commit 3347acc6fc upstream.
Commit 815f0ddb34 ("include/linux/compiler*.h: make compiler-*.h
mutually exclusive") neglected to copy barrier_data() from
compiler-gcc.h into compiler-clang.h.
The definition in compiler-gcc.h was really to work around clang's more
aggressive optimization, so this broke barrier_data() on clang, and
consequently memzero_explicit() as well.
For example, this results in at least the memzero_explicit() call in
lib/crypto/sha256.c:sha256_transform() being optimized away by clang.
Fix this by moving the definition of barrier_data() into compiler.h.
Also move the gcc/clang definition of barrier() into compiler.h,
__memory_barrier() is icc-specific (and barrier() is already defined
using it in compiler-intel.h) and doesn't belong in compiler.h.
[rdunlap@infradead.org: fix ALPHA builds when SMP is not enabled]
Link: https://lkml.kernel.org/r/20201101231835.4589-1-rdunlap@infradead.org
Fixes: 815f0ddb34 ("include/linux/compiler*.h: make compiler-*.h mutually exclusive")
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201014212631.207844-1-nivedita@alum.mit.edu
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[nd: backport to account for missing
commit e506ea4512 ("compiler.h: Split {READ,WRITE}_ONCE definitions out into rwonce.h")
commit d08b9f0ca6 ("scs: Add support for Clang's Shadow Call Stack (SCS)")
commit a3f8a30f3f ("Compiler Attributes: use feature checks instead of version checks")]
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 190113b4c6 upstream.
Prarit reported that depending on the affinity setting the
' irq $N: Affinity broken due to vector space exhaustion.'
message is showing up in dmesg, but the vector space on the CPUs in the
affinity mask is definitely not exhausted.
Shung-Hsi provided traces and analysis which pinpoints the problem:
The ordering of trying to assign an interrupt vector in
assign_irq_vector_any_locked() is simply wrong if the interrupt data has a
valid node assigned. It does:
1) Try the intersection of affinity mask and node mask
2) Try the node mask
3) Try the full affinity mask
4) Try the full online mask
Obviously #2 and #3 are in the wrong order as the requested affinity
mask has to take precedence.
In the observed cases #1 failed because the affinity mask did not contain
CPUs from node 0. That made it allocate a vector from node 0, thereby
breaking affinity and emitting the misleading message.
Revert the order of #2 and #3 so the full affinity mask without the node
intersection is tried before actually affinity is broken.
If no node is assigned then only the full affinity mask and if that fails
the full online mask is tried.
Fixes: d6ffc6ac83 ("x86/vector: Respect affinity mask in irq descriptor")
Reported-by: Prarit Bhargava <prarit@redhat.com>
Reported-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/87ft4djtyp.fsf@nanos.tec.linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit c986a70249 ]
The Thinkpad Yoga 11e 4th gen with the N3450 / Celeron CPU only has
one battery which is named BAT1 instead of the expected BAT0, add a
quirk for this. This fixes not being able to set the charging tresholds
on this model; and this alsoe fixes the following errors in dmesg:
ACPI: \_SB_.PCI0.LPCB.EC__.HKEY: BCTG evaluated but flagged as error
thinkpad_acpi: Error probing battery 2
battery: extension failed to load: ThinkPad Battery Extension
battery: extension unregistered: ThinkPad Battery Extension
Note that the added quirk is for the "R0K" BIOS versions which are
used on the Thinkpad Yoga 11e 4th gen's with a Celeron CPU, there
is a separate "R0L" BIOS for the i3/i5 based versions. This may also
need the same quirk, but if that really is necessary is unknown.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20201109103550.16265-1-hdegoede@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit f2eae1888c ]
The Yoga 11e series has 2 accelerometers described by a BOSC0200 ACPI node.
This setup relies on a Windows service which reads both accelerometers and
then calculates the angle between the 2 halves to determine laptop / tent /
tablet mode and then reports the calculated mode back to the EC by calling
special ACPI methods on the BOSC0200 node.
The bmc150 iio driver does not support this (it involves double
calculations requiring sqrt and arccos so this really needs to be done
in userspace), as a result of this on the Yoga 11e the thinkpad_acpi
code always reports SW_TABLET_MODE=0, starting with GNOME 3.38 reporting
SW_TABLET_MODE=0 causes GNOME to:
1. Not show the onscreen keyboard when a text-input field is focussed
with the touchscreen.
2. Disable accelerometer based auto display-rotation.
This makes sense when in laptop-mode but not when in tablet-mode. But
since for the Yoga 11e the thinkpad_acpi code always reports
SW_TABLET_MODE=0, GNOME does not know when the device is in tablet-mode.
Stop reporting the broken (always 0) SW_TABLET_MODE on Yoga 11e models
to fix this.
Note there are plans for userspace to support 360 degree hinges style
2-in-1s with 2 accelerometers and figure out the mode by itself, see:
https://gitlab.freedesktop.org/hadess/iio-sensor-proxy/-/issues/216
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20201106140130.46820-1-hdegoede@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 74cde1a533 ]
On systems without HW-based collections (i.e. anything except GIC-500),
we rely on firmware to perform the ITS save/restore. This doesn't
really work, as although FW can properly save everything, it cannot
fully restore the state of the command queue (the read-side is reset
to the head of the queue). This results in the ITS consuming previously
processed commands, potentially corrupting the state.
Instead, let's always save the ITS state on suspend, disabling it in the
process, and restore the full state on resume. This saves us from broken
FW as long as it doesn't enable the ITS by itself (for which we can't do
anything).
This amounts to simply dropping the ITS_FLAGS_SAVE_SUSPEND_STATE.
Signed-off-by: Xu Qiang <xuqiang36@huawei.com>
[maz: added warning on resume, rewrote commit message]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201107104226.14282-1-xuqiang36@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 73cc291c27 ]
If someone plays with the UFS clk scaling devfreq governor through sysfs,
ufshcd_devfreq_scale may be called even when HBA is not runtime ACTIVE.
This can lead to unexpected error. We cannot just protect it by calling
pm_runtime_get_sync() because that may cause a race condition since HBA
runtime suspend ops need to suspend clk scaling. To fix this call
pm_runtime_get_noresume() and check HBA's runtime status. Only proceed if
HBA is runtime ACTIVE, otherwise just bail.
governor_store
devfreq_performance_handler
update_devfreq
devfreq_set_target
ufshcd_devfreq_target
ufshcd_devfreq_scale
Link: https://lore.kernel.org/r/1600758548-28576-1-git-send-email-cang@codeaurora.org
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit e42404fa10 ]
To start stack unwinding (SP, PC and BLINK) are needed. When the
explicit execution context (pt_regs etc) is not available, unwinder
assumes the task is sleeping (in __switch_to()) and fetches SP and BLINK
from kernel mode stack.
But this assumption is not true, specially in a SMP system, when top
runs on 1 core, there may be active running processes on all cores.
So when unwinding non courrent tasks, ensure they are NOT running.
And while at it, handle the self unwinding case explicitly.
This came out of investigation of a customer reported hang with
rcutorture+top
Link: https://github.com/foss-for-synopsys-dwc-arc-processors/linux/issues/31
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit e02152ba28 ]
Currently a build with CONFIG_E200=y will fail with:
Error: invalid switch -me200
Error: unrecognized option -me200
Upstream binutils has never supported an -me200 option. Presumably it
was supported at some point by either a fork or Freescale internal
binutils.
We can't support code that we can't even build test, so drop the
addition of -me200 to the build flags, so we can at least build with
CONFIG_E200=y.
Reported-by: Németh Márton <nm127@freemail.hu>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Scott Wood <oss@buserror.net>
Link: https://lore.kernel.org/r/20201116120913.165317-1-mpe@ellerman.id.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 04516706bb ]
When we read device memory, we lock a spinlock, write the address we
want to read from the device and then spin in a loop reading the data
in 32-bit quantities from another register.
As the description makes clear, this is rather inefficient, incurring
a PCIe bus transaction for every read. In a typical device today, we
want to read 786k SMEM if it crashes, leading to 192k register reads.
Occasionally, we've seen the whole loop take over 20 seconds and then
triggering the soft lockup detector.
Clearly, it is unreasonable to spin here for such extended periods of
time.
To fix this, break the loop down into an outer and an inner loop, and
break out of the inner loop if more than half a second elapsed. To
avoid too much overhead, check for that only every 128 reads, though
there's no particular reason for that number. Then, unlock and relock
to obtain NIC access again, reprogram the start address and continue.
This will keep (interrupt) latencies on the CPU down to a reasonable
time.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Mordechay Goodstein <mordechay.goodstein@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/iwlwifi.20201022165103.45878a7e49aa.I3b9b9c5a10002915072312ce75b68ed5b3dc6e14@changeid
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d853b34069 ]
Clang warns:
drivers/spi/spi-bcm2835aux.c:532:50: warning: variable 'err' is
uninitialized when used here [-Wuninitialized]
dev_err(&pdev->dev, "could not get clk: %d\n", err);
^~~
./include/linux/dev_printk.h:112:32: note: expanded from macro 'dev_err'
_dev_err(dev, dev_fmt(fmt), ##__VA_ARGS__)
^~~~~~~~~~~
drivers/spi/spi-bcm2835aux.c:495:9: note: initialize the variable 'err'
to silence this warning
int err;
^
= 0
1 warning generated.
Restore the assignment so that the error value can be used in the
dev_err statement and there is no uninitialized memory being leaked.
Fixes: e13ee6cc47 ("spi: bcm2835aux: Fix use-after-free on unbind")
Link: https://github.com/ClangBuiltLinux/linux/issues/1199
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Link: https://lore.kernel.org/r/20201113180701.455541-1-natechancellor@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
[lukas: backport to 4.19-stable, add stable designation]
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: <stable@vger.kernel.org> # v4.4+: e13ee6cc47: spi: bcm2835aux: Fix use-after-free on unbind
Cc: <stable@vger.kernel.org> # v4.4+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4d6ffa27b8 upstream.
Commit
393f203f5f ("x86_64: kasan: add interceptors for memset/memmove/memcpy functions")
added .weak directives to arch/x86/lib/mem*_64.S instead of changing the
existing ENTRY macros to WEAK. This can lead to the assembly snippet
.weak memcpy
...
.globl memcpy
which will produce a STB_WEAK memcpy with GNU as but STB_GLOBAL memcpy
with LLVM's integrated assembler before LLVM 12. LLVM 12 (since
https://reviews.llvm.org/D90108) will error on such an overridden symbol
binding.
Commit
ef1e03152c ("x86/asm: Make some functions local")
changed ENTRY in arch/x86/lib/memcpy_64.S to SYM_FUNC_START_LOCAL, which
was ineffective due to the preceding .weak directive.
Use the appropriate SYM_FUNC_START_WEAK instead.
Fixes: 393f203f5f ("x86_64: kasan: add interceptors for memset/memmove/memcpy functions")
Fixes: ef1e03152c ("x86/asm: Make some functions local")
Reported-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Fangrui Song <maskray@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201103012358.168682-1-maskray@google.com
[nd: backport due to missing
commit e9b9d020c4 ("x86/asm: Annotate aliases")
commit ffedeeb780 ("linkage: Introduce new macros for assembler symbols")]
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b8a9092330 upstream.
Clang's integrated assembler produces the warning for assembly files:
warning: DWARF2 only supports one section per compilation unit
If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for
assembly sources (it is still emitted for C sources). This will be
re-enabled for newer DWARF versions in a follow up patch.
Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with
LLVM=1 LLVM_IAS=1 for x86_64 and arm64.
Cc: <stable@vger.kernel.org>
Link: https://github.com/ClangBuiltLinux/linux/issues/716
Reported-by: Dmitry Golovin <dima@golovin.in>
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Suggested-by: Dmitry Golovin <dima@golovin.in>
Suggested-by: Nathan Chancellor <natechancellor@gmail.com>
Suggested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Fangrui Song <maskray@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
[nd: backport to avoid conflicts from:
commit 10e68b02c8 ("Makefile: support compressed debug info")
commit 7b16994437 ("Makefile: Improve compressed debug info support detection")
commit 695afd3d7d ("kbuild: Simplify DEBUG_INFO Kconfig handling")]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c0700dfa2c upstream.
There are reports wrt lockdep splat in nftables, e.g.:
------------[ cut here ]------------
WARNING: CPU: 2 PID: 31416 at net/netfilter/nf_tables_api.c:622
lockdep_nfnl_nft_mutex_not_held+0x28/0x38 [nf_tables]
...
These are caused by an earlier, unrelated bug such as a n ABBA deadlock
in a different subsystem.
In such an event, lockdep is disabled and lockdep_is_held returns true
unconditionally. This then causes the WARN() in nf_tables.
Make the WARN conditional on lockdep still active to avoid this.
Fixes: f102d66b33 ("netfilter: nf_tables: use dedicated mutex to guard transactions")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Link: https://lore.kernel.org/linux-kselftest/CA+G9fYvFUpODs+NkSYcnwKnXm62tmP=ksLeBPmB+KFrB2rvCtQ@mail.gmail.com/
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 857c4c0a8b upstream.
Building on arch/s390/ results in this build error:
cc1: some warnings being treated as errors
../drivers/md/dm-writecache.c: In function 'persistent_memory_claim':
../drivers/md/dm-writecache.c:323:1: error: no return statement in function returning non-void [-Werror=return-type]
Fix this by replacing the BUG() with an -EOPNOTSUPP return.
Fixes: 48debafe4f ("dm: add writecache target")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 778721510e upstream.
If gfs2 tries to mount a (corrupt) file system that has no resource
groups it still tries to set preferences on the first one, which causes
a kernel null pointer dereference. This patch adds a check to function
gfs2_ri_update so this condition is detected and reported back as an
error.
Reported-by: syzbot+e3f23ce40269a4c9053a@syzkaller.appspotmail.com
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit bcee527895 upstream.
When the instances were able to use their own options, the userstacktrace
option was left hardcoded for the top level. This made the instance
userstacktrace option bascially into a nop, and will confuse users that set
it, but nothing happens (I was confused when it happened to me!)
Cc: stable@vger.kernel.org
Fixes: 16270145ce ("tracing: Add trace options for core options to instances")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 63c5395bb7 upstream
bcm_qspi_remove() calls spi_unregister_master() even though
bcm_qspi_probe() calls devm_spi_register_master(). The spi_master is
therefore unregistered and freed twice on unbind.
Moreover, since commit 0392727c26 ("spi: bcm-qspi: Handle clock probe
deferral"), bcm_qspi_probe() leaks the spi_master allocation if the call
to devm_clk_get_optional() fails.
Fix by switching over to the new devm_spi_alloc_master() helper which
keeps the private data accessible until the driver has unbound and also
avoids the spi_master leak on probe.
While at it, fix an ordering issue in bcm_qspi_remove() wherein
spi_unregister_master() is called after uninitializing the hardware,
disabling the clock and freeing an IRQ data structure. The correct
order is to call spi_unregister_master() *before* those teardown steps
because bus accesses may still be ongoing until that function returns.
Fixes: fa236a7ef2 ("spi: bcm-qspi: Add Broadcom MSPI driver")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: <stable@vger.kernel.org> # v4.9+: 123456789abc: spi: Introduce device-managed SPI controller allocation
Cc: <stable@vger.kernel.org> # v4.9+
Cc: Kamal Dasu <kdasu.kdev@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/5e31a9a59fd1c0d0b795b2fe219f25e5ee855f9d.1605121038.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>
[sudip: adjust context]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 5e844cc37a ]
SPI driver probing currently comprises two steps, whereas removal
comprises only one step:
spi_alloc_master()
spi_register_controller()
spi_unregister_controller()
That's because spi_unregister_controller() calls device_unregister()
instead of device_del(), thereby releasing the reference on the
spi_controller which was obtained by spi_alloc_master().
An SPI driver's private data is contained in the same memory allocation
as the spi_controller struct. Thus, once spi_unregister_controller()
has been called, the private data is inaccessible. But some drivers
need to access it after spi_unregister_controller() to perform further
teardown steps.
Introduce devm_spi_alloc_master() and devm_spi_alloc_slave(), which
release a reference on the spi_controller struct only after the driver
has unbound, thereby keeping the memory allocation accessible. Change
spi_unregister_controller() to not release a reference if the
spi_controller was allocated by one of these new devm functions.
The present commit is small enough to be backportable to stable.
It allows fixing drivers which use the private data in their ->remove()
hook after it's been freed. It also allows fixing drivers which neglect
to release a reference on the spi_controller in the probe error path.
Long-term, most SPI drivers shall be moved over to the devm functions
introduced herein. The few that can't shall be changed in a treewide
commit to explicitly release the last reference on the controller.
That commit shall amend spi_unregister_controller() to no longer release
a reference, thereby completing the migration.
As a result, the behaviour will be less surprising and more consistent
with subsystems such as IIO, which also includes the private data in the
allocation of the generic iio_dev struct, but calls device_del() in
iio_device_unregister().
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/272bae2ef08abd21388c98e23729886663d19192.1605121038.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1de67a3dee upstream.
Arbitration Lost (IAL) can happen after every single byte transfer. If
arbitration is lost, the I2C hardware will autonomously switch from
master mode to slave. If a transfer is not aborted in this state,
consecutive transfers will not be executed by the hardware and will
timeout.
Signed-off-by: Christian Eggers <ceggers@arri.de>
Tested (not extensively) on Vybrid VF500 (Toradex VF50):
Tested-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 384a9565f7 upstream.
According to the "VFxxx Controller Reference Manual" (and the comment
block starting at line 97), Vybrid requires writing a one for clearing
an interrupt flag. Syncing the method for clearing I2SR_IIF in
i2c_imx_isr().
Signed-off-by: Christian Eggers <ceggers@arri.de>
Fixes: 4b775022f6 ("i2c: imx: add struct to hold more configurable quirks")
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8199be001a upstream.
When investigating a slab cache bloat problem, significant amount of
negative dentry cache was seen, but confusingly they neither got shrunk
by reclaimer (the host has very tight memory) nor be shrunk by dropping
cache. The vmcore shows there are over 14M negative dentry objects on
lru, but tracing result shows they were even not scanned at all.
Further investigation shows the memcg's vfs shrinker_map bit is not set.
So the reclaimer or dropping cache just skip calling vfs shrinker. So
we have to reboot the hosts to get the memory back.
I didn't manage to come up with a reproducer in test environment, and
the problem can't be reproduced after rebooting. But it seems there is
race between shrinker map bit clear and reparenting by code inspection.
The hypothesis is elaborated as below.
The memcg hierarchy on our production environment looks like:
root
/ \
system user
The main workloads are running under user slice's children, and it
creates and removes memcg frequently. So reparenting happens very often
under user slice, but no task is under user slice directly.
So with the frequent reparenting and tight memory pressure, the below
hypothetical race condition may happen:
CPU A CPU B
reparent
dst->nr_items == 0
shrinker:
total_objects == 0
add src->nr_items to dst
set_bit
return SHRINK_EMPTY
clear_bit
child memcg offline
replace child's kmemcg_id with
parent's (in memcg_offline_kmem())
list_lru_del() between shrinker runs
see parent's kmemcg_id
dec dst->nr_items
reparent again
dst->nr_items may go negative
due to concurrent list_lru_del()
The second run of shrinker:
read nr_items without any
synchronization, so it may
see intermediate negative
nr_items then total_objects
may return 0 coincidently
keep the bit cleared
dst->nr_items != 0
skip set_bit
add scr->nr_item to dst
After this point dst->nr_item may never go zero, so reparenting will not
set shrinker_map bit anymore. And since there is no task under user
slice directly, so no new object will be added to its lru to set the
shrinker map bit either. That bit is kept cleared forever.
How does list_lru_del() race with reparenting? It is because reparenting
replaces children's kmemcg_id to parent's without protecting from
nlru->lock, so list_lru_del() may see parent's kmemcg_id but actually
deleting items from child's lru, but dec'ing parent's nr_items, so the
parent's nr_items may go negative as commit 2788cf0c40 ("memcg:
reparent list_lrus and free kmemcg_id on css offline") says.
Since it is impossible that dst->nr_items goes negative and
src->nr_items goes zero at the same time, so it seems we could set the
shrinker map bit iff src->nr_items != 0. We could synchronize
list_lru_count_one() and reparenting with nlru->lock, but it seems
checking src->nr_items in reparenting is the simplest and avoids lock
contention.
Fixes: fae91d6d8b ("mm/list_lru.c: set bit in memcg shrinker bitmap on first list_lru item appearance")
Suggested-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: <stable@vger.kernel.org> [4.19]
Link: https://lkml.kernel.org/r/20201202171749.264354-1-shy828301@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit bde3808bc8 upstream.
Fixes sparse warnings:
drivers/md/dm.c:508:12: warning: context imbalance in 'dm_prepare_ioctl' - wrong count at exit
drivers/md/dm.c:543:13: warning: context imbalance in 'dm_unprepare_ioctl' - wrong count at exit
Fixes: 971888c469 ("dm: hold DM table for duration of ioctl rather than use blkdev_get")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 67aa3ec3db upstream.
Advance the maximum number of arguments to 16.
This fixes issue where certain operations, combined with table
configured args, exceed 10 arguments.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: 48debafe4f ("dm: add writecache target")
Cc: stable@vger.kernel.org # v4.18+
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
