1. 21 Apr, 2022 8 commits
    • Sean Christopherson's avatar
      KVM: x86: Pend KVM_REQ_APICV_UPDATE during vCPU creation to fix a race · 423ecfea
      Sean Christopherson authored
      Make a KVM_REQ_APICV_UPDATE request when creating a vCPU with an
      in-kernel local APIC and APICv enabled at the module level.  Consuming
      kvm_apicv_activated() and stuffing vcpu->arch.apicv_active directly can
      race with __kvm_set_or_clear_apicv_inhibit(), as vCPU creation happens
      before the vCPU is fully onlined, i.e. it won't get the request made to
      "all" vCPUs.  If APICv is globally inhibited between setting apicv_active
      and onlining the vCPU, the vCPU will end up running with APICv enabled
      and trigger KVM's sanity check.
      
      Mark APICv as active during vCPU creation if APICv is enabled at the
      module level, both to be optimistic about it's final state, e.g. to avoid
      additional VMWRITEs on VMX, and because there are likely bugs lurking
      since KVM checks apicv_active in multiple vCPU creation paths.  While
      keeping the current behavior of consuming kvm_apicv_activated() is
      arguably safer from a regression perspective, force apicv_active so that
      vCPU creation runs with deterministic state and so that if there are bugs,
      they are found sooner than later, i.e. not when some crazy race condition
      is hit.
      
        WARNING: CPU: 0 PID: 484 at arch/x86/kvm/x86.c:9877 vcpu_enter_guest+0x2ae3/0x3ee0 arch/x86/kvm/x86.c:9877
        Modules linked in:
        CPU: 0 PID: 484 Comm: syz-executor361 Not tainted 5.16.13 #2
        Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1~cloud0 04/01/2014
        RIP: 0010:vcpu_enter_guest+0x2ae3/0x3ee0 arch/x86/kvm/x86.c:9877
        Call Trace:
         <TASK>
         vcpu_run arch/x86/kvm/x86.c:10039 [inline]
         kvm_arch_vcpu_ioctl_run+0x337/0x15e0 arch/x86/kvm/x86.c:10234
         kvm_vcpu_ioctl+0x4d2/0xc80 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3727
         vfs_ioctl fs/ioctl.c:51 [inline]
         __do_sys_ioctl fs/ioctl.c:874 [inline]
         __se_sys_ioctl fs/ioctl.c:860 [inline]
         __x64_sys_ioctl+0x16d/0x1d0 fs/ioctl.c:860
         do_syscall_x64 arch/x86/entry/common.c:50 [inline]
         do_syscall_64+0x38/0x90 arch/x86/entry/common.c:80
         entry_SYSCALL_64_after_hwframe+0x44/0xae
      
      The bug was hit by a syzkaller spamming VM creation with 2 vCPUs and a
      call to KVM_SET_GUEST_DEBUG.
      
        r0 = openat$kvm(0xffffffffffffff9c, &(0x7f0000000000), 0x0, 0x0)
        r1 = ioctl$KVM_CREATE_VM(r0, 0xae01, 0x0)
        ioctl$KVM_CAP_SPLIT_IRQCHIP(r1, 0x4068aea3, &(0x7f0000000000)) (async)
        r2 = ioctl$KVM_CREATE_VCPU(r1, 0xae41, 0x0) (async)
        r3 = ioctl$KVM_CREATE_VCPU(r1, 0xae41, 0x400000000000002)
        ioctl$KVM_SET_GUEST_DEBUG(r3, 0x4048ae9b, &(0x7f00000000c0)={0x5dda9c14aa95f5c5})
        ioctl$KVM_RUN(r2, 0xae80, 0x0)
      Reported-by: default avatarGaoning Pan <pgn@zju.edu.cn>
      Reported-by: default avatarYongkang Jia <kangel@zju.edu.cn>
      Fixes: 8df14af4 ("kvm: x86: Add support for dynamic APICv activation")
      Cc: stable@vger.kernel.org
      Cc: Maxim Levitsky <mlevitsk@redhat.com>
      Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
      Reviewed-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
      Message-Id: <20220420013732.3308816-4-seanjc@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      423ecfea
    • Sean Christopherson's avatar
      KVM: nVMX: Defer APICv updates while L2 is active until L1 is active · 7c69661e
      Sean Christopherson authored
      Defer APICv updates that occur while L2 is active until nested VM-Exit,
      i.e. until L1 regains control.  vmx_refresh_apicv_exec_ctrl() assumes L1
      is active and (a) stomps all over vmcs02 and (b) neglects to ever updated
      vmcs01.  E.g. if vmcs12 doesn't enable the TPR shadow for L2 (and thus no
      APICv controls), L1 performs nested VM-Enter APICv inhibited, and APICv
      becomes unhibited while L2 is active, KVM will set various APICv controls
      in vmcs02 and trigger a failed VM-Entry.  The kicker is that, unless
      running with nested_early_check=1, KVM blames L1 and chaos ensues.
      
      In all cases, ignoring vmcs02 and always deferring the inhibition change
      to vmcs01 is correct (or at least acceptable).  The ABSENT and DISABLE
      inhibitions cannot truly change while L2 is active (see below).
      
      IRQ_BLOCKING can change, but it is firmly a best effort debug feature.
      Furthermore, only L2's APIC is accelerated/virtualized to the full extent
      possible, e.g. even if L1 passes through its APIC to L2, normal MMIO/MSR
      interception will apply to the virtual APIC managed by KVM.
      The exception is the SELF_IPI register when x2APIC is enabled, but that's
      an acceptable hole.
      
      Lastly, Hyper-V's Auto EOI can technically be toggled if L1 exposes the
      MSRs to L2, but for that to work in any sane capacity, L1 would need to
      pass through IRQs to L2 as well, and IRQs must be intercepted to enable
      virtual interrupt delivery.  I.e. exposing Auto EOI to L2 and enabling
      VID for L2 are, for all intents and purposes, mutually exclusive.
      
      Lack of dynamic toggling is also why this scenario is all but impossible
      to encounter in KVM's current form.  But a future patch will pend an
      APICv update request _during_ vCPU creation to plug a race where a vCPU
      that's being created doesn't get included in the "all vCPUs request"
      because it's not yet visible to other vCPUs.  If userspaces restores L2
      after VM creation (hello, KVM selftests), the first KVM_RUN will occur
      while L2 is active and thus service the APICv update request made during
      VM creation.
      
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
      Message-Id: <20220420013732.3308816-3-seanjc@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      7c69661e
    • Sean Christopherson's avatar
      KVM: x86: Tag APICv DISABLE inhibit, not ABSENT, if APICv is disabled · 80f0497c
      Sean Christopherson authored
      Set the DISABLE inhibit, not the ABSENT inhibit, if APICv is disabled via
      module param.  A recent refactoring to add a wrapper for setting/clearing
      inhibits unintentionally changed the flag, probably due to a copy+paste
      goof.
      
      Fixes: 4f4c4a3e ("KVM: x86: Trace all APICv inhibit changes and capture overall status")
      Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
      Reviewed-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
      Message-Id: <20220420013732.3308816-2-seanjc@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      80f0497c
    • Sean Christopherson's avatar
      KVM: Initialize debugfs_dentry when a VM is created to avoid NULL deref · 5c697c36
      Sean Christopherson authored
      Initialize debugfs_entry to its semi-magical -ENOENT value when the VM
      is created.  KVM's teardown when VM creation fails is kludgy and calls
      kvm_uevent_notify_change() and kvm_destroy_vm_debugfs() even if KVM never
      attempted kvm_create_vm_debugfs().  Because debugfs_entry is zero
      initialized, the IS_ERR() checks pass and KVM derefs a NULL pointer.
      
        BUG: kernel NULL pointer dereference, address: 0000000000000018
        #PF: supervisor read access in kernel mode
        #PF: error_code(0x0000) - not-present page
        PGD 1068b1067 P4D 1068b1067 PUD 1068b0067 PMD 0
        Oops: 0000 [#1] SMP
        CPU: 0 PID: 871 Comm: repro Not tainted 5.18.0-rc1+ #825
        Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
        RIP: 0010:__dentry_path+0x7b/0x130
        Call Trace:
         <TASK>
         dentry_path_raw+0x42/0x70
         kvm_uevent_notify_change.part.0+0x10c/0x200 [kvm]
         kvm_put_kvm+0x63/0x2b0 [kvm]
         kvm_dev_ioctl+0x43a/0x920 [kvm]
         __x64_sys_ioctl+0x83/0xb0
         do_syscall_64+0x31/0x50
         entry_SYSCALL_64_after_hwframe+0x44/0xae
         </TASK>
        Modules linked in: kvm_intel kvm irqbypass
      
      Fixes: a44a4cc1 ("KVM: Don't create VM debugfs files outside of the VM directory")
      Cc: stable@vger.kernel.org
      Cc: Marc Zyngier <maz@kernel.org>
      Cc: Oliver Upton <oupton@google.com>
      Reported-by: syzbot+df6fbbd2ee39f21289ef@syzkaller.appspotmail.com
      Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
      Reviewed-by: default avatarOliver Upton <oupton@google.com>
      Message-Id: <20220415004622.2207751-1-seanjc@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      5c697c36
    • Sean Christopherson's avatar
      KVM: Add helpers to wrap vcpu->srcu_idx and yell if it's abused · 2031f287
      Sean Christopherson authored
      Add wrappers to acquire/release KVM's SRCU lock when stashing the index
      in vcpu->src_idx, along with rudimentary detection of illegal usage,
      e.g. re-acquiring SRCU and thus overwriting vcpu->src_idx.  Because the
      SRCU index is (currently) either 0 or 1, illegal nesting bugs can go
      unnoticed for quite some time and only cause problems when the nested
      lock happens to get a different index.
      
      Wrap the WARNs in PROVE_RCU=y, and make them ONCE, otherwise KVM will
      likely yell so loudly that it will bring the kernel to its knees.
      Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
      Tested-by: default avatarFabiano Rosas <farosas@linux.ibm.com>
      Message-Id: <20220415004343.2203171-4-seanjc@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      2031f287
    • Sean Christopherson's avatar
      KVM: RISC-V: Use kvm_vcpu.srcu_idx, drop RISC-V's unnecessary copy · fdd6f6ac
      Sean Christopherson authored
      Use the generic kvm_vcpu's srcu_idx instead of using an indentical field
      in RISC-V's version of kvm_vcpu_arch.  Generic KVM very intentionally
      does not touch vcpu->srcu_idx, i.e. there's zero chance of running afoul
      of common code.
      Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
      Message-Id: <20220415004343.2203171-3-seanjc@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      fdd6f6ac
    • Sean Christopherson's avatar
      KVM: x86: Don't re-acquire SRCU lock in complete_emulated_io() · 2d089356
      Sean Christopherson authored
      Don't re-acquire SRCU in complete_emulated_io() now that KVM acquires the
      lock in kvm_arch_vcpu_ioctl_run().  More importantly, don't overwrite
      vcpu->srcu_idx.  If the index acquired by complete_emulated_io() differs
      from the one acquired by kvm_arch_vcpu_ioctl_run(), KVM will effectively
      leak a lock and hang if/when synchronize_srcu() is invoked for the
      relevant grace period.
      
      Fixes: 8d25b7be ("KVM: x86: pull kvm->srcu read-side to kvm_arch_vcpu_ioctl_run")
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
      Reviewed-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
      Message-Id: <20220415004343.2203171-2-seanjc@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      2d089356
    • Paolo Bonzini's avatar
      Merge tag 'kvm-riscv-fixes-5.18-2' of https://github.com/kvm-riscv/linux into HEAD · 012c7225
      Paolo Bonzini authored
      KVM/riscv fixes for 5.18, take #2
      
      - Remove 's' & 'u' as valid ISA extension
      
      - Do not allow disabling the base extensions 'i'/'m'/'a'/'c'
      012c7225
  2. 20 Apr, 2022 2 commits
  3. 17 Apr, 2022 10 commits
  4. 16 Apr, 2022 6 commits
    • Linus Torvalds's avatar
      Merge tag 'soc-fixes-5.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc · 70a0cec8
      Linus Torvalds authored
      Pull ARM SoC fixes from Arnd Bergmann:
       "There are a number of SoC bugfixes that came in since the merge
        window, and more of them are already pending.
      
        This batch includes:
      
         - A boot time regression fix for davinci that triggered on
           multi_v5_defconfig when booting any platform
      
         - Defconfig updates to address removed features, changed symbol names
           or dependencies, for gemini, ux500, and pxa
      
         - Email address changes for Krzysztof Kozlowski
      
         - Build warning fixes for ep93xx and iop32x
      
         - Devicetree warning fixes across many platforms
      
         - Minor bugfixes for the reset controller, memory controller and SCMI
           firmware subsystems plus the versatile-express board"
      
      * tag 'soc-fixes-5.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (34 commits)
        ARM: config: Update Gemini defconfig
        arm64: dts: qcom/sdm845-shift-axolotl: Fix boolean properties with values
        ARM: dts: align SPI NOR node name with dtschema
        ARM: dts: Fix more boolean properties with values
        arm/arm64: dts: qcom: Fix boolean properties with values
        arm64: dts: imx: Fix imx8*-var-som touchscreen property sizes
        arm: dts: imx: Fix boolean properties with values
        arm64: dts: tegra: Fix boolean properties with values
        arm: dts: at91: Fix boolean properties with values
        arm: configs: imote2: Drop defconfig as board support dropped.
        ep93xx: clock: Don't use plain integer as NULL pointer
        ep93xx: clock: Fix UAF in ep93xx_clk_register_gate()
        ARM: vexpress/spc: Fix all the kernel-doc build warnings
        ARM: vexpress/spc: Fix kernel-doc build warning for ve_spc_cpu_in_wfi
        ARM: config: u8500: Re-enable AB8500 battery charging
        ARM: config: u8500: Add some common hardware
        memory: fsl_ifc: populate child nodes of buses and mfd devices
        ARM: config: Refresh U8500 defconfig
        firmware: arm_scmi: Fix sparse warnings in OPTEE transport driver
        firmware: arm_scmi: Replace zero-length array with flexible-array member
        ...
      70a0cec8
    • Linus Torvalds's avatar
      Merge tag 'random-5.18-rc3-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random · 92edbe32
      Linus Torvalds authored
      Pull random number generator fixes from Jason Donenfeld:
      
       - Per your suggestion, random reads now won't fail if there's a page
         fault after some non-zero amount of data has been read, which makes
         the behavior consistent with all other reads in the kernel.
      
       - Rather than an inconsistent mix of random_get_entropy() returning an
         unsigned long or a cycles_t, now it just returns an unsigned long.
      
       - A memcpy() was replaced with an memmove(), because the addresses are
         sometimes overlapping. In practice the destination is always before
         the source, so not really an issue, but better to be correct than
         not.
      
      * tag 'random-5.18-rc3-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
        random: use memmove instead of memcpy for remaining 32 bytes
        random: make random_get_entropy() return an unsigned long
        random: allow partial reads if later user copies fail
      92edbe32
    • Linus Torvalds's avatar
      Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi · 90ea17a9
      Linus Torvalds authored
      Pull SCSI fixes from James Bottomley:
       "13 fixes, all in drivers.
      
        The most extensive changes are in the iscsi series (affecting drivers
        qedi, cxgbi and bnx2i), the next most is scsi_debug, but that's just a
        simple revert and then minor updates to pm80xx"
      
      * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
        scsi: iscsi: MAINTAINERS: Add Mike Christie as co-maintainer
        scsi: qedi: Fix failed disconnect handling
        scsi: iscsi: Fix NOP handling during conn recovery
        scsi: iscsi: Merge suspend fields
        scsi: iscsi: Fix unbound endpoint error handling
        scsi: iscsi: Fix conn cleanup and stop race during iscsid restart
        scsi: iscsi: Fix endpoint reuse regression
        scsi: iscsi: Release endpoint ID when its freed
        scsi: iscsi: Fix offload conn cleanup when iscsid restarts
        scsi: iscsi: Move iscsi_ep_disconnect()
        scsi: pm80xx: Enable upper inbound, outbound queues
        scsi: pm80xx: Mask and unmask upper interrupt vectors 32-63
        Revert "scsi: scsi_debug: Address races following module load"
      90ea17a9
    • Bartosz Golaszewski's avatar
      Merge tag 'intel-gpio-v5.18-2' of... · 0ebb4fbe
      Bartosz Golaszewski authored
      Merge tag 'intel-gpio-v5.18-2' of gitolite.kernel.org:pub/scm/linux/kernel/git/andy/linux-gpio-intel into gpio/for-current
      
      intel-gpio for v5.18-2
      
      * Couple of fixes related to handling unsigned value of the pin from ACPI
      
      gpiolib:
       -  acpi: Convert type for pin to be unsigned
       -  acpi: use correct format characters
      0ebb4fbe
    • Linus Torvalds's avatar
      Merge tag 'dma-mapping-5.18-2' of git://git.infradead.org/users/hch/dma-mapping · b0086839
      Linus Torvalds authored
      Pull dma-mapping fix from Christoph Hellwig:
      
       - avoid a double memory copy for swiotlb (Chao Gao)
      
      * tag 'dma-mapping-5.18-2' of git://git.infradead.org/users/hch/dma-mapping:
        dma-direct: avoid redundant memory sync for swiotlb
      b0086839
    • Jason A. Donenfeld's avatar
      random: use memmove instead of memcpy for remaining 32 bytes · 35a33ff3
      Jason A. Donenfeld authored
      In order to immediately overwrite the old key on the stack, before
      servicing a userspace request for bytes, we use the remaining 32 bytes
      of block 0 as the key. This means moving indices 8,9,a,b,c,d,e,f ->
      4,5,6,7,8,9,a,b. Since 4 < 8, for the kernel implementations of
      memcpy(), this doesn't actually appear to be a problem in practice. But
      relying on that characteristic seems a bit brittle. So let's change that
      to a proper memmove(), which is the by-the-books way of handling
      overlapping memory copies.
      Reviewed-by: default avatarDominik Brodowski <linux@dominikbrodowski.net>
      Signed-off-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
      35a33ff3
  5. 15 Apr, 2022 14 commits
    • Linus Torvalds's avatar
      Merge branch 'akpm' (patches from Andrew) · 59250f8a
      Linus Torvalds authored
      Merge misc fixes from Andrew Morton:
       "14 patches.
      
        Subsystems affected by this patch series: MAINTAINERS, binfmt, and
        mm (tmpfs, secretmem, kasan, kfence, pagealloc, zram, compaction,
        hugetlb, vmalloc, and kmemleak)"
      
      * emailed patches from Andrew Morton <akpm@linux-foundation.org>:
        mm: kmemleak: take a full lowmem check in kmemleak_*_phys()
        mm/vmalloc: fix spinning drain_vmap_work after reading from /proc/vmcore
        revert "fs/binfmt_elf: use PT_LOAD p_align values for static PIE"
        revert "fs/binfmt_elf: fix PT_LOAD p_align values for loaders"
        hugetlb: do not demote poisoned hugetlb pages
        mm: compaction: fix compiler warning when CONFIG_COMPACTION=n
        mm: fix unexpected zeroed page mapping with zram swap
        mm, page_alloc: fix build_zonerefs_node()
        mm, kfence: support kmem_dump_obj() for KFENCE objects
        kasan: fix hw tags enablement when KUNIT tests are disabled
        irq_work: use kasan_record_aux_stack_noalloc() record callstack
        mm/secretmem: fix panic when growing a memfd_secret
        tmpfs: fix regressions from wider use of ZERO_PAGE
        MAINTAINERS: Broadcom internal lists aren't maintainers
      59250f8a
    • Linus Torvalds's avatar
      Merge tag 'for-5.18/dm-fixes-2' of... · ce673f63
      Linus Torvalds authored
      Merge tag 'for-5.18/dm-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
      
      Pull device mapper fixes from Mike Snitzer:
      
       - Fix memory corruption in DM integrity target when tag_size is less
         than digest size.
      
       - Fix DM multipath's historical-service-time path selector to not use
         sched_clock() and ktime_get_ns(); only use ktime_get_ns().
      
       - Fix dm_io->orig_bio NULL pointer dereference in dm_zone_map_bio() due
         to 5.18 changes that overlooked DM zone's use of ->orig_bio
      
       - Fix for regression that broke the use of dm_accept_partial_bio() for
         "abnormal" IO (e.g. WRITE ZEROES) that does not need duplicate bios
      
       - Fix DM's issuing of empty flush bio so that it's size is 0.
      
      * tag 'for-5.18/dm-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
        dm: fix bio length of empty flush
        dm: allow dm_accept_partial_bio() for dm_io without duplicate bios
        dm zone: fix NULL pointer dereference in dm_zone_map_bio
        dm mpath: only use ktime_get_ns() in historical selector
        dm integrity: fix memory corruption when tag_size is less than digest size
      ce673f63
    • Patrick Wang's avatar
      mm: kmemleak: take a full lowmem check in kmemleak_*_phys() · 23c2d497
      Patrick Wang authored
      The kmemleak_*_phys() apis do not check the address for lowmem's min
      boundary, while the caller may pass an address below lowmem, which will
      trigger an oops:
      
        # echo scan > /sys/kernel/debug/kmemleak
        Unable to handle kernel paging request at virtual address ff5fffffffe00000
        Oops [#1]
        Modules linked in:
        CPU: 2 PID: 134 Comm: bash Not tainted 5.18.0-rc1-next-20220407 #33
        Hardware name: riscv-virtio,qemu (DT)
        epc : scan_block+0x74/0x15c
         ra : scan_block+0x72/0x15c
        epc : ffffffff801e5806 ra : ffffffff801e5804 sp : ff200000104abc30
         gp : ffffffff815cd4e8 tp : ff60000004cfa340 t0 : 0000000000000200
         t1 : 00aaaaaac23954cc t2 : 00000000000003ff s0 : ff200000104abc90
         s1 : ffffffff81b0ff28 a0 : 0000000000000000 a1 : ff5fffffffe01000
         a2 : ffffffff81b0ff28 a3 : 0000000000000002 a4 : 0000000000000001
         a5 : 0000000000000000 a6 : ff200000104abd7c a7 : 0000000000000005
         s2 : ff5fffffffe00ff9 s3 : ffffffff815cd998 s4 : ffffffff815d0e90
         s5 : ffffffff81b0ff28 s6 : 0000000000000020 s7 : ffffffff815d0eb0
         s8 : ffffffffffffffff s9 : ff5fffffffe00000 s10: ff5fffffffe01000
         s11: 0000000000000022 t3 : 00ffffffaa17db4c t4 : 000000000000000f
         t5 : 0000000000000001 t6 : 0000000000000000
        status: 0000000000000100 badaddr: ff5fffffffe00000 cause: 000000000000000d
          scan_gray_list+0x12e/0x1a6
          kmemleak_scan+0x2aa/0x57e
          kmemleak_write+0x32a/0x40c
          full_proxy_write+0x56/0x82
          vfs_write+0xa6/0x2a6
          ksys_write+0x6c/0xe2
          sys_write+0x22/0x2a
          ret_from_syscall+0x0/0x2
      
      The callers may not quite know the actual address they pass(e.g. from
      devicetree).  So the kmemleak_*_phys() apis should guarantee the address
      they finally use is in lowmem range, so check the address for lowmem's
      min boundary.
      
      Link: https://lkml.kernel.org/r/20220413122925.33856-1-patrick.wang.shcn@gmail.comSigned-off-by: default avatarPatrick Wang <patrick.wang.shcn@gmail.com>
      Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      23c2d497
    • Omar Sandoval's avatar
      mm/vmalloc: fix spinning drain_vmap_work after reading from /proc/vmcore · c12cd77c
      Omar Sandoval authored
      Commit 3ee48b6a ("mm, x86: Saving vmcore with non-lazy freeing of
      vmas") introduced set_iounmap_nonlazy(), which sets vmap_lazy_nr to
      lazy_max_pages() + 1, ensuring that any future vunmaps() immediately
      purge the vmap areas instead of doing it lazily.
      
      Commit 690467c8 ("mm/vmalloc: Move draining areas out of caller
      context") moved the purging from the vunmap() caller to a worker thread.
      Unfortunately, set_iounmap_nonlazy() can cause the worker thread to spin
      (possibly forever).  For example, consider the following scenario:
      
       1. Thread reads from /proc/vmcore. This eventually calls
          __copy_oldmem_page() -> set_iounmap_nonlazy(), which sets
          vmap_lazy_nr to lazy_max_pages() + 1.
      
       2. Then it calls free_vmap_area_noflush() (via iounmap()), which adds 2
          pages (one page plus the guard page) to the purge list and
          vmap_lazy_nr. vmap_lazy_nr is now lazy_max_pages() + 3, so the
          drain_vmap_work is scheduled.
      
       3. Thread returns from the kernel and is scheduled out.
      
       4. Worker thread is scheduled in and calls drain_vmap_area_work(). It
          frees the 2 pages on the purge list. vmap_lazy_nr is now
          lazy_max_pages() + 1.
      
       5. This is still over the threshold, so it tries to purge areas again,
          but doesn't find anything.
      
       6. Repeat 5.
      
      If the system is running with only one CPU (which is typicial for kdump)
      and preemption is disabled, then this will never make forward progress:
      there aren't any more pages to purge, so it hangs.  If there is more
      than one CPU or preemption is enabled, then the worker thread will spin
      forever in the background.  (Note that if there were already pages to be
      purged at the time that set_iounmap_nonlazy() was called, this bug is
      avoided.)
      
      This can be reproduced with anything that reads from /proc/vmcore
      multiple times.  E.g., vmcore-dmesg /proc/vmcore.
      
      It turns out that improvements to vmap() over the years have obsoleted
      the need for this "optimization".  I benchmarked `dd if=/proc/vmcore
      of=/dev/null` with 4k and 1M read sizes on a system with a 32GB vmcore.
      The test was run on 5.17, 5.18-rc1 with a fix that avoided the hang, and
      5.18-rc1 with set_iounmap_nonlazy() removed entirely:
      
          |5.17  |5.18+fix|5.18+removal
        4k|40.86s|  40.09s|      26.73s
        1M|24.47s|  23.98s|      21.84s
      
      The removal was the fastest (by a wide margin with 4k reads).  This
      patch removes set_iounmap_nonlazy().
      
      Link: https://lkml.kernel.org/r/52f819991051f9b865e9ce25605509bfdbacadcd.1649277321.git.osandov@fb.com
      Fixes: 690467c8  ("mm/vmalloc: Move draining areas out of caller context")
      Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
      Acked-by: default avatarChris Down <chris@chrisdown.name>
      Reviewed-by: default avatarUladzislau Rezki (Sony) <urezki@gmail.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Acked-by: default avatarBaoquan He <bhe@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c12cd77c
    • Andrew Morton's avatar
      revert "fs/binfmt_elf: use PT_LOAD p_align values for static PIE" · aeb79237
      Andrew Morton authored
      Despite Mike's attempted fix (925346c1), regressions reports
      continue:
      
        https://lore.kernel.org/lkml/cb5b81bd-9882-e5dc-cd22-54bdbaaefbbc@leemhuis.info/
        https://bugzilla.kernel.org/show_bug.cgi?id=215720
        https://lkml.kernel.org/r/b685f3d0-da34-531d-1aa9-479accd3e21b@leemhuis.info
      
      So revert this patch.
      
      Fixes: 9630f0d6 ("fs/binfmt_elf: use PT_LOAD p_align values for static PIE")
      Cc: Alexey Dobriyan <adobriyan@gmail.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Chris Kennelly <ckennelly@google.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Fangrui Song <maskray@google.com>
      Cc: H.J. Lu <hjl.tools@gmail.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Ian Rogers <irogers@google.com>
      Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Mike Kravetz <mike.kravetz@oracle.com>
      Cc: Mike Rapoport <rppt@kernel.org>
      Cc: Nick Desaulniers <ndesaulniers@google.com>
      Cc: Sandeep Patil <sspatil@google.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Song Liu <songliubraving@fb.com>
      Cc: Suren Baghdasaryan <surenb@google.com>
      Cc: Thorsten Leemhuis <regressions@leemhuis.info>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      aeb79237
    • Andrew Morton's avatar
      revert "fs/binfmt_elf: fix PT_LOAD p_align values for loaders" · 354e923d
      Andrew Morton authored
      Commit 925346c1 ("fs/binfmt_elf: fix PT_LOAD p_align values for
      loaders") was an attempt to fix regressions due to 9630f0d6
      ("fs/binfmt_elf: use PT_LOAD p_align values for static PIE").
      
      But regressionss continue to be reported:
      
        https://lore.kernel.org/lkml/cb5b81bd-9882-e5dc-cd22-54bdbaaefbbc@leemhuis.info/
        https://bugzilla.kernel.org/show_bug.cgi?id=215720
        https://lkml.kernel.org/r/b685f3d0-da34-531d-1aa9-479accd3e21b@leemhuis.info
      
      This patch reverts the fix, so the original can also be reverted.
      
      Fixes: 925346c1 ("fs/binfmt_elf: fix PT_LOAD p_align values for loaders")
      Cc: H.J. Lu <hjl.tools@gmail.com>
      Cc: Chris Kennelly <ckennelly@google.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Alexey Dobriyan <adobriyan@gmail.com>
      Cc: Song Liu <songliubraving@fb.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Ian Rogers <irogers@google.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Suren Baghdasaryan <surenb@google.com>
      Cc: Sandeep Patil <sspatil@google.com>
      Cc: Fangrui Song <maskray@google.com>
      Cc: Nick Desaulniers <ndesaulniers@google.com>
      Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Mike Kravetz <mike.kravetz@oracle.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Thorsten Leemhuis <regressions@leemhuis.info>
      Cc: Mike Rapoport <rppt@kernel.org>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      354e923d
    • Mike Kravetz's avatar
      hugetlb: do not demote poisoned hugetlb pages · 5a317412
      Mike Kravetz authored
      It is possible for poisoned hugetlb pages to reside on the free lists.
      The huge page allocation routines which dequeue entries from the free
      lists make a point of avoiding poisoned pages.  There is no such check
      and avoidance in the demote code path.
      
      If a hugetlb page on the is on a free list, poison will only be set in
      the head page rather then the page with the actual error.  If such a
      page is demoted, then the poison flag may follow the wrong page.  A page
      without error could have poison set, and a page with poison could not
      have the flag set.
      
      Check for poison before attempting to demote a hugetlb page.  Also,
      return -EBUSY to the caller if only poisoned pages are on the free list.
      
      Link: https://lkml.kernel.org/r/20220307215707.50916-1-mike.kravetz@oracle.com
      Fixes: 8531fc6f ("hugetlb: add hugetlb demote page support")
      Signed-off-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
      Reviewed-by: default avatarNaoya Horiguchi <naoya.horiguchi@nec.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      5a317412
    • Charan Teja Kalla's avatar
      mm: compaction: fix compiler warning when CONFIG_COMPACTION=n · 31ca72fa
      Charan Teja Kalla authored
      The below warning is reported when CONFIG_COMPACTION=n:
      
         mm/compaction.c:56:27: warning: 'HPAGE_FRAG_CHECK_INTERVAL_MSEC' defined but not used [-Wunused-const-variable=]
            56 | static const unsigned int HPAGE_FRAG_CHECK_INTERVAL_MSEC = 500;
               |                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      
      Fix it by moving 'HPAGE_FRAG_CHECK_INTERVAL_MSEC' under
      CONFIG_COMPACTION defconfig.
      
      Also since this is just a 'static const int' type, use #define for it.
      
      Link: https://lkml.kernel.org/r/1647608518-20924-1-git-send-email-quic_charante@quicinc.comSigned-off-by: default avatarCharan Teja Kalla <quic_charante@quicinc.com>
      Reported-by: default avatarkernel test robot <lkp@intel.com>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Cc: Nitin Gupta <nigupta@nvidia.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      31ca72fa
    • Minchan Kim's avatar
      mm: fix unexpected zeroed page mapping with zram swap · e914d8f0
      Minchan Kim authored
      Two processes under CLONE_VM cloning, user process can be corrupted by
      seeing zeroed page unexpectedly.
      
            CPU A                        CPU B
      
        do_swap_page                do_swap_page
        SWP_SYNCHRONOUS_IO path     SWP_SYNCHRONOUS_IO path
        swap_readpage valid data
          swap_slot_free_notify
            delete zram entry
                                    swap_readpage zeroed(invalid) data
                                    pte_lock
                                    map the *zero data* to userspace
                                    pte_unlock
        pte_lock
        if (!pte_same)
          goto out_nomap;
        pte_unlock
        return and next refault will
        read zeroed data
      
      The swap_slot_free_notify is bogus for CLONE_VM case since it doesn't
      increase the refcount of swap slot at copy_mm so it couldn't catch up
      whether it's safe or not to discard data from backing device.  In the
      case, only the lock it could rely on to synchronize swap slot freeing is
      page table lock.  Thus, this patch gets rid of the swap_slot_free_notify
      function.  With this patch, CPU A will see correct data.
      
            CPU A                        CPU B
      
        do_swap_page                do_swap_page
        SWP_SYNCHRONOUS_IO path     SWP_SYNCHRONOUS_IO path
                                    swap_readpage original data
                                    pte_lock
                                    map the original data
                                    swap_free
                                      swap_range_free
                                        bd_disk->fops->swap_slot_free_notify
        swap_readpage read zeroed data
                                    pte_unlock
        pte_lock
        if (!pte_same)
          goto out_nomap;
        pte_unlock
        return
        on next refault will see mapped data by CPU B
      
      The concern of the patch would increase memory consumption since it
      could keep wasted memory with compressed form in zram as well as
      uncompressed form in address space.  However, most of cases of zram uses
      no readahead and do_swap_page is followed by swap_free so it will free
      the compressed form from in zram quickly.
      
      Link: https://lkml.kernel.org/r/YjTVVxIAsnKAXjTd@google.com
      Fixes: 0bcac06f ("mm, swap: skip swapcache for swapin of synchronous device")
      Reported-by: default avatarIvan Babrou <ivan@cloudflare.com>
      Tested-by: default avatarIvan Babrou <ivan@cloudflare.com>
      Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
      Cc: Nitin Gupta <ngupta@vflare.org>
      Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: David Hildenbrand <david@redhat.com>
      Cc: <stable@vger.kernel.org>	[4.14+]
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e914d8f0
    • Juergen Gross's avatar
      mm, page_alloc: fix build_zonerefs_node() · e553f62f
      Juergen Gross authored
      Since commit 6aa303de ("mm, vmscan: only allocate and reclaim from
      zones with pages managed by the buddy allocator") only zones with free
      memory are included in a built zonelist.  This is problematic when e.g.
      all memory of a zone has been ballooned out when zonelists are being
      rebuilt.
      
      The decision whether to rebuild the zonelists when onlining new memory
      is done based on populated_zone() returning 0 for the zone the memory
      will be added to.  The new zone is added to the zonelists only, if it
      has free memory pages (managed_zone() returns a non-zero value) after
      the memory has been onlined.  This implies, that onlining memory will
      always free the added pages to the allocator immediately, but this is
      not true in all cases: when e.g. running as a Xen guest the onlined new
      memory will be added only to the ballooned memory list, it will be freed
      only when the guest is being ballooned up afterwards.
      
      Another problem with using managed_zone() for the decision whether a
      zone is being added to the zonelists is, that a zone with all memory
      used will in fact be removed from all zonelists in case the zonelists
      happen to be rebuilt.
      
      Use populated_zone() when building a zonelist as it has been done before
      that commit.
      
      There was a report that QubesOS (based on Xen) is hitting this problem.
      Xen has switched to use the zone device functionality in kernel 5.9 and
      QubesOS wants to use memory hotplugging for guests in order to be able
      to start a guest with minimal memory and expand it as needed.  This was
      the report leading to the patch.
      
      Link: https://lkml.kernel.org/r/20220407120637.9035-1-jgross@suse.com
      Fixes: 6aa303de ("mm, vmscan: only allocate and reclaim from zones with pages managed by the buddy allocator")
      Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
      Reported-by: default avatarMarek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
      Acked-by: default avatarMichal Hocko <mhocko@suse.com>
      Acked-by: default avatarDavid Hildenbrand <david@redhat.com>
      Cc: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
      Reviewed-by: default avatarWei Yang <richard.weiyang@gmail.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e553f62f
    • Marco Elver's avatar
      mm, kfence: support kmem_dump_obj() for KFENCE objects · 2dfe63e6
      Marco Elver authored
      Calling kmem_obj_info() via kmem_dump_obj() on KFENCE objects has been
      producing garbage data due to the object not actually being maintained
      by SLAB or SLUB.
      
      Fix this by implementing __kfence_obj_info() that copies relevant
      information to struct kmem_obj_info when the object was allocated by
      KFENCE; this is called by a common kmem_obj_info(), which also calls the
      slab/slub/slob specific variant now called __kmem_obj_info().
      
      For completeness, kmem_dump_obj() now displays if the object was
      allocated by KFENCE.
      
      Link: https://lore.kernel.org/all/20220323090520.GG16885@xsang-OptiPlex-9020/
      Link: https://lkml.kernel.org/r/20220406131558.3558585-1-elver@google.com
      Fixes: b89fb5ef ("mm, kfence: insert KFENCE hooks for SLUB")
      Fixes: d3fb45f3 ("mm, kfence: insert KFENCE hooks for SLAB")
      Signed-off-by: default avatarMarco Elver <elver@google.com>
      Reviewed-by: default avatarHyeonggon Yoo <42.hyeyoo@gmail.com>
      Reported-by: default avatarkernel test robot <oliver.sang@intel.com>
      Acked-by: Vlastimil Babka <vbabka@suse.cz>	[slab]
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2dfe63e6
    • Vincenzo Frascino's avatar
      kasan: fix hw tags enablement when KUNIT tests are disabled · b1add418
      Vincenzo Frascino authored
      Kasan enables hw tags via kasan_enable_tagging() which based on the mode
      passed via kernel command line selects the correct hw backend.
      kasan_enable_tagging() is meant to be invoked indirectly via the cpu
      features framework of the architectures that support these backends.
      Currently the invocation of this function is guarded by
      CONFIG_KASAN_KUNIT_TEST which allows the enablement of the correct backend
      only when KUNIT tests are enabled in the kernel.
      
      This inconsistency was introduced in commit:
      
        ed6d7444 ("kasan: test: support async (again) and asymm modes for HW_TAGS")
      
      ... and prevents to enable MTE on arm64 when KUNIT tests for kasan hw_tags are
      disabled.
      
      Fix the issue making sure that the CONFIG_KASAN_KUNIT_TEST guard does not
      prevent the correct invocation of kasan_enable_tagging().
      
      Link: https://lkml.kernel.org/r/20220408124323.10028-1-vincenzo.frascino@arm.com
      Fixes: ed6d7444 ("kasan: test: support async (again) and asymm modes for HW_TAGS")
      Signed-off-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
      Reviewed-by: default avatarAndrey Konovalov <andreyknvl@gmail.com>
      Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
      Cc: Alexander Potapenko <glider@google.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Will Deacon <will@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b1add418
    • Zqiang's avatar
      irq_work: use kasan_record_aux_stack_noalloc() record callstack · 25934fcf
      Zqiang authored
      On PREEMPT_RT kernel and KASAN is enabled.  the kasan_record_aux_stack()
      may call alloc_pages(), and the rt-spinlock will be acquired, if currently
      in atomic context, will trigger warning:
      
        BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46
        in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 239, name: bootlogd
        Preemption disabled at:
        [<ffffffffbab1a531>] rt_mutex_slowunlock+0xa1/0x4e0
        CPU: 3 PID: 239 Comm: bootlogd Tainted: G        W 5.17.1-rt17-yocto-preempt-rt+ #105
        Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
        Call Trace:
           __might_resched.cold+0x13b/0x173
           rt_spin_lock+0x5b/0xf0
           get_page_from_freelist+0x20c/0x1610
           __alloc_pages+0x25e/0x5e0
           __stack_depot_save+0x3c0/0x4a0
           kasan_save_stack+0x3a/0x50
           __kasan_record_aux_stack+0xb6/0xc0
           kasan_record_aux_stack+0xe/0x10
           irq_work_queue_on+0x6a/0x1c0
           pull_rt_task+0x631/0x6b0
           do_balance_callbacks+0x56/0x80
           __balance_callbacks+0x63/0x90
           rt_mutex_setprio+0x349/0x880
           rt_mutex_slowunlock+0x22a/0x4e0
           rt_spin_unlock+0x49/0x80
           uart_write+0x186/0x2b0
           do_output_char+0x2e9/0x3a0
           n_tty_write+0x306/0x800
           file_tty_write.isra.0+0x2af/0x450
           tty_write+0x22/0x30
           new_sync_write+0x27c/0x3a0
           vfs_write+0x3f7/0x5d0
           ksys_write+0xd9/0x180
           __x64_sys_write+0x43/0x50
           do_syscall_64+0x44/0x90
           entry_SYSCALL_64_after_hwframe+0x44/0xae
      
      Fix it by using kasan_record_aux_stack_noalloc() to avoid the call to
      alloc_pages().
      
      Link: https://lkml.kernel.org/r/20220402142555.2699582-1-qiang1.zhang@intel.comSigned-off-by: default avatarZqiang <qiang1.zhang@intel.com>
      Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
      Cc: Alexander Potapenko <glider@google.com>
      Cc: Andrey Konovalov <andreyknvl@gmail.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      25934fcf
    • Axel Rasmussen's avatar
      mm/secretmem: fix panic when growing a memfd_secret · f9b141f9
      Axel Rasmussen authored
      When one tries to grow an existing memfd_secret with ftruncate, one gets
      a panic [1].  For example, doing the following reliably induces the
      panic:
      
          fd = memfd_secret();
      
          ftruncate(fd, 10);
          ptr = mmap(NULL, 10, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
          strcpy(ptr, "123456789");
      
          munmap(ptr, 10);
          ftruncate(fd, 20);
      
      The basic reason for this is, when we grow with ftruncate, we call down
      into simple_setattr, and then truncate_inode_pages_range, and eventually
      we try to zero part of the memory.  The normal truncation code does this
      via the direct map (i.e., it calls page_address() and hands that to
      memset()).
      
      For memfd_secret though, we specifically don't map our pages via the
      direct map (i.e.  we call set_direct_map_invalid_noflush() on every
      fault).  So the address returned by page_address() isn't useful, and
      when we try to memset() with it we panic.
      
      This patch avoids the panic by implementing a custom setattr for
      memfd_secret, which detects resizes specifically (setting the size for
      the first time works just fine, since there are no existing pages to try
      to zero), and rejects them with EINVAL.
      
      One could argue growing should be supported, but I think that will
      require a significantly more lengthy change.  So, I propose a minimal
      fix for the benefit of stable kernels, and then perhaps to extend
      memfd_secret to support growing in a separate patch.
      
      [1]:
      
        BUG: unable to handle page fault for address: ffffa0a889277028
        #PF: supervisor write access in kernel mode
        #PF: error_code(0x0002) - not-present page
        PGD afa01067 P4D afa01067 PUD 83f909067 PMD 83f8bf067 PTE 800ffffef6d88060
        Oops: 0002 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI
        CPU: 0 PID: 281 Comm: repro Not tainted 5.17.0-dbg-DEV #1
        Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
        RIP: 0010:memset_erms+0x9/0x10
        Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 <f3> aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01
        RSP: 0018:ffffb932c09afbf0 EFLAGS: 00010246
        RAX: 0000000000000000 RBX: ffffda63c4249dc0 RCX: 0000000000000fd8
        RDX: 0000000000000fd8 RSI: 0000000000000000 RDI: ffffa0a889277028
        RBP: ffffb932c09afc00 R08: 0000000000001000 R09: ffffa0a889277028
        R10: 0000000000020023 R11: 0000000000000000 R12: ffffda63c4249dc0
        R13: ffffa0a890d70d98 R14: 0000000000000028 R15: 0000000000000fd8
        FS:  00007f7294899580(0000) GS:ffffa0af9bc00000(0000) knlGS:0000000000000000
        CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
        CR2: ffffa0a889277028 CR3: 0000000107ef6006 CR4: 0000000000370ef0
        DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
        DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
        Call Trace:
         ? zero_user_segments+0x82/0x190
         truncate_inode_partial_folio+0xd4/0x2a0
         truncate_inode_pages_range+0x380/0x830
         truncate_setsize+0x63/0x80
         simple_setattr+0x37/0x60
         notify_change+0x3d8/0x4d0
         do_sys_ftruncate+0x162/0x1d0
         __x64_sys_ftruncate+0x1c/0x20
         do_syscall_64+0x44/0xa0
         entry_SYSCALL_64_after_hwframe+0x44/0xae
        Modules linked in: xhci_pci xhci_hcd virtio_net net_failover failover virtio_blk virtio_balloon uhci_hcd ohci_pci ohci_hcd evdev ehci_pci ehci_hcd 9pnet_virtio 9p netfs 9pnet
        CR2: ffffa0a889277028
      
      [lkp@intel.com: secretmem_iops can be static]
      Signed-off-by: default avatarkernel test robot <lkp@intel.com>
      [axelrasmussen@google.com: return EINVAL]
      
      Link: https://lkml.kernel.org/r/20220324210909.1843814-1-axelrasmussen@google.com
      Link: https://lkml.kernel.org/r/20220412193023.279320-1-axelrasmussen@google.comSigned-off-by: default avatarAxel Rasmussen <axelrasmussen@google.com>
      Cc: Mike Rapoport <rppt@kernel.org>
      Cc: Matthew Wilcox <willy@infradead.org>
      Cc: <stable@vger.kernel.org>
      Cc: kernel test robot <lkp@intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f9b141f9