* Re: Bug with report THP eligibility for each vma [not found] <CALouPAi8KEuPw_Ly5W=MkYi8Yw3J6vr8mVezYaxxVyKCxH1x_g@mail.gmail.com> @ 2018-12-24 7:49 ` Michal Hocko 2018-12-24 11:35 ` William Kucharski 2018-12-24 12:12 ` Mike Rapoport 0 siblings, 2 replies; 5+ messages in thread From: Michal Hocko @ 2018-12-24 7:49 UTC (permalink / raw) To: Paul Oppenheimer, Andrew Morton Cc: Vlastimil Babka, David Rientjes, Jan Kara, Mike Rapoport, linux-mm, LKML [Cc-ing mailing list and people involved in the original patch] On Fri 21-12-18 13:42:24, Paul Oppenheimer wrote: > Hello! I've never reported a kernel bug before, and since its on the > "next" tree I was told to email the author of the relevant commit. > Please redirect me to the correct place if I've made a mistake. > > When opening firefox or chrome, and using it for a good 7 seconds, it > hangs in "uninterruptible sleep" and I recieve a "BUG" in dmesg. This > doesn't occur when reverting this commit: > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=48cf516f8c. > Ive attached the output of decode_stacktrace.sh and the relevant dmesg > log to this email. > > Thanks > BUG: unable to handle kernel NULL pointer dereference at 00000000000000e8 Thanks for the bug report! This is offset 232 and that matches file->f_mapping as per pahole pahole -C file ./vmlinux | grep f_mapping struct address_space * f_mapping; /* 232 8 */ I thought that each file really has to have a mapping. But the following should heal the issue and add an extra care. diff --git a/mm/huge_memory.c b/mm/huge_memory.c index f64733c23067..fc9d70a9fbd1 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -66,6 +66,8 @@ bool transparent_hugepage_enabled(struct vm_area_struct *vma) { if (vma_is_anonymous(vma)) return __transparent_hugepage_enabled(vma); + if (!vma->vm_file || !vma->vm_file->f_mapping) + return false; if (shmem_mapping(vma->vm_file->f_mapping) && shmem_huge_enabled(vma)) return __transparent_hugepage_enabled(vma); Andrew, could you fold it to the original patch please? Keeping the rest for the reference. > #PF error: [normal kernel read fault] > PGD 0 P4D 0 > Oops: 0000 [#1] PREEMPT SMP PTI > CPU: 7 PID: 2687 Comm: StreamTrans #56 Tainted: G U 4.20.0-rc7-next-20181221-beppy+ #15 > Hardware name: Dell Inc. XPS 13 9360/0TPN17, BIOS 2.10.0 09/27/2018 > RIP: 0010:transparent_hugepage_enabled (??:?) > Code: 17 fd 00 e9 20 ff ff ff 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 53 48 89 fb 48 83 bf 90 00 00 00 00 74 27 48 8b 87 a0 00 00 00 <48> 8b b8 e8 00 00 00 e8 7a cc fa ff 84 c0 75 04 31 c0 5b c3 48 89 > All code > ======== > 0: 17 (bad) > 1: fd std > 2: 00 e9 add %ch,%cl > 4: 20 ff and %bh,%bh > 6: ff (bad) > 7: ff 0f decl (%rdi) > 9: 1f (bad) > a: 84 00 test %al,(%rax) > c: 00 00 add %al,(%rax) > e: 00 00 add %al,(%rax) > 10: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) > 15: 53 push %rbx > 16: 48 89 fb mov %rdi,%rbx > 19: 48 83 bf 90 00 00 00 cmpq $0x0,0x90(%rdi) > 20: 00 > 21: 74 27 je 0x4a > 23: 48 8b 87 a0 00 00 00 mov 0xa0(%rdi),%rax > 2a:* 48 8b b8 e8 00 00 00 mov 0xe8(%rax),%rdi <-- trapping instruction > 31: e8 7a cc fa ff callq 0xfffffffffffaccb0 > 36: 84 c0 test %al,%al > 38: 75 04 jne 0x3e > 3a: 31 c0 xor %eax,%eax > 3c: 5b pop %rbx > 3d: c3 retq > 3e: 48 rex.W > 3f: 89 .byte 0x89 > > Code starting with the faulting instruction > =========================================== > 0: 48 8b b8 e8 00 00 00 mov 0xe8(%rax),%rdi > 7: e8 7a cc fa ff callq 0xfffffffffffacc86 > c: 84 c0 test %al,%al > e: 75 04 jne 0x14 > 10: 31 c0 xor %eax,%eax > 12: 5b pop %rbx > 13: c3 retq > 14: 48 rex.W > 15: 89 .byte 0x89 > RSP: 0018:ffffb79744f17d28 EFLAGS: 00010282 > RAX: 0000000000000000 RBX: ffff8948c17aff00 RCX: 0000000000000000 > RDX: 0000000000000004 RSI: ffffffffab1165ba RDI: ffff8948c17aff00 > RBP: ffff8948c17aff00 R08: 0000000000000007 R09: ffff894927e547b2 > R10: 0000000000000000 R11: ffff894927e549da R12: ffffb79744f17d38 > R13: ffff8948c17aff00 R14: ffff89489bef9400 R15: ffff89488b775a80 > FS: 00007fa54ad43700(0000) GS:ffff8949363c0000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00000000000000e8 CR3: 000000025c0ee003 CR4: 00000000003606e0 > Call Trace: > show_smap (/home/bep/.opt/kernel/linux-e/fs/proc/task_mmu.c:805) > seq_read (/home/bep/.opt/kernel/linux-e/fs/seq_file.c:269) > __vfs_read (/home/bep/.opt/kernel/linux-e/fs/read_write.c:421) > vfs_read (/home/bep/.opt/kernel/linux-e/fs/read_write.c:452 /home/bep/.opt/kernel/linux-e/fs/read_write.c:437) > ksys_read (/home/bep/.opt/kernel/linux-e/fs/read_write.c:579) > do_syscall_64 (/home/bep/.opt/kernel/linux-e/arch/x86/entry/common.c:290) > entry_SYSCALL_64_after_hwframe (/home/bep/.opt/kernel/linux/arch/x86/entry/entry_64.S:184) > RIP: 0033:0x7fa585fb3184 > Code: c3 0f 1f 44 00 00 41 54 49 89 d4 55 48 89 f5 53 89 fb 48 83 ec 10 e8 5b fc ff ff 4c 89 e2 48 89 ee 89 df 41 89 c0 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 38 44 89 c7 48 89 44 24 08 e8 97 fc ff ff 48 > All code > ======== > 0: c3 retq > 1: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) > 6: 41 54 push %r12 > 8: 49 89 d4 mov %rdx,%r12 > b: 55 push %rbp > c: 48 89 f5 mov %rsi,%rbp > f: 53 push %rbx > 10: 89 fb mov %edi,%ebx > 12: 48 83 ec 10 sub $0x10,%rsp > 16: e8 5b fc ff ff callq 0xfffffffffffffc76 > 1b: 4c 89 e2 mov %r12,%rdx > 1e: 48 89 ee mov %rbp,%rsi > 21: 89 df mov %ebx,%edi > 23: 41 89 c0 mov %eax,%r8d > 26: 31 c0 xor %eax,%eax > 28: 0f 05 syscall > 2a:* 48 3d 00 f0 ff ff cmp $0xfffffffffffff000,%rax <-- trapping instruction > 30: 77 38 ja 0x6a > 32: 44 89 c7 mov %r8d,%edi > 35: 48 89 44 24 08 mov %rax,0x8(%rsp) > 3a: e8 97 fc ff ff callq 0xfffffffffffffcd6 > 3f: 48 rex.W > > Code starting with the faulting instruction > =========================================== > 0: 48 3d 00 f0 ff ff cmp $0xfffffffffffff000,%rax > 6: 77 38 ja 0x40 > 8: 44 89 c7 mov %r8d,%edi > b: 48 89 44 24 08 mov %rax,0x8(%rsp) > 10: e8 97 fc ff ff callq 0xfffffffffffffcac > 15: 48 rex.W > RSP: 002b:00007fa54ad42060 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 > RAX: ffffffffffffffda RBX: 000000000000002c RCX: 00007fa585fb3184 > RDX: 0000000000001fff RSI: 00007fa54ffb2000 RDI: 000000000000002c > RBP: 00007fa54ffb2000 R08: 0000000000000000 R09: 000000000000001e > R10: 00007fa585c0dae0 R11: 0000000000000246 R12: 0000000000001fff > R13: 00007fa54ad42510 R14: 00007fa54ffb2fc5 R15: 00007fa54ad42498 > Modules linked in: thunderbolt sch_cake rfcomm fuse arc4 iwlmvm mac80211 btusb btrtl btbcm btintel bnep bluetooth iwlwifi snd_hda_codec_hdmi ecdh_generic snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel cfg80211 snd_hda_codec nf_log_ipv6 ip6t_REJECT nf_reject_ipv6 snd_hwdep xt_hl snd_hda_core ip6t_rt nf_log_ipv4 nf_log_common joydev snd_pcm mousedev ipt_REJECT nf_reject_ipv4 hid_multitouch intel_rapl xt_LOG xt_comment nls_iso8859_1 intel_pmc_core nls_cp437 intel_powerclamp xt_limit kvm_intel xt_addrtype xt_tcpudp dell_laptop snd_timer xt_conntrack ledtrig_audio snd dell_wmi nf_conntrack efi_pstore dell_smbios mei_me dcdbas input_leds idma64 mei wmi_bmof intel_wmi_thunderbolt dell_wmi_descriptor efivars rfkill intel_pch_thermal intel_lpss_pci processor_thermal_device i2c_i801 soundcore intel_lpss intel_soc_dts_iosf i2c_hid evdev int3403_thermal int3400_thermal intel_vbtn rtc_cmos int340x_thermal_zone acpi_thermal_rel intel_hid mac_hid nf_defrag_ipv6 nf_defrag_ipv4 > ip6table_filter ip6_tables iptable_filter bpfilter coretemp msr dell_smm_hwmon crypto_user ip_tables x_tables algif_skcipher af_alg rtsx_pci_sdmmc mmc_core crct10dif_pclmul crc32_pclmul xhci_pci ghash_clmulni_intel serio_raw rtsx_pci xhci_hcd i915 kvmgt vfio_mdev mdev vfio_iommu_type1 vfio kvm irqbypass intel_gtt > CR2: 00000000000000e8 > ---[ end trace 77d24d35c4e5213f ]--- > RIP: 0010:transparent_hugepage_enabled (??:?) > Code: 17 fd 00 e9 20 ff ff ff 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 53 48 89 fb 48 83 bf 90 00 00 00 00 74 27 48 8b 87 a0 00 00 00 <48> 8b b8 e8 00 00 00 e8 7a cc fa ff 84 c0 75 04 31 c0 5b c3 48 89 > All code > ======== > 0: 17 (bad) > 1: fd std > 2: 00 e9 add %ch,%cl > 4: 20 ff and %bh,%bh > 6: ff (bad) > 7: ff 0f decl (%rdi) > 9: 1f (bad) > a: 84 00 test %al,(%rax) > c: 00 00 add %al,(%rax) > e: 00 00 add %al,(%rax) > 10: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) > 15: 53 push %rbx > 16: 48 89 fb mov %rdi,%rbx > 19: 48 83 bf 90 00 00 00 cmpq $0x0,0x90(%rdi) > 20: 00 > 21: 74 27 je 0x4a > 23: 48 8b 87 a0 00 00 00 mov 0xa0(%rdi),%rax > 2a:* 48 8b b8 e8 00 00 00 mov 0xe8(%rax),%rdi <-- trapping instruction > 31: e8 7a cc fa ff callq 0xfffffffffffaccb0 > 36: 84 c0 test %al,%al > 38: 75 04 jne 0x3e > 3a: 31 c0 xor %eax,%eax > 3c: 5b pop %rbx > 3d: c3 retq > 3e: 48 rex.W > 3f: 89 .byte 0x89 > > Code starting with the faulting instruction > =========================================== > 0: 48 8b b8 e8 00 00 00 mov 0xe8(%rax),%rdi > 7: e8 7a cc fa ff callq 0xfffffffffffacc86 > c: 84 c0 test %al,%al > e: 75 04 jne 0x14 > 10: 31 c0 xor %eax,%eax > 12: 5b pop %rbx > 13: c3 retq > 14: 48 rex.W > 15: 89 .byte 0x89 > RSP: 0018:ffffb79744f17d28 EFLAGS: 00010282 > RAX: 0000000000000000 RBX: ffff8948c17aff00 RCX: 0000000000000000 > RDX: 0000000000000004 RSI: ffffffffab1165ba RDI: ffff8948c17aff00 > RBP: ffff8948c17aff00 R08: 0000000000000007 R09: ffff894927e547b2 > R10: 0000000000000000 R11: ffff894927e549da R12: ffffb79744f17d38 > R13: ffff8948c17aff00 R14: ffff89489bef9400 R15: ffff89488b775a80 > FS: 00007fa54ad43700(0000) GS:ffff8949363c0000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > BUG: unable to handle kernel NULL pointer dereference at 00000000000000e8 > #PF error: [normal kernel read fault] > PGD 0 P4D 0 > Oops: 0000 [#1] PREEMPT SMP PTI > CPU: 7 PID: 2687 Comm: StreamTrans #56 Tainted: G U 4.20.0-rc7-next-20181221-beppy+ #15 > Hardware name: Dell Inc. XPS 13 9360/0TPN17, BIOS 2.10.0 09/27/2018 > RIP: 0010:transparent_hugepage_enabled+0x1a/0xa0 > Code: 17 fd 00 e9 20 ff ff ff 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 53 48 89 fb 48 83 bf 90 00 00 00 00 74 27 48 8b 87 a0 00 00 00 <48> 8b b8 e8 00 00 00 e8 7a cc fa ff 84 c0 75 04 31 c0 5b c3 48 89 > RSP: 0018:ffffb79744f17d28 EFLAGS: 00010282 > RAX: 0000000000000000 RBX: ffff8948c17aff00 RCX: 0000000000000000 > RDX: 0000000000000004 RSI: ffffffffab1165ba RDI: ffff8948c17aff00 > RBP: ffff8948c17aff00 R08: 0000000000000007 R09: ffff894927e547b2 > R10: 0000000000000000 R11: ffff894927e549da R12: ffffb79744f17d38 > R13: ffff8948c17aff00 R14: ffff89489bef9400 R15: ffff89488b775a80 > FS: 00007fa54ad43700(0000) GS:ffff8949363c0000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00000000000000e8 CR3: 000000025c0ee003 CR4: 00000000003606e0 > Call Trace: > show_smap+0xd7/0x200 > seq_read+0x2e8/0x410 > __vfs_read+0x36/0x1a0 > vfs_read+0x8a/0x140 > ksys_read+0x52/0xc0 > do_syscall_64+0x48/0xf0 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > RIP: 0033:0x7fa585fb3184 > Code: c3 0f 1f 44 00 00 41 54 49 89 d4 55 48 89 f5 53 89 fb 48 83 ec 10 e8 5b fc ff ff 4c 89 e2 48 89 ee 89 df 41 89 c0 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 38 44 89 c7 48 89 44 24 08 e8 97 fc ff ff 48 > RSP: 002b:00007fa54ad42060 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 > RAX: ffffffffffffffda RBX: 000000000000002c RCX: 00007fa585fb3184 > RDX: 0000000000001fff RSI: 00007fa54ffb2000 RDI: 000000000000002c > RBP: 00007fa54ffb2000 R08: 0000000000000000 R09: 000000000000001e > R10: 00007fa585c0dae0 R11: 0000000000000246 R12: 0000000000001fff > R13: 00007fa54ad42510 R14: 00007fa54ffb2fc5 R15: 00007fa54ad42498 > Modules linked in: thunderbolt sch_cake rfcomm fuse arc4 iwlmvm mac80211 btusb btrtl btbcm btintel bnep bluetooth iwlwifi snd_hda_codec_hdmi ecdh_generic snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel cfg80211 snd_hda_codec nf_log_ipv6 ip6t_REJECT nf_reject_ipv6 snd_hwdep xt_hl snd_hda_core ip6t_rt nf_log_ipv4 nf_log_common joydev snd_pcm mousedev ipt_REJECT nf_reject_ipv4 hid_multitouch intel_rapl xt_LOG xt_comment nls_iso8859_1 intel_pmc_core nls_cp437 intel_powerclamp xt_limit kvm_intel xt_addrtype xt_tcpudp dell_laptop snd_timer xt_conntrack ledtrig_audio snd dell_wmi nf_conntrack efi_pstore dell_smbios mei_me dcdbas input_leds idma64 mei wmi_bmof intel_wmi_thunderbolt dell_wmi_descriptor efivars rfkill intel_pch_thermal intel_lpss_pci processor_thermal_device i2c_i801 soundcore intel_lpss intel_soc_dts_iosf i2c_hid evdev int3403_thermal int3400_thermal intel_vbtn rtc_cmos int340x_thermal_zone acpi_thermal_rel intel_hid mac_hid nf_defrag_ipv6 nf_defrag_ipv4 > ip6table_filter ip6_tables iptable_filter bpfilter coretemp msr dell_smm_hwmon crypto_user ip_tables x_tables algif_skcipher af_alg rtsx_pci_sdmmc mmc_core crct10dif_pclmul crc32_pclmul xhci_pci ghash_clmulni_intel serio_raw rtsx_pci xhci_hcd i915 kvmgt vfio_mdev mdev vfio_iommu_type1 vfio kvm irqbypass intel_gtt > CR2: 00000000000000e8 > ---[ end trace 77d24d35c4e5213f ]--- > RIP: 0010:transparent_hugepage_enabled+0x1a/0xa0 > Code: 17 fd 00 e9 20 ff ff ff 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 53 48 89 fb 48 83 bf 90 00 00 00 00 74 27 48 8b 87 a0 00 00 00 <48> 8b b8 e8 00 00 00 e8 7a cc fa ff 84 c0 75 04 31 c0 5b c3 48 89 > RSP: 0018:ffffb79744f17d28 EFLAGS: 00010282 > RAX: 0000000000000000 RBX: ffff8948c17aff00 RCX: 0000000000000000 > RDX: 0000000000000004 RSI: ffffffffab1165ba RDI: ffff8948c17aff00 > RBP: ffff8948c17aff00 R08: 0000000000000007 R09: ffff894927e547b2 > R10: 0000000000000000 R11: ffff894927e549da R12: ffffb79744f17d38 > R13: ffff8948c17aff00 R14: ffff89489bef9400 R15: ffff89488b775a80 > FS: 00007fa54ad43700(0000) GS:ffff8949363c0000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00000000000000e8 CR3: 000000025c0ee003 CR4: 00000000003606e0 -- Michal Hocko SUSE Labs ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: Bug with report THP eligibility for each vma 2018-12-24 7:49 ` Bug with report THP eligibility for each vma Michal Hocko @ 2018-12-24 11:35 ` William Kucharski 2018-12-24 11:35 ` William Kucharski 2018-12-24 12:12 ` Mike Rapoport 1 sibling, 1 reply; 5+ messages in thread From: William Kucharski @ 2018-12-24 11:35 UTC (permalink / raw) To: Michal Hocko Cc: Paul Oppenheimer, Andrew Morton, Vlastimil Babka, David Rientjes, Jan Kara, Mike Rapoport, linux-mm, LKML > On Dec 24, 2018, at 12:49 AM, Michal Hocko <mhocko@suse.com> wrote: > > [Cc-ing mailing list and people involved in the original patch] > > On Fri 21-12-18 13:42:24, Paul Oppenheimer wrote: >> Hello! I've never reported a kernel bug before, and since its on the >> "next" tree I was told to email the author of the relevant commit. >> Please redirect me to the correct place if I've made a mistake. >> >> When opening firefox or chrome, and using it for a good 7 seconds, it >> hangs in "uninterruptible sleep" and I recieve a "BUG" in dmesg. This >> doesn't occur when reverting this commit: >> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=48cf516f8c. >> Ive attached the output of decode_stacktrace.sh and the relevant dmesg >> log to this email. >> >> Thanks > >> BUG: unable to handle kernel NULL pointer dereference at 00000000000000e8 > > Thanks for the bug report! This is offset 232 and that matches > file->f_mapping as per pahole > pahole -C file ./vmlinux | grep f_mapping > struct address_space * f_mapping; /* 232 8 */ > > I thought that each file really has to have a mapping. But the following > should heal the issue and add an extra care. > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index f64733c23067..fc9d70a9fbd1 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -66,6 +66,8 @@ bool transparent_hugepage_enabled(struct vm_area_struct *vma) > { > if (vma_is_anonymous(vma)) > return __transparent_hugepage_enabled(vma); > + if (!vma->vm_file || !vma->vm_file->f_mapping) > + return false; > if (shmem_mapping(vma->vm_file->f_mapping) && shmem_huge_enabled(vma)) > return __transparent_hugepage_enabled(vma); From what I see in code in mm/mmap.c, it seems if vma->vm_file is non-zero vma->vm_file->f_mapping may be assumed to be non-NULL; see unlink_file_vma() and __vma_link_file() for two examples, which both use the construct: file = vma->vm_file; if (file) { struct address_space *mapping = file->f_mapping; [ ... ] [ code that dereferences "mapping" without further checks ] } I see nothing wrong with your second check but a few extra instructions performed, but depending upon how often transparent_hugepage_enabled() is called there may be at least theoretical performance concerns. William Kucharski william.kucharski@oracle.com ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Bug with report THP eligibility for each vma 2018-12-24 11:35 ` William Kucharski @ 2018-12-24 11:35 ` William Kucharski 0 siblings, 0 replies; 5+ messages in thread From: William Kucharski @ 2018-12-24 11:35 UTC (permalink / raw) To: Michal Hocko Cc: Paul Oppenheimer, Andrew Morton, Vlastimil Babka, David Rientjes, Jan Kara, Mike Rapoport, linux-mm, LKML > On Dec 24, 2018, at 12:49 AM, Michal Hocko <mhocko@suse.com> wrote: > > [Cc-ing mailing list and people involved in the original patch] > > On Fri 21-12-18 13:42:24, Paul Oppenheimer wrote: >> Hello! I've never reported a kernel bug before, and since its on the >> "next" tree I was told to email the author of the relevant commit. >> Please redirect me to the correct place if I've made a mistake. >> >> When opening firefox or chrome, and using it for a good 7 seconds, it >> hangs in "uninterruptible sleep" and I recieve a "BUG" in dmesg. This >> doesn't occur when reverting this commit: >> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=48cf516f8c. >> Ive attached the output of decode_stacktrace.sh and the relevant dmesg >> log to this email. >> >> Thanks > >> BUG: unable to handle kernel NULL pointer dereference at 00000000000000e8 > > Thanks for the bug report! This is offset 232 and that matches > file->f_mapping as per pahole > pahole -C file ./vmlinux | grep f_mapping > struct address_space * f_mapping; /* 232 8 */ > > I thought that each file really has to have a mapping. But the following > should heal the issue and add an extra care. > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index f64733c23067..fc9d70a9fbd1 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -66,6 +66,8 @@ bool transparent_hugepage_enabled(struct vm_area_struct *vma) > { > if (vma_is_anonymous(vma)) > return __transparent_hugepage_enabled(vma); > + if (!vma->vm_file || !vma->vm_file->f_mapping) > + return false; > if (shmem_mapping(vma->vm_file->f_mapping) && shmem_huge_enabled(vma)) > return __transparent_hugepage_enabled(vma); From what I see in code in mm/mmap.c, it seems if vma->vm_file is non-zero vma->vm_file->f_mapping may be assumed to be non-NULL; see unlink_file_vma() and __vma_link_file() for two examples, which both use the construct: file = vma->vm_file; if (file) { struct address_space *mapping = file->f_mapping; [ ... ] [ code that dereferences "mapping" without further checks ] } I see nothing wrong with your second check but a few extra instructions performed, but depending upon how often transparent_hugepage_enabled() is called there may be at least theoretical performance concerns. William Kucharski william.kucharski@oracle.com ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Bug with report THP eligibility for each vma 2018-12-24 7:49 ` Bug with report THP eligibility for each vma Michal Hocko 2018-12-24 11:35 ` William Kucharski @ 2018-12-24 12:12 ` Mike Rapoport 2018-12-24 18:51 ` Michal Hocko 1 sibling, 1 reply; 5+ messages in thread From: Mike Rapoport @ 2018-12-24 12:12 UTC (permalink / raw) To: Michal Hocko Cc: Paul Oppenheimer, Andrew Morton, Vlastimil Babka, David Rientjes, Jan Kara, linux-mm, LKML On Mon, Dec 24, 2018 at 08:49:16AM +0100, Michal Hocko wrote: > [Cc-ing mailing list and people involved in the original patch] > > On Fri 21-12-18 13:42:24, Paul Oppenheimer wrote: > > Hello! I've never reported a kernel bug before, and since its on the > > "next" tree I was told to email the author of the relevant commit. > > Please redirect me to the correct place if I've made a mistake. > > > > When opening firefox or chrome, and using it for a good 7 seconds, it > > hangs in "uninterruptible sleep" and I recieve a "BUG" in dmesg. This > > doesn't occur when reverting this commit: > > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=48cf516f8c. > > Ive attached the output of decode_stacktrace.sh and the relevant dmesg > > log to this email. > > > > Thanks > > > BUG: unable to handle kernel NULL pointer dereference at 00000000000000e8 > > Thanks for the bug report! This is offset 232 and that matches > file->f_mapping as per pahole > pahole -C file ./vmlinux | grep f_mapping > struct address_space * f_mapping; /* 232 8 */ > > I thought that each file really has to have a mapping. But the following > should heal the issue and add an extra care. > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index f64733c23067..fc9d70a9fbd1 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -66,6 +66,8 @@ bool transparent_hugepage_enabled(struct vm_area_struct *vma) > { > if (vma_is_anonymous(vma)) > return __transparent_hugepage_enabled(vma); > + if (!vma->vm_file || !vma->vm_file->f_mapping) > + return false; > if (shmem_mapping(vma->vm_file->f_mapping) && shmem_huge_enabled(vma)) > return __transparent_hugepage_enabled(vma); We have vma_is_shmem(), it can be used to replace shmem_mapping() without adding the check for !vma->vm_file > > Andrew, could you fold it to the original patch please? > > Keeping the rest for the reference. > > > #PF error: [normal kernel read fault] > > PGD 0 P4D 0 > > Oops: 0000 [#1] PREEMPT SMP PTI > > CPU: 7 PID: 2687 Comm: StreamTrans #56 Tainted: G U 4.20.0-rc7-next-20181221-beppy+ #15 > > Hardware name: Dell Inc. XPS 13 9360/0TPN17, BIOS 2.10.0 09/27/2018 > > RIP: 0010:transparent_hugepage_enabled (??:?) > > Code: 17 fd 00 e9 20 ff ff ff 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 53 48 89 fb 48 83 bf 90 00 00 00 00 74 27 48 8b 87 a0 00 00 00 <48> 8b b8 e8 00 00 00 e8 7a cc fa ff 84 c0 75 04 31 c0 5b c3 48 89 > > All code > > ======== > > 0: 17 (bad) > > 1: fd std > > 2: 00 e9 add %ch,%cl > > 4: 20 ff and %bh,%bh > > 6: ff (bad) > > 7: ff 0f decl (%rdi) > > 9: 1f (bad) > > a: 84 00 test %al,(%rax) > > c: 00 00 add %al,(%rax) > > e: 00 00 add %al,(%rax) > > 10: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) > > 15: 53 push %rbx > > 16: 48 89 fb mov %rdi,%rbx > > 19: 48 83 bf 90 00 00 00 cmpq $0x0,0x90(%rdi) > > 20: 00 > > 21: 74 27 je 0x4a > > 23: 48 8b 87 a0 00 00 00 mov 0xa0(%rdi),%rax > > 2a:* 48 8b b8 e8 00 00 00 mov 0xe8(%rax),%rdi <-- trapping instruction > > 31: e8 7a cc fa ff callq 0xfffffffffffaccb0 > > 36: 84 c0 test %al,%al > > 38: 75 04 jne 0x3e > > 3a: 31 c0 xor %eax,%eax > > 3c: 5b pop %rbx > > 3d: c3 retq > > 3e: 48 rex.W > > 3f: 89 .byte 0x89 > > > > Code starting with the faulting instruction > > =========================================== > > 0: 48 8b b8 e8 00 00 00 mov 0xe8(%rax),%rdi > > 7: e8 7a cc fa ff callq 0xfffffffffffacc86 > > c: 84 c0 test %al,%al > > e: 75 04 jne 0x14 > > 10: 31 c0 xor %eax,%eax > > 12: 5b pop %rbx > > 13: c3 retq > > 14: 48 rex.W > > 15: 89 .byte 0x89 > > RSP: 0018:ffffb79744f17d28 EFLAGS: 00010282 > > RAX: 0000000000000000 RBX: ffff8948c17aff00 RCX: 0000000000000000 > > RDX: 0000000000000004 RSI: ffffffffab1165ba RDI: ffff8948c17aff00 > > RBP: ffff8948c17aff00 R08: 0000000000000007 R09: ffff894927e547b2 > > R10: 0000000000000000 R11: ffff894927e549da R12: ffffb79744f17d38 > > R13: ffff8948c17aff00 R14: ffff89489bef9400 R15: ffff89488b775a80 > > FS: 00007fa54ad43700(0000) GS:ffff8949363c0000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 00000000000000e8 CR3: 000000025c0ee003 CR4: 00000000003606e0 > > Call Trace: > > show_smap (/home/bep/.opt/kernel/linux-e/fs/proc/task_mmu.c:805) > > seq_read (/home/bep/.opt/kernel/linux-e/fs/seq_file.c:269) > > __vfs_read (/home/bep/.opt/kernel/linux-e/fs/read_write.c:421) > > vfs_read (/home/bep/.opt/kernel/linux-e/fs/read_write.c:452 /home/bep/.opt/kernel/linux-e/fs/read_write.c:437) > > ksys_read (/home/bep/.opt/kernel/linux-e/fs/read_write.c:579) > > do_syscall_64 (/home/bep/.opt/kernel/linux-e/arch/x86/entry/common.c:290) > > entry_SYSCALL_64_after_hwframe (/home/bep/.opt/kernel/linux/arch/x86/entry/entry_64.S:184) > > RIP: 0033:0x7fa585fb3184 > > Code: c3 0f 1f 44 00 00 41 54 49 89 d4 55 48 89 f5 53 89 fb 48 83 ec 10 e8 5b fc ff ff 4c 89 e2 48 89 ee 89 df 41 89 c0 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 38 44 89 c7 48 89 44 24 08 e8 97 fc ff ff 48 > > All code > > ======== > > 0: c3 retq > > 1: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) > > 6: 41 54 push %r12 > > 8: 49 89 d4 mov %rdx,%r12 > > b: 55 push %rbp > > c: 48 89 f5 mov %rsi,%rbp > > f: 53 push %rbx > > 10: 89 fb mov %edi,%ebx > > 12: 48 83 ec 10 sub $0x10,%rsp > > 16: e8 5b fc ff ff callq 0xfffffffffffffc76 > > 1b: 4c 89 e2 mov %r12,%rdx > > 1e: 48 89 ee mov %rbp,%rsi > > 21: 89 df mov %ebx,%edi > > 23: 41 89 c0 mov %eax,%r8d > > 26: 31 c0 xor %eax,%eax > > 28: 0f 05 syscall > > 2a:* 48 3d 00 f0 ff ff cmp $0xfffffffffffff000,%rax <-- trapping instruction > > 30: 77 38 ja 0x6a > > 32: 44 89 c7 mov %r8d,%edi > > 35: 48 89 44 24 08 mov %rax,0x8(%rsp) > > 3a: e8 97 fc ff ff callq 0xfffffffffffffcd6 > > 3f: 48 rex.W > > > > Code starting with the faulting instruction > > =========================================== > > 0: 48 3d 00 f0 ff ff cmp $0xfffffffffffff000,%rax > > 6: 77 38 ja 0x40 > > 8: 44 89 c7 mov %r8d,%edi > > b: 48 89 44 24 08 mov %rax,0x8(%rsp) > > 10: e8 97 fc ff ff callq 0xfffffffffffffcac > > 15: 48 rex.W > > RSP: 002b:00007fa54ad42060 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 > > RAX: ffffffffffffffda RBX: 000000000000002c RCX: 00007fa585fb3184 > > RDX: 0000000000001fff RSI: 00007fa54ffb2000 RDI: 000000000000002c > > RBP: 00007fa54ffb2000 R08: 0000000000000000 R09: 000000000000001e > > R10: 00007fa585c0dae0 R11: 0000000000000246 R12: 0000000000001fff > > R13: 00007fa54ad42510 R14: 00007fa54ffb2fc5 R15: 00007fa54ad42498 > > Modules linked in: thunderbolt sch_cake rfcomm fuse arc4 iwlmvm mac80211 btusb btrtl btbcm btintel bnep bluetooth iwlwifi snd_hda_codec_hdmi ecdh_generic snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel cfg80211 snd_hda_codec nf_log_ipv6 ip6t_REJECT nf_reject_ipv6 snd_hwdep xt_hl snd_hda_core ip6t_rt nf_log_ipv4 nf_log_common joydev snd_pcm mousedev ipt_REJECT nf_reject_ipv4 hid_multitouch intel_rapl xt_LOG xt_comment nls_iso8859_1 intel_pmc_core nls_cp437 intel_powerclamp xt_limit kvm_intel xt_addrtype xt_tcpudp dell_laptop snd_timer xt_conntrack ledtrig_audio snd dell_wmi nf_conntrack efi_pstore dell_smbios mei_me dcdbas input_leds idma64 mei wmi_bmof intel_wmi_thunderbolt dell_wmi_descriptor efivars rfkill intel_pch_thermal intel_lpss_pci processor_thermal_device i2c_i801 soundcore intel_lpss intel_soc_dts_iosf i2c_hid evdev int3403_thermal int3400_thermal intel_vbtn rtc_cmos int340x_thermal_zone acpi_thermal_rel intel_hid mac_hid nf_defrag_ipv6 nf_defrag_ipv4 > > ip6table_filter ip6_tables iptable_filter bpfilter coretemp msr dell_smm_hwmon crypto_user ip_tables x_tables algif_skcipher af_alg rtsx_pci_sdmmc mmc_core crct10dif_pclmul crc32_pclmul xhci_pci ghash_clmulni_intel serio_raw rtsx_pci xhci_hcd i915 kvmgt vfio_mdev mdev vfio_iommu_type1 vfio kvm irqbypass intel_gtt > > CR2: 00000000000000e8 > > ---[ end trace 77d24d35c4e5213f ]--- > > RIP: 0010:transparent_hugepage_enabled (??:?) > > Code: 17 fd 00 e9 20 ff ff ff 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 53 48 89 fb 48 83 bf 90 00 00 00 00 74 27 48 8b 87 a0 00 00 00 <48> 8b b8 e8 00 00 00 e8 7a cc fa ff 84 c0 75 04 31 c0 5b c3 48 89 > > All code > > ======== > > 0: 17 (bad) > > 1: fd std > > 2: 00 e9 add %ch,%cl > > 4: 20 ff and %bh,%bh > > 6: ff (bad) > > 7: ff 0f decl (%rdi) > > 9: 1f (bad) > > a: 84 00 test %al,(%rax) > > c: 00 00 add %al,(%rax) > > e: 00 00 add %al,(%rax) > > 10: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) > > 15: 53 push %rbx > > 16: 48 89 fb mov %rdi,%rbx > > 19: 48 83 bf 90 00 00 00 cmpq $0x0,0x90(%rdi) > > 20: 00 > > 21: 74 27 je 0x4a > > 23: 48 8b 87 a0 00 00 00 mov 0xa0(%rdi),%rax > > 2a:* 48 8b b8 e8 00 00 00 mov 0xe8(%rax),%rdi <-- trapping instruction > > 31: e8 7a cc fa ff callq 0xfffffffffffaccb0 > > 36: 84 c0 test %al,%al > > 38: 75 04 jne 0x3e > > 3a: 31 c0 xor %eax,%eax > > 3c: 5b pop %rbx > > 3d: c3 retq > > 3e: 48 rex.W > > 3f: 89 .byte 0x89 > > > > Code starting with the faulting instruction > > =========================================== > > 0: 48 8b b8 e8 00 00 00 mov 0xe8(%rax),%rdi > > 7: e8 7a cc fa ff callq 0xfffffffffffacc86 > > c: 84 c0 test %al,%al > > e: 75 04 jne 0x14 > > 10: 31 c0 xor %eax,%eax > > 12: 5b pop %rbx > > 13: c3 retq > > 14: 48 rex.W > > 15: 89 .byte 0x89 > > RSP: 0018:ffffb79744f17d28 EFLAGS: 00010282 > > RAX: 0000000000000000 RBX: ffff8948c17aff00 RCX: 0000000000000000 > > RDX: 0000000000000004 RSI: ffffffffab1165ba RDI: ffff8948c17aff00 > > RBP: ffff8948c17aff00 R08: 0000000000000007 R09: ffff894927e547b2 > > R10: 0000000000000000 R11: ffff894927e549da R12: ffffb79744f17d38 > > R13: ffff8948c17aff00 R14: ffff89489bef9400 R15: ffff89488b775a80 > > FS: 00007fa54ad43700(0000) GS:ffff8949363c0000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > BUG: unable to handle kernel NULL pointer dereference at 00000000000000e8 > > #PF error: [normal kernel read fault] > > PGD 0 P4D 0 > > Oops: 0000 [#1] PREEMPT SMP PTI > > CPU: 7 PID: 2687 Comm: StreamTrans #56 Tainted: G U 4.20.0-rc7-next-20181221-beppy+ #15 > > Hardware name: Dell Inc. XPS 13 9360/0TPN17, BIOS 2.10.0 09/27/2018 > > RIP: 0010:transparent_hugepage_enabled+0x1a/0xa0 > > Code: 17 fd 00 e9 20 ff ff ff 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 53 48 89 fb 48 83 bf 90 00 00 00 00 74 27 48 8b 87 a0 00 00 00 <48> 8b b8 e8 00 00 00 e8 7a cc fa ff 84 c0 75 04 31 c0 5b c3 48 89 > > RSP: 0018:ffffb79744f17d28 EFLAGS: 00010282 > > RAX: 0000000000000000 RBX: ffff8948c17aff00 RCX: 0000000000000000 > > RDX: 0000000000000004 RSI: ffffffffab1165ba RDI: ffff8948c17aff00 > > RBP: ffff8948c17aff00 R08: 0000000000000007 R09: ffff894927e547b2 > > R10: 0000000000000000 R11: ffff894927e549da R12: ffffb79744f17d38 > > R13: ffff8948c17aff00 R14: ffff89489bef9400 R15: ffff89488b775a80 > > FS: 00007fa54ad43700(0000) GS:ffff8949363c0000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 00000000000000e8 CR3: 000000025c0ee003 CR4: 00000000003606e0 > > Call Trace: > > show_smap+0xd7/0x200 > > seq_read+0x2e8/0x410 > > __vfs_read+0x36/0x1a0 > > vfs_read+0x8a/0x140 > > ksys_read+0x52/0xc0 > > do_syscall_64+0x48/0xf0 > > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > RIP: 0033:0x7fa585fb3184 > > Code: c3 0f 1f 44 00 00 41 54 49 89 d4 55 48 89 f5 53 89 fb 48 83 ec 10 e8 5b fc ff ff 4c 89 e2 48 89 ee 89 df 41 89 c0 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 38 44 89 c7 48 89 44 24 08 e8 97 fc ff ff 48 > > RSP: 002b:00007fa54ad42060 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 > > RAX: ffffffffffffffda RBX: 000000000000002c RCX: 00007fa585fb3184 > > RDX: 0000000000001fff RSI: 00007fa54ffb2000 RDI: 000000000000002c > > RBP: 00007fa54ffb2000 R08: 0000000000000000 R09: 000000000000001e > > R10: 00007fa585c0dae0 R11: 0000000000000246 R12: 0000000000001fff > > R13: 00007fa54ad42510 R14: 00007fa54ffb2fc5 R15: 00007fa54ad42498 > > Modules linked in: thunderbolt sch_cake rfcomm fuse arc4 iwlmvm mac80211 btusb btrtl btbcm btintel bnep bluetooth iwlwifi snd_hda_codec_hdmi ecdh_generic snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel cfg80211 snd_hda_codec nf_log_ipv6 ip6t_REJECT nf_reject_ipv6 snd_hwdep xt_hl snd_hda_core ip6t_rt nf_log_ipv4 nf_log_common joydev snd_pcm mousedev ipt_REJECT nf_reject_ipv4 hid_multitouch intel_rapl xt_LOG xt_comment nls_iso8859_1 intel_pmc_core nls_cp437 intel_powerclamp xt_limit kvm_intel xt_addrtype xt_tcpudp dell_laptop snd_timer xt_conntrack ledtrig_audio snd dell_wmi nf_conntrack efi_pstore dell_smbios mei_me dcdbas input_leds idma64 mei wmi_bmof intel_wmi_thunderbolt dell_wmi_descriptor efivars rfkill intel_pch_thermal intel_lpss_pci processor_thermal_device i2c_i801 soundcore intel_lpss intel_soc_dts_iosf i2c_hid evdev int3403_thermal int3400_thermal intel_vbtn rtc_cmos int340x_thermal_zone acpi_thermal_rel intel_hid mac_hid nf_defrag_ipv6 nf_defrag_ipv4 > > ip6table_filter ip6_tables iptable_filter bpfilter coretemp msr dell_smm_hwmon crypto_user ip_tables x_tables algif_skcipher af_alg rtsx_pci_sdmmc mmc_core crct10dif_pclmul crc32_pclmul xhci_pci ghash_clmulni_intel serio_raw rtsx_pci xhci_hcd i915 kvmgt vfio_mdev mdev vfio_iommu_type1 vfio kvm irqbypass intel_gtt > > CR2: 00000000000000e8 > > ---[ end trace 77d24d35c4e5213f ]--- > > RIP: 0010:transparent_hugepage_enabled+0x1a/0xa0 > > Code: 17 fd 00 e9 20 ff ff ff 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 53 48 89 fb 48 83 bf 90 00 00 00 00 74 27 48 8b 87 a0 00 00 00 <48> 8b b8 e8 00 00 00 e8 7a cc fa ff 84 c0 75 04 31 c0 5b c3 48 89 > > RSP: 0018:ffffb79744f17d28 EFLAGS: 00010282 > > RAX: 0000000000000000 RBX: ffff8948c17aff00 RCX: 0000000000000000 > > RDX: 0000000000000004 RSI: ffffffffab1165ba RDI: ffff8948c17aff00 > > RBP: ffff8948c17aff00 R08: 0000000000000007 R09: ffff894927e547b2 > > R10: 0000000000000000 R11: ffff894927e549da R12: ffffb79744f17d38 > > R13: ffff8948c17aff00 R14: ffff89489bef9400 R15: ffff89488b775a80 > > FS: 00007fa54ad43700(0000) GS:ffff8949363c0000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 00000000000000e8 CR3: 000000025c0ee003 CR4: 00000000003606e0 > > > -- > Michal Hocko > SUSE Labs > -- Sincerely yours, Mike. ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Bug with report THP eligibility for each vma 2018-12-24 12:12 ` Mike Rapoport @ 2018-12-24 18:51 ` Michal Hocko 0 siblings, 0 replies; 5+ messages in thread From: Michal Hocko @ 2018-12-24 18:51 UTC (permalink / raw) To: Mike Rapoport, Andrew Morton Cc: Paul Oppenheimer, Vlastimil Babka, David Rientjes, Jan Kara, linux-mm, LKML On Mon 24-12-18 14:12:51, Mike Rapoport wrote: > On Mon, Dec 24, 2018 at 08:49:16AM +0100, Michal Hocko wrote: > > [Cc-ing mailing list and people involved in the original patch] > > > > On Fri 21-12-18 13:42:24, Paul Oppenheimer wrote: > > > Hello! I've never reported a kernel bug before, and since its on the > > > "next" tree I was told to email the author of the relevant commit. > > > Please redirect me to the correct place if I've made a mistake. > > > > > > When opening firefox or chrome, and using it for a good 7 seconds, it > > > hangs in "uninterruptible sleep" and I recieve a "BUG" in dmesg. This > > > doesn't occur when reverting this commit: > > > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=48cf516f8c. > > > Ive attached the output of decode_stacktrace.sh and the relevant dmesg > > > log to this email. > > > > > > Thanks > > > > > BUG: unable to handle kernel NULL pointer dereference at 00000000000000e8 > > > > Thanks for the bug report! This is offset 232 and that matches > > file->f_mapping as per pahole > > pahole -C file ./vmlinux | grep f_mapping > > struct address_space * f_mapping; /* 232 8 */ > > > > I thought that each file really has to have a mapping. But the following > > should heal the issue and add an extra care. > > > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > > index f64733c23067..fc9d70a9fbd1 100644 > > --- a/mm/huge_memory.c > > +++ b/mm/huge_memory.c > > @@ -66,6 +66,8 @@ bool transparent_hugepage_enabled(struct vm_area_struct *vma) > > { > > if (vma_is_anonymous(vma)) > > return __transparent_hugepage_enabled(vma); > > + if (!vma->vm_file || !vma->vm_file->f_mapping) > > + return false; > > if (shmem_mapping(vma->vm_file->f_mapping) && shmem_huge_enabled(vma)) > > return __transparent_hugepage_enabled(vma); > > We have vma_is_shmem(), it can be used to replace shmem_mapping() without > adding the check for !vma->vm_file Yes, this looks like a much better choice. Thanks! Andrew, could you fold this in instead. diff --git a/mm/huge_memory.c b/mm/huge_memory.c index f64733c23067..e093cf5e4640 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -66,7 +66,7 @@ bool transparent_hugepage_enabled(struct vm_area_struct *vma) { if (vma_is_anonymous(vma)) return __transparent_hugepage_enabled(vma); - if (shmem_mapping(vma->vm_file->f_mapping) && shmem_huge_enabled(vma)) + if (vma_is_shmem(vma) && shmem_huge_enabled(vma)) return __transparent_hugepage_enabled(vma); return false; -- Michal Hocko SUSE Labs ^ permalink raw reply related [flat|nested] 5+ messages in thread
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2018-12-24 7:49 ` Bug with report THP eligibility for each vma Michal Hocko
2018-12-24 11:35 ` William Kucharski
2018-12-24 11:35 ` William Kucharski
2018-12-24 12:12 ` Mike Rapoport
2018-12-24 18:51 ` Michal Hocko
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