"Nicholas Piggin" <npig...@gmail.com> writes: > On Wed Oct 19, 2022 at 8:21 PM AEST, Dan Horák wrote: >> Hi, >> >> in my first boot with the 6.1 rc1 kernel I have received a couple of >> warnings from change_protection on Talos II P9 system, see the details >> below. Nothing like that was noticed in 6.0 or earlier. > > Thanks for the report. This is a false positive in a warning I added > because page_savedwrite overloads the _PAGE_PRIVILEGED bit. The warning > should be harmless and the code will do the right thing (and it will > flush). I think this should do it as a minimal fix. > > I don't really like that we use that bit for this, I think it should not > cause a hardware access issue like with KUAP because there are no RWX > permissions, but having something like pte_user suddenly return false on > these seems a bit fragile. I'd rather use another bit for this, > something like _PAGE_SAO. But that shouldn't be done for this release...
There is an RFC to remove the savedwrite stuff entirely: https://lore.kernel.org/all/20220926152618.194810-1-da...@redhat.com/ cheers > diff --git a/arch/powerpc/include/asm/book3s/64/tlbflush.h > b/arch/powerpc/include/asm/book3s/64/tlbflush.h > index 67655cd60545..4b9eab0995ec 100644 > --- a/arch/powerpc/include/asm/book3s/64/tlbflush.h > +++ b/arch/powerpc/include/asm/book3s/64/tlbflush.h > @@ -178,9 +178,19 @@ static inline bool __pte_flags_need_flush(unsigned long > oldval, > > /* > * We do not expect kernel mappings or non-PTEs or not-present PTEs. > + * pte_savedwrite does use _PAGE_PRIVILEGED for user mappings, so > + * have to filter that out. > */ > - VM_WARN_ON_ONCE(oldval & _PAGE_PRIVILEGED); > - VM_WARN_ON_ONCE(newval & _PAGE_PRIVILEGED); > + if (!IS_ENABLED(CONFIG_NUMA_BALANCING) || > + ((oldval & (_PAGE_PRESENT | _PAGE_PTE | _PAGE_RWX)) != > + (_PAGE_PRESENT | _PAGE_PTE))) > + VM_WARN_ON_ONCE(oldval & _PAGE_PRIVILEGED); > + > + if (!IS_ENABLED(CONFIG_NUMA_BALANCING) || > + ((newval & (_PAGE_PRESENT | _PAGE_PTE | _PAGE_RWX)) != > + (_PAGE_PRESENT | _PAGE_PTE))) > + VM_WARN_ON_ONCE(newval & _PAGE_PRIVILEGED); > + > VM_WARN_ON_ONCE(!(oldval & _PAGE_PTE)); > VM_WARN_ON_ONCE(!(newval & _PAGE_PTE)); > VM_WARN_ON_ONCE(!(oldval & _PAGE_PRESENT)); >> >> >> Thanks, >> >> Dan >> >> [ 79.229100] ------------[ cut here ]------------ >> [ 79.229109] WARNING: CPU: 61 PID: 2987 at >> arch/powerpc/include/asm/book3s/64/tlbflush.h:183 >> change_protection+0xfd0/0x1610 >> [ 79.229125] Modules linked in: nft_reject_inet nf_reject_ipv4 >> nf_reject_ipv6 nft_reject nft_objref nf_conntrack_tftp nft_ct kvm_hv kvm >> nfsv3 nfs_acl rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace >> sunrpc fscache netfs nf_tables ebtable_nat ebtable_broute ip6table_nat >> ip6table_mangle ip6table_raw ip6table_security iptable_nat nf_nat >> nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_mangle iptable_raw >> iptable_security bridge stp llc ip_set nfnetlink rfkill ebtable_filter >> ebtables ip6table_filter iptable_filter binfmt_misc dm_crypt xfs >> snd_hda_codec_realtek snd_hda_codec_generic ledtrig_audio snd_hda_codec_hdmi >> ftdi_sio onboard_usb_hub snd_hda_intel snd_intel_dspcfg snd_hda_codec >> snd_hda_core snd_hwdep snd_seq snd_seq_device snd_pcm snd_timer ses >> enclosure ofpart snd soundcore scsi_transport_sas at24 ipmi_powernv >> ipmi_devintf powernv_flash regmap_i2c opal_prd crct10dif_vpmsum i2c_opal >> ipmi_msghandler mtd rtc_opal amdgpu raid1 drm_ttm_helper ttm mfd_core gpu_sc >> hed vmx_crypto >> [ 79.229258] crc32c_vpmsum drm_buddy nvme drm_display_helper nvme_core >> tg3 nvme_common aacraid cec ip6_tables ip_tables i2c_dev fuse >> [ 79.229283] CPU: 61 PID: 2987 Comm: lightdm-gtk-gre Not tainted >> 6.1.0-0.rc1.15.fc38.ppc64le #1 >> [ 79.229289] Hardware name: T2P9D01 REV 1.00 POWER9 0x4e1202 >> opal:skiboot-bc106a0 PowerNV >> [ 79.229291] NIP: c000000000495aa0 LR: c000000000495608 CTR: >> 0000000000000000 >> [ 79.229295] REGS: c00020001766f690 TRAP: 0700 Not tainted >> (6.1.0-0.rc1.15.fc38.ppc64le) >> [ 79.229299] MSR: 9000000000029033 <SF,HV,EE,ME,IR,DR,RI,LE> CR: >> 44242420 XER: 00000156 >> [ 79.229316] CFAR: c00000000049562c IRQMASK: 0 >> GPR00: c000000000495608 c00020001766f930 c000000001dd7100 >> c00020001e4e3700 >> GPR04: 0000000154440000 c00020004eac3920 84030a73002000c0 >> 88030a73002000c0 >> GPR08: 0000000000000040 0000000000000001 0000000000000040 >> 0000000000000009 >> GPR12: c00020001795f708 c0002007be1a9700 c0002000554b0000 >> 0000000154440000 >> GPR16: c01fffffffff9f40 fffffffffffffe7f c000000002acdbb8 >> c000000002a3aef0 >> GPR20: c00020001766fac8 ff7fffffffffefbf 0801000000000080 >> c00c00080013ab28 >> GPR24: 0000000000000004 c00c00080013ab00 0000000154600000 >> 00000001549b0000 >> GPR28: 88030a73002000c0 c000200054354510 000000000000000d >> c00020004eac3920 >> [ 79.229377] NIP [c000000000495aa0] change_protection+0xfd0/0x1610 >> [ 79.229384] LR [c000000000495608] change_protection+0xb38/0x1610 >> [ 79.229390] Call Trace: >> [ 79.229392] [c00020001766f930] [c000000000495608] >> change_protection+0xb38/0x1610 (unreliable) >> [ 79.229401] [c00020001766faa0] [c0000000004eda5c] >> change_prot_numa+0x7c/0x120 >> [ 79.229408] [c00020001766fb70] [c0000000001ad5dc] >> task_numa_work+0x2cc/0x500 >> [ 79.229414] [c00020001766fc70] [c000000000185bb4] task_work_run+0xf4/0x180 >> [ 79.229421] [c00020001766fcc0] [c0000000000218c4] >> do_notify_resume+0x434/0x470 >> [ 79.229429] [c00020001766fd80] [c00000000002c29c] >> interrupt_exit_user_prepare_main+0x1dc/0x2c0 >> [ 79.229437] [c00020001766fde0] [c00000000002c618] >> interrupt_exit_user_prepare+0x58/0xb0 >> [ 79.229444] [c00020001766fe10] [c00000000000c8f4] >> interrupt_return_srr_user+0x8/0x138 >> [ 79.229452] --- interrupt: 900 at 0x7fffa62b7cfc >> [ 79.229458] NIP: 00007fffa62b7cfc LR: 00007fffa62b7c48 CTR: >> 0000000000000639 >> [ 79.229461] REGS: c00020001766fe80 TRAP: 0900 Not tainted >> (6.1.0-0.rc1.15.fc38.ppc64le) >> [ 79.229464] MSR: 900000000280f033 >> <SF,HV,VEC,VSX,EE,PR,FP,ME,IR,DR,RI,LE> CR: 88444424 XER: 00000156 >> [ 79.229484] CFAR: 0000000000000000 IRQMASK: 0 >> GPR00: 00007fffa62b7c28 00007fffc324a3e0 00007fffa63f7a00 >> 00007ffe53000000 >> GPR04: 00007ffe532d7800 00007fff594d9610 00007fff594d8e90 >> 00000000000000b8 >> GPR08: 00007ffe532d7d20 00007fff594d7d30 00000000000000b9 >> 0000000000000000 >> GPR12: 00007fffa611bfd0 00007fffa6e58d00 0000000000000008 >> 00007fffa5d97480 >> GPR16: 0000000154958000 000000000000000b 0000000000000020 >> 0001000000000000 >> GPR20: 000000000000027f 0000000154907000 00000001543e9100 >> 0000000000000000 >> GPR24: 0000000000000004 00000000000004b0 0000000000000780 >> 0000000000001e00 >> GPR28: 000000000000032c 0000000000001e00 00007fff594d7810 >> 00000001548d71a0 >> [ 79.229545] NIP [00007fffa62b7cfc] 0x7fffa62b7cfc >> [ 79.229548] LR [00007fffa62b7c48] 0x7fffa62b7c48 >> [ 79.229551] --- interrupt: 900 >> [ 79.229553] Instruction dump: >> [ 79.229555] 0fe00000 60000000 60000000 60420000 0fe00000 60000000 >> 60000000 60420000 >> [ 79.229568] 0fe00000 60000000 60000000 60420000 <0fe00000> 60000000 >> 60000000 60420000 >> [ 79.229580] ---[ end trace 0000000000000000 ]--- >> [ 245.260381] ------------[ cut here ]------------ >> [ 245.260388] WARNING: CPU: 4 PID: 4468 at >> arch/powerpc/include/asm/book3s/64/tlbflush.h:182 >> change_protection+0xfc0/0x1610 >> [ 245.260405] Modules linked in: nft_reject_inet nf_reject_ipv4 >> nf_reject_ipv6 nft_reject nft_objref nf_conntrack_tftp nft_ct kvm_hv kvm >> nfsv3 nfs_acl rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace >> sunrpc fscache netfs nf_tables ebtable_nat ebtable_broute ip6table_nat >> ip6table_mangle ip6table_raw ip6table_security iptable_nat nf_nat >> nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_mangle iptable_raw >> iptable_security bridge stp llc ip_set nfnetlink rfkill ebtable_filter >> ebtables ip6table_filter iptable_filter binfmt_misc dm_crypt xfs >> snd_hda_codec_realtek snd_hda_codec_generic ledtrig_audio snd_hda_codec_hdmi >> ftdi_sio onboard_usb_hub snd_hda_intel snd_intel_dspcfg snd_hda_codec >> snd_hda_core snd_hwdep snd_seq snd_seq_device snd_pcm snd_timer ses >> enclosure ofpart snd soundcore scsi_transport_sas at24 ipmi_powernv >> ipmi_devintf powernv_flash regmap_i2c opal_prd crct10dif_vpmsum i2c_opal >> ipmi_msghandler mtd rtc_opal amdgpu raid1 drm_ttm_helper ttm mfd_core gpu_sc >> hed vmx_crypto >> [ 245.260542] crc32c_vpmsum drm_buddy nvme drm_display_helper nvme_core >> tg3 nvme_common aacraid cec ip6_tables ip_tables i2c_dev fuse >> [ 245.260565] CPU: 4 PID: 4468 Comm: WebExtensions Tainted: G W >> ------- --- 6.1.0-0.rc1.15.fc38.ppc64le #1 >> [ 245.260571] Hardware name: T2P9D01 REV 1.00 POWER9 0x4e1202 >> opal:skiboot-bc106a0 PowerNV >> [ 245.260574] NIP: c000000000495a90 LR: c000000000495608 CTR: >> 0000000000000000 >> [ 245.260578] REGS: c000000039adf3e0 TRAP: 0700 Tainted: G W >> ------- --- (6.1.0-0.rc1.15.fc38.ppc64le) >> [ 245.260582] MSR: 9000000000029033 <SF,HV,EE,ME,IR,DR,RI,LE> CR: >> 48422244 XER: 0000007d >> [ 245.260600] CFAR: c000000000495624 IRQMASK: 0 >> GPR00: c000000000495608 c000000039adf680 c000000001dd7100 >> c00000002c576900 >> GPR04: 00002ce2ebc90000 c000000091a2e148 8803c8a6000000c0 >> 8603c8a6000000c0 >> GPR08: 0000000000000040 0000000000000001 0000000000000040 >> 0000000000000009 >> GPR12: 0000000000000005 c0000007bfdeba00 c00000007195b9d8 >> 00002ce2ebc90000 >> GPR16: c01fffffffff9f40 fffffffffffffe7f c000000002acdbb8 >> c000000002a3aef0 >> GPR20: c000000039adf938 ff7fffffffffefbf 0401000000000080 >> c00c0000002468a8 >> GPR24: 0000000000000000 c00c000000246880 00002ce2ebca0000 >> 00002ce2ebca0000 >> GPR28: 8603c8a6000000c0 c000000091a18af0 0000000000000000 >> c000000091a2e148 >> [ 245.260660] NIP [c000000000495a90] change_protection+0xfc0/0x1610 >> [ 245.260666] LR [c000000000495608] change_protection+0xb38/0x1610 >> [ 245.260673] Call Trace: >> [ 245.260675] [c000000039adf680] [c000000000495608] >> change_protection+0xb38/0x1610 (unreliable) >> [ 245.260684] [c000000039adf7f0] [c000000000496214] >> mprotect_fixup+0x134/0x3a0 >> [ 245.260691] [c000000039adf8d0] [c0000000004967c0] >> do_mprotect_pkey+0x340/0x580 >> [ 245.260699] [c000000039adfa20] [c000000000496a30] sys_mprotect+0x30/0x40 >> [ 245.260706] [c000000039adfa40] [c00000000002d308] >> system_call_exception+0x178/0x320 >> [ 245.260715] [c000000039adfe10] [c00000000000c170] >> system_call_vectored_common+0xf0/0x280 >> [ 245.260725] --- interrupt: 3000 at 0x7fff90f5d698 >> [ 245.260731] NIP: 00007fff90f5d698 LR: 0000000000000000 CTR: >> 0000000000000000 >> [ 245.260734] REGS: c000000039adfe80 TRAP: 3000 Tainted: G W >> ------- --- (6.1.0-0.rc1.15.fc38.ppc64le) >> [ 245.260737] MSR: 900000000280f033 >> <SF,HV,VEC,VSX,EE,PR,FP,ME,IR,DR,RI,LE> CR: 44244448 XER: 00000000 >> [ 245.260758] IRQMASK: 0 >> GPR00: 000000000000007d 00007fffc4e69ec0 00007fff91066e00 >> 00002ce2ebc90000 >> GPR04: 0000000000010000 0000000000000003 0000000000000000 >> 0000000000000018 >> GPR08: 000000000000057b 0000000000000000 0000000000000000 >> 0000000000000000 >> GPR12: 0000000000000000 00007fff9187c300 0000000000000000 >> 0000000000000000 >> GPR16: 0000000000000000 0000000000000000 0000000000000000 >> 0000000000000000 >> GPR20: 0000000155b45178 0000000156140ec8 0000000155c1e300 >> 0000000000000000 >> GPR24: 0000000000000000 00007fffc4e6a080 00007fffc4e6a220 >> 00007fffc4e69fc8 >> GPR28: 00002ce2ebc90000 0000000000000004 000000000001ffb7 >> 0000000000100000 >> [ 245.260815] NIP [00007fff90f5d698] 0x7fff90f5d698 >> [ 245.260818] LR [0000000000000000] 0x0 >> [ 245.260821] --- interrupt: 3000 >> [ 245.260823] Instruction dump: >> [ 245.260826] 3b180001 61290008 b1340020 4bfffc54 0fe00000 60000000 >> 60000000 60420000 >> [ 245.260838] 0fe00000 60000000 60000000 60420000 <0fe00000> 60000000 >> 60000000 60420000 >> [ 245.260850] ---[ end trace 0000000000000000 ]---
