If a series of scripts are executed, each triggering module loading via
unprintable bytes in the script header, kernel stack contents can leak
into the command line.
Normally execution of binfmt_script and binfmt_misc happens recursively.
However, when modules are enabled, and unprintable bytes exist in the
bprm->buf, execution will restart after attempting to load matching
binfmt modules. Unfortunately, the logic in binfmt_script and
binfmt_misc does not expect to get restarted. They leave bprm->interp
pointing to their local stack. This means on restart bprm->interp is
left pointing into unused stack memory which can then be copied into the
userspace argv areas.
After additional study, it seems that both recursion and restart remains
the desirable way to handle exec with scripts, misc, and modules. As
such, we need to protect the changes to interp.
This changes the logic to require allocation for any changes to the
bprm->interp. To avoid adding a new kmalloc to every exec, the default
value is left as-is. Only when passing through binfmt_script or
binfmt_misc does an allocation take place.
For a proof of concept, see DoTest.sh from:
http://www.halfdog.net/Security/2012/LinuxKernelBinfmtScriptStackDataDisclosure/
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: halfdog <me@halfdog.net>
Cc: P J P <ppandit@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull IOMMU updates from Joerg Roedel:
"A few new features this merge-window. The most important one is
probably, that dma-debug now warns if a dma-handle is not checked with
dma_mapping_error by the device driver. This requires minor changes
to some architectures which make use of dma-debug. Most of these
changes have the respective Acks by the Arch-Maintainers.
Besides that there are updates to the AMD IOMMU driver for refactor
the IOMMU-Groups support and to make sure it does not trigger a
hardware erratum.
The OMAP changes (for which I pulled in a branch from Tony Lindgren's
tree) have a conflict in linux-next with the arm-soc tree. The
conflict is in the file arch/arm/mach-omap2/clock44xx_data.c which is
deleted in the arm-soc tree. It is safe to delete the file too so
solve the conflict. Similar changes are done in the arm-soc tree in
the common clock framework migration. A missing hunk from the patch
in the IOMMU tree will be submitted as a seperate patch when the
merge-window is closed."
* tag 'iommu-updates-v3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: (29 commits)
ARM: dma-mapping: support debug_dma_mapping_error
ARM: OMAP4: hwmod data: ipu and dsp to use parent clocks instead of leaf clocks
iommu/omap: Adapt to runtime pm
iommu/omap: Migrate to hwmod framework
iommu/omap: Keep mmu enabled when requested
iommu/omap: Remove redundant clock handling on ISR
iommu/amd: Remove obsolete comment
iommu/amd: Don't use 512GB pages
iommu/tegra: smmu: Move bus_set_iommu after probe for multi arch
iommu/tegra: gart: Move bus_set_iommu after probe for multi arch
iommu/tegra: smmu: Remove unnecessary PTC/TLB flush all
tile: dma_debug: add debug_dma_mapping_error support
sh: dma_debug: add debug_dma_mapping_error support
powerpc: dma_debug: add debug_dma_mapping_error support
mips: dma_debug: add debug_dma_mapping_error support
microblaze: dma-mapping: support debug_dma_mapping_error
ia64: dma_debug: add debug_dma_mapping_error support
c6x: dma_debug: add debug_dma_mapping_error support
ARM64: dma_debug: add debug_dma_mapping_error support
intel-iommu: Prevent devices with RMRRs from being placed into SI Domain
...
Pull virtio update from Rusty Russell:
"Some nice cleanups, and even a patch my wife did as a "live" demo for
Latinoware 2012.
There's a slightly non-trivial merge in virtio-net, as we cleaned up
the virtio add_buf interface while DaveM accepted the mq virtio-net
patches."
* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (27 commits)
virtio_console: Add support for remoteproc serial
virtio_console: Merge struct buffer_token into struct port_buffer
virtio: add drv_to_virtio to make code clearly
virtio: use dev_to_virtio wrapper in virtio
virtio-mmio: Fix irq parsing in command line parameter
virtio_console: Free buffers from out-queue upon close
virtio: Convert dev_printk(KERN_<LEVEL> to dev_<level>(
virtio_console: Use kmalloc instead of kzalloc
virtio_console: Free buffer if splice fails
virtio: tools: make it clear that virtqueue_add_buf() no longer returns > 0
virtio: scsi: make it clear that virtqueue_add_buf() no longer returns > 0
virtio: rpmsg: make it clear that virtqueue_add_buf() no longer returns > 0
virtio: net: make it clear that virtqueue_add_buf() no longer returns > 0
virtio: console: make it clear that virtqueue_add_buf() no longer returns > 0
virtio: make virtqueue_add_buf() returning 0 on success, not capacity.
virtio: console: don't rely on virtqueue_add_buf() returning capacity.
virtio_net: don't rely on virtqueue_add_buf() returning capacity.
virtio-net: remove unused skb_vnet_hdr->num_sg field
virtio-net: correct capacity math on ring full
virtio: move queue_index and num_free fields into core struct virtqueue.
...
Pull ARM SoC fixes from Olof Johansson:
"This is a batch of fixes for arm-soc platforms, most of it is for OMAP
but there are others too (i.MX, Tegra, ep93xx). Fixes warnings, some
broken platforms and drivers, etc. A bit all over the map really."
There was some concern about commit 68136b10 ("RM: sunxi: Change device
tree naming scheme for sunxi"), but Tony says:
"Looks like that's trivial to fix as needed, no need to rebuild the
branch to fix that AFAIK.
The fix can be done once Olof is available online again.
Linus, I suggest that you go ahead and pull this if there are no other
issues with this branch."
* tag 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (32 commits)
ARM: sunxi: Change device tree naming scheme for sunxi
ARM: ux500: fix missing include
ARM: u300: delete custom pin hog code
ARM: davinci: fix build break due to missing include
ARM: exynos: Fix warning due to missing 'inline' in stub
ARM: imx: Move platform-mx2-emma to arch/arm/mach-imx/devices
ARM i.MX51 clock: Fix regression since enabling MIPI/HSP clocks
ARM: dts: mx27: Fix the AIPI bus for FEC
ARM: OMAP2+: common: remove use of vram
ARM: OMAP3/4: cpuidle: fix sparse and checkpatch warnings
ARM: OMAP4: clock data: DPLLs are missing bypass clocks in their parent lists
ARM: OMAP4: clock data: div_iva_hs_clk is a power-of-two divider
ARM: OMAP4: Fix EMU clock domain always on
ARM: OMAP4460: Workaround ABE DPLL failing to turn-on
ARM: OMAP4: Enhance support for DPLLs with 4X multiplier
ARM: OMAP4: Add function table for non-M4X dplls
ARM: OMAP4: Update timer clock aliases
ARM: OMAP: Move plat/omap-serial.h to include/linux/platform_data/serial-omap.h
ARM: dts: Add build target for omap4-panda-a4
ARM: dts: OMAP2420: Correct H4 board memory size
...
Documentation says that code requiring dma-buf should add it to
select, so inline fallbacks are not going to be used. A link error
will make it obvious what went wrong, instead of silently doing
nothing at runtime.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Rob Clark <rob.clark@linaro.org>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Pull networking fixes from David Miller:
1) Really fix tuntap SKB use after free bug, from Eric Dumazet.
2) Adjust SKB data pointer to point past the transport header before
calling icmpv6_notify() so that the headers are in the state which
that function expects. From Duan Jiong.
3) Fix ambiguities in the new tuntap multi-queue APIs. From Jason
Wang.
4) mISDN needs to use del_timer_sync(), from Konstantin Khlebnikov.
5) Don't destroy mutex after freeing up device private in mac802154,
fix also from Konstantin Khlebnikov.
6) Fix INET request socket leak in TCP and DCCP, from Christoph Paasch.
7) SCTP HMAC kconfig rework, from Neil Horman.
8) Fix SCTP jprobes function signature, otherwise things explode, from
Daniel Borkmann.
9) Fix typo in ipv6-offload Makefile variable reference, from Simon
Arlott.
10) Don't fail USBNET open just because remote wakeup isn't supported,
from Oliver Neukum.
11) be2net driver bug fixes from Sathya Perla.
12) SOLOS PCI ATM driver bug fixes from Nathan Williams and David
Woodhouse.
13) Fix MTU changing regression in 8139cp driver, from John Greene.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (45 commits)
solos-pci: ensure all TX packets are aligned to 4 bytes
solos-pci: add firmware upgrade support for new models
solos-pci: remove superfluous debug output
solos-pci: add GPIO support for newer versions on Geos board
8139cp: Prevent dev_close/cp_interrupt race on MTU change
net: qmi_wwan: add ZTE MF880
drivers/net: Use of_match_ptr() macro in smsc911x.c
drivers/net: Use of_match_ptr() macro in smc91x.c
ipv6: addrconf.c: remove unnecessary "if"
bridge: Correctly encode addresses when dumping mdb entries
bridge: Do not unregister all PF_BRIDGE rtnl operations
use generic usbnet_manage_power()
usbnet: generic manage_power()
usbnet: handle PM failure gracefully
ksz884x: fix receive polling race condition
qlcnic: update driver version
qlcnic: fix unused variable warnings
net: fec: forbid FEC_PTP on SoCs that do not support
be2net: fix wrong frag_idx reported by RX CQ
be2net: fix be_close() to ensure all events are ack'ed
...
Pull devicetree, gpio and spi bugfixes from Grant Likely:
"Device tree v3.8 bug fix:
- Fixes an undefined struct device build error and a missing symbol
export.
GPIO device driver bug fixes:
- gpio/mvebu-gpio: Make mvebu-gpio depend on OF_CONFIG
- gpio/ich: Add missing spinlock init
SPI device driver bug fixes:
- Most of this is bug fixes to the core code and the sh-hspi and
s3c64xx device drivers.
- There is also a patch here to add DT support to the Atmel driver.
This one should have been in the first round, but I missed it.
It's a low risk change contained within a single driver and the
Atmel maintainer has requested it."
* tag 'dt-for-linus' of git://git.secretlab.ca/git/linux-2.6:
of: define struct device in of_platform.h if !OF_DEVICE and !OF_ADDRESS
of: Fix export of of_find_matching_node_and_match()
* tag 'gpio-for-linus' of git://git.secretlab.ca/git/linux-2.6:
gpio/mvebu-gpio: Make mvebu-gpio depend on OF_CONFIG
gpio/ich: Add missing spinlock init
* tag 'spi-for-linus' of git://git.secretlab.ca/git/linux-2.6:
spi/sh-hspi: fix return value check in hspi_probe().
spi: fix tegra SPI binding examples
spi/atmel: add DT support
of/spi: Fix SPI module loading by using proper "spi:" modalias prefixes.
spi: Change FIFO flush operation and spi channel off
spi: Keep chipselect assertion during one message
Pull MTD updates from David Woodhouse:
- Various cleanups especially in NAND tests
- Add support for NAND flash on BCMA bus
- DT support for sh_flctl and denali NAND drivers
- Kill obsolete/superceded drivers (fortunet, nomadik_nand)
- Fix JFFS2 locking bug in ENOMEM failure path
- New SPI flash chips, as usual
- Support writing in 'reliable mode' for DiskOnChip G4
- Debugfs support in nandsim
* tag 'for-linus-20121219' of git://git.infradead.org/linux-mtd: (96 commits)
mtd: nand: typo in nand_id_has_period() comments
mtd: nand/gpio: use io{read,write}*_rep accessors
mtd: block2mtd: throttle writes by calling balance_dirty_pages_ratelimited.
mtd: nand: gpmi: reset BCH earlier, too, to avoid NAND startup problems
mtd: nand/docg4: fix and improve read of factory bbt
mtd: nand/docg4: reserve bb marker area in ecclayout
mtd: nand/docg4: add support for writing in reliable mode
mtd: mxc_nand: reorder part_probes to let cmdline override other sources
mtd: mxc_nand: fix unbalanced clk_disable() in error path
mtd: nandsim: Introduce debugfs infrastructure
mtd: physmap_of: error checking to prevent a NULL pointer dereference
mtg: docg3: potential divide by zero in doc_write_oob()
mtd: bcm47xxnflash: writing support
mtd: tests/read: initialize buffer for whole next page
mtd: at91: atmel_nand: return bit flips for the PMECC read_page()
mtd: fix recovery after failed write-buffer operation in cfi_cmdset_0002.c
mtd: nand: onfi need to be probed in 8 bits mode
mtd: nand: add NAND_BUSWIDTH_AUTO to autodetect bus width
mtd: nand: print flash size during detection
mted: nand_wait_ready timeout fix
...
Centralise common code for manage_power() in usbnet
by making a generic simple implementation
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
If a device fails to do remote wakeup, this is no reason
to abort an open totally. This patch just continues without
runtime PM.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull pwm changes from Thierry Reding:
"A new driver has been added for the SPEAr platform and the
TWL4030/6030 driver has been replaced by two drivers that control the
regular PWMs and the PWM driven LEDs provided by the chips.
The vt8500, tiecap, tiehrpwm, i.MX, LPC32xx and Samsung drivers have
all been improved and the device tree bindings now support the PWM
signal polarity."
Fix up trivial conflicts due to __devinit/exit removal.
* tag 'for-3.8-rc1' of git://gitorious.org/linux-pwm/linux-pwm: (21 commits)
pwm: samsung: add missing s3c->pwm_id assignment
pwm: lpc32xx: Set the chip base for dynamic allocation
pwm: lpc32xx: Properly disable the clock on device removal
pwm: lpc32xx: Fix the PWM polarity
pwm: i.MX: eliminate build warning
pwm: Export of_pwm_xlate_with_flags()
pwm: Remove pwm-twl6030 driver
pwm: New driver to support PWM driven LEDs on TWL4030/6030 series of PMICs
pwm: New driver to support PWMs on TWL4030/6030 series of PMICs
pwm: pwm-tiehrpwm: pinctrl support
pwm: tiehrpwm: Add device-tree binding
pwm: pwm-tiehrpwm: Adding TBCLK gating support.
pwm: pwm-tiecap: pinctrl support
pwm: tiecap: Add device-tree binding
pwm: Add TI PWM subsystem driver
pwm: Device tree support for PWM polarity
pwm: vt8500: Ensure PWM clock is enabled during pwm_config
pwm: vt8500: Fix build error
pwm: spear: Staticize spear_pwm_config()
pwm: Add SPEAr PWM chip driver support
...
Fixes the following warning:
include/linux/of_platform.h:106:13: warning: 'struct device' declared
inside parameter list [enabled by default]
include/linux/of_platform.h:106:13: warning: its scope is only this
definition or declaration, which is probably not what you want [enabled
by default]
Signed-off-by: Jonas Gorski <jogo@openwrt.org>
Signed-off-by: Rob Herring <robherring2@gmail.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Pull module update from Rusty Russell:
"Nothing all that exciting; a new module-from-fd syscall for those who
want to verify the source of the module (ChromeOS) and/or use standard
IMA on it or other security hooks."
* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
MODSIGN: Fix kbuild output when using default extra_certificates
MODSIGN: Avoid using .incbin in C source
modules: don't hand 0 to vmalloc.
module: Remove a extra null character at the top of module->strtab.
ASN.1: Use the ASN1_LONG_TAG and ASN1_INDEFINITE_LENGTH constants
ASN.1: Define indefinite length marker constant
moduleparam: use __UNIQUE_ID()
__UNIQUE_ID()
MODSIGN: Add modules_sign make target
powerpc: add finit_module syscall.
ima: support new kernel module syscall
add finit_module syscall to asm-generic
ARM: add finit_module syscall to ARM
security: introduce kernel_module_from_file hook
module: add flags arg to sys_finit_module()
module: add syscall to load module from fd
Pull preparatory gcc intrisics bswap patch from David Woodhouse:
"This single patch is effectively a no-op for now. It enables
architectures to opt in to using GCC's __builtin_bswapXX() intrinsics
for byteswapping, and if we merge this now then the architecture
maintainers can enable it for their arch during the next cycle without
dependency issues.
It's worth making it a par-arch opt-in, because although in *theory*
the compiler should never do worse than hand-coded assembler (and of
course it also ought to do a lot better on platforms like Atom and
PowerPC which have load-and-swap or store-and-swap instructions), that
isn't always the case. See
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46453
for example."
* tag 'byteswap-for-linus-20121219' of git://git.infradead.org/users/dwmw2/byteswap:
byteorder: allow arch to opt to use GCC intrinsics for byteswapping
Commit 8dd2cb7e88 ("block: discard granularity might not be power of
2") changed a couple of 'binary and' operations into modulus operations.
Which turned the harmless case of a zero discard_granularity into a
possible divide-by-zero.
The code also had a much more subtle bug: it was doing the modulus of a
value in bytes using 'sector_t'. That was always conceptually wrong,
but didn't actually matter back when the code assumed a power-of-two
granularity: we only looked at the low bits anyway.
But with potentially arbitrary sector numbers, using a 'sector_t' to
express bytes is very very wrong: depending on configuration it limits
the starting offset of the device to just 32 bits, and any overflow
would result in a wrong value if the modulus wasn't a power-of-two.
So re-write the code to not only protect against the divide-by-zero, but
to do the starting sector arithmetic in sectors, and using the proper
types.
[ For any mathematicians out there: it also looks monumentally stupid to
do the 'modulo granularity' operation *twice*, never mind having a "+
granularity" in the second modulus op.
But that's the easiest way to avoid negative values or overflow, and
it is how the original code was done. ]
Reported-by: Ingo Molnar <mingo@kernel.org>
Reported-by: Doug Anderson <dianders@chromium.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Shaohua Li <shli@fusionio.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull i2c-embedded changes from Wolfram Sang:
- CBUS driver (an I2C variant)
- continued rework of the omap driver
- s3c2410 gets lots of fixes and gains pinctrl support
- at91 gains DMA support
- the GPIO muxer gains devicetree probing
- typical fixes and additions all over
* 'i2c-embedded/for-next' of git://git.pengutronix.de/git/wsa/linux: (45 commits)
i2c: omap: Remove the OMAP_I2C_FLAG_RESET_REGS_POSTIDLE flag
i2c: at91: add dma support
i2c: at91: change struct members indentation
i2c: at91: fix compilation warning
i2c: mxs: Do not disable the I2C SMBus quick mode
i2c: mxs: Handle i2c DMA failure properly
i2c: s3c2410: Remove recently introduced performance overheads
i2c: ocores: Move grlib set/get functions into #ifdef CONFIG_OF block
i2c: s3c2410: Add fix for i2c suspend/resume
i2c: s3c2410: Fix code to free gpios
i2c: i2c-cbus-gpio: introduce driver
i2c: ocores: Add support for the GRLIB port of the controller and use function pointers for getreg and setreg functions
i2c: ocores: Add irq support for sparc
i2c: omap: Move the remove constraint
ARM: dts: cfa10049: Add the i2c muxer buses to the CFA-10049
i2c: s3c2410: do not special case HDMIPHY stuck bus detection
i2c: s3c2410: use exponential back off while polling for bus idle
i2c: s3c2410: do not generate STOP for QUIRK_HDMIPHY
i2c: s3c2410: grab adapter lock while changing i2c clock
i2c: s3c2410: Add support for pinctrl
...
Merge patches from Andrew Morton:
"Most of the rest of MM, plus a few dribs and drabs.
I still have quite a few irritating patches left around: ones with
dubious testing results, lack of review, ones which should have gone
via maintainer trees but the maintainers are slack, etc.
I need to be more activist in getting these things wrapped up outside
the merge window, but they're such a PITA."
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (48 commits)
mm/vmscan.c: avoid possible deadlock caused by too_many_isolated()
vmscan: comment too_many_isolated()
mm/kmemleak.c: remove obsolete simple_strtoul
mm/memory_hotplug.c: improve comments
mm/hugetlb: create hugetlb cgroup file in hugetlb_init
mm/mprotect.c: coding-style cleanups
Documentation: ABI: /sys/devices/system/node/
slub: drop mutex before deleting sysfs entry
memcg: add comments clarifying aspects of cache attribute propagation
kmem: add slab-specific documentation about the kmem controller
slub: slub-specific propagation changes
slab: propagate tunable values
memcg: aggregate memcg cache values in slabinfo
memcg/sl[au]b: shrink dead caches
memcg/sl[au]b: track all the memcg children of a kmem_cache
memcg: destroy memcg caches
sl[au]b: allocate objects from memcg cache
sl[au]b: always get the cache from its page in kmem_cache_free()
memcg: skip memcg kmem allocations in specified code regions
memcg: infrastructure to match an allocation to the right cache
...
Build kernel with CONFIG_HUGETLBFS=y,CONFIG_HUGETLB_PAGE=y and
CONFIG_CGROUP_HUGETLB=y, then specify hugepagesz=xx boot option, system
will fail to boot.
This failure is caused by following code path:
setup_hugepagesz
hugetlb_add_hstate
hugetlb_cgroup_file_init
cgroup_add_cftypes
kzalloc <--slab is *not available* yet
For this path, slab is not available yet, so memory allocated will be
failed, and cause WARN_ON() in hugetlb_cgroup_file_init().
So I move hugetlb_cgroup_file_init() into hugetlb_init().
[akpm@linux-foundation.org: tweak coding-style, remove pointless __init on inlined function]
[akpm@linux-foundation.org: fix warning]
Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch clarifies two aspects of cache attribute propagation.
First, the expected context for the for_each_memcg_cache macro in
memcontrol.h. The usages already in the codebase are safe. In mm/slub.c,
it is trivially safe because the lock is acquired right before the loop.
In mm/slab.c, it is less so: the lock is acquired by an outer function a
few steps back in the stack, so a VM_BUG_ON() is added to make sure it is
indeed safe.
A comment is also added to detail why we are returning the value of the
parent cache and ignoring the children's when we propagate the attributes.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
SLUB allows us to tune a particular cache behavior with sysfs-based
tunables. When creating a new memcg cache copy, we'd like to preserve any
tunables the parent cache already had.
This can be done by tapping into the store attribute function provided by
the allocator. We of course don't need to mess with read-only fields.
Since the attributes can have multiple types and are stored internally by
sysfs, the best strategy is to issue a ->show() in the root cache, and
then ->store() in the memcg cache.
The drawback of that, is that sysfs can allocate up to a page in buffering
for show(), that we are likely not to need, but also can't guarantee. To
avoid always allocating a page for that, we can update the caches at store
time with the maximum attribute size ever stored to the root cache. We
will then get a buffer big enough to hold it. The corolary to this, is
that if no stores happened, nothing will be propagated.
It can also happen that a root cache has its tunables updated during
normal system operation. In this case, we will propagate the change to
all caches that are already active.
[akpm@linux-foundation.org: tweak code to avoid __maybe_unused]
Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
SLAB allows us to tune a particular cache behavior with tunables. When
creating a new memcg cache copy, we'd like to preserve any tunables the
parent cache already had.
This could be done by an explicit call to do_tune_cpucache() after the
cache is created. But this is not very convenient now that the caches are
created from common code, since this function is SLAB-specific.
Another method of doing that is taking advantage of the fact that
do_tune_cpucache() is always called from enable_cpucache(), which is
called at cache initialization. We can just preset the values, and then
things work as expected.
It can also happen that a root cache has its tunables updated during
normal system operation. In this case, we will propagate the change to
all caches that are already active.
This change will require us to move the assignment of root_cache in
memcg_params a bit earlier. We need this to be already set - which
memcg_kmem_register_cache will do - when we reach __kmem_cache_create()
Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
