| Message ID | 1526537487-14804-1-git-send-email-hejianet@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Jia, On 17/05/18 07:11, Jia He wrote: > I ever met a panic under memory pressure tests(start 20 guests and run > memhog in the host). Please avoid using "I" in the commit description and preferably stick to an objective description. > > The root cause might be what I fixed at [1]. But from arm kvm points of > view, it would be better we caught the exception earlier and clearer. > > If the size is not PAGE_SIZE aligned, unmap_stage2_range might unmap the > wrong(more or less) page range. Hence it caused the "BUG: Bad page > state" I don't see why we should ever panic with a "positive" size value. Anyways, the unmap requests must be in units of pages. So this check might be useful. Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> > > [1] https://lkml.org/lkml/2018/5/3/1042 > > Signed-off-by: jia.he@hxt-semitech.com > --- > virt/kvm/arm/mmu.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c > index 7f6a944..8dac311 100644 > --- a/virt/kvm/arm/mmu.c > +++ b/virt/kvm/arm/mmu.c > @@ -297,6 +297,8 @@ static void unmap_stage2_range(struct kvm *kvm, phys_addr_t start, u64 size) > phys_addr_t next; > > assert_spin_locked(&kvm->mmu_lock); > + WARN_ON(size & ~PAGE_MASK); > + > pgd = kvm->arch.pgd + stage2_pgd_index(addr); > do { > /* >
diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c index 7f6a944..8dac311 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -297,6 +297,8 @@ static void unmap_stage2_range(struct kvm *kvm, phys_addr_t start, u64 size) phys_addr_t next; assert_spin_locked(&kvm->mmu_lock); + WARN_ON(size & ~PAGE_MASK); + pgd = kvm->arch.pgd + stage2_pgd_index(addr); do { /*
I ever met a panic under memory pressure tests(start 20 guests and run memhog in the host). ---------------------------------begin-------------------------------- [35380.800950] BUG: Bad page state in process qemu-kvm pfn:dd0b6 [35380.805825] page:ffff7fe003742d80 count:-4871 mapcount:-2126053375 mapping: (null) index:0x0 [35380.815024] flags: 0x1fffc00000000000() [35380.818845] raw: 1fffc00000000000 0000000000000000 0000000000000000 ffffecf981470000 [35380.826569] raw: dead000000000100 dead000000000200 ffff8017c001c000 0000000000000000 [35380.805825] page:ffff7fe003742d80 count:-4871 mapcount:-2126053375 mapping: (null) index:0x0 [35380.815024] flags: 0x1fffc00000000000() [35380.818845] raw: 1fffc00000000000 0000000000000000 0000000000000000 ffffecf981470000 [35380.826569] raw: dead000000000100 dead000000000200 ffff8017c001c000 0000000000000000 [35380.834294] page dumped because: nonzero _refcount [35380.839069] Modules linked in: vhost_net vhost tap ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter fcoe libfcoe libfc 8021q garp mrp stp llc scsi_transport_fc openvswitch nf_conntrack_ipv6 nf_nat_ipv6 nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_defrag_ipv6 nf_nat nf_conntrack vfat fat rpcrdma ib_isert iscsi_target_mod ib_iser libiscsi scsi_transport_iscsi ib_srpt target_core_mod ib_srp scsi_transport_srp ib_ipoib rdma_ucm ib_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm mlx5_ib ib_core crc32_ce ipmi_ssif tpm_tis tpm_tis_core sg nfsd auth_rpcgss nfs_acl lockd grace sunrpc dm_multipath ip_tables xfs libcrc32c mlx5_core mlxfw devlink ahci_platform libahci_platform libahci qcom_emac sdhci_acpi sdhci hdma mmc_core hdma_mgmt i2c_qup dm_mirror dm_region_hash dm_log dm_mod [35380.908341] CPU: 29 PID: 18323 Comm: qemu-kvm Tainted: G W 4.14.15-5.hxt.aarch64 #1 [35380.917107] Hardware name: <snip for confidential issues> [35380.930909] Call trace: [35380.933345] [<ffff000008088f00>] dump_backtrace+0x0/0x22c [35380.938723] [<ffff000008089150>] show_stack+0x24/0x2c [35380.943759] [<ffff00000893c078>] dump_stack+0x8c/0xb0 [35380.948794] [<ffff00000820ab50>] bad_page+0xf4/0x154 [35380.953740] [<ffff000008211ce8>] free_pages_check_bad+0x90/0x9c [35380.959642] [<ffff00000820c430>] free_pcppages_bulk+0x464/0x518 [35380.965545] [<ffff00000820db98>] free_hot_cold_page+0x22c/0x300 [35380.971448] [<ffff0000082176fc>] __put_page+0x54/0x60 [35380.976484] [<ffff0000080b1164>] unmap_stage2_range+0x170/0x2b4 [35380.982385] [<ffff0000080b12d8>] kvm_unmap_hva_handler+0x30/0x40 [35380.988375] [<ffff0000080b0104>] handle_hva_to_gpa+0xb0/0xec [35380.994016] [<ffff0000080b2644>] kvm_unmap_hva_range+0x5c/0xd0 [35380.999833] [<ffff0000080a8054>] kvm_mmu_notifier_invalidate_range_start+0x60/0xb0 [35381.007387] [<ffff000008271f44>] __mmu_notifier_invalidate_range_start+0x64/0x8c [35381.014765] [<ffff0000082547c8>] try_to_unmap_one+0x78c/0x7a4 [35381.020493] [<ffff000008276d04>] rmap_walk_ksm+0x124/0x1a0 [35381.025961] [<ffff0000082551b4>] rmap_walk+0x94/0x98 [35381.030909] [<ffff0000082555e4>] try_to_unmap+0x100/0x124 [35381.036293] [<ffff00000828243c>] unmap_and_move+0x480/0x6fc [35381.041847] [<ffff000008282b6c>] migrate_pages+0x10c/0x288 [35381.047318] [<ffff00000823c164>] compact_zone+0x238/0x954 [35381.052697] [<ffff00000823c944>] compact_zone_order+0xc4/0xe8 [35381.058427] [<ffff00000823d25c>] try_to_compact_pages+0x160/0x294 [35381.064503] [<ffff00000820f074>] __alloc_pages_direct_compact+0x68/0x194 [35381.071187] [<ffff000008210138>] __alloc_pages_nodemask+0xc20/0xf7c [35381.077437] [<ffff0000082709e4>] alloc_pages_vma+0x1a4/0x1c0 [35381.083080] [<ffff000008285b68>] do_huge_pmd_anonymous_page+0x128/0x324 [35381.089677] [<ffff000008248a24>] __handle_mm_fault+0x71c/0x7e8 [35381.095492] [<ffff000008248be8>] handle_mm_fault+0xf8/0x194 [35381.101049] [<ffff000008240dcc>] __get_user_pages+0x124/0x34c [35381.106777] [<ffff000008241870>] populate_vma_page_range+0x90/0x9c [35381.112941] [<ffff000008241940>] __mm_populate+0xc4/0x15c [35381.118322] [<ffff00000824b294>] SyS_mlockall+0x100/0x164 [35381.123705] Exception stack(0xffff800dce5f3ec0 to 0xffff800dce5f4000) [35381.130128] 3ec0: 0000000000000003 d6e6024cc9b87e00 0000aaaabe94f000 0000000000000000 [35381.137940] 3ee0: 0000000000000002 0000000000000000 0000000000000000 0000aaaacf6fc3c0 [35381.145753] 3f00: 00000000000000e6 0000aaaacf6fc490 0000ffffeeeab0f0 d6e6024cc9b87e00 [35381.153565] 3f20: 0000000000000000 0000aaaabe81b3c0 0000000000000020 00009e53eff806b5 [35381.161379] 3f40: 0000aaaabe94de48 0000ffffa7c269b0 0000000000000011 0000ffffeeeabf68 [35381.169190] 3f60: 0000aaaaceacfe60 0000aaaabe94f000 0000aaaabe9ba358 0000aaaabe7ffb80 [35381.177003] 3f80: 0000aaaabe9ba000 0000aaaabe959f64 0000000000000000 0000aaaabe94f000 [35381.184815] 3fa0: 0000000000000000 0000ffffeeeabdb0 0000aaaabe5f3bf8 0000ffffeeeabdb0 [35381.192628] 3fc0: 0000ffffa7c269b8 0000000060000000 0000000000000003 00000000000000e6 [35381.200440] 3fe0: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [35381.208254] [<ffff00000808339c>] __sys_trace_return+0x0/0x4 [35381.213809] Disabling lock debugging due to kernel taint --------------------------------end-------------------------------------- The root cause might be what I fixed at [1]. But from arm kvm points of view, it would be better we caught the exception earlier and clearer. If the size is not PAGE_SIZE aligned, unmap_stage2_range might unmap the wrong(more or less) page range. Hence it caused the "BUG: Bad page state" [1] https://lkml.org/lkml/2018/5/3/1042 Signed-off-by: jia.he@hxt-semitech.com --- virt/kvm/arm/mmu.c | 2 ++ 1 file changed, 2 insertions(+)