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Groups > linux.kernel > #1721393
| From | Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 4.12 47/99] dax: fix deadlock due to misaligned PMD faults |
| Date | 2017-08-28 11:20 +0200 |
| Message-ID | <ujon7-3MV-13@gated-at.bofh.it> (permalink) |
| References | <ujnhn-38X-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
4.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ross Zwisler <ross.zwisler@linux.intel.com> commit fffa281b48a91ad6dac1a18c5907ece58fa3879b upstream. In DAX there are two separate places where the 2MiB range of a PMD is defined. The first is in the page tables, where a PMD mapping inserted for a given address spans from (vmf->address & PMD_MASK) to ((vmf->address & PMD_MASK) + PMD_SIZE - 1). That is, from the 2MiB boundary below the address to the 2MiB boundary above the address. So, for example, a fault at address 3MiB (0x30 0000) falls within the PMD that ranges from 2MiB (0x20 0000) to 4MiB (0x40 0000). The second PMD range is in the mapping->page_tree, where a given file offset is covered by a radix tree entry that spans from one 2MiB aligned file offset to another 2MiB aligned file offset. So, for example, the file offset for 3MiB (pgoff 768) falls within the PMD range for the order 9 radix tree entry that ranges from 2MiB (pgoff 512) to 4MiB (pgoff 1024). This system works so long as the addresses and file offsets for a given mapping both have the same offsets relative to the start of each PMD. Consider the case where the starting address for a given file isn't 2MiB aligned - say our faulting address is 3 MiB (0x30 0000), but that corresponds to the beginning of our file (pgoff 0). Now all the PMDs in the mapping are misaligned so that the 2MiB range defined in the page tables never matches up with the 2MiB range defined in the radix tree. The current code notices this case for DAX faults to storage with the following test in dax_pmd_insert_mapping(): if (pfn_t_to_pfn(pfn) & PG_PMD_COLOUR) goto unlock_fallback; This test makes sure that the pfn we get from the driver is 2MiB aligned, and relies on the assumption that the 2MiB alignment of the pfn we get back from the driver matches the 2MiB alignment of the faulting address. However, faults to holes were not checked and we could hit the problem described above. This was reported in response to the NVML nvml/src/test/pmempool_sync TEST5: $ cd nvml/src/test/pmempool_sync $ make TEST5 You can grab NVML here: https://github.com/pmem/nvml/ The dmesg warning you see when you hit this error is: WARNING: CPU: 13 PID: 2900 at fs/dax.c:641 dax_insert_mapping_entry+0x2df/0x310 Where we notice in dax_insert_mapping_entry() that the radix tree entry we are about to replace doesn't match the locked entry that we had previously inserted into the tree. This happens because the initial insertion was done in grab_mapping_entry() using a pgoff calculated from the faulting address (vmf->address), and the replacement in dax_pmd_load_hole() => dax_insert_mapping_entry() is done using vmf->pgoff. In our failure case those two page offsets (one calculated from vmf->address, one using vmf->pgoff) point to different order 9 radix tree entries. This failure case can result in a deadlock because the radix tree unlock also happens on the pgoff calculated from vmf->address. This means that the locked radix tree entry that we swapped in to the tree in dax_insert_mapping_entry() using vmf->pgoff is never unlocked, so all future faults to that 2MiB range will block forever. Fix this by validating that the faulting address's PMD offset matches the PMD offset from the start of the file. This check is done at the very beginning of the fault and covers faults that would have mapped to storage as well as faults to holes. I left the COLOUR check in dax_pmd_insert_mapping() in place in case we ever hit the insanity condition where the alignment of the pfn we get from the driver doesn't match the alignment of the userspace address. Link: http://lkml.kernel.org/r/20170822222436.18926-1-ross.zwisler@linux.intel.com Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reported-by: "Slusarz, Marcin" <marcin.slusarz@intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- fs/dax.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/fs/dax.c +++ b/fs/dax.c @@ -1380,6 +1380,16 @@ static int dax_iomap_pmd_fault(struct vm trace_dax_pmd_fault(inode, vmf, max_pgoff, 0); + /* + * Make sure that the faulting address's PMD offset (color) matches + * the PMD offset from the start of the file. This is necessary so + * that a PMD range in the page table overlaps exactly with a PMD + * range in the radix tree. + */ + if ((vmf->pgoff & PG_PMD_COLOUR) != + ((vmf->address >> PAGE_SHIFT) & PG_PMD_COLOUR)) + goto fallback; + /* Fall back to PTEs if we're going to COW */ if (write && !(vma->vm_flags & VM_SHARED)) goto fallback;
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[PATCH 4.12 00/99] 4.12.10-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:10 +0200
[PATCH 4.12 90/99] iio: magnetometer: st_magn: fix status register address for LSM303AGR Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:10 +0200
[PATCH 4.12 23/99] irda: do not leak initialized list.dev to userspace Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:10 +0200
[PATCH 4.12 40/99] ALSA: firewire: fix NULL pointer dereference when releasing uninitialized data of iso-resource Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:10 +0200
[PATCH 4.12 38/99] ALSA: core: Fix unexpected error at replacing user TLV Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:10 +0200
[PATCH 4.12 20/99] ipv6: repair fib6 tree in failure case Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:10 +0200
[PATCH 4.12 44/99] ARCv2: PAE40: set MSB even if !CONFIG_ARC_HAS_PAE40 but PAE exists in SoC Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:10 +0200
[PATCH 4.12 17/99] sctp: fully initialize the IPv6 address in sctp_v6_to_addr() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:10 +0200
[PATCH 4.12 68/99] cifs: Fix df output for users with quota limits Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:10 +0200
[PATCH 4.12 11/99] net: igmp: Use ingress interface rather than vrf device Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:10 +0200
[PATCH 4.12 18/99] tipc: fix use-after-free Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:10 +0200
[PATCH 4.12 13/99] ptr_ring: use kmalloc_array() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:10 +0200
[PATCH 4.12 36/99] KVM: x86: block guest protection keys unless the host has them enabled Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:10 +0200
[PATCH 4.12 31/99] Input: ALPS - fix two-finger scroll breakage in right side on ALPS touchpad Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:10 +0200
[PATCH 4.12 10/99] bpf: fix bpf_trace_printk on 32 bit archs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:10 +0200
[PATCH 4.12 93/99] iommu: Fix wrong freeing of iommu_device->dev Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
[PATCH 4.12 75/99] timers: Fix excessive granularity of new timers after a nohz idle Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
[PATCH 4.12 79/99] netfilter: nat: fix src map lookup Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
[PATCH 4.12 77/99] net: sunrpc: svcsock: fix NULL-pointer exception Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
[PATCH 4.12 99/99] powerpc/mm: Ensure cpumask update is ordered Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
[PATCH 4.12 81/99] Bluetooth: hidp: fix possible might sleep error in hidp_session_thread Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
[PATCH 4.12 91/99] iio: magnetometer: st_magn: remove ihl property for LSM303AGR Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 76/99] x86/mm: Fix use-after-free of ldt_struct Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 80/99] netfilter: nfnetlink: Improve input length sanitization in nfnetlink_rcv Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 69/99] cifs: return ENAMETOOLONG for overlong names in cifs_open()/cifs_lookup() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 96/99] ntb: transport shouldnt disable link due to bogus values in SPADs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 89/99] iio: hid-sensor-trigger: Fix the race with user space powering up sensors Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 73/99] ftrace: Check for null ret_stack on profile function graph entry function Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 95/99] ntb: ntb_test: ensure the link is up before trying to configure the mws Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 63/99] tracing: Missing error code in tracer_alloc_buffers() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 82/99] Bluetooth: cmtp: fix possible might sleep error in cmtp_session Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 94/99] Clarify (and fix) MAX_LFS_FILESIZE macros Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 74/99] perf/core: Fix group {cpu,task} validation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 71/99] ring-buffer: Have ring_buffer_alloc_read_page() return error on offline CPU Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 35/99] KVM, pkeys: do not use PKRU value in vcpu->arch.guest_fpu.state Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 83/99] Bluetooth: bnep: fix possible might sleep error in bnep_session Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 72/99] virtio_pci: fix cpu affinity support Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 97/99] ACPI: APD: Fix HID for Hisilicon Hip07/08 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 87/99] ANDROID: binder: fix proc->tsk check. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 37/99] ALSA: usb-audio: Add delay quirk for H650e/Jabra 550a USB headsets Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 85/99] binder: use group leader instead of open thread Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 78/99] netfilter: expect: fix crash when putting uninited expectation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 98/99] ACPI: EC: Fix regression related to wrong ECDT initialization order Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 70/99] nfsd: Limit end of page list when decoding NFSv4 WRITE Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 39/99] ALSA: hda - Add stereo mic quirk for Lenovo G50-70 (17aa:3978) Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:10 +0200
[PATCH 4.12 33/99] KVM: s390: sthyi: fix specification exception detection Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 64/99] tracing: Fix kmemleak in tracing_map_array_free() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 52/99] arm64: fpsimd: Prevent registers leaking across exec Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 03/99] bonding: ratelimit failed speed/duplex update warning Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 07/99] ipv4: fix NULL dereference in free_fib_info_rcu() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 47/99] dax: fix deadlock due to misaligned PMD faults Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 57/99] drm/atomic: If the atomic check fails, return its value first Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 45/99] PM/hibernate: touch NMI watchdog when creating snapshot Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 43/99] ARCv2: PAE40: Explicitly set MSB counterpart of SLC region ops addresses Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 08/99] net_sched/sfq: update hierarchical backlog when drop packet Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 61/99] ACPI: device property: Fix node lookup in acpi_graph_get_child_prop_value() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 48/99] i2c: designware: Fix system suspend Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 66/99] RDMA/uverbs: Initialize cq_context appropriately Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 30/99] Input: elan_i2c - add ELAN0602 ACPI ID to support Lenovo Yoga310 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 46/99] mm, shmem: fix handling /sys/kernel/mm/transparent_hugepage/shmem_enabled Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 60/99] Revert "drm/amdgpu: fix vblank_time when displays are off" Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 32/99] KVM: s390: sthyi: fix sthyi inline assembly Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 09/99] net_sched: remove warning from qdisc_hash_add Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 65/99] tracing: Fix freeing of filter in create_filter() when set_str is false Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 41/99] ALSA: firewire-motu: destroy stream data surely at failure of card initialization Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 05/99] dccp: purge write queue in dccp_destroy_sock() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 42/99] ARCv2: SLC: Make sure busy bit is set properly for region ops Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 49/99] mm/madvise.c: fix freeing of locked page with MADV_FREE Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:20 +0200
[PATCH 4.12 21/99] tcp: when rearming RTO, if RTO time is in past then fire RTO ASAP Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:30 +0200
[PATCH 4.12 12/99] openvswitch: fix skb_panic due to the incorrect actions attrlen Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:30 +0200
[PATCH 4.12 16/99] tun: handle register_netdevice() failures properly Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:30 +0200
[PATCH 4.12 24/99] net: sched: fix NULL pointer dereference when action calls some targets Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:30 +0200
[PATCH 4.12 02/99] bonding: require speed/duplex only for 802.3ad, alb and tlb Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:30 +0200
[PATCH 4.12 28/99] bpf/verifier: fix min/max handling in BPF_SUB Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:30 +0200
[PATCH 4.12 26/99] bpf, verifier: add additional patterns to evaluate_reg_imm_alu Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:30 +0200
[PATCH 4.12 14/99] ipv4: better IP_MAX_MTU enforcement Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:30 +0200
[PATCH 4.12 19/99] ipv6: reset fn->rr_ptr when replacing route Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 11:30 +0200
Re: [PATCH 4.12 00/99] 4.12.10-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2017-08-28 21:50 +0200
Re: [PATCH 4.12 00/99] 4.12.10-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-29 07:00 +0200
Re: [PATCH 4.12 00/99] 4.12.10-stable review Guenter Roeck <linux@roeck-us.net> - 2017-08-29 02:20 +0200
Re: [PATCH 4.12 00/99] 4.12.10-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-29 07:00 +0200
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