can_stop_idle_tick() checks whether the do_timer() duty has been taken over
by a CPU on boot. That's silly because the boot CPU always takes over with
the initial clockevent device.
But even if no CPU would have installed a clockevent and taken over the
duty then the question whether the tick on the current CPU can be stopped
or not is moot. In that case the current CPU would have no clockevent
either, so there would be nothing to keep ticking.
Remove it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20201206212002.725238293@linutronix.de
tick_handover_do_timer() which is invoked when a CPU is unplugged has a
check for cpumask_first(cpu_online_mask) when it tries to hand over the
tick update duty.
Checking the result of cpumask_first() there is pointless because if the
online mask is empty at this point, then this would be the last CPU in the
system going offline, which is impossible. There is always at least one CPU
remaining. If online mask would be really empty then the timer duty would
be the least of the resulting problems.
Remove the well meant check simply because it is pointless and confusing.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20201206212002.582579516@linutronix.de
Core:
- Robustness improvements for the NOHZ tick management
- Fixes and consolidation of the NTP/RTC synchronization code
- Small fixes and improvements in various places
- A set of function documentation udpates and fixes
Drivers:
- Cleanups and improvements in various clocksoure/event drivers
- Removal of the EZChip NPS clocksource driver as the platfrom support
was removed from ARC
- The usual set of new device tree binding and json conversions
- The RTC driver which have been acked by the RTC maintainer:
- Fix a long standing bug in the MC146818 library code which can cause
reading garbage during the RTC internal update.
- The changes related to the NTP/RTC consolidation work.
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Merge tag 'timers-core-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timers and timekeeping updates from Thomas Gleixner:
"Core:
- Robustness improvements for the NOHZ tick management
- Fixes and consolidation of the NTP/RTC synchronization code
- Small fixes and improvements in various places
- A set of function documentation udpates and fixes
Drivers:
- Cleanups and improvements in various clocksoure/event drivers
- Removal of the EZChip NPS clocksource driver as the platfrom
support was removed from ARC
- The usual set of new device tree binding and json conversions
- The RTC driver which have been acked by the RTC maintainer:
* fix a long standing bug in the MC146818 library code which can
cause reading garbage during the RTC internal update.
* changes related to the NTP/RTC consolidation work"
* tag 'timers-core-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (46 commits)
ntp: Fix prototype in the !CONFIG_GENERIC_CMOS_UPDATE case
tick/sched: Make jiffies update quick check more robust
ntp: Consolidate the RTC update implementation
ntp: Make the RTC sync offset less obscure
ntp, rtc: Move rtc_set_ntp_time() to ntp code
ntp: Make the RTC synchronization more reliable
rtc: core: Make the sync offset default more realistic
rtc: cmos: Make rtc_cmos sync offset correct
rtc: mc146818: Reduce spinlock section in mc146818_set_time()
rtc: mc146818: Prevent reading garbage
clocksource/drivers/sh_cmt: Fix potential deadlock when calling runtime PM
clocksource/drivers/arm_arch_timer: Correct fault programming of CNTKCTL_EL1.EVNTI
clocksource/drivers/arm_arch_timer: Use stable count reader in erratum sne
clocksource/drivers/dw_apb_timer_of: Add error handling if no clock available
clocksource/drivers/riscv: Make RISCV_TIMER depends on RISCV_SBI
clocksource/drivers/ingenic: Fix section mismatch
clocksource/drivers/cadence_ttc: Fix memory leak in ttc_setup_clockevent()
dt-bindings: timer: renesas: tmu: Convert to json-schema
dt-bindings: timer: renesas: tmu: Document r8a774e1 bindings
clocksource/drivers/orion: Add missing clk_disable_unprepare() on error path
...
Core:
- Better handling of page table leaves on archictectures which have
architectures have non-pagetable aligned huge/large pages. For such
architectures a leaf can actually be part of a larger entry.
- Prevent a deadlock vs. exec_update_mutex
Architectures:
- The related updates for page size calculation of leaf entries
- The usual churn to support new CPUs
- Small fixes and improvements all over the place
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Merge tag 'perf-core-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf updates from Thomas Gleixner:
"Core:
- Better handling of page table leaves on archictectures which have
architectures have non-pagetable aligned huge/large pages. For such
architectures a leaf can actually be part of a larger entry.
- Prevent a deadlock vs exec_update_mutex
Architectures:
- The related updates for page size calculation of leaf entries
- The usual churn to support new CPUs
- Small fixes and improvements all over the place"
* tag 'perf-core-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
perf/x86/intel: Add Tremont Topdown support
uprobes/x86: Fix fall-through warnings for Clang
perf/x86: Fix fall-through warnings for Clang
kprobes/x86: Fix fall-through warnings for Clang
perf/x86/intel/lbr: Fix the return type of get_lbr_cycles()
perf/x86/intel: Fix rtm_abort_event encoding on Ice Lake
x86/kprobes: Restore BTF if the single-stepping is cancelled
perf: Break deadlock involving exec_update_mutex
sparc64/mm: Implement pXX_leaf_size() support
powerpc/8xx: Implement pXX_leaf_size() support
arm64/mm: Implement pXX_leaf_size() support
perf/core: Fix arch_perf_get_page_size()
mm: Introduce pXX_leaf_size()
mm/gup: Provide gup_get_pte() more generic
perf/x86/intel: Add event constraint for CYCLE_ACTIVITY.STALLS_MEM_ANY
perf/x86/intel/uncore: Add Rocket Lake support
perf/x86/msr: Add Rocket Lake CPU support
perf/x86/cstate: Add Rocket Lake CPU support
perf/x86/intel: Add Rocket Lake CPU support
perf,mm: Handle non-page-table-aligned hugetlbfs
...
- A few extensions to the rwsem API and support for opportunistic
spinning and lock stealing
- lockdep selftest improvements
- Documentation updates
- Cleanups and small fixes all over the place
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Merge tag 'locking-core-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Thomas Gleixner:
"A moderate set of locking updates:
- A few extensions to the rwsem API and support for opportunistic
spinning and lock stealing
- lockdep selftest improvements
- Documentation updates
- Cleanups and small fixes all over the place"
* tag 'locking-core-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits)
seqlock: kernel-doc: Specify when preemption is automatically altered
seqlock: Prefix internal seqcount_t-only macros with a "do_"
Documentation: seqlock: s/LOCKTYPE/LOCKNAME/g
locking/rwsem: Remove reader optimistic spinning
locking/rwsem: Enable reader optimistic lock stealing
locking/rwsem: Prevent potential lock starvation
locking/rwsem: Pass the current atomic count to rwsem_down_read_slowpath()
locking/rwsem: Fold __down_{read,write}*()
locking/rwsem: Introduce rwsem_write_trylock()
locking/rwsem: Better collate rwsem_read_trylock()
rwsem: Implement down_read_interruptible
rwsem: Implement down_read_killable_nested
refcount: Fix a kernel-doc markup
completion: Drop init_completion define
atomic: Update MAINTAINERS
atomic: Delete obsolete documentation
seqlock: Rename __seqprop() users
lockdep/selftest: Add spin_nest_lock test
lockdep/selftests: Fix PROVE_RAW_LOCK_NESTING
seqlock: avoid -Wshadow warnings
...
RCU:
- Avoid cpuinfo-induced IPI pileups and idle-CPU IPIs.
- Lockdep-RCU updates reducing the need for __maybe_unused.
- Tasks-RCU updates.
- Miscellaneous fixes.
- Documentation updates.
- Torture-test updates.
KCSAN:
- updates for selftests, avoiding setting watchpoints on NULL pointers
- fix to watchpoint encoding
LKMM:
- updates for documentation along with some updates to example-code
litmus tests
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Merge tag 'core-rcu-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU updates from Thomas Gleixner:
"RCU, LKMM and KCSAN updates collected by Paul McKenney.
RCU:
- Avoid cpuinfo-induced IPI pileups and idle-CPU IPIs
- Lockdep-RCU updates reducing the need for __maybe_unused
- Tasks-RCU updates
- Miscellaneous fixes
- Documentation updates
- Torture-test updates
KCSAN:
- updates for selftests, avoiding setting watchpoints on NULL pointers
- fix to watchpoint encoding
LKMM:
- updates for documentation along with some updates to example-code
litmus tests"
* tag 'core-rcu-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (72 commits)
srcu: Take early exit on memory-allocation failure
rcu/tree: Defer kvfree_rcu() allocation to a clean context
rcu: Do not report strict GPs for outgoing CPUs
rcu: Fix a typo in rcu_blocking_is_gp() header comment
rcu: Prevent lockdep-RCU splats on lock acquisition/release
rcu/tree: nocb: Avoid raising softirq for offloaded ready-to-execute CBs
rcu,ftrace: Fix ftrace recursion
rcu/tree: Make struct kernel_param_ops definitions const
rcu/tree: Add a warning if CPU being onlined did not report QS already
rcu: Clarify nocb kthreads naming in RCU_NOCB_CPU config
rcu: Fix single-CPU check in rcu_blocking_is_gp()
rcu: Implement rcu_segcblist_is_offloaded() config dependent
list.h: Update comment to explicitly note circular lists
rcu: Panic after fixed number of stalls
x86/smpboot: Move rcu_cpu_starting() earlier
rcu: Allow rcu_irq_enter_check_tick() from NMI
tools/memory-model: Label MP tests' producers and consumers
tools/memory-model: Use "buf" and "flag" for message-passing tests
tools/memory-model: Add types to litmus tests
tools/memory-model: Add a glossary of LKMM terms
...
- More generalization of entry/exit functionality
- The consolidation work to reclaim TIF flags on x86 and also for non-x86
specific TIF flags which are solely relevant for syscall related work
and have been moved into their own storage space. The x86 specific part
had to be merged in to avoid a major conflict.
- The TIF_NOTIFY_SIGNAL work which replaces the inefficient signal
delivery mode of task work and results in an impressive performance
improvement for io_uring. The non-x86 consolidation of this is going to
come seperate via Jens.
- The selective syscall redirection facility which provides a clean and
efficient way to support the non-Linux syscalls of WINE by catching them
at syscall entry and redirecting them to the user space emulation. This
can be utilized for other purposes as well and has been designed
carefully to avoid overhead for the regular fastpath. This includes the
core changes and the x86 support code.
- Simplification of the context tracking entry/exit handling for the users
of the generic entry code which guarantee the proper ordering and
protection.
- Preparatory changes to make the generic entry code accomodate S390
specific requirements which are mostly related to their syscall restart
mechanism.
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Merge tag 'core-entry-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core entry/exit updates from Thomas Gleixner:
"A set of updates for entry/exit handling:
- More generalization of entry/exit functionality
- The consolidation work to reclaim TIF flags on x86 and also for
non-x86 specific TIF flags which are solely relevant for syscall
related work and have been moved into their own storage space. The
x86 specific part had to be merged in to avoid a major conflict.
- The TIF_NOTIFY_SIGNAL work which replaces the inefficient signal
delivery mode of task work and results in an impressive performance
improvement for io_uring. The non-x86 consolidation of this is
going to come seperate via Jens.
- The selective syscall redirection facility which provides a clean
and efficient way to support the non-Linux syscalls of WINE by
catching them at syscall entry and redirecting them to the user
space emulation. This can be utilized for other purposes as well
and has been designed carefully to avoid overhead for the regular
fastpath. This includes the core changes and the x86 support code.
- Simplification of the context tracking entry/exit handling for the
users of the generic entry code which guarantee the proper ordering
and protection.
- Preparatory changes to make the generic entry code accomodate S390
specific requirements which are mostly related to their syscall
restart mechanism"
* tag 'core-entry-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
entry: Add syscall_exit_to_user_mode_work()
entry: Add exit_to_user_mode() wrapper
entry_Add_enter_from_user_mode_wrapper
entry: Rename exit_to_user_mode()
entry: Rename enter_from_user_mode()
docs: Document Syscall User Dispatch
selftests: Add benchmark for syscall user dispatch
selftests: Add kselftest for syscall user dispatch
entry: Support Syscall User Dispatch on common syscall entry
kernel: Implement selective syscall userspace redirection
signal: Expose SYS_USER_DISPATCH si_code type
x86: vdso: Expose sigreturn address on vdso to the kernel
MAINTAINERS: Add entry for common entry code
entry: Fix boot for !CONFIG_GENERIC_ENTRY
x86: Support HAVE_CONTEXT_TRACKING_OFFSTACK
context_tracking: Only define schedule_user() on !HAVE_CONTEXT_TRACKING_OFFSTACK archs
sched: Detect call to schedule from critical entry code
context_tracking: Don't implement exception_enter/exit() on CONFIG_HAVE_CONTEXT_TRACKING_OFFSTACK
context_tracking: Introduce HAVE_CONTEXT_TRACKING_OFFSTACK
x86: Reclaim unused x86 TI flags
...
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Merge tag 'fixes-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull misc fixes from Christian Brauner:
"This contains several fixes which felt worth being combined into a
single branch:
- Use put_nsproxy() instead of open-coding it switch_task_namespaces()
- Kirill's work to unify lifecycle management for all namespaces. The
lifetime counters are used identically for all namespaces types.
Namespaces may of course have additional unrelated counters and
these are not altered. This work allows us to unify the type of the
counters and reduces maintenance cost by moving the counter in one
place and indicating that basic lifetime management is identical
for all namespaces.
- Peilin's fix adding three byte padding to Dmitry's
PTRACE_GET_SYSCALL_INFO uapi struct to prevent an info leak.
- Two smal patches to convert from the /* fall through */ comment
annotation to the fallthrough keyword annotation which I had taken
into my branch and into -next before df561f6688 ("treewide: Use
fallthrough pseudo-keyword") made it upstream which fixed this
tree-wide.
Since I didn't want to invalidate all testing for other commits I
didn't rebase and kept them"
* tag 'fixes-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
nsproxy: use put_nsproxy() in switch_task_namespaces()
sys: Convert to the new fallthrough notation
signal: Convert to the new fallthrough notation
time: Use generic ns_common::count
cgroup: Use generic ns_common::count
mnt: Use generic ns_common::count
user: Use generic ns_common::count
pid: Use generic ns_common::count
ipc: Use generic ns_common::count
uts: Use generic ns_common::count
net: Use generic ns_common::count
ns: Add a common refcount into ns_common
ptrace: Prevent kernel-infoleak in ptrace_get_syscall_info()
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Merge tag 'time-namespace-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull time namespace updates from Christian Brauner:
"When time namespaces were introduced we missed to virtualize the
'btime' field in /proc/stat. This confuses tasks which are in another
time namespace with a virtualized boottime which is common in some
container workloads. This contains Michael's series to fix 'btime'
which Thomas asked me to take through my tree.
To fix 'btime' virtualization we simply subtract the offset of the
time namespace's boottime from btime before printing the stats. Note
that since start_boottime of processes are seconds since boottime and
the boottime stamp is now shifted according to the time namespace's
offset, the offset of the time namespace also needs to be applied
before the process stats are given to userspace. This avoids that
processes shown by tools such as 'ps' appear as time travelers in the
corresponding time namespace.
Selftests are included to verify that btime virtualization in
/proc/stat works as expected"
* tag 'time-namespace-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
namespace: make timens_on_fork() return nothing
selftests/timens: added selftest for /proc/stat btime
fs/proc: apply the time namespace offset to /proc/stat btime
timens: additional helper functions for boottime offset handling
- Expose tag address bits in siginfo. The original arm64 ABI did not
expose any of the bits 63:56 of a tagged address in siginfo. In the
presence of user ASAN or MTE, this information may be useful. The
implementation is generic to other architectures supporting tags (like
SPARC ADI, subject to wiring up the arch code). The user will have to
opt in via sigaction(SA_EXPOSE_TAGBITS) so that the extra bits, if
available, become visible in si_addr.
- Default to 32-bit wide ZONE_DMA. Previously, ZONE_DMA was set to the
lowest 1GB to cope with the Raspberry Pi 4 limitations, to the
detriment of other platforms. With these changes, the kernel scans the
Device Tree dma-ranges and the ACPI IORT information before deciding
on a smaller ZONE_DMA.
- Strengthen READ_ONCE() to acquire when CONFIG_LTO=y. When building
with LTO, there is an increased risk of the compiler converting an
address dependency headed by a READ_ONCE() invocation into a control
dependency and consequently allowing for harmful reordering by the
CPU.
- Add CPPC FFH support using arm64 AMU counters.
- set_fs() removal on arm64. This renders the User Access Override (UAO)
ARMv8 feature unnecessary.
- Perf updates: PMU driver for the ARM DMC-620 memory controller, sysfs
identifier file for SMMUv3, stop event counters support for i.MX8MP,
enable the perf events-based hard lockup detector.
- Reorganise the kernel VA space slightly so that 52-bit VA
configurations can use more virtual address space.
- Improve the robustness of the arm64 memory offline event notifier.
- Pad the Image header to 64K following the EFI header definition
updated recently to increase the section alignment to 64K.
- Support CONFIG_CMDLINE_EXTEND on arm64.
- Do not use tagged PC in the kernel (TCR_EL1.TBID1==1), freeing up 8
bits for PtrAuth.
- Switch to vmapped shadow call stacks.
- Miscellaneous clean-ups.
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas:
- Expose tag address bits in siginfo. The original arm64 ABI did not
expose any of the bits 63:56 of a tagged address in siginfo. In the
presence of user ASAN or MTE, this information may be useful. The
implementation is generic to other architectures supporting tags
(like SPARC ADI, subject to wiring up the arch code). The user will
have to opt in via sigaction(SA_EXPOSE_TAGBITS) so that the extra
bits, if available, become visible in si_addr.
- Default to 32-bit wide ZONE_DMA. Previously, ZONE_DMA was set to the
lowest 1GB to cope with the Raspberry Pi 4 limitations, to the
detriment of other platforms. With these changes, the kernel scans
the Device Tree dma-ranges and the ACPI IORT information before
deciding on a smaller ZONE_DMA.
- Strengthen READ_ONCE() to acquire when CONFIG_LTO=y. When building
with LTO, there is an increased risk of the compiler converting an
address dependency headed by a READ_ONCE() invocation into a control
dependency and consequently allowing for harmful reordering by the
CPU.
- Add CPPC FFH support using arm64 AMU counters.
- set_fs() removal on arm64. This renders the User Access Override
(UAO) ARMv8 feature unnecessary.
- Perf updates: PMU driver for the ARM DMC-620 memory controller, sysfs
identifier file for SMMUv3, stop event counters support for i.MX8MP,
enable the perf events-based hard lockup detector.
- Reorganise the kernel VA space slightly so that 52-bit VA
configurations can use more virtual address space.
- Improve the robustness of the arm64 memory offline event notifier.
- Pad the Image header to 64K following the EFI header definition
updated recently to increase the section alignment to 64K.
- Support CONFIG_CMDLINE_EXTEND on arm64.
- Do not use tagged PC in the kernel (TCR_EL1.TBID1==1), freeing up 8
bits for PtrAuth.
- Switch to vmapped shadow call stacks.
- Miscellaneous clean-ups.
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (78 commits)
perf/imx_ddr: Add system PMU identifier for userspace
bindings: perf: imx-ddr: add compatible string
arm64: Fix build failure when HARDLOCKUP_DETECTOR_PERF is enabled
arm64: mte: fix prctl(PR_GET_TAGGED_ADDR_CTRL) if TCF0=NONE
arm64: mark __system_matches_cap as __maybe_unused
arm64: uaccess: remove vestigal UAO support
arm64: uaccess: remove redundant PAN toggling
arm64: uaccess: remove addr_limit_user_check()
arm64: uaccess: remove set_fs()
arm64: uaccess cleanup macro naming
arm64: uaccess: split user/kernel routines
arm64: uaccess: refactor __{get,put}_user
arm64: uaccess: simplify __copy_user_flushcache()
arm64: uaccess: rename privileged uaccess routines
arm64: sdei: explicitly simulate PAN/UAO entry
arm64: sdei: move uaccess logic to arch/arm64/
arm64: head.S: always initialize PSTATE
arm64: head.S: cleanup SCTLR_ELx initialization
arm64: head.S: rename el2_setup -> init_kernel_el
arm64: add C wrappers for SET_PSTATE_*()
...
Pull crypto updates from Herbert Xu:
"API:
- Add speed testing on 1420-byte blocks for networking
Algorithms:
- Improve performance of chacha on ARM for network packets
- Improve performance of aegis128 on ARM for network packets
Drivers:
- Add support for Keem Bay OCS AES/SM4
- Add support for QAT 4xxx devices
- Enable crypto-engine retry mechanism in caam
- Enable support for crypto engine on sdm845 in qce
- Add HiSilicon PRNG driver support"
* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (161 commits)
crypto: qat - add capability detection logic in qat_4xxx
crypto: qat - add AES-XTS support for QAT GEN4 devices
crypto: qat - add AES-CTR support for QAT GEN4 devices
crypto: atmel-i2c - select CONFIG_BITREVERSE
crypto: hisilicon/trng - replace atomic_add_return()
crypto: keembay - Add support for Keem Bay OCS AES/SM4
dt-bindings: Add Keem Bay OCS AES bindings
crypto: aegis128 - avoid spurious references crypto_aegis128_update_simd
crypto: seed - remove trailing semicolon in macro definition
crypto: x86/poly1305 - Use TEST %reg,%reg instead of CMP $0,%reg
crypto: x86/sha512 - Use TEST %reg,%reg instead of CMP $0,%reg
crypto: aesni - Use TEST %reg,%reg instead of CMP $0,%reg
crypto: cpt - Fix sparse warnings in cptpf
hwrng: ks-sa - Add dependency on IOMEM and OF
crypto: lib/blake2s - Move selftest prototype into header file
crypto: arm/aes-ce - work around Cortex-A57/A72 silion errata
crypto: ecdh - avoid unaligned accesses in ecdh_set_secret()
crypto: ccree - rework cache parameters handling
crypto: cavium - Use dma_set_mask_and_coherent to simplify code
crypto: marvell/octeontx - Use dma_set_mask_and_coherent to simplify code
...
- Correct a few problems in the x86 and the generic membarrier
implementation. Small corrections for assumptions about visibility
which have turned out not to be true.
- Make the PAT bits for memory encryption correct vs. 4K and 2M/1G page
table entries as they are at a different location.
- Fix a concurrency issue in the the local bandwidth readout of resource
control leading to incorrect values
- Fix the ordering of allocating a vector for an interrupt. The order
missed to respect the provided cpumask when the first attempt of
allocating node local in the mask fails. It then tries the node instead
of trying the full provided mask first. This leads to erroneous error
messages and breaking the (user) supplied affinity request. Reorder it.
- Make the INT3 padding detection in optprobe work correctly.
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Merge tag 'x86-urgent-2020-12-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Thomas Gleixner:
"A set of x86 and membarrier fixes:
- Correct a few problems in the x86 and the generic membarrier
implementation. Small corrections for assumptions about visibility
which have turned out not to be true.
- Make the PAT bits for memory encryption correct vs 4K and 2M/1G
page table entries as they are at a different location.
- Fix a concurrency issue in the the local bandwidth readout of
resource control leading to incorrect values
- Fix the ordering of allocating a vector for an interrupt. The order
missed to respect the provided cpumask when the first attempt of
allocating node local in the mask fails. It then tries the node
instead of trying the full provided mask first. This leads to
erroneous error messages and breaking the (user) supplied affinity
request. Reorder it.
- Make the INT3 padding detection in optprobe work correctly"
* tag 'x86-urgent-2020-12-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/kprobes: Fix optprobe to detect INT3 padding correctly
x86/apic/vector: Fix ordering in vector assignment
x86/resctrl: Fix incorrect local bandwidth when mba_sc is enabled
x86/mm/mem_encrypt: Fix definition of PMD_FLAGS_DEC_WP
membarrier: Execute SYNC_CORE on the calling thread
membarrier: Explicitly sync remote cores when SYNC_CORE is requested
membarrier: Add an actual barrier before rseq_preempt()
x86/membarrier: Get rid of a dubious optimization
The quick check in tick_do_update_jiffies64() whether jiffies need to be
updated is not really correct under all circumstances and on all
architectures, especially not on 32bit systems.
The quick check does:
if (now < READ_ONCE(tick_next_period))
return;
and the counterpart in the update is:
WRITE_ONCE(tick_next_period, next_update_time);
This has two problems:
1) On weakly ordered architectures there is no guarantee that the stores
before the WRITE_ONCE() are visible which means that other CPUs can
operate on a stale jiffies value.
2) On 32bit the store of tick_next_period which is an u64 is split into
two 32bit stores. If the first 32bit store advances tick_next_period
far out and the second 32bit store is delayed (virt, NMI ...) then
jiffies will become stale until the second 32bit store happens.
Address this by seperating the handling for 32bit and 64bit.
On 64bit problem #1 is addressed by replacing READ_ONCE() / WRITE_ONCE()
with smp_load_acquire() / smp_store_release().
On 32bit problem #2 is addressed by protecting the quick check with the
jiffies sequence counter. The load and stores can be plain because the
sequence count mechanics provides the required barriers already.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/87czzpc02w.fsf@nanos.tec.linutronix.de
Remove bpf_ prefix, which causes these helpers to be reported in verifier
dump as bpf_bpf_this_cpu_ptr() and bpf_bpf_per_cpu_ptr(), respectively. Lets
fix it as long as it is still possible before UAPI freezes on these helpers.
Fixes: eaa6bcb71e ("bpf: Introduce bpf_per_cpu_ptr()")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kernel/elfcore.c only contains weak symbols, which triggers a bug with
clang in combination with recordmcount:
Cannot find symbol for section 2: .text.
kernel/elfcore.o: failed
Move the empty stubs into linux/elfcore.h as inline functions. As only
two architectures use these, just use the architecture specific Kconfig
symbols to key off the declaration.
Link: https://lkml.kernel.org/r/20201204165742.3815221-2-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Barret Rhoden <brho@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The code for the legacy RTC and the RTC class based update are pretty much
the same. Consolidate the common parts into one function and just invoke
the actual setter functions.
For RTC class based devices the update code checks whether the offset is
valid for the device, which is usually not the case for the first
invocation. If it's not the same it stores the correct offset and lets the
caller try again. That's not much different from the previous approach
where the first invocation had a pretty low probability to actually hit the
allowed window.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201206220542.355743355@linutronix.de
The current RTC set_offset_nsec value is not really intuitive to
understand.
tsched twrite(t2.tv_sec - 1) t2 (seconds increment)
The offset is calculated from twrite based on the assumption that t2 -
twrite == 1s. That means for the MC146818 RTC the offset needs to be
negative so that the write happens 500ms before t2.
It's easier to understand when the whole calculation is based on t2. That
avoids negative offsets and the meaning is obvious:
t2 - twrite: The time defined by the chip when seconds increment
after the write.
twrite - tsched: The time for the transport to the point where the chip
is updated.
==> set_offset_nsec = t2 - tsched
ttransport = twrite - tsched
tRTCinc = t2 - twrite
==> set_offset_nsec = ttransport + tRTCinc
tRTCinc is a chip property and can be obtained from the data sheet.
ttransport depends on how the RTC is connected. It is close to 0 for
directly accessible RTCs. For RTCs behind a slow bus, e.g. i2c, it's the
time required to send the update over the bus. This can be estimated or
even calibrated, but that's a different problem.
Adjust the implementation and update comments accordingly.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201206220542.263204937@linutronix.de
rtc_set_ntp_time() is not really RTC functionality as the code is just a
user of RTC. Move it into the NTP code which allows further cleanups.
Requested-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201206220542.166871172@linutronix.de
Miroslav reported that the periodic RTC synchronization in the NTP code
fails more often than not to hit the specified update window.
The reason is that the code uses delayed_work to schedule the update which
needs to be in thread context as the underlying RTC might be connected via
a slow bus, e.g. I2C. In the update function it verifies whether the
current time is correct vs. the requirements of the underlying RTC.
But delayed_work is using the timer wheel for scheduling which is
inaccurate by design. Depending on the distance to the expiry the wheel
gets less granular to allow batching and to avoid the cascading of the
original timer wheel. See 500462a9de ("timers: Switch to a non-cascading
wheel") and the code for further details.
The code already deals with this by splitting the 660 seconds period into a
long 659 seconds timer and then retrying with a smaller delta.
But looking at the actual granularities of the timer wheel (which depend on
the HZ configuration) the 659 seconds timer ends up in an outer wheel level
and is affected by a worst case granularity of:
HZ Granularity
1000 32s
250 16s
100 40s
So the initial timer can be already off by max 12.5% which is not a big
issue as the period of the sync is defined as ~11 minutes.
The fine grained second attempt schedules to the desired update point with
a timer expiring less than a second from now. Depending on the actual delta
and the HZ setting even the second attempt can end up in outer wheel levels
which have a large enough granularity to make the correctness check fail.
As this is a fundamental property of the timer wheel there is no way to
make this more accurate short of iterating in one jiffies steps towards the
update point.
Switch it to an hrtimer instead which schedules the actual update work. The
hrtimer will expire precisely (max 1 jiffie delay when high resolution
timers are not available). The actual scheduling delay of the work is the
same as before.
The update is triggered from do_adjtimex() which is a bit racy but not much
more racy than it was before:
if (ntp_synced())
queue_delayed_work(system_power_efficient_wq, &sync_work, 0);
which is racy when the work is currently executed and has not managed to
reschedule itself.
This becomes now:
if (ntp_synced() && !hrtimer_is_queued(&sync_hrtimer))
queue_work(system_power_efficient_wq, &sync_work, 0);
which is racy when the hrtimer has expired and the work is currently
executed and has not yet managed to rearm the hrtimer.
Not a big problem as it just schedules work for nothing.
The new implementation has a safe guard in place to catch the case where
the hrtimer is queued on entry to the work function and avoids an extra
update attempt of the RTC that way.
Reported-by: Miroslav Lichvar <mlichvar@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Miroslav Lichvar <mlichvar@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201206220542.062910520@linutronix.de
Pull networking fixes from David Miller:
1) IPsec compat fixes, from Dmitry Safonov.
2) Fix memory leak in xfrm_user_policy(). Fix from Yu Kuai.
3) Fix polling in xsk sockets by using sk_poll_wait() instead of
datagram_poll() which keys off of sk_wmem_alloc and such which xsk
sockets do not update. From Xuan Zhuo.
4) Missing init of rekey_data in cfgh80211, from Sara Sharon.
5) Fix destroy of timer before init, from Davide Caratti.
6) Missing CRYPTO_CRC32 selects in ethernet driver Kconfigs, from Arnd
Bergmann.
7) Missing error return in rtm_to_fib_config() switch case, from Zhang
Changzhong.
8) Fix some src/dest address handling in vrf and add a testcase. From
Stephen Suryaputra.
9) Fix multicast handling in Seville switches driven by mscc-ocelot
driver. From Vladimir Oltean.
10) Fix proto value passed to skb delivery demux in udp, from Xin Long.
11) HW pkt counters not reported correctly in enetc driver, from Claudiu
Manoil.
12) Fix deadlock in bridge, from Joseph Huang.
13) Missing of_node_pur() in dpaa2 driver, fromn Christophe JAILLET.
14) Fix pid fetching in bpftool when there are a lot of results, from
Andrii Nakryiko.
15) Fix long timeouts in nft_dynset, from Pablo Neira Ayuso.
16) Various stymmac fixes, from Fugang Duan.
17) Fix null deref in tipc, from Cengiz Can.
18) When mss is biog, coose more resonable rcvq_space in tcp, fromn Eric
Dumazet.
19) Revert a geneve change that likely isnt necessary, from Jakub
Kicinski.
20) Avoid premature rx buffer reuse in various Intel driversm from Björn
Töpel.
21) retain EcT bits during TIS reflection in tcp, from Wei Wang.
22) Fix Tso deferral wrt. cwnd limiting in tcp, from Neal Cardwell.
23) MPLS_OPT_LSE_LABEL attribute is 342 ot 8 bits, from Guillaume Nault
24) Fix propagation of 32-bit signed bounds in bpf verifier and add test
cases, from Alexei Starovoitov.
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (81 commits)
selftests: fix poll error in udpgro.sh
selftests/bpf: Fix "dubious pointer arithmetic" test
selftests/bpf: Fix array access with signed variable test
selftests/bpf: Add test for signed 32-bit bound check bug
bpf: Fix propagation of 32-bit signed bounds from 64-bit bounds.
MAINTAINERS: Add entry for Marvell Prestera Ethernet Switch driver
net: sched: Fix dump of MPLS_OPT_LSE_LABEL attribute in cls_flower
net/mlx4_en: Handle TX error CQE
net/mlx4_en: Avoid scheduling restart task if it is already running
tcp: fix cwnd-limited bug for TSO deferral where we send nothing
net: flow_offload: Fix memory leak for indirect flow block
tcp: Retain ECT bits for tos reflection
ethtool: fix stack overflow in ethnl_parse_bitset()
e1000e: fix S0ix flow to allow S0i3.2 subset entry
ice: avoid premature Rx buffer reuse
ixgbe: avoid premature Rx buffer reuse
i40e: avoid premature Rx buffer reuse
igb: avoid transmit queue timeout in xdp path
igb: use xdp_do_flush
igb: skb add metasize for xdp
...
Alexei Starovoitov says:
====================
pull-request: bpf 2020-12-10
The following pull-request contains BPF updates for your *net* tree.
We've added 21 non-merge commits during the last 12 day(s) which contain
a total of 21 files changed, 163 insertions(+), 88 deletions(-).
The main changes are:
1) Fix propagation of 32-bit signed bounds from 64-bit bounds, from Alexei.
2) Fix ring_buffer__poll() return value, from Andrii.
3) Fix race in lwt_bpf, from Cong.
4) Fix test_offload, from Toke.
5) Various xsk fixes.
Please consider pulling these changes from:
git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git
Thanks a lot!
Also thanks to reporters, reviewers and testers of commits in this pull-request:
Cong Wang, Hulk Robot, Jakub Kicinski, Jean-Philippe Brucker, John
Fastabend, Magnus Karlsson, Maxim Mikityanskiy, Yonghong Song
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
The 64-bit signed bounds should not affect 32-bit signed bounds unless the
verifier knows that upper 32-bits are either all 1s or all 0s. For example the
register with smin_value==1 doesn't mean that s32_min_value is also equal to 1,
since smax_value could be larger than 32-bit subregister can hold.
The verifier refines the smax/s32_max return value from certain helpers in
do_refine_retval_range(). Teach the verifier to recognize that smin/s32_min
value is also bounded. When both smin and smax bounds fit into 32-bit
subregister the verifier can propagate those bounds.
Fixes: 3f50f132d8 ("bpf: Verifier, do explicit ALU32 bounds tracking")
Reported-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Syzbot reported a lock inversion involving perf. The sore point being
perf holding exec_update_mutex() for a very long time, specifically
across a whole bunch of filesystem ops in pmu::event_init() (uprobes)
and anon_inode_getfile().
This then inverts against procfs code trying to take
exec_update_mutex.
Move the permission checks later, such that we need to hold the mutex
over less code.
Reported-by: syzbot+db9cdf3dd1f64252c6ef@syzkaller.appspotmail.com
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reader optimistic spinning is helpful when the reader critical section
is short and there aren't that many readers around. It also improves
the chance that a reader can get the lock as writer optimistic spinning
disproportionally favors writers much more than readers.
Since commit d3681e269f ("locking/rwsem: Wake up almost all readers
in wait queue"), all the waiting readers are woken up so that they can
all get the read lock and run in parallel. When the number of contending
readers is large, allowing reader optimistic spinning will likely cause
reader fragmentation where multiple smaller groups of readers can get
the read lock in a sequential manner separated by writers. That reduces
reader parallelism.
One possible way to address that drawback is to limit the number of
readers (preferably one) that can do optimistic spinning. These readers
act as representatives of all the waiting readers in the wait queue as
they will wake up all those waiting readers once they get the lock.
Alternatively, as reader optimistic lock stealing has already enhanced
fairness to readers, it may be easier to just remove reader optimistic
spinning and simplifying the optimistic spinning code as a result.
Performance measurements (locking throughput kops/s) using a locking
microbenchmark with 50/50 reader/writer distribution and turbo-boost
disabled was done on a 2-socket Cascade Lake system (48-core 96-thread)
to see the impacts of these changes:
1) Vanilla - 5.10-rc3 kernel
2) Before - 5.10-rc3 kernel with previous patches in this series
2) limit-rspin - 5.10-rc3 kernel with limited reader spinning patch
3) no-rspin - 5.10-rc3 kernel with reader spinning disabled
# of threads CS Load Vanilla Before limit-rspin no-rspin
------------ ------- ------- ------ ----------- --------
2 1 5,185 5,662 5,214 5,077
4 1 5,107 4,983 5,188 4,760
8 1 4,782 4,564 4,720 4,628
16 1 4,680 4,053 4,567 3,402
32 1 4,299 1,115 1,118 1,098
64 1 3,218 983 1,001 957
96 1 1,938 944 957 930
2 20 2,008 2,128 2,264 1,665
4 20 1,390 1,033 1,046 1,101
8 20 1,472 1,155 1,098 1,213
16 20 1,332 1,077 1,089 1,122
32 20 967 914 917 980
64 20 787 874 891 858
96 20 730 836 847 844
2 100 372 356 360 355
4 100 492 425 434 392
8 100 533 537 529 538
16 100 548 572 568 598
32 100 499 520 527 537
64 100 466 517 526 512
96 100 406 497 506 509
The column "CS Load" represents the number of pause instructions issued
in the locking critical section. A CS load of 1 is extremely short and
is not likey in real situations. A load of 20 (moderate) and 100 (long)
are more realistic.
It can be seen that the previous patches in this series have reduced
performance in general except in highly contended cases with moderate
or long critical sections that performance improves a bit. This change
is mostly caused by the "Prevent potential lock starvation" patch that
reduce reader optimistic spinning and hence reduce reader fragmentation.
The patch that further limit reader optimistic spinning doesn't seem to
have too much impact on overall performance as shown in the benchmark
data.
The patch that disables reader optimistic spinning shows reduced
performance at lightly loaded cases, but comparable or slightly better
performance on with heavier contention.
This patch just removes reader optimistic spinning for now. As readers
are not going to do optimistic spinning anymore, we don't need to
consider if the OSQ is empty or not when doing lock stealing.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Link: https://lkml.kernel.org/r/20201121041416.12285-6-longman@redhat.com
If the optimistic spinning queue is empty and the rwsem does not have
the handoff or write-lock bits set, it is actually not necessary to
call rwsem_optimistic_spin() to spin on it. Instead, it can steal the
lock directly as its reader bias is in the count already. If it is
the first reader in this state, it will try to wake up other readers
in the wait queue.
With this patch applied, the following were the lock event counts
after rebooting a 2-socket system and a "make -j96" kernel rebuild.
rwsem_opt_rlock=4437
rwsem_rlock=29
rwsem_rlock_steal=19
So lock stealing represents about 0.4% of all the read locks acquired
in the slow path.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Link: https://lkml.kernel.org/r/20201121041416.12285-4-longman@redhat.com
The lock handoff bit is added in commit 4f23dbc1e6 ("locking/rwsem:
Implement lock handoff to prevent lock starvation") to avoid lock
starvation. However, allowing readers to do optimistic spinning does
introduce an unlikely scenario where lock starvation can happen.
The lock handoff bit may only be set when a waiter is being woken up.
In the case of reader unlock, wakeup happens only when the reader count
reaches 0. If there is a continuous stream of incoming readers acquiring
read lock via optimistic spinning, it is possible that the reader count
may never reach 0 and so the handoff bit will never be asserted.
One way to prevent this scenario from happening is to disallow optimistic
spinning if the rwsem is currently owned by readers. If the previous
or current owner is a writer, optimistic spinning will be allowed.
If the previous owner is a reader but the reader count has reached 0
before, a wakeup should have been issued. So the handoff mechanism
will be kicked in to prevent lock starvation. As a result, it should
be OK to do optimistic spinning in this case.
This patch may have some impact on reader performance as it reduces
reader optimistic spinning especially if the lock critical sections
are short the number of contending readers are small.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Link: https://lkml.kernel.org/r/20201121041416.12285-3-longman@redhat.com
The atomic count value right after reader count increment can be useful
to determine the rwsem state at trylock time. So the count value is
passed down to rwsem_down_read_slowpath() to be used when appropriate.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Link: https://lkml.kernel.org/r/20201121041416.12285-2-longman@redhat.com
In preparation for converting exec_update_mutex to a rwsem so that
multiple readers can execute in parallel and not deadlock, add
down_read_interruptible. This is needed for perf_event_open to be
converted (with no semantic changes) from working on a mutex to
wroking on a rwsem.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/87k0tybqfy.fsf@x220.int.ebiederm.org
In preparation for converting exec_update_mutex to a rwsem so that
multiple readers can execute in parallel and not deadlock, add
down_read_killable_nested. This is needed so that kcmp_lock
can be converted from working on a mutexes to working on rw_semaphores.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/87o8jabqh3.fsf@x220.int.ebiederm.org
membarrier()'s MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE is documented as
syncing the core on all sibling threads but not necessarily the calling
thread. This behavior is fundamentally buggy and cannot be used safely.
Suppose a user program has two threads. Thread A is on CPU 0 and thread B
is on CPU 1. Thread A modifies some text and calls
membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE).
Then thread B executes the modified code. If, at any point after
membarrier() decides which CPUs to target, thread A could be preempted and
replaced by thread B on CPU 0. This could even happen on exit from the
membarrier() syscall. If this happens, thread B will end up running on CPU
0 without having synced.
In principle, this could be fixed by arranging for the scheduler to issue
sync_core_before_usermode() whenever switching between two threads in the
same mm if there is any possibility of a concurrent membarrier() call, but
this would have considerable overhead. Instead, make membarrier() sync the
calling CPU as well.
As an optimization, this avoids an extra smp_mb() in the default
barrier-only mode and an extra rseq preempt on the caller.
Fixes: 70216e18e5 ("membarrier: Provide core serializing command, *_SYNC_CORE")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/r/250ded637696d490c69bef1877148db86066881c.1607058304.git.luto@kernel.org
membarrier() does not explicitly sync_core() remote CPUs; instead, it
relies on the assumption that an IPI will result in a core sync. On x86,
this may be true in practice, but it's not architecturally reliable. In
particular, the SDM and APM do not appear to guarantee that interrupt
delivery is serializing. While IRET does serialize, IPI return can
schedule, thereby switching to another task in the same mm that was
sleeping in a syscall. The new task could then SYSRET back to usermode
without ever executing IRET.
Make this more robust by explicitly calling sync_core_before_usermode()
on remote cores. (This also helps people who search the kernel tree for
instances of sync_core() and sync_core_before_usermode() -- one might be
surprised that the core membarrier code doesn't currently show up in a
such a search.)
Fixes: 70216e18e5 ("membarrier: Provide core serializing command, *_SYNC_CORE")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/776b448d5f7bd6b12690707f5ed67bcda7f1d427.1607058304.git.luto@kernel.org
It seems that most RSEQ membarrier users will expect any stores done before
the membarrier() syscall to be visible to the target task(s). While this
is extremely likely to be true in practice, nothing actually guarantees it
by a strict reading of the x86 manuals. Rather than providing this
guarantee by accident and potentially causing a problem down the road, just
add an explicit barrier.
Fixes: 70216e18e5 ("membarrier: Provide core serializing command, *_SYNC_CORE")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/d3e7197e034fa4852afcf370ca49c30496e58e40.1607058304.git.luto@kernel.org
While writing an application that requires user stack trace option
to work in instances, I found that the instance option has a bug
that makes it a nop. The check for performing the user stack trace
in an instance, checks the top level options (not the instance options)
to determine if a user stack trace should be performed or not.
This is not only incorrect, but also confusing for users. It confused
me for a bit!
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Merge tag 'trace-v5.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fix from Steven Rostedt:
"Fix userstacktrace option for instances
While writing an application that requires user stack trace option to
work in instances, I found that the instance option has a bug that
makes it a nop. The check for performing the user stack trace in an
instance, checks the top level options (not the instance options) to
determine if a user stack trace should be performed or not.
This is not only incorrect, but also confusing for users. It confused
me for a bit!"
* tag 'trace-v5.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix userstacktrace option for instances
- 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.
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Merge tag 'irq-urgent-2020-12-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
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
Three commits fixing possible missed TLB invalidations for multi-threaded
processes when CPUs are hotplugged in and out.
A fix for a host crash triggerable by host userspace (qemu) in KVM on Power9.
A fix for a host crash in machine check handling when running HPT guests on a
HPT host.
One commit fixing potential missed TLB invalidations when using the hash MMU on
Power9 or later.
A regression fix for machines with CPUs on node 0 but no memory.
Thanks to:
Aneesh Kumar K.V, Cédric Le Goater, Greg Kurz, Milan Mohanty, Milton Miller,
Nicholas Piggin, Paul Mackerras, Srikar Dronamraju.
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Merge tag 'powerpc-5.10-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman:
"Some more powerpc fixes for 5.10:
- Three commits fixing possible missed TLB invalidations for
multi-threaded processes when CPUs are hotplugged in and out.
- A fix for a host crash triggerable by host userspace (qemu) in KVM
on Power9.
- A fix for a host crash in machine check handling when running HPT
guests on a HPT host.
- One commit fixing potential missed TLB invalidations when using the
hash MMU on Power9 or later.
- A regression fix for machines with CPUs on node 0 but no memory.
Thanks to Aneesh Kumar K.V, Cédric Le Goater, Greg Kurz, Milan
Mohanty, Milton Miller, Nicholas Piggin, Paul Mackerras, and Srikar
Dronamraju"
* tag 'powerpc-5.10-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/64s/powernv: Fix memory corruption when saving SLB entries on MCE
KVM: PPC: Book3S HV: XIVE: Fix vCPU id sanity check
powerpc/numa: Fix a regression on memoryless node 0
powerpc/64s: Trim offlined CPUs from mm_cpumasks
kernel/cpu: add arch override for clear_tasks_mm_cpumask() mm handling
powerpc/64s/pseries: Fix hash tlbiel_all_isa300 for guest kernels
powerpc/64s: Fix hash ISA v3.0 TLBIEL instruction generation
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>
The (new) page-table walker in arch_perf_get_page_size() is broken in
various ways. Specifically while it is used in a lockless manner, it
doesn't depend on CONFIG_HAVE_FAST_GUP nor uses the proper _lockless
offset methods, nor is careful to only read each entry only once.
Also the hugetlb support is broken due to calling pte_page() without
first checking pte_special().
Rewrite the whole thing to be a proper lockless page-table walker and
employ the new pXX_leaf_size() pgtable functions to determine the
pagetable size without looking at the page-frames.
Fixes: 51b646b2d9 ("perf,mm: Handle non-page-table-aligned hugetlbfs")
Fixes: 8d97e71811 ("perf/core: Add PERF_SAMPLE_DATA_PAGE_SIZE")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Kan Liang <kan.liang@linux.intel.com>
Link: https://lkml.kernel.org/r/20201126124207.GM3040@hirez.programming.kicks-ass.net
This is the same as syscall_exit_to_user_mode() but without calling
exit_to_user_mode(). This can be used if there is an architectural reason
to avoid the combo function, e.g. restarting a syscall without returning to
userspace. Before returning to user space the caller has to invoke
exit_to_user_mode().
[ tglx: Amended comments ]
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201201142755.31931-6-svens@linux.ibm.com
Called from architecture specific code when syscall_exit_to_user_mode() is
not suitable. It simply calls __exit_to_user_mode().
This way __exit_to_user_mode() can still be inlined because it is declared
static __always_inline.
[ tglx: Amended comments and moved it to a different place in the header ]
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201201142755.31931-5-svens@linux.ibm.com
To be called from architecture specific code if the combo interfaces are
not suitable. It simply calls __enter_from_user_mode(). This way
__enter_from_user_mode will still be inlined because it is declared static
__always_inline.
[ tglx: Amend comments and move it to a different location in the header ]
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201201142755.31931-4-svens@linux.ibm.com
In order to make this function publicly available rename it so it can still
be inlined. An additional exit_to_user_mode() function will be added with
a later commit.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201201142755.31931-3-svens@linux.ibm.com
In order to make this function publicly available rename it so it can still
be inlined. An additional enter_from_user_mode() function will be added with
a later commit.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201201142755.31931-2-svens@linux.ibm.com
Syscall User Dispatch (SUD) must take precedence over seccomp and
ptrace, since the use case is emulation (it can be invoked with a
different ABI) such that seccomp filtering by syscall number doesn't
make sense in the first place. In addition, either the syscall is
dispatched back to userspace, in which case there is no resource for to
trace, or the syscall will be executed, and seccomp/ptrace will execute
next.
Since SUD runs before tracepoints, it needs to be a SYSCALL_WORK_EXIT as
well, just to prevent a trace exit event when dispatch was triggered.
For that, the on_syscall_dispatch() examines context to skip the
tracepoint, audit and other work.
[ tglx: Add a comment on the exit side ]
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201127193238.821364-5-krisman@collabora.com
