Pull x86 fixes from Ingo Molnar:
"A 32-bit build fix, CONFIG_RETPOLINE fixes and rename CONFIG_RESCTRL
to CONFIG_X86_RESCTRL"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, modpost: Replace last remnants of RETPOLINE with CONFIG_RETPOLINE
x86/cache: Rename config option to CONFIG_X86_RESCTRL
samples/seccomp: Fix 32-bit build
Pull ACPI fixes from Rafael Wysocki:
"Fix a build failure introduced recently, fix the xpower PMIC ACPI
driver, clean up the handling of duplicate entries in _PRx power
resource lists and fix addresses in NUMA-related messages on 32-bit
with PAE.
Specifics:
- Fix build failures with both CONFIG_NLS and CONFIG_PCI unset that
can occur since ACPI can be built without PCI now (Sinan Kaya).
- Clean up the handling of duplicate entries in power resource lists
returned by _PRx evaluation to avoid triggering WARN_ON() on
attempts to add duplicate symlinks in sysfs (Hans de Goede).
- Fix issues with the TS current-source switching on systems using
the xpower PMIC by avoiding to update unrelated bits in the TS
pin-ctrl register and avoiding to unconditionally enable TS
current-source on systems where it is not used (Hans de Goede).
- Fix addresses in NUMA-related messages on 32-bit with PAE which can
be truncated due to integer type conversions (Chao Fan)"
* tag 'acpi-5.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI / PMIC: xpower: Fix TS-pin current-source handling
ACPI: NUMA: Use correct type for printing addresses on i386-PAE
ACPI: power: Skip duplicate power resource references in _PRx
ACPI: Fix build failure when CONFIG_NLS is set to 'n'
Pull power management updates from Rafael Wysocki:
"These fix fallout after starting to use hrtimers in the runtime PM
framework, fix a few cpufreq issues, fix a recently broken reference
to cpuidle documentation, update MAINTAINERS entries for cpufreq and
cpuidle and make the recently added system suspend and resume support
in devfreq actually work.
Specifics:
- Prevent integer overflows from occurring on 32-bit when converting
milliseconds to nanoseconds in the runtime PM framework and update
comments that still refer to jiffies in it (Vincent Guittot,
Ladislav Michl).
- Fix the SCMI cpufreq driver to always use the same frequency units
for arch_set_freq_scale() and make the scale-invariant load
tracking acutally work with this driver (Quentin Perret).
- Fix freeing of dynamic OPPs in the SCPI and SCMI cpufreq drivers
broken during the 4.20 defelopment cycle (Viresh Kumar).
- Prevent the cpufreq core from attempting to return the current
frequency of offline CPUs (Sudeep Holla).
- Add devfreq suspend and resume hooks (missed previously) to the PM
core to make the recently added system suspend and resume support
in devfreq actually work (Lukasz Luba).
- Update MAINTAINERS entries for cpufreq and cpuidle, mostly to add
references to new/current documentation to them (Rafael Wysocki).
- Fix a recently broken reference to cpuidle documentation (Otto
Sabart)"
* tag 'pm-5.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
PM-runtime: Fix autosuspend_delay on 32bits arch
PM-runtime: Fix 'jiffies' in comments after switch to hrtimers
cpufreq: scmi: Fix frequency invariance in slow path
doc: trace: fix reference to cpuidle documentation file
cpufreq: check if policy is inactive early in __cpufreq_get()
cpufreq: scpi/scmi: Fix freeing of dynamic OPPs
cpuidle / Documentation: Update cpuidle MAINTAINERS entry
cpufreq / Documentation: Update cpufreq MAINTAINERS entry
PM: sleep: call devfreq suspend/resume
Pull drm fixes from Dave Airlie:
"Not a huge amount for rc2, assume the usual quiet period, and rc3 will
be most of it.
amdgpu:
- Powerplay fixes
- Virtual display pinning fixes
- Golden register updates for Vega
- Pitch and gem size validation fixes
- SR-IOV init error fix
- Pagetables in system RAM disable for some Raven system
- DP-MST resume fixes
tc358767 bridge:
- fix to work with displayport connector"
* tag 'drm-fixes-2019-01-11' of git://anongit.freedesktop.org/drm/drm: (26 commits)
drm/amdgpu: disable system memory page tables for now
drm/amdgpu: set WRITE_BURST_LENGTH to 64B to workaround SDMA1 hang
drm/amdgpu: fix CPDMA hang in PRT mode for VEGA20
drm/bridge: tc358767: use DP connector if no panel set
drm/bridge: tc358767: fix output H/V syncs
drm/bridge: tc358767: reject modes which require too much BW
drm/bridge: tc358767: fix initial DP0/1_SRCCTRL value
drm/bridge: tc358767: fix single lane configuration
drm/bridge: tc358767: add defines for DP1_SRCCTRL & PHY_2LANE
drm/bridge: tc358767: add bus flags
drm/dp_mst: Add __must_check to drm_dp_mst_topology_mgr_resume()
drm/amdgpu: Don't fail resume process if resuming atomic state fails
drm/amdgpu: Don't ignore rc from drm_dp_mst_topology_mgr_resume()
drm/amdgpu: validate user GEM object size
drm/amdgpu: validate user pitch alignment
drm/amd/powerplay: drop the unnecessary uclk hard min setting
drm/amd/powerplay: avoid possible buffer overflow
drm/amd/powerplay: create pp_od_clk_voltage device file under OD support
drm/amd/powerplay: update OD support flag for SKU with no OD capabilities
drm/amdgpu: make gfx9 enter into rlc safe mode when set MGCG
...
* acpi-pci:
ACPI: Fix build failure when CONFIG_NLS is set to 'n'
* acpi-power:
ACPI: power: Skip duplicate power resource references in _PRx
* acpi-misc:
ACPI: NUMA: Use correct type for printing addresses on i386-PAE
Pull RISC-V updates from Palmer Dabbelt:
"This tag contains a handful of updates that slipped through the cracks
during the merge window due to the holidays. The fixes are mostly
independent, with the exception of one larger audit-related branch.
Core RISC-V updates:
- The BSS has been moved, which shrinks flat images.
- A fix to test-bpf so it compiles on RV64I-based systems.
- A fix to respect the kernel commandline when there is no device
tree.
- A fix to prevent CPUs from trying to put themselves to sleep when
bringing down the system.
- Support for MODULE_SECTIONS on RV32I-based systems.
- [new in v2] The addition of an SBI earlycon driver. This is
definately a new feature, but I'd like to include it now because I
dropped this patch when submitting the merge window PR that removed
our EARLY_PRINTK support.
RISC-V audit updates:
- The addition of NR_syscalls into unistd.h, which is necessary for
CONFIG_FTRACE_SYSCALLS.
- The definition of CREATE_TRACE_POINTS so __tracepoint_sys_{enter,exit}
get defined.
- A fix for trace_sys_exit() so we can enable HAVE_SYSCALL_TRACEPOINTS
As usual, I've tested this by booting a Fedora-based image on a recent
QEMU (this time just whatever I had lying around).
* tag 'riscv-for-linus-4.21-rc2-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux:
tty/serial: Add RISC-V SBI earlycon support
riscv: add HAVE_SYSCALL_TRACEPOINTS to Kconfig
riscv: fix trace_sys_exit hook
riscv: define CREATE_TRACE_POINTS in ptrace.c
riscv: define NR_syscalls in unistd.h
riscv: audit: add audit hook in do_syscall_trace_enter/exit()
riscv: add audit support
RISC-V: Support MODULE_SECTIONS mechanism on RV32
MAINTAINERS: SiFive drivers: add myself as a SiFive driver maintainer
MAINTAINERS: SiFive drivers: change the git tree to a SiFive git tree
riscv: don't stop itself in smp_send_stop
arch: riscv: support kernel command line forcing when no DTB passed
tools uapi: fix RISC-V 64-bit support
RISC-V: Make BSS section as the last section in vmlinux.lds.S
Pull VFIO fixes from Alex Williamson:
- Fix trace header include path for in-tree builds (Masahiro Yamada)
- Fix overflow in unmap wrap-around test (Alex Williamson)
* tag 'vfio-v5.0-rc2' of git://github.com/awilliam/linux-vfio:
vfio/type1: Fix unmap overflow off-by-one
vfio/pci: set TRACE_INCLUDE_PATH to fix the build error
Pull sound fixes from Takashi Iwai:
"A collection of small fixes for USB-audio, HD-audio and cs46xx.
The USB-audio fixes are for out-of-bound accesses and a regression in
the recent cleanup, while HD-audio fixes are usual device-specific
quirks"
* tag 'sound-5.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: hda/realtek - Disable headset Mic VREF for headset mode of ALC225
ALSA: hda/realtek - Add unplug function into unplug state of Headset Mode for ALC225
ALSA: usb-audio: fix CM6206 register definitions
ALSA: cs46xx: Potential NULL dereference in probe
ALSA: hda/realtek - Support Dell headset mode for New AIO platform
ALSA: usb-audio: Fix an out-of-bound read in create_composite_quirks
ALSA: usb-audio: Always check descriptor sizes in parser code
ALSA: usb-audio: Check mixer unit descriptors more strictly
ALSA: usb-audio: Avoid access before bLength check in build_audio_procunit()
Pull mtd fixes from Boris Brezillon:
"Core MTD Fixes:
- Fix a bug introduced when exposing MTD devs as NVMEM providers and
check for add_mtd_device() return code everywhere
raw NAND fixes:
- Fix a memory corruption in the QCOM driver"
* tag 'mtd/fixes-for-5.0-rc2' of git://git.infradead.org/linux-mtd:
mtd: rawnand: qcom: fix memory corruption that causes panic
mtd: Check add_mtd_device() ret code
mtd: Fix the check on nvmem_register() ret code
Cast autosuspend_delay to u64 to make sure that the full computation
of 'expires' or slack will be done in u64, even on 32bits arch.
Otherwise, any delay greater than 2^31 nsec can overflow if signed
32bits is used when converting delay from msec to nsec.
Fixes: 8234f6734c (PM-runtime: Switch autosuspend over to using hrtimers)
Reported-by: Tony Lindgren <tony@atomide.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
PM-runtime now uses the hrtimers infrastructure for autosuspend, however
comments still reference 'jiffies'.
Fixes: 8234f6734c (PM-runtime: Switch autosuspend over to using hrtimers)
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
In RISC-V, the M-mode runtime firmware provide SBI calls for
debug prints. This patch adds earlycon support using RISC-V
SBI console calls. To enable it, just pass "earlycon=sbi" in
kernel parameters.
Signed-off-by: Anup Patel <anup@brainfault.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Pull arch/csky bug fixes from Guo Ren:
"Here are some fixup patches for 5.0-rc1:
- fix compile error with pte_alloc
- fix handle_irq_perbit break irq flow
- fix CACHEV1 store instruction fast retire
- fix module relocation error with 807 & 860
- add csky kernel features to documentation"
* tag 'csky-for-linus-5.0-rc1' of git://github.com/c-sky/csky-linux:
irqchip/csky: fixup handle_irq_perbit break irq
csky: fixup compile error with pte_alloc
csky: fixup CACHEV1 store instruction fast retire
csky: fixup relocation error with 807 & 860
Documentation/features: Add csky kernel features
The scmi-cpufreq driver calls the arch_set_freq_scale() callback on
frequency changes to provide scale-invariant load-tracking signals to
the scheduler. However, in the slow path, it does so while specifying
the current and max frequencies in different units, hence resulting in a
broken freq_scale factor.
Fix this by passing all frequencies in KHz, as stored in the CPUFreq
frequency table.
Fixes: 99d6bdf338 (cpufreq: add support for CPU DVFS based on SCMI message protocol)
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Cc: 4.17+ <stable@vger.kernel.org> # v4.17+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Old cpuidle/sysfs.txt file was replaced in aa5eee355b. So, refer to
an updated file.
Fixes: aa5eee355b (Documentation: admin-guide: PM: Add cpuidle document)
Signed-off-by: Otto Sabart <ottosabart@seberm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Initially DP0_SRCCTRL is set to a static value which includes
DP0_SRCCTRL_LANES_2 and DP0_SRCCTRL_BW27, even when only 1 lane of
1.62Gbps speed is used. DP1_SRCCTRL is configured to a magic number.
This patch changes the configuration as follows:
Configure DP0_SRCCTRL by using tc_srcctrl() which provides the correct
value.
DP1_SRCCTRL needs two bits to be set to the same value as DP0_SRCCTRL:
SSCG and BW27. All other bits can be zero.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190103115954.12785-5-tomi.valkeinen@ti.com
Disable Headset Mic VREF for headset mode of ALC225.
This will be controlled by coef bits of headset mode functions.
[ Fixed a compile warning and code simplification -- tiwai ]
Signed-off-by: Kailang Yang <kailang@realtek.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Merge misc fixes from Andrew Morton:
"14 fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
mm, page_alloc: do not wake kswapd with zone lock held
hugetlbfs: revert "use i_mmap_rwsem for more pmd sharing synchronization"
hugetlbfs: revert "Use i_mmap_rwsem to fix page fault/truncate race"
mm: page_mapped: don't assume compound page is huge or THP
mm/memory.c: initialise mmu_notifier_range correctly
tools/vm/page_owner: use page_owner_sort in the use example
kasan: fix krealloc handling for tag-based mode
kasan: make tag based mode work with CONFIG_HARDENED_USERCOPY
kasan, arm64: use ARCH_SLAB_MINALIGN instead of manual aligning
mm, memcg: fix reclaim deadlock with writeback
mm/usercopy.c: no check page span for stack objects
slab: alien caches must not be initialized if the allocation of the alien cache failed
fork, memcg: fix cached_stacks case
zram: idle writeback fixes and cleanup
The commit 594cc251fd ("make 'user_access_begin()' do 'access_ok()'")
exposed incorrect implementations of access_ok() macro in several
architectures. This change fixes 2 issues found in OpenRISC.
OpenRISC was not properly using parenthesis for arguments and also using
arguments twice. This patch fixes those 2 issues.
I test booted this patch with v5.0-rc1 on qemu and it's working fine.
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Stafford Horne <shorne@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
syzbot reported the following regression in the latest merge window and
it was confirmed by Qian Cai that a similar bug was visible from a
different context.
======================================================
WARNING: possible circular locking dependency detected
4.20.0+ #297 Not tainted
------------------------------------------------------
syz-executor0/8529 is trying to acquire lock:
000000005e7fb829 (&pgdat->kswapd_wait){....}, at:
__wake_up_common_lock+0x19e/0x330 kernel/sched/wait.c:120
but task is already holding lock:
000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: spin_lock
include/linux/spinlock.h:329 [inline]
000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: rmqueue_bulk
mm/page_alloc.c:2548 [inline]
000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: __rmqueue_pcplist
mm/page_alloc.c:3021 [inline]
000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: rmqueue_pcplist
mm/page_alloc.c:3050 [inline]
000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: rmqueue
mm/page_alloc.c:3072 [inline]
000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at:
get_page_from_freelist+0x1bae/0x52a0 mm/page_alloc.c:3491
It appears to be a false positive in that the only way the lock ordering
should be inverted is if kswapd is waking itself and the wakeup
allocates debugging objects which should already be allocated if it's
kswapd doing the waking. Nevertheless, the possibility exists and so
it's best to avoid the problem.
This patch flags a zone as needing a kswapd using the, surprisingly,
unused zone flag field. The flag is read without the lock held to do
the wakeup. It's possible that the flag setting context is not the same
as the flag clearing context or for small races to occur. However, each
race possibility is harmless and there is no visible degredation in
fragmentation treatment.
While zone->flag could have continued to be unused, there is potential
for moving some existing fields into the flags field instead.
Particularly read-mostly ones like zone->initialized and
zone->contiguous.
Link: http://lkml.kernel.org/r/20190103225712.GJ31517@techsingularity.net
Fixes: 1c30844d2d ("mm: reclaim small amounts of memory when an external fragmentation event occurs")
Reported-by: syzbot+93d94a001cfbce9e60e1@syzkaller.appspotmail.com
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Qian Cai <cai@lca.pw>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts b43a999005
The reverted commit caused issues with migration and poisoning of anon
huge pages. The LTP move_pages12 test will cause an "unable to handle
kernel NULL pointer" BUG would occur with stack similar to:
RIP: 0010:down_write+0x1b/0x40
Call Trace:
migrate_pages+0x81f/0xb90
__ia32_compat_sys_migrate_pages+0x190/0x190
do_move_pages_to_node.isra.53.part.54+0x2a/0x50
kernel_move_pages+0x566/0x7b0
__x64_sys_move_pages+0x24/0x30
do_syscall_64+0x5b/0x180
entry_SYSCALL_64_after_hwframe+0x44/0xa9
The purpose of the reverted patch was to fix some long existing races
with huge pmd sharing. It used i_mmap_rwsem for this purpose with the
idea that this could also be used to address truncate/page fault races
with another patch. Further analysis has determined that i_mmap_rwsem
can not be used to address all these hugetlbfs synchronization issues.
Therefore, revert this patch while working an another approach to the
underlying issues.
Link: http://lkml.kernel.org/r/20190103235452.29335-2-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: Jan Stancek <jstancek@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Prakash Sangappa <prakash.sangappa@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
LTP proc01 testcase has been observed to rarely trigger crashes
on arm64:
page_mapped+0x78/0xb4
stable_page_flags+0x27c/0x338
kpageflags_read+0xfc/0x164
proc_reg_read+0x7c/0xb8
__vfs_read+0x58/0x178
vfs_read+0x90/0x14c
SyS_read+0x60/0xc0
The issue is that page_mapped() assumes that if compound page is not
huge, then it must be THP. But if this is 'normal' compound page
(COMPOUND_PAGE_DTOR), then following loop can keep running (for
HPAGE_PMD_NR iterations) until it tries to read from memory that isn't
mapped and triggers a panic:
for (i = 0; i < hpage_nr_pages(page); i++) {
if (atomic_read(&page[i]._mapcount) >= 0)
return true;
}
I could replicate this on x86 (v4.20-rc4-98-g60b548237fed) only
with a custom kernel module [1] which:
- allocates compound page (PAGEC) of order 1
- allocates 2 normal pages (COPY), which are initialized to 0xff (to
satisfy _mapcount >= 0)
- 2 PAGEC page structs are copied to address of first COPY page
- second page of COPY is marked as not present
- call to page_mapped(COPY) now triggers fault on access to 2nd COPY
page at offset 0x30 (_mapcount)
[1] https://github.com/jstancek/reproducers/blob/master/kernel/page_mapped_crash/repro.c
Fix the loop to iterate for "1 << compound_order" pages.
Kirrill said "IIRC, sound subsystem can producuce custom mapped compound
pages".
Link: http://lkml.kernel.org/r/c440d69879e34209feba21e12d236d06bc0a25db.1543577156.git.jstancek@redhat.com
Fixes: e1534ae950 ("mm: differentiate page_mapped() from page_mapcount() for compound pages")
Signed-off-by: Jan Stancek <jstancek@redhat.com>
Debugged-by: Laszlo Ersek <lersek@redhat.com>
Suggested-by: "Kirill A. Shutemov" <kirill@shutemov.name>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Right now tag-based KASAN can retag the memory that is reallocated via
krealloc and return a differently tagged pointer even if the same slab
object gets used and no reallocated technically happens.
There are a few issues with this approach. One is that krealloc callers
can't rely on comparing the return value with the passed argument to
check whether reallocation happened. Another is that if a caller knows
that no reallocation happened, that it can access object memory through
the old pointer, which leads to false positives. Look at
nf_ct_ext_add() to see an example.
Fix this by keeping the same tag if the memory don't actually gets
reallocated during krealloc.
Link: http://lkml.kernel.org/r/bb2a71d17ed072bcc528cbee46fcbd71a6da3be4.1546540962.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Liu Bo has experienced a deadlock between memcg (legacy) reclaim and the
ext4 writeback
task1:
wait_on_page_bit+0x82/0xa0
shrink_page_list+0x907/0x960
shrink_inactive_list+0x2c7/0x680
shrink_node_memcg+0x404/0x830
shrink_node+0xd8/0x300
do_try_to_free_pages+0x10d/0x330
try_to_free_mem_cgroup_pages+0xd5/0x1b0
try_charge+0x14d/0x720
memcg_kmem_charge_memcg+0x3c/0xa0
memcg_kmem_charge+0x7e/0xd0
__alloc_pages_nodemask+0x178/0x260
alloc_pages_current+0x95/0x140
pte_alloc_one+0x17/0x40
__pte_alloc+0x1e/0x110
alloc_set_pte+0x5fe/0xc20
do_fault+0x103/0x970
handle_mm_fault+0x61e/0xd10
__do_page_fault+0x252/0x4d0
do_page_fault+0x30/0x80
page_fault+0x28/0x30
task2:
__lock_page+0x86/0xa0
mpage_prepare_extent_to_map+0x2e7/0x310 [ext4]
ext4_writepages+0x479/0xd60
do_writepages+0x1e/0x30
__writeback_single_inode+0x45/0x320
writeback_sb_inodes+0x272/0x600
__writeback_inodes_wb+0x92/0xc0
wb_writeback+0x268/0x300
wb_workfn+0xb4/0x390
process_one_work+0x189/0x420
worker_thread+0x4e/0x4b0
kthread+0xe6/0x100
ret_from_fork+0x41/0x50
He adds
"task1 is waiting for the PageWriteback bit of the page that task2 has
collected in mpd->io_submit->io_bio, and tasks2 is waiting for the
LOCKED bit the page which tasks1 has locked"
More precisely task1 is handling a page fault and it has a page locked
while it charges a new page table to a memcg. That in turn hits a
memory limit reclaim and the memcg reclaim for legacy controller is
waiting on the writeback but that is never going to finish because the
writeback itself is waiting for the page locked in the #PF path. So
this is essentially ABBA deadlock:
lock_page(A)
SetPageWriteback(A)
unlock_page(A)
lock_page(B)
lock_page(B)
pte_alloc_pne
shrink_page_list
wait_on_page_writeback(A)
SetPageWriteback(B)
unlock_page(B)
# flush A, B to clear the writeback
This accumulating of more pages to flush is used by several filesystems
to generate a more optimal IO patterns.
Waiting for the writeback in legacy memcg controller is a workaround for
pre-mature OOM killer invocations because there is no dirty IO
throttling available for the controller. There is no easy way around
that unfortunately. Therefore fix this specific issue by pre-allocating
the page table outside of the page lock. We have that handy
infrastructure for that already so simply reuse the fault-around pattern
which already does this.
There are probably other hidden __GFP_ACCOUNT | GFP_KERNEL allocations
from under a fs page locked but they should be really rare. I am not
aware of a better solution unfortunately.
[akpm@linux-foundation.org: fix mm/memory.c:__do_fault()]
[akpm@linux-foundation.org: coding-style fixes]
[mhocko@kernel.org: enhance comment, per Johannes]
Link: http://lkml.kernel.org/r/20181214084948.GA5624@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/20181213092221.27270-1-mhocko@kernel.org
Fixes: c3b94f44fc ("memcg: further prevent OOM with too many dirty pages")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Liu Bo <bo.liu@linux.alibaba.com>
Debugged-by: Liu Bo <bo.liu@linux.alibaba.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It is easy to trigger this with CONFIG_HARDENED_USERCOPY_PAGESPAN=y,
usercopy: Kernel memory overwrite attempt detected to spans multiple pages (offset 0, size 23)!
kernel BUG at mm/usercopy.c:102!
For example,
print_worker_info
char name[WQ_NAME_LEN] = { };
char desc[WORKER_DESC_LEN] = { };
probe_kernel_read(name, wq->name, sizeof(name) - 1);
probe_kernel_read(desc, worker->desc, sizeof(desc) - 1);
__copy_from_user_inatomic
check_object_size
check_heap_object
check_page_span
This is because on-stack variables could cross PAGE_SIZE boundary, and
failed this check,
if (likely(((unsigned long)ptr & (unsigned long)PAGE_MASK) ==
((unsigned long)end & (unsigned long)PAGE_MASK)))
ptr = FFFF889007D7EFF8
end = FFFF889007D7F00E
Hence, fix it by checking if it is a stack object first.
[keescook@chromium.org: improve comments after reorder]
Link: http://lkml.kernel.org/r/20190103165151.GA32845@beast
Link: http://lkml.kernel.org/r/20181231030254.99441-1-cai@lca.pw
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
