Pull ARM updates from Russell King:
- further Spectre variant 1 fixes for user accessors.
- kbuild cleanups (Masahiro Yamada)
- hook up sync core functionality (Will Deacon)
- nommu updates for hypervisor mode booting (Vladimir Murzin)
- use compiler built-ins for fls and ffs (Nicolas Pitre)
* 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: spectre-v1: mitigate user accesses
ARM: spectre-v1: use get_user() for __get_user()
ARM: use __inttype() in get_user()
ARM: oabi-compat: copy semops using __copy_from_user()
ARM: vfp: use __copy_from_user() when restoring VFP state
ARM: 8785/1: use compiler built-ins for ffs and fls
ARM: 8784/1: NOMMU: Allow enter in Hyp mode
ARM: 8783/1: NOMMU: Extend check for VBAR support
ARM: 8782/1: vfp: clean up arch/arm/vfp/Makefile
ARM: signal: copy registers using __copy_from_user()
ARM: tcm: ensure inline stub functions are marked static
ARM: 8779/1: add endianness option to LDFLAGS instead of LD
ARM: 8777/1: Hook up SYNC_CORE functionality for sys_membarrier()
Pull s390 updates from Heiko Carstens:
"Since Martin is on vacation you get the s390 pull request from me:
- Host large page support for KVM guests. As the patches have large
impact on arch/s390/mm/ this series goes out via both the KVM and
the s390 tree.
- Add an option for no compression to the "Kernel compression mode"
menu, this will come in handy with the rework of the early boot
code.
- A large rework of the early boot code that will make life easier
for KASAN and KASLR. With the rework the bootable uncompressed
image is not generated anymore, only the bzImage is available. For
debuggung purposes the new "no compression" option is used.
- Re-enable the gcc plugins as the issue with the latent entropy
plugin is solved with the early boot code rework.
- More spectre relates changes:
+ Detect the etoken facility and remove expolines automatically.
+ Add expolines to a few more indirect branches.
- A rewrite of the common I/O layer trace points to make them
consumable by 'perf stat'.
- Add support for format-3 PCI function measurement blocks.
- Changes for the zcrypt driver:
+ Add attributes to indicate the load of cards and queues.
+ Restructure some code for the upcoming AP device support in KVM.
- Build flags improvements in various Makefiles.
- A few fixes for the kdump support.
- A couple of patches for gcc 8 compile warning cleanup.
- Cleanup s390 specific proc handlers.
- Add s390 support to the restartable sequence self tests.
- Some PTR_RET vs PTR_ERR_OR_ZERO cleanup.
- Lots of bug fixes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (107 commits)
s390/dasd: fix hanging offline processing due to canceled worker
s390/dasd: fix panic for failed online processing
s390/mm: fix addressing exception after suspend/resume
rseq/selftests: add s390 support
s390: fix br_r1_trampoline for machines without exrl
s390/lib: use expoline for all bcr instructions
s390/numa: move initial setup of node_to_cpumask_map
s390/kdump: Fix elfcorehdr size calculation
s390/cpum_sf: save TOD clock base in SDBs for time conversion
KVM: s390: Add huge page enablement control
s390/mm: Add huge page gmap linking support
s390/mm: hugetlb pages within a gmap can not be freed
KVM: s390: Add skey emulation fault handling
s390/mm: Add huge pmd storage key handling
s390/mm: Clear skeys for newly mapped huge guest pmds
s390/mm: Clear huge page storage keys on enable_skey
s390/mm: Add huge page dirty sync support
s390/mm: Add gmap pmd invalidation and clearing
s390/mm: Add gmap pmd notification bit setting
s390/mm: Add gmap pmd linking
...
Pull x86 timer updates from Thomas Gleixner:
"Early TSC based time stamping to allow better boot time analysis.
This comes with a general cleanup of the TSC calibration code which
grew warts and duct taping over the years and removes 250 lines of
code. Initiated and mostly implemented by Pavel with help from various
folks"
* 'x86-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits)
x86/kvmclock: Mark kvm_get_preset_lpj() as __init
x86/tsc: Consolidate init code
sched/clock: Disable interrupts when calling generic_sched_clock_init()
timekeeping: Prevent false warning when persistent clock is not available
sched/clock: Close a hole in sched_clock_init()
x86/tsc: Make use of tsc_calibrate_cpu_early()
x86/tsc: Split native_calibrate_cpu() into early and late parts
sched/clock: Use static key for sched_clock_running
sched/clock: Enable sched clock early
sched/clock: Move sched clock initialization and merge with generic clock
x86/tsc: Use TSC as sched clock early
x86/tsc: Initialize cyc2ns when tsc frequency is determined
x86/tsc: Calibrate tsc only once
ARM/time: Remove read_boot_clock64()
s390/time: Remove read_boot_clock64()
timekeeping: Default boot time offset to local_clock()
timekeeping: Replace read_boot_clock64() with read_persistent_wall_and_boot_offset()
s390/time: Add read_persistent_wall_and_boot_offset()
x86/xen/time: Output xen sched_clock time from 0
x86/xen/time: Initialize pv xen time in init_hypervisor_platform()
...
Pull x86 PTI updates from Thomas Gleixner:
"The Speck brigade sadly provides yet another large set of patches
destroying the perfomance which we carefully built and preserved
- PTI support for 32bit PAE. The missing counter part to the 64bit
PTI code implemented by Joerg.
- A set of fixes for the Global Bit mechanics for non PCID CPUs which
were setting the Global Bit too widely and therefore possibly
exposing interesting memory needlessly.
- Protection against userspace-userspace SpectreRSB
- Support for the upcoming Enhanced IBRS mode, which is preferred
over IBRS. Unfortunately we dont know the performance impact of
this, but it's expected to be less horrible than the IBRS
hammering.
- Cleanups and simplifications"
* 'x86/pti' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (60 commits)
x86/mm/pti: Move user W+X check into pti_finalize()
x86/relocs: Add __end_rodata_aligned to S_REL
x86/mm/pti: Clone kernel-image on PTE level for 32 bit
x86/mm/pti: Don't clear permissions in pti_clone_pmd()
x86/mm/pti: Fix 32 bit PCID check
x86/mm/init: Remove freed kernel image areas from alias mapping
x86/mm/init: Add helper for freeing kernel image pages
x86/mm/init: Pass unconverted symbol addresses to free_init_pages()
mm: Allow non-direct-map arguments to free_reserved_area()
x86/mm/pti: Clear Global bit more aggressively
x86/speculation: Support Enhanced IBRS on future CPUs
x86/speculation: Protect against userspace-userspace spectreRSB
x86/kexec: Allocate 8k PGDs for PTI
Revert "perf/core: Make sure the ring-buffer is mapped in all page-tables"
x86/mm: Remove in_nmi() warning from vmalloc_fault()
x86/entry/32: Check for VM86 mode in slow-path check
perf/core: Make sure the ring-buffer is mapped in all page-tables
x86/pti: Check the return value of pti_user_pagetable_walk_pmd()
x86/pti: Check the return value of pti_user_pagetable_walk_p4d()
x86/entry/32: Add debug code to check entry/exit CR3
...
Pull x86 vdso update from Thomas Gleixner:
"Use LD to link the VDSO libs instead of indirecting trough CC which
causes build failures with Clang"
* 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86: vdso: Use $LD instead of $CC to link
Pull misc x86 fixes from Thomas Gleixner:
"Two fixes for x86:
- Provide a declaration for native_save_fl() which unbreaks the
wreckage caused by making it 'extern inline'.
- Fix the failing paravirt patching which is supposed to replace
indirect with direct calls. The wreckage is caused by an incorrect
clobber test"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/paravirt: Fix spectre-v2 mitigations for paravirt guests
x86/irqflags: Provide a declaration for native_save_fl
Pull x86 mm updates from Thomas Gleixner:
- Make lazy TLB mode even lazier to avoid pointless switch_mm()
operations, which reduces CPU load by 1-2% for memcache workloads
- Small cleanups and improvements all over the place
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm: Remove redundant check for kmem_cache_create()
arm/asm/tlb.h: Fix build error implicit func declaration
x86/mm/tlb: Make clear_asid_other() static
x86/mm/tlb: Skip atomic operations for 'init_mm' in switch_mm_irqs_off()
x86/mm/tlb: Always use lazy TLB mode
x86/mm/tlb: Only send page table free TLB flush to lazy TLB CPUs
x86/mm/tlb: Make lazy TLB mode lazier
x86/mm/tlb: Restructure switch_mm_irqs_off()
x86/mm/tlb: Leave lazy TLB mode at page table free time
mm: Allocate the mm_cpumask (mm->cpu_bitmap[]) dynamically based on nr_cpu_ids
x86/mm: Add TLB purge to free pmd/pte page interfaces
ioremap: Update pgtable free interfaces with addr
x86/mm: Disable ioremap free page handling on x86-PAE
Pull x86 platform updates from Thomas Gleixner:
"Trivial cleanups and improvements"
* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/platform/UV: Remove redundant check of p == q
x86/platform/olpc: Use PTR_ERR_OR_ZERO()
x86/platform/UV: Mark memblock related init code and data correctly
Pull x86 cache QoS (RDT/CAR) updates from Thomas Gleixner:
"Add support for pseudo-locked cache regions.
Cache Allocation Technology (CAT) allows on certain CPUs to isolate a
region of cache and 'lock' it. Cache pseudo-locking builds on the fact
that a CPU can still read and write data pre-allocated outside its
current allocated area on cache hit. With cache pseudo-locking data
can be preloaded into a reserved portion of cache that no application
can fill, and from that point on will only serve cache hits. The cache
pseudo-locked memory is made accessible to user space where an
application can map it into its virtual address space and thus have a
region of memory with reduced average read latency.
The locking is not perfect and gets totally screwed by WBINDV and
similar mechanisms, but it provides a reasonable enhancement for
certain types of latency sensitive applications.
The implementation extends the current CAT mechanism and provides a
generally useful exclusive CAT mode on which it builds the extra
pseude-locked regions"
* 'x86-cache-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (45 commits)
x86/intel_rdt: Disable PMU access
x86/intel_rdt: Fix possible circular lock dependency
x86/intel_rdt: Make CPU information accessible for pseudo-locked regions
x86/intel_rdt: Support restoration of subset of permissions
x86/intel_rdt: Fix cleanup of plr structure on error
x86/intel_rdt: Move pseudo_lock_region_clear()
x86/intel_rdt: Limit C-states dynamically when pseudo-locking active
x86/intel_rdt: Support L3 cache performance event of Broadwell
x86/intel_rdt: More precise L2 hit/miss measurements
x86/intel_rdt: Create character device exposing pseudo-locked region
x86/intel_rdt: Create debugfs files for pseudo-locking testing
x86/intel_rdt: Create resctrl debug area
x86/intel_rdt: Ensure RDT cleanup on exit
x86/intel_rdt: Resctrl files reflect pseudo-locked information
x86/intel_rdt: Support creation/removal of pseudo-locked region
x86/intel_rdt: Pseudo-lock region creation/removal core
x86/intel_rdt: Discover supported platforms via prefetch disable bits
x86/intel_rdt: Add utilities to test pseudo-locked region possibility
x86/intel_rdt: Split resource group removal in two
x86/intel_rdt: Enable entering of pseudo-locksetup mode
...
Pull x86/hyper-v update from Thomas Gleixner:
"Add fast hypercall support for guest running on the Microsoft HyperV(isor)"
* 'x86-hyperv-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/hyper-v: Fix wrong merge conflict resolution
x86/hyper-v: Check for VP_INVAL in hyperv_flush_tlb_others()
x86/hyper-v: Check cpumask_to_vpset() return value in hyperv_flush_tlb_others_ex()
x86/hyper-v: Trace PV IPI send
x86/hyper-v: Use cheaper HVCALL_SEND_IPI hypercall when possible
x86/hyper-v: Use 'fast' hypercall for HVCALL_SEND_IPI
x86/hyper-v: Implement hv_do_fast_hypercall16
x86/hyper-v: Use cheaper HVCALL_FLUSH_VIRTUAL_ADDRESS_{LIST,SPACE} hypercalls when possible
Pull x86 dump printing cleanup from Thomas Gleixner:
"Clean up the show_opcodes() printout so nested dumps can be properly
differentiated"
* 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86: Avoid pr_cont() in show_opcodes()
Pull x86 cpu updates from Thomas Gleixner:
"Two small updates for the CPU code:
- Improve NUMA emulation
- Add the EPT_AD CPU feature bit"
* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/cpufeatures: Add EPT_AD feature bit
x86/numa_emulation: Introduce uniform split capability
x86/numa_emulation: Fix emulated-to-physical node mapping
Pull x86 cleanups from Thomas Gleixner:
"Trival cleanups"
* 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/iommu: Use NULL instead of 0
x86/platform/pcspeaker: Use PTR_ERR_OR_ZERO() to fix ptr_ret.cocci warning
Pull x86 build cleanup from Thomas Gleixner:
"Remove a stale quirk for a no longer supported GCC version"
* 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/build: Remove old -funit-at-a-time GCC quirk
Pull x86 asm updates from Thomas Gleixner:
"The lowlevel and ASM code updates for x86:
- Make stack trace unwinding more reliable
- ASM instruction updates for better code generation
- Various cleanups"
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/entry/64: Add two more instruction suffixes
x86/asm/64: Use 32-bit XOR to zero registers
x86/build/vdso: Simplify 'cmd_vdso2c'
x86/build/vdso: Remove unused vdso-syms.lds
x86/stacktrace: Enable HAVE_RELIABLE_STACKTRACE for the ORC unwinder
x86/unwind/orc: Detect the end of the stack
x86/stacktrace: Do not fail for ORC with regs on stack
x86/stacktrace: Clarify the reliable success paths
x86/stacktrace: Remove STACKTRACE_DUMP_ONCE
x86/stacktrace: Do not unwind after user regs
x86/asm: Use CC_SET/CC_OUT in percpu_cmpxchg8b_double() to micro-optimize code generation
Pull x86 boot updates from Thomas Gleixner:
"Boot code updates for x86:
- Allow to skip a given amount of huge pages for address layout
randomization on the kernel command line to prevent regressions in
the huge page allocation with small memory sizes
- Various cleanups"
* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/boot: Use CC_SET()/CC_OUT() instead of open coding it
x86/boot/KASLR: Make local variable mem_limit static
x86/boot/KASLR: Skip specified number of 1GB huge pages when doing physical randomization (KASLR)
x86/boot/KASLR: Add two new functions for 1GB huge pages handling
Pull x86 apic update from Thomas Gleixner:
"Trivial cleanups of the APIC related code"
* 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/apic: Trivial coding style fixes
x86/vector: Merge allocate_vector() into assign_vector_locked()
Pull timer updates from Thomas Gleixner:
"The timers departement more or less proudly presents:
- More Y2038 timekeeping work mostly in the core code. The work is
slowly, but steadily targeting the actuall syscalls.
- Enhanced timekeeping suspend/resume support by utilizing
clocksources which do not stop during suspend, but are otherwise
not the main timekeeping clocksources.
- Make NTP adjustmets more accurate and immediate when the frequency
is set directly and not incrementally.
- Sanitize the overrung handing of posix timers
- A new timer driver for Mediatek SoCs
- The usual pile of fixes and updates all over the place"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (32 commits)
clockevents: Warn if cpu_all_mask is used as cpumask
tick/broadcast-hrtimer: Use cpu_possible_mask for ce_broadcast_hrtimer
clocksource/drivers/arm_arch_timer: Fix bogus cpu_all_mask usage
clocksource: ti-32k: Remove CLOCK_SOURCE_SUSPEND_NONSTOP flag
timers: Clear timer_base::must_forward_clk with timer_base::lock held
clocksource/drivers/sprd: Register one always-on timer to compensate suspend time
clocksource/drivers/timer-mediatek: Add support for system timer
clocksource/drivers/timer-mediatek: Convert the driver to timer-of
clocksource/drivers/timer-mediatek: Use specific prefix for GPT
clocksource/drivers/timer-mediatek: Rename mtk_timer to timer-mediatek
clocksource/drivers/timer-mediatek: Add system timer bindings
clocksource/drivers: Set clockevent device cpumask to cpu_possible_mask
time: Introduce one suspend clocksource to compensate the suspend time
time: Fix extra sleeptime injection when suspend fails
timekeeping/ntp: Constify some function arguments
ntp: Use kstrtos64 for s64 variable
ntp: Remove redundant arguments
timer: Fix coding style
ktime: Provide typesafe ktime_to_ns()
hrtimer: Improve kernel message printing
...
Pull perf update from Thomas Gleixner:
"The perf crowd presents:
Kernel updates:
- Removal of jprobes
- Cleanup and consolidatation the handling of kprobes
- Cleanup and consolidation of hardware breakpoints
- The usual pile of fixes and updates to PMUs and event descriptors
Tooling updates:
- Updates and improvements all over the place. Nothing outstanding,
just the (good) boring incremental grump work"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (103 commits)
perf trace: Do not require --no-syscalls to suppress strace like output
perf bpf: Include uapi/linux/bpf.h from the 'perf trace' script's bpf.h
perf tools: Allow overriding MAX_NR_CPUS at compile time
perf bpf: Show better message when failing to load an object
perf list: Unify metric group description format with PMU event description
perf vendor events arm64: Update ThunderX2 implementation defined pmu core events
perf cs-etm: Generate branch sample for CS_ETM_TRACE_ON packet
perf cs-etm: Generate branch sample when receiving a CS_ETM_TRACE_ON packet
perf cs-etm: Support dummy address value for CS_ETM_TRACE_ON packet
perf cs-etm: Fix start tracing packet handling
perf build: Fix installation directory for eBPF
perf c2c report: Fix crash for empty browser
perf tests: Fix indexing when invoking subtests
perf trace: Beautify the AF_INET & AF_INET6 'socket' syscall 'protocol' args
perf trace beauty: Add beautifiers for 'socket''s 'protocol' arg
perf trace beauty: Do not print NULL strarray entries
perf beauty: Add a generator for IPPROTO_ socket's protocol constants
tools include uapi: Grab a copy of linux/in.h
perf tests: Fix complex event name parsing
perf evlist: Fix error out while applying initial delay and LBR
...
Pull locking/atomics update from Thomas Gleixner:
"The locking, atomics and memory model brains delivered:
- A larger update to the atomics code which reworks the ordering
barriers, consolidates the atomic primitives, provides the new
atomic64_fetch_add_unless() primitive and cleans up the include
hell.
- Simplify cmpxchg() instrumentation and add instrumentation for
xchg() and cmpxchg_double().
- Updates to the memory model and documentation"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (48 commits)
locking/atomics: Rework ordering barriers
locking/atomics: Instrument cmpxchg_double*()
locking/atomics: Instrument xchg()
locking/atomics: Simplify cmpxchg() instrumentation
locking/atomics/x86: Reduce arch_cmpxchg64*() instrumentation
tools/memory-model: Rename litmus tests to comply to norm7
tools/memory-model/Documentation: Fix typo, smb->smp
sched/Documentation: Update wake_up() & co. memory-barrier guarantees
locking/spinlock, sched/core: Clarify requirements for smp_mb__after_spinlock()
sched/core: Use smp_mb() in wake_woken_function()
tools/memory-model: Add informal LKMM documentation to MAINTAINERS
locking/atomics/Documentation: Describe atomic_set() as a write operation
tools/memory-model: Make scripts executable
tools/memory-model: Remove ACCESS_ONCE() from model
tools/memory-model: Remove ACCESS_ONCE() from recipes
locking/memory-barriers.txt/kokr: Update Korean translation to fix broken DMA vs. MMIO ordering example
MAINTAINERS: Add Daniel Lustig as an LKMM reviewer
tools/memory-model: Fix ISA2+pooncelock+pooncelock+pombonce name
tools/memory-model: Add litmus test for full multicopy atomicity
locking/refcount: Always allow checked forms
...
Pull CPU hotplug update from Thomas Gleixner:
"A trivial name fix for the hotplug state machine"
* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
cpu/hotplug: Clarify CPU hotplug step name for timers
Pull scheduler updates from Thomas Gleixner:
- Cleanup and improvement of NUMA balancing
- Refactoring and improvements to the PELT (Per Entity Load Tracking)
code
- Watchdog simplification and related cleanups
- The usual pile of small incremental fixes and improvements
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits)
watchdog: Reduce message verbosity
stop_machine: Reflow cpu_stop_queue_two_works()
sched/numa: Move task_numa_placement() closer to numa_migrate_preferred()
sched/numa: Use group_weights to identify if migration degrades locality
sched/numa: Update the scan period without holding the numa_group lock
sched/numa: Remove numa_has_capacity()
sched/numa: Modify migrate_swap() to accept additional parameters
sched/numa: Remove unused task_capacity from 'struct numa_stats'
sched/numa: Skip nodes that are at 'hoplimit'
sched/debug: Reverse the order of printing faults
sched/numa: Use task faults only if numa_group is not yet set up
sched/numa: Set preferred_node based on best_cpu
sched/numa: Simplify load_too_imbalanced()
sched/numa: Evaluate move once per node
sched/numa: Remove redundant field
sched/debug: Show the sum wait time of a task group
sched/fair: Remove #ifdefs from scale_rt_capacity()
sched/core: Remove get_cpu() from sched_fork()
sched/cpufreq: Clarify sugov_get_util()
sched/sysctl: Remove unused sched_time_avg_ms sysctl
...
Pull scheduler fix from Thomas Gleixner:
"A single bugfix to prevent a pinned thread which queues stomp machine
work to be preempted by the stopper thread on its CPU which causes a
live lock as it is unable to wake the second CPUs stopper thread"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
stop_machine: Atomically queue and wake stopper threads
Pull x86 RAS updates from Thomas Gleixner:
"A small set of changes to the RAS core:
- Rework of the MCE bank scanning code
- Y2038 converion"
* 'ras-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mce: Cleanup __mc_scan_banks()
x86/mce: Carve out bank scanning code
x86/mce: Remove !banks check
x86/mce: Carve out the crashing_cpu check
x86/mce: Always use 64-bit timestamps
Pull RCU updates from Thomas Gleixner:
"A large update to RCU:
Preparatory work for consolidating the RCU flavors:
- Introduce grace-period sequence numbers to the RCU-bh, RCU-preempt,
and RCU-sched flavors, replacing the old ->gpnum and ->completed
pair of fields.
This change allows lockless code to obtain the complete
grace-period state with a single READ_ONCE(), which is needed to
maintain tolerable lock contention during the upcoming
consolidation of the three RCU flavors.
Note that grace-period sequence numbers are already used by
rcu_barrier(), expedited RCU grace periods, and SRCU, and are thus
already heavily used and well-tested. Joel Fernandes contributed a
number of excellent fixes and improvements.
- Clean up some grace-period-reporting loose ends, including
improving the handling of quiescent states from offline CPUs and
fixing some false-positive WARN_ON_ONCE() invocations.
(Strictly speaking, the WARN_ON_ONCE() invocations were quite
correct, but their invariants were (harmlessly) violated by the
earlier sloppy handling of quiescent states from offline CPUs.)
In addition, improve grace-period forward-progress guarantees so as
to allow removal of fail-safe checks that required otherwise
needless lock acquisitions. Finally, add more diagnostics to help
debug the upcoming consolidation of the RCU-bh, RCU-preempt, and
RCU-sched flavors.
The rest:
- SRCU updates
- Updates to rcutorture and associated scripting.
- The usual pile of miscellaneous fixes"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (118 commits)
rcutorture: Fix rcu_barrier successes counter
rcutorture: Add support to detect if boost kthread prio is too low
rcutorture: Use monotonic timestamp for stall detection
rcutorture: Make boost test more robust
rcutorture: Disable RT throttling for boost tests
rcutorture: Emphasize testing of single reader protection type
rcutorture: Handle extended read-side critical sections
rcutorture: Make rcu_torture_timer() use rcu_torture_one_read()
rcutorture: Use per-CPU random state for rcu_torture_timer()
rcutorture: Use atomic increment for n_rcu_torture_timers
rcutorture: Extract common code from rcu_torture_reader()
rcuperf: Remove unused torturing_tasks() function
rcu: Remove rcutorture test version and sequence number
rcutorture: Change units of onoff_interval to jiffies
rcu: Assign higher prio to RCU threads if rcutorture is built-in
rculist: Improve documentation for list_for_each_entry_from_rcu()
srcu: Add grace-period number to rcutorture statistics printout
rcu: Print stall-warning NMI dyntick state in hexadecimal
MAINTAINERS: Update RCU, SRCU, and TORTURE-TEST entries
rcu: Make rcu_seq_diff() more exact
...
Pull genirq updates from Thomas Gleixner:
"The irq departement provides:
- A synchronization fix for free_irq() to synchronize just the
removed interrupt thread on shared interrupt lines.
- Consolidate the multi low level interrupt entry handling and mvoe
it to the generic code instead of adding yet another copy for
RISC-V
- Refactoring of the ARM LPI allocator and LPI exposure to the
hypervisor
- Yet another interrupt chip driver for the JZ4725B SoC
- Speed up for /proc/interrupts as people seem to love reading this
file with high frequency
- Miscellaneous fixes and updates"
* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
irqchip/gic-v3-its: Make its_lock a raw_spin_lock_t
genirq/irqchip: Remove MULTI_IRQ_HANDLER as it's now obselete
openrisc: Use the new GENERIC_IRQ_MULTI_HANDLER
arm64: Use the new GENERIC_IRQ_MULTI_HANDLER
ARM: Convert to GENERIC_IRQ_MULTI_HANDLER
irqchip: Port the ARM IRQ drivers to GENERIC_IRQ_MULTI_HANDLER
irqchip/gic-v3-its: Reduce minimum LPI allocation to 1 for PCI devices
dt-bindings: irqchip: renesas-irqc: Document r8a77980 support
dt-bindings: irqchip: renesas-irqc: Document r8a77470 support
irqchip/ingenic: Add support for the JZ4725B SoC
irqchip/stm32: Add exti0 translation for stm32mp1
genirq: Remove redundant NULL pointer check in __free_irq()
irqchip/gic-v3-its: Honor hypervisor enforced LPI range
irqchip/gic-v3: Expose GICD_TYPER in the rdist structure
irqchip/gic-v3-its: Drop chunk allocation compatibility
irqchip/gic-v3-its: Move minimum LPI requirements to individual busses
irqchip/gic-v3-its: Use full range of LPIs
irqchip/gic-v3-its: Refactor LPI allocator
genirq: Synchronize only with single thread on free_irq()
genirq: Update code comments wrt recycled thread_mask
...
Pull EFI updates from Thomas Gleixner:
"The EFI pile:
- Make mixed mode UEFI runtime service invocations mutually
exclusive, as mandated by the UEFI spec
- Perform UEFI runtime services calls from a work queue so the calls
into the firmware occur from a kernel thread
- Honor the UEFI memory map attributes for live memory regions
configured by UEFI as a framebuffer. This works around a coherency
problem with KVM guests running on ARM.
- Cleanups, improvements and fixes all over the place"
* 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
efivars: Call guid_parse() against guid_t type of variable
efi/cper: Use consistent types for UUIDs
efi/x86: Replace references to efi_early->is64 with efi_is_64bit()
efi: Deduplicate efi_open_volume()
efi/x86: Add missing NULL initialization in UGA draw protocol discovery
efi/x86: Merge 32-bit and 64-bit UGA draw protocol setup routines
efi/x86: Align efi_uga_draw_protocol typedef names to convention
efi/x86: Merge the setup_efi_pci32() and setup_efi_pci64() routines
efi/x86: Prevent reentrant firmware calls in mixed mode
efi/esrt: Only call efi_mem_reserve() for boot services memory
fbdev/efifb: Honour UEFI memory map attributes when mapping the FB
efi: Drop type and attribute checks in efi_mem_desc_lookup()
efi/libstub/arm: Add opt-in Kconfig option for the DTB loader
efi: Remove the declaration of efi_late_init() as the function is unused
efi/cper: Avoid using get_seconds()
efi: Use a work queue to invoke EFI Runtime Services
efi/x86: Use non-blocking SetVariable() for efi_delete_dummy_variable()
efi/x86: Clean up the eboot code
Pull debugobjects update from Thomas Gleixner:
"Two simple updates for the debug objects code:
- Make the stack check warning more informative by adding the object
and the stack page address to the printout
- Remove a redundant NULL pointer check"
* 'core-debugobjects-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
debugobjects: Remove redundant NULL pointer check
debugobjects: Make stack check warning more informative
- Enable mac_scsi PDMA on PowerBook 500,
- Generic dma_noncoherent_ops conversion,
- Time handling improvements,
- I/O accessor improvements,
- Conversion to MEMBLOCK and NO_BOOTMEM, to bring m68k in line with
other mainstream architectures,
- Miscellaneous fixes and cleanups,
- Defconfig updates.
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Merge tag 'm68k-for-v4.19-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k
Pull m68k updates from Geert Uytterhoeven:
- Enable mac_scsi PDMA on PowerBook 500
- Generic dma_noncoherent_ops conversion
- Time handling improvements
- I/O accessor improvements
- Conversion to MEMBLOCK and NO_BOOTMEM, to bring m68k in line with
other mainstream architectures
- Miscellaneous fixes and cleanups
- Defconfig updates
* tag 'm68k-for-v4.19-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k:
m68k/defconfig: Update defconfigs for v4.18-rc6
m68k: switch to MEMBLOCK + NO_BOOTMEM
m68k/page_no.h: force __va argument to be unsigned long
m68k/bitops: convert __ffs to match generic declaration
m68k/io: Switch mmu variant to <asm-generic/io.h>
m68k/io: Move mem*io define guards to <asm/kmap.h>
Input: hilkbd - Add casts to HP9000/300 I/O accessors
net: mac8390: Use standard memcpy_{from,to}io()
m68k/io: Add missing ioremap define guards, fix typo
m68k: Remove unused set_clock_mmss() helpers
m68k: mac: Use time64_t in RTC handling
m68k: Use generic dma_noncoherent_ops
nubus: Set default dma mask for nubus_board devices
m68k/mac: Enable PDMA for PowerBook 500 series
Eight fixes. The most important one is the mpt3sas fix which makes
the driver work again on big endian systems. The rest are mostly
minor error path or checker issues and the vmw_scsi one fixes a
performance problem.
Signed-off-by: James E.J. Bottomley <jejb@linux.vnet.ibm.com>
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Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Pull SCSI fixes from James Bottomley:
"Eight fixes.
The most important one is the mpt3sas fix which makes the driver work
again on big endian systems. The rest are mostly minor error path or
checker issues and the vmw_scsi one fixes a performance problem"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: vmw_pvscsi: Return DID_RESET for status SAM_STAT_COMMAND_TERMINATED
scsi: sr: Avoid that opening a CD-ROM hangs with runtime power management enabled
scsi: mpt3sas: Swap I/O memory read value back to cpu endianness
scsi: fcoe: clear FC_RP_STARTED flags when receiving a LOGO
scsi: fcoe: drop frames in ELS LOGO error path
scsi: fcoe: fix use-after-free in fcoe_ctlr_els_send
scsi: qedi: Fix a potential buffer overflow
scsi: qla2xxx: Fix memory leak for allocating abort IOCB
This is purely a preparatory patch for upcoming changes during the 4.19
merge window.
We have a function called "boot_cpu_state_init()" that isn't really
about the bootup cpu state: that is done much earlier by the similarly
named "boot_cpu_init()" (note lack of "state" in name).
This function initializes some hotplug CPU state, and needs to run after
the percpu data has been properly initialized. It even has a comment to
that effect.
Except it _doesn't_ actually run after the percpu data has been properly
initialized. On x86 it happens to do that, but on at least arm and
arm64, the percpu base pointers are initialized by the arch-specific
'smp_prepare_boot_cpu()' hook, which ran _after_ boot_cpu_state_init().
This had some unexpected results, and in particular we have a patch
pending for the merge window that did the obvious cleanup of using
'this_cpu_write()' in the cpu hotplug init code:
- per_cpu_ptr(&cpuhp_state, smp_processor_id())->state = CPUHP_ONLINE;
+ this_cpu_write(cpuhp_state.state, CPUHP_ONLINE);
which is obviously the right thing to do. Except because of the
ordering issue, it actually failed miserably and unexpectedly on arm64.
So this just fixes the ordering, and changes the name of the function to
be 'boot_cpu_hotplug_init()' to make it obvious that it's about cpu
hotplug state, because the core CPU state was supposed to have already
been done earlier.
Marked for stable, since the (not yet merged) patch that will show this
problem is marked for stable.
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull vfs fixes from Al Viro:
"A bunch of race fixes, mostly around lazy pathwalk.
All of it is -stable fodder, a large part going back to 2013"
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
make sure that __dentry_kill() always invalidates d_seq, unhashed or not
fix __legitimize_mnt()/mntput() race
fix mntput/mntput race
root dentries need RCU-delayed freeing
Pull networking fixes from David Miller:
"Last bit of straggler fixes...
1) Fix btf library licensing to LGPL, from Martin KaFai lau.
2) Fix error handling in bpf sockmap code, from Daniel Borkmann.
3) XDP cpumap teardown handling wrt. execution contexts, from Jesper
Dangaard Brouer.
4) Fix loss of runtime PM on failed vlan add/del, from Ivan
Khoronzhuk.
5) xen-netfront caches skb_shinfo(skb) across a __pskb_pull_tail()
call, which potentially changes the skb's data buffer, and thus
skb_shinfo(). Fix from Juergen Gross"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
xen/netfront: don't cache skb_shinfo()
net: ethernet: ti: cpsw: fix runtime_pm while add/kill vlan
net: ethernet: ti: cpsw: clear all entries when delete vid
xdp: fix bug in devmap teardown code path
samples/bpf: xdp_redirect_cpu adjustment to reproduce teardown race easier
xdp: fix bug in cpumap teardown code path
bpf, sockmap: fix cork timeout for select due to epipe
bpf, sockmap: fix leak in bpf_tcp_sendmsg wait for mem path
bpf, sockmap: fix bpf_tcp_sendmsg sock error handling
bpf: btf: Change tools/lib/bpf/btf to LGPL
skb_shinfo() can change when calling __pskb_pull_tail(): Don't cache
its return value.
Cc: stable@vger.kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Grygorii Strashko says:
====================
net: ethernet: ti: cpsw: fix runtime pm while add/del reserved vid
Here 2 not critical fixes for:
- vlan ale table leak while error if deleting vlan (simplifies next fix)
- runtime pm while try to set reserved vlan
====================
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It's exclusive with normal behaviour but if try to set vlan to one of
the reserved values is made, the cpsw runtime pm is broken.
Fixes: a6c5d14f51 ("drivers: net: cpsw: ndev: fix accessing to suspended device")
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
In cases if some of the entries were not found in forwarding table
while killing vlan, the rest not needed entries still left in the
table. No need to stop, as entry was deleted anyway. So fix this by
returning error only after all was cleaned. To implement this, return
-ENOENT in cpsw_ale_del_mcast() as it's supposed to be.
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
If zram supports writeback feature, it's no longer a
BD_CAP_SYNCHRONOUS_IO device beause zram does asynchronous IO operations
for incompressible pages.
Do not pretend to be synchronous IO device. It makes the system very
sluggish due to waiting for IO completion from upper layers.
Furthermore, it causes a user-after-free problem because swap thinks the
opearion is done when the IO functions returns so it can free the page
(e.g., lock_page_or_retry and goto out_release in do_swap_page) but in
fact, IO is asynchronous so the driver could access a just freed page
afterward.
This patch fixes the problem.
BUG: Bad page state in process qemu-system-x86 pfn:3dfab21
page:ffffdfb137eac840 count:0 mapcount:0 mapping:0000000000000000 index:0x1
flags: 0x17fffc000000008(uptodate)
raw: 017fffc000000008 dead000000000100 dead000000000200 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: PAGE_FLAGS_CHECK_AT_PREP flag set
bad because of flags: 0x8(uptodate)
CPU: 4 PID: 1039 Comm: qemu-system-x86 Tainted: G B 4.18.0-rc5+ #1
Hardware name: Supermicro Super Server/X10SRL-F, BIOS 2.0b 05/02/2017
Call Trace:
dump_stack+0x5c/0x7b
bad_page+0xba/0x120
get_page_from_freelist+0x1016/0x1250
__alloc_pages_nodemask+0xfa/0x250
alloc_pages_vma+0x7c/0x1c0
do_swap_page+0x347/0x920
__handle_mm_fault+0x7b4/0x1110
handle_mm_fault+0xfc/0x1f0
__get_user_pages+0x12f/0x690
get_user_pages_unlocked+0x148/0x1f0
__gfn_to_pfn_memslot+0xff/0x3c0 [kvm]
try_async_pf+0x87/0x230 [kvm]
tdp_page_fault+0x132/0x290 [kvm]
kvm_mmu_page_fault+0x74/0x570 [kvm]
kvm_arch_vcpu_ioctl_run+0x9b3/0x1990 [kvm]
kvm_vcpu_ioctl+0x388/0x5d0 [kvm]
do_vfs_ioctl+0xa2/0x630
ksys_ioctl+0x70/0x80
__x64_sys_ioctl+0x16/0x20
do_syscall_64+0x55/0x100
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Link: https://lore.kernel.org/lkml/0516ae2d-b0fd-92c5-aa92-112ba7bd32fc@contabo.de/
Link: http://lkml.kernel.org/r/20180802051112.86174-1-minchan@kernel.org
[minchan@kernel.org: fix changelog, add comment]
Link: https://lore.kernel.org/lkml/0516ae2d-b0fd-92c5-aa92-112ba7bd32fc@contabo.de/
Link: http://lkml.kernel.org/r/20180802051112.86174-1-minchan@kernel.org
Link: http://lkml.kernel.org/r/20180805233722.217347-1-minchan@kernel.org
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reported-by: Tino Lehnig <tino.lehnig@contabo.de>
Tested-by: Tino Lehnig <tino.lehnig@contabo.de>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: <stable@vger.kernel.org> [4.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ioremap_prot() can return NULL which could lead to an oops.
Link: http://lkml.kernel.org/r/1533195441-58594-1-git-send-email-chenjie6@huawei.com
Signed-off-by: chen jie <chenjie6@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: chenjie <chenjie6@huawei.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With gcc-8 fsanitize=null become very noisy. GCC started to complain
about things like &a->b, where 'a' is NULL pointer. There is no NULL
dereference, we just calculate address to struct member. It's
technically undefined behavior so UBSAN is correct to report it. But as
long as there is no real NULL-dereference, I think, we should be fine.
-fno-delete-null-pointer-checks compiler flag should protect us from any
consequences. So let's just no use -fsanitize=null as it's not useful
for us. If there is a real NULL-deref we will see crash. Even if
userspace mapped something at NULL (root can do this), with things like
SMAP should catch the issue.
Link: http://lkml.kernel.org/r/20180802153209.813-1-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This entry was created with my personal e-mail address. Update this entry
to my open-source kernel.org account.
Link: http://lkml.kernel.org/r/20180806143904.4716-4-kieran.bingham@ideasonboard.com
Signed-off-by: Kieran Bingham <kbingham@kernel.org>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The user page-table gets the updated kernel mappings in pti_finalize(),
which runs after the RO+X permissions got applied to the kernel page-table
in mark_readonly().
But with CONFIG_DEBUG_WX enabled, the user page-table is already checked in
mark_readonly() for insecure mappings. This causes false-positive
warnings, because the user page-table did not get the updated mappings yet.
Move the W+X check for the user page-table into pti_finalize() after it
updated all required mappings.
[ tglx: Folded !NX supported fix ]
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Waiman Long <llong@redhat.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "David H . Gutteridge" <dhgutteridge@sympatico.ca>
Cc: joro@8bytes.org
Link: https://lkml.kernel.org/r/1533727000-9172-1-git-send-email-joro@8bytes.org
Pull i2c fix from Wolfram Sang:
"A single driver bugfix for I2C.
The bug was found by systematically stress testing the driver, so I am
confident to merge it that late in the cycle although it is probably
unusually large"
* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
i2c: xlp9xx: Fix case where SSIF read transaction completes early
Daniel Borkmann says:
====================
pull-request: bpf 2018-08-10
The following pull-request contains BPF updates for your *net* tree.
The main changes are:
1) Fix cpumap and devmap on teardown as they're under RCU context
and won't have same assumption as running under NAPI protection,
from Jesper.
2) Fix various sockmap bugs in bpf_tcp_sendmsg() code, e.g. we had
a bug where socket error was not propagated correctly, from Daniel.
3) Fix incompatible libbpf header license for BTF code and match it
before it gets officially released with the rest of libbpf which
is LGPL-2.1, from Martin.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
RCU pathwalk relies upon the assumption that anything that changes
->d_inode of a dentry will invalidate its ->d_seq. That's almost
true - the one exception is that the final dput() of already unhashed
dentry does *not* touch ->d_seq at all. Unhashing does, though,
so for anything we'd found by RCU dcache lookup we are fine.
Unfortunately, we can *start* with an unhashed dentry or jump into
it.
We could try and be careful in the (few) places where that could
happen. Or we could just make the final dput() invalidate the damn
thing, unhashed or not. The latter is much simpler and easier to
backport, so let's do it that way.
Reported-by: "Dae R. Jeong" <threeearcat@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
__legitimize_mnt() has two problems - one is that in case of success
the check of mount_lock is not ordered wrt preceding increment of
refcount, making it possible to have successful __legitimize_mnt()
on one CPU just before the otherwise final mntpu() on another,
with __legitimize_mnt() not seeing mntput() taking the lock and
mntput() not seeing the increment done by __legitimize_mnt().
Solved by a pair of barriers.
Another is that failure of __legitimize_mnt() on the second
read_seqretry() leaves us with reference that'll need to be
dropped by caller; however, if that races with final mntput()
we can end up with caller dropping rcu_read_lock() and doing
mntput() to release that reference - with the first mntput()
having freed the damn thing just as rcu_read_lock() had been
dropped. Solution: in "do mntput() yourself" failure case
grab mount_lock, check if MNT_DOOMED has been set by racing
final mntput() that has missed our increment and if it has -
undo the increment and treat that as "failure, caller doesn't
need to drop anything" case.
It's not easy to hit - the final mntput() has to come right
after the first read_seqretry() in __legitimize_mnt() *and*
manage to miss the increment done by __legitimize_mnt() before
the second read_seqretry() in there. The things that are almost
impossible to hit on bare hardware are not impossible on SMP
KVM, though...
Reported-by: Oleg Nesterov <oleg@redhat.com>
Fixes: 48a066e72d ("RCU'd vsfmounts")
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
mntput_no_expire() does the calculation of total refcount under mount_lock;
unfortunately, the decrement (as well as all increments) are done outside
of it, leading to false positives in the "are we dropping the last reference"
test. Consider the following situation:
* mnt is a lazy-umounted mount, kept alive by two opened files. One
of those files gets closed. Total refcount of mnt is 2. On CPU 42
mntput(mnt) (called from __fput()) drops one reference, decrementing component
* After it has looked at component #0, the process on CPU 0 does
mntget(), incrementing component #0, gets preempted and gets to run again -
on CPU 69. There it does mntput(), which drops the reference (component #69)
and proceeds to spin on mount_lock.
* On CPU 42 our first mntput() finishes counting. It observes the
decrement of component #69, but not the increment of component #0. As the
result, the total it gets is not 1 as it should've been - it's 0. At which
point we decide that vfsmount needs to be killed and proceed to free it and
shut the filesystem down. However, there's still another opened file
on that filesystem, with reference to (now freed) vfsmount, etc. and we are
screwed.
It's not a wide race, but it can be reproduced with artificial slowdown of
the mnt_get_count() loop, and it should be easier to hit on SMP KVM setups.
Fix consists of moving the refcount decrement under mount_lock; the tricky
part is that we want (and can) keep the fast case (i.e. mount that still
has non-NULL ->mnt_ns) entirely out of mount_lock. All places that zero
mnt->mnt_ns are dropping some reference to mnt and they call synchronize_rcu()
before that mntput(). IOW, if mntput() observes (under rcu_read_lock())
a non-NULL ->mnt_ns, it is guaranteed that there is another reference yet to
be dropped.
Reported-by: Jann Horn <jannh@google.com>
Tested-by: Jann Horn <jannh@google.com>
Fixes: 48a066e72d ("RCU'd vsfmounts")
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Jesper Dangaard Brouer says:
====================
Removing entries from cpumap and devmap, goes through a number of
syncronization steps to make sure no new xdp_frames can be enqueued.
But there is a small chance, that xdp_frames remains which have not
been flushed/processed yet. Flushing these during teardown, happens
from RCU context and not as usual under RX NAPI context.
The optimization introduced in commt 389ab7f01a ("xdp: introduce
xdp_return_frame_rx_napi"), missed that the flush operation can also
be called from RCU context. Thus, we cannot always use the
xdp_return_frame_rx_napi call, which take advantage of the protection
provided by XDP RX running under NAPI protection.
The samples/bpf xdp_redirect_cpu have a --stress-mode, that is
adjusted to easier reproduce (verified by Red Hat QA).
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Linus Torvalds
Russell King
Juergen Gross
David S. Miller
Ivan Khoronzhuk
Minchan Kim
jie@chenjie6@huwei.com
Andrey Ryabinin
Kieran Bingham
Joerg Roedel
Al Viro
Daniel Borkmann