
because it always write PAGE_CACHE_SIZE, but read a dynamic size.
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
The 'is_merge' is an historical naming from when only a single lower layer
could exist. With the introduction of multiple lower layers the meaning of
this flag was changed to mean only the "lowest layer" (while all lower
layers were being merged).
So now 'is_merge' is inaccurate and hence renaming to 'is_lowest'
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This patch fixes a newline warning found by the checkpatch.pl tool
Signed-off-by: Sohom-Bhattacharjee <soham.bhattacharjee15@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
In some instances xfs has been created with ftype=0 and there if a file
on lower fs is removed, overlay leaves a whiteout in upper fs but that
whiteout does not get filtered out and is visible to overlayfs users.
And reason it does not get filtered out because upper filesystem does
not report file type of whiteout as DT_CHR during iterate_dir().
So it seems to be a requirement that upper filesystem support d_type for
overlayfs to work properly. Do this check during mount and fail if d_type
is not supported.
Suggested-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Print a warning when overlayfs copies up a file if the process that
triggered the copy up has a R/O fd open to the lower file being copied up.
This can help catch applications that do things like the following:
fd1 = open("foo", O_RDONLY);
fd2 = open("foo", O_RDWR);
where they expect fd1 and fd2 to refer to the same file - which will no
longer be the case post-copy up.
With this patch, the following commands:
bash 5</mnt/a/foo128
6<>/mnt/a/foo128
assuming /mnt/a/foo128 to be an un-copied up file on an overlay will
produce the following warning in the kernel log:
overlayfs: Copying up foo129, but open R/O on fd 5 which will cease
to be coherent [pid=3818 bash]
This is enabled by setting:
/sys/module/overlay/parameters/check_copy_up
to 1.
The warnings are ratelimited and are also limited to one warning per file -
assuming the copy up completes in each case.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This patch hides error about missing lowerdir if MS_SILENT is set.
We use mount(NULL, "/", "overlay", MS_SILENT, NULL) for testing support of
overlayfs: syscall returns -ENODEV if it's not supported. Otherwise kernel
automatically loads module and returns -EINVAL because lowerdir is missing.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Unlink and rename in overlayfs checked the upper dentry for staleness by
verifying upper->d_parent against upperdir. However the dentry can go
stale also by being unhashed, for example.
Expand the verification to actually look up the name again (under parent
lock) and check if it matches the upper dentry. This matches what the VFS
does before passing the dentry to filesytem's unlink/rename methods, which
excludes any inconsistency caused by overlayfs.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Otherwise we can run into problems with the writeback code.
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This reverts commit c02196834456f2d5fad334088b70e98ce4967c34.
In the meantime we moved get_user_pages() outside of the reservation lock,
so that shouldn't be an issue any more
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Use $(FULL_AMD_PATH) like everything else.
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
tdp_table is being leaked on failed allocations of
hwmgr->dyn_state.cac_dtp_table. kfree tdp_table on the error
return path to fix the leak.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
We could end up dereferencing an error pointer when we call
regulator_disable().
Fixes: 4bdcb1dd9f ('net: Add MDIO bus driver for the Allwinner EMAC')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The change to use the generic DMA engine API in the smc911x
driver has led to a harmless warning about unused local variables:
smsc/smc911x.c: In function 'smc911x_probe':
smsc/smc911x.c:1796:20: error: unused variable 'param'
smsc/smc911x.c:1795:17: error: unused variable 'mask'
smsc/smc911x.c:1794:26: error: unused variable 'config'
This puts the variable declarations inside of the same #ifdef
that protects their use.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 79d3b59a93 ("net: smc911x: convert pxa dma to dmaengine")
Signed-off-by: David S. Miller <davem@davemloft.net>
i915 get_eld ops may return an error when no encoder is connected, and
currently we regard the error as fatal and skip the whole ELD
handling. This ended up with the missing ELD update at unplugging.
This patch fixes the issue by treating the error as the unplugged
state, instead of skipping the rest.
Reported-by: Libin Yang <libin.yang@linux.intel.com>
Cc: <stable@vger.kernel.org> # v4.5
Signed-off-by: Takashi Iwai <tiwai@suse.de>
The Kconfig currently controlling compilation of this code is:
arch/x86/xen/Kconfig:config XEN_PVHVM
arch/x86/xen/Kconfig: def_bool y
...meaning that it currently is not being built as a module by anyone.
Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.
Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.
Also note that MODULE_DEVICE_TABLE is a no-op for non-modular code.
We also delete the MODULE_LICENSE tag etc. since all that information
was (or is now) contained at the top of the file in the comments.
In removing "module" from the init fcn name, we observe a namespace
collision with the probe function, so we use "probe" in the name of
the probe function, and "init" in the registration fcn, as per
standard convention, as suggested by Stefano.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
The Kconfig currently controlling compilation of this code is:
config XEN_SYS_HYPERVISOR
bool "Create xen entries under /sys/hypervisor"
...meaning that it currently is not being built as a module by anyone.
Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.
Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit. However
one could argue that fs_initcall() might make more sense here.
This change means that the one line function xen_properties_destroy()
has only one user left, and since that is inside an #ifdef, we just
manually inline it there vs. adding more ifdeffery around the function
to avoid compile warnings about "defined but not used".
In order to be consistent we also manually inline the other _destroy
functions that are also just one line sysfs functions calls with only
one call site remaing, even though they wouldn't need #ifdeffery.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
The Makefile / Kconfig currently controlling compilation here is:
obj-y += xenbus_dev_frontend.o
[...]
obj-$(CONFIG_XEN_BACKEND) += xenbus_dev_backend.o
...with:
drivers/xen/Kconfig:config XEN_BACKEND
drivers/xen/Kconfig: bool "Backend driver support"
...meaning that they currently are not being built as modules by anyone.
Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.
Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.
We also delete the MODULE_LICENSE tag since all that information
is already contained at the top of the file in the comments.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
The Makefile / Kconfig currently controlling compilation here is:
obj-y += grant-table.o features.o balloon.o manage.o preempt.o time.o
[...]
obj-$(CONFIG_XEN_BALLOON) += xen-balloon.o
...with:
drivers/xen/Kconfig:config XEN_BALLOON
drivers/xen/Kconfig: bool "Xen memory balloon driver"
...meaning that they currently are not being built as modules by anyone.
Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.
In doing so we uncover two implict includes that were obtained
by module.h having such a wide include scope itself:
In file included from drivers/xen/xen-balloon.c:41:0:
include/xen/balloon.h:26:51: warning: ‘struct page’ declared inside parameter list [enabled by default]
int alloc_xenballooned_pages(int nr_pages, struct page **pages);
^
include/xen/balloon.h: In function ‘register_xen_selfballooning’:
include/xen/balloon.h:35:10: error: ‘ENOSYS’ undeclared (first use in this function)
return -ENOSYS;
^
This is fixed by adding mm-types.h and errno.h to the list.
We also delete the MODULE_LICENSE tags since all that information
is already contained at the top of the file in the comments.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Code that uses no modular facilities whatsoever should not be
sourcing module.h at all, since that header drags in a bunch
of other headers with it.
Similarly, code that is not explicitly using modular facilities
like module_init() but only is declaring module_param setup
variables should be using moduleparam.h and not the larger
module.h file for that.
In making this change, we also uncover an implicit use of BUG()
in inline fcns within arch/arm/include/asm/xen/hypercall.h so
we explicitly source <linux/bug.h> for that file now.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Support for TI Message Manager Module. This hardware block manages a
bunch of hardware queues meant for communication between processor
entities.
Clients sitting on top of this would manage the required protocol
for communicating with the counterpart entities.
For more details on TI Message Manager hardware block, see documentation
that will is available here: http://www.ti.com/lit/ug/spruhy8/spruhy8.pdf
Chapter 8.1(Message Manager)
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
Message Manager is a hardware block used to communicate with various
processor systems within certain Texas Instrument's Keystone
generation SoCs.
This hardware engine is used to transfer messages from various compute
entities(or processors) within the SoC. It is designed to be self
contained without needing software initialization for operation.
Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
Commit a9ceb78bc7 (cpuidle,menu: use interactivity_req to disable
polling) changed the behavior of the fallback state selection part
of menu_select() so it looks at interactivity_req instead of
data->next_timer_us when it makes its decision. That effectively
caused polling to be used more often as fallback idle which led to
significant increases of energy consumption in some cases.
Commit e132b9b3bc (cpuidle: menu: use high confidence factors
only when considering polling) changed that logic again to be more
predictable, but that didn't help with the increased energy
consumption problem.
For this reason, go back to making decisions on which state to fall
back to based on data->next_timer_us which is the time we know for
sure something will happen rather than a prediction (which may be
inaccurate and turns out to be so often enough to be problematic).
However, take the target residency of the first proper idle state
(C1) into account, so that state is not used as the fallback one
if its target residency is greater than data->next_timer_us.
Fixes: a9ceb78bc7 (cpuidle,menu: use interactivity_req to disable polling)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reported-and-tested-by: Doug Smythies <dsmythies@telus.net>
Commit c40a3d38af (Btrfs: Compute and look up csums based on
sectorsized blocks) changes around how we walk the bios while looking up
crcs. There's an inner loop that is jumping to the next bvec based on
sectors and before it derefs the next bvec, it needs to make sure we're
still in the bio.
In this case, the outer loop would have decided to stop moving forward
too, and the bvec deref is never actually used for anything. But
CONFIG_DEBUG_PAGEALLOC catches it because we're outside our bio.
Signed-off-by: Chris Mason <clm@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
With the recent rewrite of the arm64 KVM hypervisor code in C, enabling
certain options like KASAN would allow the compiler to generate memory
accesses or function calls to addresses not mapped at EL2. This patch
disables the compiler instrumentation on the arm64 hypervisor code for
gcov-based profiling (GCOV_KERNEL), undefined behaviour sanity checker
(UBSAN) and kernel address sanitizer (KASAN).
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: <stable@vger.kernel.org> # 4.5+
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Commit e7e127e3c7 ("PCI: Include pci/hotplug Kconfig directly from
pci/Kconfig") added one line to pci/Kconfig. However, for some mysterious
reason it isn't there now, even though there are no traces of removing it
in the git log.
I detected this issue when 'make oldconfig' removed all the options that
depended on HOTPLUG_PCI.
[bhelgaas: I botched the cfeb8139a1 ("Merge branch 'pci/host-hv' into
next") merge. "git diff cfeb8139a1^ cfeb8139a1" shows a conflict in
drivers/pci/Kconfig, and I mistakenly dropped the hotplug/Kconfig piece.]
Signed-off-by: Tero Roponen <tero.roponen@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
The printk() implementation has a limit of LOG_LINE_MAX (== 1024 - 32)
buffer per call which the arm64 mem_init() breaches when printing the
virtual memory layout with CONFIG_KASAN enabled. The result is that the
last line is no longer printed. This patch splits the call into a
pr_notice() + additional pr_cont() calls.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
After commit 65da0a8e34 ("arm64: use non-global mappings for UEFI
runtime regions"), nobody use __local_flush_icache_all() anymore,
so drop it.
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Commit f80fb3a3d5 ("arm64: add support for kernel ASLR") missed a
DSB necessary to complete I-cache maintenance in the primary boot path,
and hence stale instructions may still be present in the I-cache and may
be executed until the I-cache maintenance naturally completes.
Since commit 8ec4198743 ("arm64: mm: ensure patched kernel text is
fetched from PoU"), all CPUs invalidate their I-caches after their MMU
is enabled. Prior a CPU's MMU having been enabled, arbitrary lines may
have been fetched from the PoC into I-caches. We never patch text
expected to be executed with the MMU off. Thus, it is unnecessary to
perform broadcast I-cache maintenance in the primary boot path.
This patch reduces the scope of the I-cache maintenance to the local
CPU, and adds the missing DSB with similar scope, matching prior
maintenance in the primary boot path.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Ard Biesehvuel <ard.biesheuvel@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The implementation of macro inv_entry refers to its 'el' argument without
the required leading backslash, which results in an undefined symbol
'el' to be passed into the kernel_entry macro rather than the index of
the exception level as intended.
This undefined symbol strangely enough does not result in build failures,
although it is visible in vmlinux:
$ nm -n vmlinux |head
U el
0000000000000000 A _kernel_flags_le_hi32
0000000000000000 A _kernel_offset_le_hi32
0000000000000000 A _kernel_size_le_hi32
000000000000000a A _kernel_flags_le_lo32
.....
However, it does result in incorrect code being generated for invalid
exceptions taken from EL0, since the argument check in kernel_entry
assumes EL1 if its argument does not equal '0'.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Commit c6b90653f1 ("drivers/perf: arm_pmu: make info messages more
verbose") breaks booting on systems where the PMU is probed without
devicetree (e.g by inspecting the MIDR of the current CPU). In this case,
pdev->dev.of_node is NULL and we shouldn't try to access its ->fullname
field when printing probe error messages.
This patch fixes the probing code to use of_node_full_name, which safely
handles NULL nodes and removes the "Error %i" part of the string, since
it's not terribly useful.
Reported-by: Guenter Roeck <private@roeck-us.net>
Signed-off-by: Will Deacon <will.deacon@arm.com>
The ev_sel_ext in PCU_MSR_PMON_CTL is locked on some CPU models, so despite
it being documented in the SDM, if we write 1 to that bit then we can get a #GP
fault.
Which #GP the perf fuzzer happily triggered in Peter Zijlstra's testing.
Also, there are no public events which use that bit, so remove ev_sel_ext
bit support for PCU.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1458500301-3594-1-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
- Use for() instead of while() loop in some functions
to make the code simpler.
- Use this_cpu_ptr() instead of per_cpu_ptr() to make the code
cleaner and a bit faster.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/d8a7ef9592f55224630cb26dea239f05b6398a4e.1458187654.git.zhaolei@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The name of the 'reset' parameter to cpuusage_write() is quite confusing,
because the only valid value we allow is '0', so !reset is actually the
case that resets ...
Rename it to 'val' and explain it in a comment that we only allow 0.
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: cgroups@vger.kernel.org
Cc: tj@kernel.org
Link: http://lkml.kernel.org/r/1450696483-2864-1-git-send-email-yangds.fnst@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
It's not entirely obvious how the main loop in select_idle_sibling()
works on first glance. Sprinkle a few comments to explain the design
and intention behind the loop based on some conversations with Mike
and Peter.
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.com>
Cc: Mike Galbraith <mgalbraith@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1457535548-15329-1-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
__clear_bit_unlock() is a special little snowflake. While it carries the
non-atomic '__' prefix, it is specifically documented to pair with
test_and_set_bit() and therefore should be 'somewhat' atomic.
Therefore the generic implementation of __clear_bit_unlock() cannot use
the fully non-atomic __clear_bit() as a default.
If an arch is able to do better; is must provide an implementation of
__clear_bit_unlock() itself.
Specifically, this came up as a result of hackbench livelock'ing in
slab_lock() on ARC with SMP + SLUB + !LLSC.
The issue was incorrect pairing of atomic ops.
slab_lock() -> bit_spin_lock() -> test_and_set_bit()
slab_unlock() -> __bit_spin_unlock() -> __clear_bit()
The non serializing __clear_bit() was getting "lost"
80543b8e: ld_s r2,[r13,0] <--- (A) Finds PG_locked is set
80543b90: or r3,r2,1 <--- (B) other core unlocks right here
80543b94: st_s r3,[r13,0] <--- (C) sets PG_locked (overwrites unlock)
Fixes ARC STAR 9000817404 (and probably more).
Reported-by: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Tested-by: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Helge Deller <deller@gmx.de>
Cc: James E.J. Bottomley <jejb@parisc-linux.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Noam Camus <noamc@ezchip.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20160309114054.GJ6356@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pavan reported that in the presence of very light tasks (or cgroups)
the placement of migrated tasks can cause severe fairness issues.
The problem is that enqueue_entity() places the task before it updates
time, thereby it can place the task far in the past (remember that
light tasks will shoot virtual time forward at a high speed, so in
relation to the pre-existing light task, we can land far in the past).
This is done because update_curr() needs the current task, and we
might be placing the current task.
The obvious solution is to differentiate between the current and any
other task; placing the current before we update time, and placing any
other task after, such that !curr tasks end up at the current moment
in time, and not in the past.
Reported-by: Pavan Kondeti <pkondeti@codeaurora.org>
Tested-by: Pavan Kondeti <pkondeti@codeaurora.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: byungchul.park@lge.com
Link: http://lkml.kernel.org/r/20160309120403.GK6344@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The CPU controller hasn't kept up with the various changes in the whole
cgroup initialization / destruction sequence, and commit:
2e91fa7f6d ("cgroup: keep zombies associated with their original cgroups")
caused it to explode.
The reason for this is that zombies do not inhibit css_offline() from
being called, but do stall css_released(). Now we tear down the cfs_rq
structures on css_offline() but zombies can run after that, leading to
use-after-free issues.
The solution is to move the tear-down to css_released(), which
guarantees nobody (including no zombies) is still using our cgroup.
Furthermore, a few simple cleanups are possible too. There doesn't
appear to be any point to us using css_online() (anymore?) so fold that
in css_alloc().
And since cgroup code guarantees an RCU grace period between
css_released() and css_free() we can forgo using call_rcu() and free the
stuff immediately.
Suggested-by: Tejun Heo <tj@kernel.org>
Reported-by: Kazuki Yamaguchi <k@rhe.jp>
Reported-by: Niklas Cassel <niklas.cassel@axis.com>
Tested-by: Niklas Cassel <niklas.cassel@axis.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 2e91fa7f6d ("cgroup: keep zombies associated with their original cgroups")
Link: http://lkml.kernel.org/r/20160316152245.GY6344@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When running with VHE, there is no need to translate kernel pointers
to the EL2 memory space, since we're already there (and we have a much
saner memory map to start with).
Unfortunately, kvm_ksym_ref is getting in the way, and the first
call into the "hypervisor" section is going to end up in fireworks,
since we're now branching into nowhereland. Meh.
A potential solution is to test if VHE is engaged or not, and only
perform the translation in the negative case. With this in place,
VHE is able to run again.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Preemption must be disabled when calling smp_call_function_many
Reported-by: bartosz.wawrzyniak@tieto.com
Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
