kernel/linux.git, branch v4.9.257

Linux 4.9.257

2021-02-10T08:09:27+00:00

Tested-by: Florian Fainelli Tested-by: Shuah Khan Tested-by: Linux Kernel Functional Testing Tested-by: Igor Matheus Andrade Torrente Tested-by: Jason Self Tested-by: Guenter Roeck Tested-by: Ross Schmidt Link: https://lore.kernel.org/r/20210208145810.230485165@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman

ALSA: hda/realtek - Fix typo of pincfg for Dell quirk

2021-02-10T08:09:27+00:00

commit b4576de87243c32fab50dda9f8eba1e3cf13a7e2 upstream. The PIN number for Dell headset mode of ALC3271 is wrong. Fixes: fcc6c877a01f ("ALSA: hda/realtek - Support Dell headset mode for ALC3271") Signed-off-by: Shih-Yuan Lee (FourDollars) Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

iommu/vt-d: Do not use flush-queue when caching-mode is on

2021-02-10T08:09:27+00:00

commit 29b32839725f8c89a41cb6ee054c85f3116ea8b5 upstream. When an Intel IOMMU is virtualized, and a physical device is passed-through to the VM, changes of the virtual IOMMU need to be propagated to the physical IOMMU. The hypervisor therefore needs to monitor PTE mappings in the IOMMU page-tables. Intel specifications provide "caching-mode" capability that a virtual IOMMU uses to report that the IOMMU is virtualized and a TLB flush is needed after mapping to allow the hypervisor to propagate virtual IOMMU mappings to the physical IOMMU. To the best of my knowledge no real physical IOMMU reports "caching-mode" as turned on. Synchronizing the virtual and the physical IOMMU tables is expensive if the hypervisor is unaware which PTEs have changed, as the hypervisor is required to walk all the virtualized tables and look for changes. Consequently, domain flushes are much more expensive than page-specific flushes on virtualized IOMMUs with passthrough devices. The kernel therefore exploited the "caching-mode" indication to avoid domain flushing and use page-specific flushing in virtualized environments. See commit 78d5f0f500e6 ("intel-iommu: Avoid global flushes with caching mode.") This behavior changed after commit 13cf01744608 ("iommu/vt-d: Make use of iova deferred flushing"). Now, when batched TLB flushing is used (the default), full TLB domain flushes are performed frequently, requiring the hypervisor to perform expensive synchronization between the virtual TLB and the physical one. Getting batched TLB flushes to use page-specific invalidations again in such circumstances is not easy, since the TLB invalidation scheme assumes that "full" domain TLB flushes are performed for scalability. Disable batched TLB flushes when caching-mode is on, as the performance benefit from using batched TLB invalidations is likely to be much smaller than the overhead of the virtual-to-physical IOMMU page-tables synchronization. Fixes: 13cf01744608 ("iommu/vt-d: Make use of iova deferred flushing") Signed-off-by: Nadav Amit Cc: David Woodhouse Cc: Lu Baolu Cc: Joerg Roedel Cc: Will Deacon Cc: stable@vger.kernel.org Acked-by: Lu Baolu Link: https://lore.kernel.org/r/20210127175317.1600473-1-namit@vmware.com Signed-off-by: Joerg Roedel Signed-off-by: Nadav Amit Signed-off-by: Greg Kroah-Hartman

ACPI: thermal: Do not call acpi_thermal_check() directly

2021-02-10T08:09:27+00:00

commit 81b704d3e4674e09781d331df73d76675d5ad8cb upstream. Calling acpi_thermal_check() from acpi_thermal_notify() directly is problematic if _TMP triggers Notify () on the thermal zone for which it has been evaluated (which happens on some systems), because it causes a new acpi_thermal_notify() invocation to be queued up every time and if that takes place too often, an indefinite number of pending work items may accumulate in kacpi_notify_wq over time. Besides, it is not really useful to queue up a new invocation of acpi_thermal_check() if one of them is pending already. For these reasons, rework acpi_thermal_notify() to queue up a thermal check instead of calling acpi_thermal_check() directly and only allow one thermal check to be pending at a time. Moreover, only allow one acpi_thermal_check_fn() instance at a time to run thermal_zone_device_update() for one thermal zone and make it return early if it sees other instances running for the same thermal zone. While at it, fold acpi_thermal_check() into acpi_thermal_check_fn(), as it is only called from there after the other changes made here. [This issue appears to have been exposed by commit 6d25be5782e4 ("sched/core, workqueues: Distangle worker accounting from rq lock"), but it is unclear why it was not visible earlier.] BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=208877 Reported-by: Stephen Berman Diagnosed-by: Sebastian Andrzej Siewior Signed-off-by: Rafael J. Wysocki Reviewed-by: Sebastian Andrzej Siewior Tested-by: Stephen Berman Cc: All applicable [bigeasy: Backported to v4.9.y, use atomic_t instead of refcount_t] Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Greg Kroah-Hartman

Input: xpad - sync supported devices with fork on GitHub

2021-02-10T08:09:27+00:00

commit 9bbd77d5bbc9aff8cb74d805c31751f5f0691ba8 upstream. There is a fork of this driver on GitHub [0] that has been updated with new device IDs. Merge those into the mainline driver, so the out-of-tree fork is not needed for users of those devices anymore. [0] https://github.com/paroj/xpad Signed-off-by: Benjamin Valentin Link: https://lore.kernel.org/r/20210121142523.1b6b050f@rechenknecht2k11 Signed-off-by: Dmitry Torokhov Signed-off-by: Greg Kroah-Hartman

x86/apic: Add extra serialization for non-serializing MSRs

2021-02-10T08:09:27+00:00

commit 25a068b8e9a4eb193d755d58efcb3c98928636e0 upstream. Jan Kiszka reported that the x2apic_wrmsr_fence() function uses a plain MFENCE while the Intel SDM (10.12.3 MSR Access in x2APIC Mode) calls for MFENCE; LFENCE. Short summary: we have special MSRs that have weaker ordering than all the rest. Add fencing consistent with current SDM recommendations. This is not known to cause any issues in practice, only in theory. Longer story below: The reason the kernel uses a different semantic is that the SDM changed (roughly in late 2017). The SDM changed because folks at Intel were auditing all of the recommended fences in the SDM and realized that the x2apic fences were insufficient. Why was the pain MFENCE judged insufficient? WRMSR itself is normally a serializing instruction. No fences are needed because the instruction itself serializes everything. But, there are explicit exceptions for this serializing behavior written into the WRMSR instruction documentation for two classes of MSRs: IA32_TSC_DEADLINE and the X2APIC MSRs. Back to x2apic: WRMSR is *not* serializing in this specific case. But why is MFENCE insufficient? MFENCE makes writes visible, but only affects load/store instructions. WRMSR is unfortunately not a load/store instruction and is unaffected by MFENCE. This means that a non-serializing WRMSR could be reordered by the CPU to execute before the writes made visible by the MFENCE have even occurred in the first place. This means that an x2apic IPI could theoretically be triggered before there is any (visible) data to process. Does this affect anything in practice? I honestly don't know. It seems quite possible that by the time an interrupt gets to consume the (not yet) MFENCE'd data, it has become visible, mostly by accident. To be safe, add the SDM-recommended fences for all x2apic WRMSRs. This also leaves open the question of the _other_ weakly-ordered WRMSR: MSR_IA32_TSC_DEADLINE. While it has the same ordering architecture as the x2APIC MSRs, it seems substantially less likely to be a problem in practice. While writes to the in-memory Local Vector Table (LVT) might theoretically be reordered with respect to a weakly-ordered WRMSR like TSC_DEADLINE, the SDM has this to say: In x2APIC mode, the WRMSR instruction is used to write to the LVT entry. The processor ensures the ordering of this write and any subsequent WRMSR to the deadline; no fencing is required. But, that might still leave xAPIC exposed. The safest thing to do for now is to add the extra, recommended LFENCE. [ bp: Massage commit message, fix typos, drop accidentally added newline to tools/arch/x86/include/asm/barrier.h. ] Reported-by: Jan Kiszka Signed-off-by: Dave Hansen Signed-off-by: Borislav Petkov Acked-by: Peter Zijlstra (Intel) Acked-by: Thomas Gleixner Cc: Link: https://lkml.kernel.org/r/20200305174708.F77040DD@viggo.jf.intel.com Signed-off-by: Greg Kroah-Hartman

x86/build: Disable CET instrumentation in the kernel

2021-02-10T08:09:26+00:00

commit 20bf2b378729c4a0366a53e2018a0b70ace94bcd upstream. With retpolines disabled, some configurations of GCC, and specifically the GCC versions 9 and 10 in Ubuntu will add Intel CET instrumentation to the kernel by default. That breaks certain tracing scenarios by adding a superfluous ENDBR64 instruction before the fentry call, for functions which can be called indirectly. CET instrumentation isn't currently necessary in the kernel, as CET is only supported in user space. Disable it unconditionally and move it into the x86's Makefile as CET/CFI... enablement should be a per-arch decision anyway. [ bp: Massage and extend commit message. ] Fixes: 29be86d7f9cb ("kbuild: add -fcf-protection=none when using retpoline flags") Reported-by: Nikolay Borisov Signed-off-by: Josh Poimboeuf Signed-off-by: Borislav Petkov Reviewed-by: Nikolay Borisov Tested-by: Nikolay Borisov Cc: Cc: Seth Forshee Cc: Masahiro Yamada Link: https://lkml.kernel.org/r/20210128215219.6kct3h2eiustncws@treble Signed-off-by: Greg Kroah-Hartman

mm: thp: fix MADV_REMOVE deadlock on shmem THP

2021-02-10T08:09:26+00:00

commit 1c2f67308af4c102b4e1e6cd6f69819ae59408e0 upstream. Sergey reported deadlock between kswapd correctly doing its usual lock_page(page) followed by down_read(page->mapping->i_mmap_rwsem), and madvise(MADV_REMOVE) on an madvise(MADV_HUGEPAGE) area doing down_write(page->mapping->i_mmap_rwsem) followed by lock_page(page). This happened when shmem_fallocate(punch hole)'s unmap_mapping_range() reaches zap_pmd_range()'s call to __split_huge_pmd(). The same deadlock could occur when partially truncating a mapped huge tmpfs file, or using fallocate(FALLOC_FL_PUNCH_HOLE) on it. __split_huge_pmd()'s page lock was added in 5.8, to make sure that any concurrent use of reuse_swap_page() (holding page lock) could not catch the anon THP's mapcounts and swapcounts while they were being split. Fortunately, reuse_swap_page() is never applied to a shmem or file THP (not even by khugepaged, which checks PageSwapCache before calling), and anonymous THPs are never created in shmem or file areas: so that __split_huge_pmd()'s page lock can only be necessary for anonymous THPs, on which there is no risk of deadlock with i_mmap_rwsem. Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2101161409470.2022@eggly.anvils Fixes: c444eb564fb1 ("mm: thp: make the THP mapcount atomic against __split_huge_pmd_locked()") Signed-off-by: Hugh Dickins Reported-by: Sergey Senozhatsky Reviewed-by: Andrea Arcangeli Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm: hugetlb: remove VM_BUG_ON_PAGE from page_huge_active

2021-02-10T08:09:26+00:00

commit ecbf4724e6061b4b01be20f6d797d64d462b2bc8 upstream. The page_huge_active() can be called from scan_movable_pages() which do not hold a reference count to the HugeTLB page. So when we call page_huge_active() from scan_movable_pages(), the HugeTLB page can be freed parallel. Then we will trigger a BUG_ON which is in the page_huge_active() when CONFIG_DEBUG_VM is enabled. Just remove the VM_BUG_ON_PAGE. Link: https://lkml.kernel.org/r/20210115124942.46403-6-songmuchun@bytedance.com Fixes: 7e1f049efb86 ("mm: hugetlb: cleanup using paeg_huge_active()") Signed-off-by: Muchun Song Reviewed-by: Mike Kravetz Acked-by: Michal Hocko Reviewed-by: Oscar Salvador Cc: David Hildenbrand Cc: Yang Shi Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm: hugetlb: fix a race between isolating and freeing page

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commit 0eb2df2b5629794020f75e94655e1994af63f0d4 upstream. There is a race between isolate_huge_page() and __free_huge_page(). CPU0: CPU1: if (PageHuge(page)) put_page(page) __free_huge_page(page) spin_lock(&hugetlb_lock) update_and_free_page(page) set_compound_page_dtor(page, NULL_COMPOUND_DTOR) spin_unlock(&hugetlb_lock) isolate_huge_page(page) // trigger BUG_ON VM_BUG_ON_PAGE(!PageHead(page), page) spin_lock(&hugetlb_lock) page_huge_active(page) // trigger BUG_ON VM_BUG_ON_PAGE(!PageHuge(page), page) spin_unlock(&hugetlb_lock) When we isolate a HugeTLB page on CPU0. Meanwhile, we free it to the buddy allocator on CPU1. Then, we can trigger a BUG_ON on CPU0, because it is already freed to the buddy allocator. Link: https://lkml.kernel.org/r/20210115124942.46403-5-songmuchun@bytedance.com Fixes: c8721bbbdd36 ("mm: memory-hotplug: enable memory hotplug to handle hugepage") Signed-off-by: Muchun Song Reviewed-by: Mike Kravetz Acked-by: Michal Hocko Reviewed-by: Oscar Salvador Cc: David Hildenbrand Cc: Yang Shi Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman