mirror of https://gitee.com/openkylin/linux.git
6 Commits
| Author | SHA1 | Message | Date |
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Marc Zyngier
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d6dbdd3c85 |
KVM: arm/arm64: Handle possible NULL stage2 pud when ageing pages
Under memory pressure, we start ageing pages, which amounts to parsing the page tables. Since we don't want to allocate any extra level, we pass NULL for our private allocation cache. Which means that stage2_get_pud() is allowed to fail. This results in the following splat: [ 1520.409577] Unable to handle kernel NULL pointer dereference at virtual address 00000008 [ 1520.417741] pgd = ffff810f52fef000 [ 1520.421201] [00000008] *pgd=0000010f636c5003, *pud=0000010f56f48003, *pmd=0000000000000000 [ 1520.429546] Internal error: Oops: 96000006 [#1] PREEMPT SMP [ 1520.435156] Modules linked in: [ 1520.438246] CPU: 15 PID: 53550 Comm: qemu-system-aar Tainted: G W 4.12.0-rc4-00027-g1885c397eaec #7205 [ 1520.448705] Hardware name: FOXCONN R2-1221R-A4/C2U4N_MB, BIOS G31FB12A 10/26/2016 [ 1520.463726] task: ffff800ac5fb4e00 task.stack: ffff800ce04e0000 [ 1520.469666] PC is at stage2_get_pmd+0x34/0x110 [ 1520.474119] LR is at kvm_age_hva_handler+0x44/0xf0 [ 1520.478917] pc : [<ffff0000080b137c>] lr : [<ffff0000080b149c>] pstate: 40000145 [ 1520.486325] sp : ffff800ce04e33d0 [ 1520.489644] x29: ffff800ce04e33d0 x28: 0000000ffff40064 [ 1520.494967] x27: 0000ffff27e00000 x26: 0000000000000000 [ 1520.500289] x25: ffff81051ba65008 x24: 0000ffff40065000 [ 1520.505618] x23: 0000ffff40064000 x22: 0000000000000000 [ 1520.510947] x21: ffff810f52b20000 x20: 0000000000000000 [ 1520.516274] x19: 0000000058264000 x18: 0000000000000000 [ 1520.521603] x17: 0000ffffa6fe7438 x16: ffff000008278b70 [ 1520.526940] x15: 000028ccd8000000 x14: 0000000000000008 [ 1520.532264] x13: ffff7e0018298000 x12: 0000000000000002 [ 1520.537582] x11: ffff000009241b93 x10: 0000000000000940 [ 1520.542908] x9 : ffff0000092ef800 x8 : 0000000000000200 [ 1520.548229] x7 : ffff800ce04e36a8 x6 : 0000000000000000 [ 1520.553552] x5 : 0000000000000001 x4 : 0000000000000000 [ 1520.558873] x3 : 0000000000000000 x2 : 0000000000000008 [ 1520.571696] x1 : ffff000008fd5000 x0 : ffff0000080b149c [ 1520.577039] Process qemu-system-aar (pid: 53550, stack limit = 0xffff800ce04e0000) [...] [ 1521.510735] [<ffff0000080b137c>] stage2_get_pmd+0x34/0x110 [ 1521.516221] [<ffff0000080b149c>] kvm_age_hva_handler+0x44/0xf0 [ 1521.522054] [<ffff0000080b0610>] handle_hva_to_gpa+0xb8/0xe8 [ 1521.527716] [<ffff0000080b3434>] kvm_age_hva+0x44/0xf0 [ 1521.532854] [<ffff0000080a58b0>] kvm_mmu_notifier_clear_flush_young+0x70/0xc0 [ 1521.539992] [<ffff000008238378>] __mmu_notifier_clear_flush_young+0x88/0xd0 [ 1521.546958] [<ffff00000821eca0>] page_referenced_one+0xf0/0x188 [ 1521.552881] [<ffff00000821f36c>] rmap_walk_anon+0xec/0x250 [ 1521.558370] [<ffff000008220f78>] rmap_walk+0x78/0xa0 [ 1521.563337] [<ffff000008221104>] page_referenced+0x164/0x180 [ 1521.569002] [<ffff0000081f1af0>] shrink_active_list+0x178/0x3b8 [ 1521.574922] [<ffff0000081f2058>] shrink_node_memcg+0x328/0x600 [ 1521.580758] [<ffff0000081f23f4>] shrink_node+0xc4/0x328 [ 1521.585986] [<ffff0000081f2718>] do_try_to_free_pages+0xc0/0x340 [ 1521.592000] [<ffff0000081f2a64>] try_to_free_pages+0xcc/0x240 [...] The trivial fix is to handle this NULL pud value early, rather than dereferencing it blindly. Cc: stable@vger.kernel.org Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Christoffer Dall <cdall@linaro.org> |
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Suzuki K Poulose
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0c428a6a92 |
kvm: arm/arm64: Fix use after free of stage2 page table
We yield the kvm->mmu_lock occassionaly while performing an operation (e.g, unmap or permission changes) on a large area of stage2 mappings. However this could possibly cause another thread to clear and free up the stage2 page tables while we were waiting for regaining the lock and thus the original thread could end up in accessing memory that was freed. This patch fixes the problem by making sure that the stage2 pagetable is still valid after we regain the lock. The fact that mmu_notifer->release() could be called twice (via __mmu_notifier_release and mmu_notifier_unregsister) enhances the possibility of hitting this race where there are two threads trying to unmap the entire guest shadow pages. While at it, cleanup the redudant checks around cond_resched_lock in stage2_wp_range(), as cond_resched_lock already does the same checks. Cc: Mark Rutland <mark.rutland@arm.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: andreyknvl@google.com Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: stable@vger.kernel.org Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Christoffer Dall <cdall@linaro.org> |
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Suzuki K Poulose
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2952a6070e |
kvm: arm/arm64: Force reading uncached stage2 PGD
Make sure we don't use a cached value of the KVM stage2 PGD while resetting the PGD. Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: stable@vger.kernel.org Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Christoffer Dall <cdall@linaro.org> |
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Suzuki K Poulose
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6c0d706b56 |
kvm: arm/arm64: Fix race in resetting stage2 PGD
In kvm_free_stage2_pgd() we check the stage2 PGD before holding the lock and proceed to take the lock if it is valid. And we unmap the page tables, followed by releasing the lock. We reset the PGD only after dropping this lock, which could cause a race condition where another thread waiting on or even holding the lock, could potentially see that the PGD is still valid and proceed to perform a stage2 operation and later encounter a NULL PGD. [223090.242280] Unable to handle kernel NULL pointer dereference at virtual address 00000040 [223090.262330] PC is at unmap_stage2_range+0x8c/0x428 [223090.262332] LR is at kvm_unmap_hva_handler+0x2c/0x3c [223090.262531] Call trace: [223090.262533] [<ffff0000080adb78>] unmap_stage2_range+0x8c/0x428 [223090.262535] [<ffff0000080adf40>] kvm_unmap_hva_handler+0x2c/0x3c [223090.262537] [<ffff0000080ace2c>] handle_hva_to_gpa+0xb0/0x104 [223090.262539] [<ffff0000080af988>] kvm_unmap_hva+0x5c/0xbc [223090.262543] [<ffff0000080a2478>] kvm_mmu_notifier_invalidate_page+0x50/0x8c [223090.262547] [<ffff0000082274f8>] __mmu_notifier_invalidate_page+0x5c/0x84 [223090.262551] [<ffff00000820b700>] try_to_unmap_one+0x1d0/0x4a0 [223090.262553] [<ffff00000820c5c8>] rmap_walk+0x1cc/0x2e0 [223090.262555] [<ffff00000820c90c>] try_to_unmap+0x74/0xa4 [223090.262557] [<ffff000008230ce4>] migrate_pages+0x31c/0x5ac [223090.262561] [<ffff0000081f869c>] compact_zone+0x3fc/0x7ac [223090.262563] [<ffff0000081f8ae0>] compact_zone_order+0x94/0xb0 [223090.262564] [<ffff0000081f91c0>] try_to_compact_pages+0x108/0x290 [223090.262569] [<ffff0000081d5108>] __alloc_pages_direct_compact+0x70/0x1ac [223090.262571] [<ffff0000081d64a0>] __alloc_pages_nodemask+0x434/0x9f4 [223090.262572] [<ffff0000082256f0>] alloc_pages_vma+0x230/0x254 [223090.262574] [<ffff000008235e5c>] do_huge_pmd_anonymous_page+0x114/0x538 [223090.262576] [<ffff000008201bec>] handle_mm_fault+0xd40/0x17a4 [223090.262577] [<ffff0000081fb324>] __get_user_pages+0x12c/0x36c [223090.262578] [<ffff0000081fb804>] get_user_pages_unlocked+0xa4/0x1b8 [223090.262579] [<ffff0000080a3ce8>] __gfn_to_pfn_memslot+0x280/0x31c [223090.262580] [<ffff0000080a3dd0>] gfn_to_pfn_prot+0x4c/0x5c [223090.262582] [<ffff0000080af3f8>] kvm_handle_guest_abort+0x240/0x774 [223090.262584] [<ffff0000080b2bac>] handle_exit+0x11c/0x1ac [223090.262586] [<ffff0000080ab99c>] kvm_arch_vcpu_ioctl_run+0x31c/0x648 [223090.262587] [<ffff0000080a1d78>] kvm_vcpu_ioctl+0x378/0x768 [223090.262590] [<ffff00000825df5c>] do_vfs_ioctl+0x324/0x5a4 [223090.262591] [<ffff00000825e26c>] SyS_ioctl+0x90/0xa4 [223090.262595] [<ffff000008085d84>] el0_svc_naked+0x38/0x3c This patch moves the stage2 PGD manipulation under the lock. Reported-by: Alexander Graf <agraf@suse.de> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Reviewed-by: Christoffer Dall <cdall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Christoffer Dall <cdall@linaro.org> |
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Paolo Bonzini
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36c344f3f1 |
Second round of KVM/ARM Changes for v4.12.
Changes include:
- A fix related to the 32-bit idmap stub
- A fix to the bitmask used to deode the operands of an AArch32 CP
instruction
- We have moved the files shared between arch/arm/kvm and
arch/arm64/kvm to virt/kvm/arm
- We add support for saving/restoring the virtual ITS state to
userspace
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Merge tag 'kvm-arm-for-v4.12-round2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
Second round of KVM/ARM Changes for v4.12.
Changes include:
- A fix related to the 32-bit idmap stub
- A fix to the bitmask used to deode the operands of an AArch32 CP
instruction
- We have moved the files shared between arch/arm/kvm and
arch/arm64/kvm to virt/kvm/arm
- We add support for saving/restoring the virtual ITS state to
userspace
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Christoffer Dall
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35d2d5d490 |
KVM: arm/arm64: Move shared files to virt/kvm/arm
For some time now we have been having a lot of shared functionality between the arm and arm64 KVM support in arch/arm, which not only required a horrible inter-arch reference from the Makefile in arch/arm64/kvm, but also created confusion for newcomers to the code base, as was recently seen on the mailing list. Further, it causes confusion for things like cscope, which needs special attention to index specific shared files for arm64 from the arm tree. Move the shared files into virt/kvm/arm and move the trace points along with it. When moving the tracepoints we have to modify the way the vgic creates definitions of the trace points, so we take the chance to include the VGIC tracepoints in its very own special vgic trace.h file. Signed-off-by: Christoffer Dall <cdall@linaro.org> |