TCPM at present lacks the notion of VSAFE0V. There
are three vbus threshold levels that are critical to track:
a. vSafe5V - VBUS “5 volts” as defined by the USB
PD specification.
b. vSinkDisconnect - Threshold used for transition from
Attached.SNK to Unattached.SNK.
c. vSafe0V - VBUS “0 volts” as defined by the USB
PD specification.
Tracking vSafe0V is crucial for entry into Try.SNK and
Attached.SRC and turning vbus back on by the source in
response to hard reset.
>From "4.5.2.2.8.2 Exiting from AttachWait.SRC State" section
in the Type-C spec:
"The port shall transition to Attached.SRC when VBUS is at
vSafe0V and the SRC.Rd state is detected on exactly one of
the CC1 or CC2 pins for at least tCCDebounce."
"A DRP that strongly prefers the Sink role may optionally
transition to Try.SNK instead of Attached.SRC when VBUS
is at vSafe0V and the SRC.Rd state is detected on exactly
one of the CC1 or CC2 pins for at least tCCDebounce."
>From "7.1.5 Response to Hard Resets" section in the PD spec:
"After establishing the vSafe0V voltage condition on VBUS,
the Source Shall wait tSrcRecover before re-applying VCONN
and restoring VBUS to vSafe5V."
vbus_present in the TCPM code tracks vSafe5V(vbus_present is true)
and vSinkDisconnect(vbus_present is false).
This change adds is_vbus_vsafe0v callback which when set makes
TCPM query for vSafe0V voltage level when needed.
Since not all TCPC controllers might have the capability
to report vSafe0V, TCPM assumes that vSafe0V is same as
vSinkDisconnect when is_vbus_vsafe0v callback is not set.
This allows TCPM to continue to support controllers which don't
have the support for reporting vSafe0V.
Introducing vSafe0V helps fix the failure reported at
"Step 15. CVS verifies PUT remains in AttachWait.SRC for 500ms"
of "TD 4.7.2 Try. SNK DRP Connect DRP Test" of
"Universal Serial Bus Type-C (USB Type-C) Functional Test
Specification Chapters 4 and 5". Here the compliance tester
intentionally maintains vbus at greater than vSafe0V and expects
the Product under test to stay in AttachWait.SRC till vbus drops
to vSafe0V.
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Link: https://lore.kernel.org/r/20201202040840.663578-1-badhri@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tcpm_check_send_discover does not clear the send_discover flag
when any of the following conditions are not met.
1. data_role is TYPEC_HOST
2. link is pd_capable
Discovery indentity would anyways not be attempted during
the current session anymore when the above conditions are not
met. Hence clear the send_discover flag here to prevent
tcpm_enable_frs_work from rescheduling indefinetly.
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Link: https://lore.kernel.org/r/20201203031908.1491542-1-badhri@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nRetryCount was updated from 3 to 2 between PD2.0 and PD3.0 spec.
nRetryCount in "Table 6-34 Counter parameters" of the PD 2.0
spec is set to 3, whereas, nRetryCount in "Table 6-59 Counter
parameters" is set to 2.
Pass down negotiated rev in pd_transmit so that low level chip
drivers can update the retry count accordingly before attempting
packet transmission.
This helps in passing "TEST.PD.PORT.ALL.02" of the
"Power Delivery Merged" test suite which was initially failing
with "The UUT did not retransmit the message nReryCount times"
In fusb302 & tcpci drivers, by default the driver sets the retry
count to 3 (Default for PD 2.0). Update this to 2,
if the negotiated rev is PD 3.0.
In wcove, since the retry count is intentionally set to max, leaving
it as is.
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Link: https://lore.kernel.org/r/20201202031733.647808-1-badhri@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Synopsys xHC has an internal TRB cache of size TRB_CACHE_SIZE for
each endpoint. The default value for TRB_CACHE_SIZE is 16 for SS and 8
for HS. The controller loads and updates the TRB cache from the transfer
ring in system memory whenever the driver issues a start transfer or
update transfer command.
For chained TRBs, the Synopsys xHC requires that the total amount of
bytes for all TRBs loaded in the TRB cache be greater than or equal to 1
MPS. Or the chain ends within the TRB cache (with a last TRB).
If this requirement is not met, the controller will not be able to send
or receive a packet and it will hang causing a driver timeout and error.
This can be a problem if a class driver queues SG requests with many
small-buffer entries. The XHCI driver will create a chained TRB for each
entry which may trigger this issue.
This patch adds logic to the XHCI driver to detect and prevent this from
happening.
For every (TRB_CACHE_SIZE - 2), we check the total buffer size of
the SG list and if the last window of (TRB_CACHE_SIZE - 2) SG list length
and we don't make up at least 1 MPS, we create a temporary buffer to
consolidate full SG list into the buffer.
We check at (TRB_CACHE_SIZE - 2) window because it is possible that there
would be a link and/or event data TRB that take up to 2 of the cache
entries.
We discovered this issue with devices on other platforms but have not
yet come across any device that triggers this on Linux. But it could be
a real problem now or in the future. All it takes is N number of small
chained TRBs. And other instances of the Synopsys IP may have smaller
values for the TRB_CACHE_SIZE which would exacerbate the problem.
Signed-off-by: Tejas Joglekar <joglekar@synopsys.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20201208092912.1773650-3-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Mika writes:
thunderbolt: Changes for v5.11 merge window
This includes following Thunderbolt/USB4 changes for v5.11 merge window:
* DMA traffic test driver
* USB4 router NVM upgrade improvements
* USB4 router operations proxy implementation available in the recent
Intel Connection Manager firmwares
* Support for Intel Maple Ridge discrete Thunderbolt 4 controller
* A couple of cleanups and minor improvements.
* tag 'thunderbolt-for-v5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/westeri/thunderbolt: (22 commits)
thunderbolt: Add support for Intel Maple Ridge
thunderbolt: Add USB4 router operation proxy for firmware connection manager
thunderbolt: Move constants for USB4 router operations to tb_regs.h
thunderbolt: Add connection manager specific hooks for USB4 router operations
thunderbolt: Pass TX and RX data directly to usb4_switch_op()
thunderbolt: Pass metadata directly to usb4_switch_op()
thunderbolt: Perform USB4 router NVM upgrade in two phases
thunderbolt: Return -ENOTCONN when ERR_CONN is received
thunderbolt: Keep the parent runtime resumed for a while on device disconnect
thunderbolt: Log adapter numbers in decimal in path activation/deactivation
thunderbolt: Log which connection manager implementation is used
thunderbolt: Move max_boot_acl field to correct place in struct icm
MAINTAINERS: Add Isaac as maintainer of Thunderbolt DMA traffic test driver
thunderbolt: Add DMA traffic test driver
thunderbolt: Add support for end-to-end flow control
thunderbolt: Make it possible to allocate one directional DMA tunnel
thunderbolt: Create debugfs directory automatically for services
thunderbolt: Add functions for enabling and disabling lane bonding on XDomain
thunderbolt: Add link_speed and link_width to XDomain
thunderbolt: Create XDomain devices for loops back to the host
...
This is more in line with what tcpm does and will be needed
to avoid recursive dependency like
> drivers/power/supply/Kconfig:2:error: recursive dependency detected!
drivers/power/supply/Kconfig:2: symbol POWER_SUPPLY is selected by TYPEC_TPS6598X
drivers/usb/typec/Kconfig:64: symbol TYPEC_TPS6598X depends on REGMAP_I2C
drivers/base/regmap/Kconfig:19: symbol REGMAP_I2C is selected by CHARGER_ADP5061
drivers/power/supply/Kconfig:93: symbol CHARGER_ADP5061 depends on POWER_SUPPLY
For a resolution refer to Documentation/kbuild/kconfig-language.rst
subsection "Kconfig recursive dependency limitations"
when selecting POWER_SUPPLY.
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Guido Günther <agx@sigxcpu.org>
Link: https://lore.kernel.org/r/6d11417c42d82caf66e08af160397959eb7d0d60.1607166657.git.agx@sigxcpu.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The new control-message helpers include a pipe-type check which is
almost completely redundant.
Control messages are generally sent to the default pipe which always
exists and is of the correct type since its endpoint representation is
created by USB core as part of enumeration for all devices.
There is currently only one instance of a driver in the tree which use
a control endpoint other than endpoint 0 (and it does not use the new
helpers).
Drivers should be testing for the existence of their resources at probe
rather than at runtime, but to catch drivers failing to do so USB core
already does a sanity check on URB submission and triggers a WARN().
Having the same sanity check done in the helper only suppresses the
warning without allowing us to find and fix the drivers.
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20201204085110.20055-2-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull char/misc driver fixes from Greg KH:
"Here are some small driver fixes, and one "large" revert, for
5.10-rc7.
They include:
- revert mei patch from 5.10-rc1 that was using a reserved userspace
value. It will be resubmitted once the proper id has been assigned
by the virtio people.
- habanalabs fixes found by the fall-through audit from Gustavo
- speakup driver fixes for reported issues
- fpga config build fix for reported issue.
All of these except the revert have been in linux-next with no
reported issues. The revert is "clean" and just removes a
previously-added driver, so no real issue there"
* tag 'char-misc-5.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
Revert "mei: virtio: virtualization frontend driver"
fpga: Specify HAS_IOMEM dependency for FPGA_DFL
habanalabs: put devices before driver removal
habanalabs: free host huge va_range if not used
speakup: Reject setting the speakup line discipline outside of speakup
Pull tty fixes from Greg KH:
"Here are two tty core fixes for 5.10-rc7.
They resolve some reported locking issues in the tty core. While they
have not been in a released linux-next yet, they have passed all of
the 0-day bot testing as well as the submitter's testing"
* tag 'tty-5.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
tty: Fix ->session locking
tty: Fix ->pgrp locking in tiocspgrp()
Pull USB fixes from Greg KH:
"Here are some small USB fixes for 5.10-rc7 that resolve a number of
reported issues, and add some new device ids.
Nothing major here, but these solve some problems that people were
having with the 5.10-rc tree:
- reverts for USB storage dma settings that broke working devices
- thunderbolt use-after-free fix
- cdns3 driver fixes
- gadget driver userspace copy fix
- new device ids
All of these except for the reverts have been in linux-next with no
reported issues. The reverts are "clean" and were tested by Hans, as
well as passing the 0-day tests"
* tag 'usb-5.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
usb: gadget: f_fs: Use local copy of descriptors for userspace copy
usb: ohci-omap: Fix descriptor conversion
Revert "usb-storage: fix sdev->host->dma_dev"
Revert "uas: fix sdev->host->dma_dev"
Revert "uas: bump hw_max_sectors to 2048 blocks for SS or faster drives"
USB: serial: kl5kusb105: fix memleak on open
USB: serial: ch341: sort device-id entries
USB: serial: ch341: add new Product ID for CH341A
USB: serial: option: fix Quectel BG96 matching
usb: cdns3: core: fix goto label for error path
usb: cdns3: gadget: clear trb->length as zero after preparing every trb
usb: cdns3: Fix hardware based role switch
USB: serial: option: add support for Thales Cinterion EXS82
USB: serial: option: add Fibocom NL668 variants
thunderbolt: Fix use-after-free in remove_unplugged_switch()
Pull x86 fixes from Thomas Gleixner:
"A set of fixes for x86:
- Make the AMD L3 QoS code and data priorization enable/disable
mechanism work correctly.
The control bit was only set/cleared on one of the CPUs in a L3
domain, but it has to be modified on all CPUs in the domain. The
initial documentation was not clear about this, but the updated one
from Oct 2020 spells it out.
- Fix an off by one in the UV platform detection code which causes
the UV hubs to be identified wrongly.
The chip revisions start at 1 not at 0.
- Fix a long standing bug in the evaluation of prefixes in the
uprobes code which fails to handle repeated prefixes properly.
The aggregate size of the prefixes can be larger than the bytes
array but the code blindly iterated over the aggregate size beyond
the array boundary. Add a macro to handle this case properly and
use it at the affected places"
* tag 'x86-urgent-2020-12-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sev-es: Use new for_each_insn_prefix() macro to loop over prefixes bytes
x86/insn-eval: Use new for_each_insn_prefix() macro to loop over prefixes bytes
x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytes
x86/platform/uv: Fix UV4 hub revision adjustment
x86/resctrl: Fix AMD L3 QOS CDP enable/disable
Pull perf fixes from Thomas Gleixner:
"Two fixes for performance monitoring on X86:
- Add recursion protection to another callchain invoked from
x86_pmu_stop() which can recurse back into x86_pmu_stop(). The
first attempt to fix this missed this extra code path.
- Use the already filtered status variable to check for PEBS counter
overflow bits and not the unfiltered full status read from
IA32_PERF_GLOBAL_STATUS which can have unrelated bits check which
would be evaluated incorrectly"
* tag 'perf-urgent-2020-12-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/intel: Check PEBS status correctly
perf/x86/intel: Fix a warning on x86_pmu_stop() with large PEBS
Pull irq fixes from Thomas Gleixner:
"A set of updates for the interrupt subsystem:
- Make multiqueue devices which use the managed interrupt affinity
infrastructure work on PowerPC/Pseries. PowerPC does not use the
generic infrastructure for setting up PCI/MSI interrupts and the
multiqueue changes failed to update the legacy PCI/MSI
infrastructure. Make this work by passing the affinity setup
information down to the mapping and allocation functions.
- Move Jason Cooper from MAINTAINERS to CREDITS as his mail is
bouncing and he's not reachable. We hope all is well with him and
say thanks for his work over the years"
* tag 'irq-urgent-2020-12-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
powerpc/pseries: Pass MSI affinity to irq_create_mapping()
genirq/irqdomain: Add an irq_create_mapping_affinity() function
MAINTAINERS: Move Jason Cooper to CREDITS
Pull intel_idle build fix from Thomas Gleixner:
"A tiny build fix for a recent change in the intel_idle driver which
missed a CONFIG dependency and broke the build for certain
configurations"
* tag 'locking-urgent-2020-12-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
intel_idle: Build fix
Pull Kbuild fixes from Masahiro Yamada:
- Move -Wcast-align to W=3, which tends to be false-positive and there
is no tree-wide solution.
- Pass -fmacro-prefix-map to KBUILD_CPPFLAGS because it is a
preprocessor option and makes sense for .S files as well.
- Disable -gdwarf-2 for Clang's integrated assembler to avoid warnings.
- Disable --orphan-handling=warn for LLD 10.0.1 to avoid warnings.
- Fix undesirable line breaks in *.mod files.
* tag 'kbuild-fixes-v5.10-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kbuild: avoid split lines in .mod files
kbuild: Disable CONFIG_LD_ORPHAN_WARN for ld.lld 10.0.1
kbuild: Hoist '--orphan-handling' into Kconfig
Kbuild: do not emit debug info for assembly with LLVM_IAS=1
kbuild: use -fmacro-prefix-map for .S sources
Makefile.extrawarn: move -Wcast-align to W=3
Merge misc fixes from Andrew Morton:
"12 patches.
Subsystems affected by this patch series: mm (memcg, zsmalloc, swap,
mailmap, selftests, pagecache, hugetlb, pagemap), lib, and coredump"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
mm/mmap.c: fix mmap return value when vma is merged after call_mmap()
hugetlb_cgroup: fix offline of hugetlb cgroup with reservations
mm/filemap: add static for function __add_to_page_cache_locked
userfaultfd: selftests: fix SIGSEGV if huge mmap fails
tools/testing/selftests/vm: fix build error
mailmap: add two more addresses of Uwe Kleine-König
mm/swapfile: do not sleep with a spin lock held
mm/zsmalloc.c: drop ZSMALLOC_PGTABLE_MAPPING
mm: list_lru: set shrinker map bit when child nr_items is not zero
mm: memcg/slab: fix obj_cgroup_charge() return value handling
coredump: fix core_pattern parse error
zlib: export S390 symbols for zlib modules
Adrian Moreno was ruuning a kubernetes 1.19 + containerd/docker workload
using hugetlbfs. In this environment the issue is reproduced by:
- Start a simple pod that uses the recently added HugePages medium
feature (pod yaml attached)
- Start a DPDK app. It doesn't need to run successfully (as in transfer
packets) nor interact with real hardware. It seems just initializing
the EAL layer (which handles hugepage reservation and locking) is
enough to trigger the issue
- Delete the Pod (or let it "Complete").
This would result in a kworker thread going into a tight loop (top output):
1425 root 20 0 0 0 0 R 99.7 0.0 5:22.45 kworker/28:7+cgroup_destroy
'perf top -g' reports:
- 63.28% 0.01% [kernel] [k] worker_thread
- 49.97% worker_thread
- 52.64% process_one_work
- 62.08% css_killed_work_fn
- hugetlb_cgroup_css_offline
41.52% _raw_spin_lock
- 2.82% _cond_resched
rcu_all_qs
2.66% PageHuge
- 0.57% schedule
- 0.57% __schedule
We are spinning in the do-while loop in hugetlb_cgroup_css_offline.
Worse yet, we are holding the master cgroup lock (cgroup_mutex) while
infinitely spinning. Little else can be done on the system as the
cgroup_mutex can not be acquired.
Do note that the issue can be reproduced by simply offlining a hugetlb
cgroup containing pages with reservation counts.
The loop in hugetlb_cgroup_css_offline is moving page counts from the
cgroup being offlined to the parent cgroup. This is done for each
hstate, and is repeated until hugetlb_cgroup_have_usage returns false.
The routine moving counts (hugetlb_cgroup_move_parent) is only moving
'usage' counts. The routine hugetlb_cgroup_have_usage is checking for
both 'usage' and 'reservation' counts. Discussion about what to do with
reservation counts when reparenting was discussed here:
https://lore.kernel.org/linux-kselftest/CAHS8izMFAYTgxym-Hzb_JmkTK1N_S9tGN71uS6MFV+R7swYu5A@mail.gmail.com/
The decision was made to leave a zombie cgroup for with reservation
counts. Unfortunately, the code checking reservation counts was
incorrectly added to hugetlb_cgroup_have_usage.
To fix the issue, simply remove the check for reservation counts. While
fixing this issue, a related bug in hugetlb_cgroup_css_offline was
noticed. The hstate index is not reinitialized each time through the
do-while loop. Fix this as well.
Fixes: 1adc4d419a ("hugetlb_cgroup: add interface for charge/uncharge hugetlb reservations")
Reported-by: Adrian Moreno <amorenoz@redhat.com>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Adrian Moreno <amorenoz@redhat.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201203220242.158165-1-mike.kravetz@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The error handling in hugetlb_allocate_area() was incorrect for the
hugetlb_shared test case.
Previously the behavior was:
- mmap a hugetlb area
- If this fails, set the pointer to NULL, and carry on
- mmap an alias of the same hugetlb fd
- If this fails, munmap the original area
If the original mmap failed, it's likely the second one did too. If
both failed, we'd blindly try to munmap a NULL pointer, causing a
SIGSEGV. Instead, "goto fail" so we return before trying to mmap the
alias.
This issue can be hit "in real life" by forgetting to set
/proc/sys/vm/nr_hugepages (leaving it at 0), and then trying to run the
hugetlb_shared test.
Another small improvement is, when the original mmap fails, don't just
print "it failed": perror(), so we can see *why*. :)
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Alan Gilbert <dgilbert@redhat.com>
Link: https://lkml.kernel.org/r/20201204203443.2714693-1-axelrasmussen@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While I was doing zram testing, I found sometimes decompression failed
since the compression buffer was corrupted. With investigation, I found
below commit calls cond_resched unconditionally so it could make a
problem in atomic context if the task is reschedule.
BUG: sleeping function called from invalid context at mm/vmalloc.c:108
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 946, name: memhog
3 locks held by memhog/946:
#0: ffff9d01d4b193e8 (&mm->mmap_lock#2){++++}-{4:4}, at: __mm_populate+0x103/0x160
#1: ffffffffa3d53de0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath.constprop.0+0xa98/0x1160
#2: ffff9d01d56b8110 (&zspage->lock){.+.+}-{3:3}, at: zs_map_object+0x8e/0x1f0
CPU: 0 PID: 946 Comm: memhog Not tainted 5.9.3-00011-gc5bfc0287345-dirty #316
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014
Call Trace:
unmap_kernel_range_noflush+0x2eb/0x350
unmap_kernel_range+0x14/0x30
zs_unmap_object+0xd5/0xe0
zram_bvec_rw.isra.0+0x38c/0x8e0
zram_rw_page+0x90/0x101
bdev_write_page+0x92/0xe0
__swap_writepage+0x94/0x4a0
pageout+0xe3/0x3a0
shrink_page_list+0xb94/0xd60
shrink_inactive_list+0x158/0x460
We can fix this by removing the ZSMALLOC_PGTABLE_MAPPING feature (which
contains the offending calling code) from zsmalloc.
Even though this option showed some amount improvement(e.g., 30%) in
some arm32 platforms, it has been headache to maintain since it have
abused APIs[1](e.g., unmap_kernel_range in atomic context).
Since we are approaching to deprecate 32bit machines and already made
the config option available for only builtin build since v5.8, lastly it
has been not default option in zsmalloc, it's time to drop the option
for better maintenance.
[1] http://lore.kernel.org/linux-mm/20201105170249.387069-1-minchan@kernel.org
Fixes: e47110e905 ("mm/vunmap: add cond_resched() in vunmap_pmd_range")
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Harish Sriram <harish@linux.ibm.com>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201117202916.GA3856507@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
Commit 10befea91b ("mm: memcg/slab: use a single set of kmem_caches
for all allocations") introduced a regression into the handling of the
obj_cgroup_charge() return value. If a non-zero value is returned
(indicating of exceeding one of memory.max limits), the allocation
should fail, instead of falling back to non-accounted mode.
To make the code more readable, move memcg_slab_pre_alloc_hook() and
memcg_slab_post_alloc_hook() calling conditions into bodies of these
hooks.
Fixes: 10befea91b ("mm: memcg/slab: use a single set of kmem_caches for all allocations")
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201127161828.GD840171@carbon.dhcp.thefacebook.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
"xargs echo" is not a safe way to remove line breaks because the input
may exceed the command line limit and xargs may break it up into
multiple invocations of echo. This should never happen because
scripts/gen_autoksyms.sh expects all undefined symbols are placed in
the second line of .mod files.
One possible way is to replace "xargs echo" with
"sed ':x;N;$!bx;s/\n/ /g'" or something, but I rewrote the code by
using awk because it is more readable.
This issue was reported by Sami Tolvanen; in his Clang LTO patch set,
$(multi-used-m) is no longer an ELF object, but a thin archive that
contains LLVM bitcode files. llvm-nm prints out symbols for each
archive member separately, which results a lot of dupications, in some
places, beyond the system-defined limit.
This problem must be fixed irrespective of LTO, and we must ensure
zero possibility of having this issue.
Link: https://lkml.org/lkml/2020/12/1/1658
Reported-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
