1. 15 Jan, 2020 16 commits
  2. 14 Jan, 2020 24 commits
    • Linus Torvalds's avatar
      Merge tag 'nfs-for-5.5-2' of git://git.linux-nfs.org/projects/anna/linux-nfs · 95e20af9
      Linus Torvalds authored
      Pull NFS client bugfixes from Anna Schumaker:
       "Three NFS over RDMA fixes for bugs Chuck found that can be hit during
        device removal:
      
         - Fix create_qp crash on device unload
      
         - Fix completion wait during device removal
      
         - Fix oops in receive handler after device removal"
      
      * tag 'nfs-for-5.5-2' of git://git.linux-nfs.org/projects/anna/linux-nfs:
        xprtrdma: Fix oops in Receive handler after device removal
        xprtrdma: Fix completion wait during device removal
        xprtrdma: Fix create_qp crash on device unload
      95e20af9
    • Chuck Lever's avatar
      xprtrdma: Fix oops in Receive handler after device removal · 671c450b
      Chuck Lever authored
      Since v5.4, a device removal occasionally triggered this oops:
      
      Dec  2 17:13:53 manet kernel: BUG: unable to handle page fault for address: 0000000c00000219
      Dec  2 17:13:53 manet kernel: #PF: supervisor read access in kernel mode
      Dec  2 17:13:53 manet kernel: #PF: error_code(0x0000) - not-present page
      Dec  2 17:13:53 manet kernel: PGD 0 P4D 0
      Dec  2 17:13:53 manet kernel: Oops: 0000 [#1] SMP
      Dec  2 17:13:53 manet kernel: CPU: 2 PID: 468 Comm: kworker/2:1H Tainted: G        W         5.4.0-00050-g53717e43af61 #883
      Dec  2 17:13:53 manet kernel: Hardware name: Supermicro SYS-6028R-T/X10DRi, BIOS 1.1a 10/16/2015
      Dec  2 17:13:53 manet kernel: Workqueue: ib-comp-wq ib_cq_poll_work [ib_core]
      Dec  2 17:13:53 manet kernel: RIP: 0010:rpcrdma_wc_receive+0x7c/0xf6 [rpcrdma]
      Dec  2 17:13:53 manet kernel: Code: 6d 8b 43 14 89 c1 89 45 78 48 89 4d 40 8b 43 2c 89 45 14 8b 43 20 89 45 18 48 8b 45 20 8b 53 14 48 8b 30 48 8b 40 10 48 8b 38 <48> 8b 87 18 02 00 00 48 85 c0 75 18 48 8b 05 1e 24 c4 e1 48 85 c0
      Dec  2 17:13:53 manet kernel: RSP: 0018:ffffc900035dfe00 EFLAGS: 00010246
      Dec  2 17:13:53 manet kernel: RAX: ffff888467290000 RBX: ffff88846c638400 RCX: 0000000000000048
      Dec  2 17:13:53 manet kernel: RDX: 0000000000000048 RSI: 00000000f942e000 RDI: 0000000c00000001
      Dec  2 17:13:53 manet kernel: RBP: ffff888467611b00 R08: ffff888464e4a3c4 R09: 0000000000000000
      Dec  2 17:13:53 manet kernel: R10: ffffc900035dfc88 R11: fefefefefefefeff R12: ffff888865af4428
      Dec  2 17:13:53 manet kernel: R13: ffff888466023000 R14: ffff88846c63f000 R15: 0000000000000010
      Dec  2 17:13:53 manet kernel: FS:  0000000000000000(0000) GS:ffff88846fa80000(0000) knlGS:0000000000000000
      Dec  2 17:13:53 manet kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      Dec  2 17:13:53 manet kernel: CR2: 0000000c00000219 CR3: 0000000002009002 CR4: 00000000001606e0
      Dec  2 17:13:53 manet kernel: Call Trace:
      Dec  2 17:13:53 manet kernel: __ib_process_cq+0x5c/0x14e [ib_core]
      Dec  2 17:13:53 manet kernel: ib_cq_poll_work+0x26/0x70 [ib_core]
      Dec  2 17:13:53 manet kernel: process_one_work+0x19d/0x2cd
      Dec  2 17:13:53 manet kernel: ? cancel_delayed_work_sync+0xf/0xf
      Dec  2 17:13:53 manet kernel: worker_thread+0x1a6/0x25a
      Dec  2 17:13:53 manet kernel: ? cancel_delayed_work_sync+0xf/0xf
      Dec  2 17:13:53 manet kernel: kthread+0xf4/0xf9
      Dec  2 17:13:53 manet kernel: ? kthread_queue_delayed_work+0x74/0x74
      Dec  2 17:13:53 manet kernel: ret_from_fork+0x24/0x30
      
      The proximal cause is that this rpcrdma_rep has a rr_rdmabuf that
      is still pointing to the old ib_device, which has been freed. The
      only way that is possible is if this rpcrdma_rep was not destroyed
      by rpcrdma_ia_remove.
      
      Debugging showed that was indeed the case: this rpcrdma_rep was
      still in use by a completing RPC at the time of the device removal,
      and thus wasn't on the rep free list. So, it was not found by
      rpcrdma_reps_destroy().
      
      The fix is to introduce a list of all rpcrdma_reps so that they all
      can be found when a device is removed. That list is used to perform
      only regbuf DMA unmapping, replacing that call to
      rpcrdma_reps_destroy().
      
      Meanwhile, to prevent corruption of this list, I've moved the
      destruction of temp rpcrdma_rep objects to rpcrdma_post_recvs().
      rpcrdma_xprt_drain() ensures that post_recvs (and thus rep_destroy) is
      not invoked while rpcrdma_reps_unmap is walking rb_all_reps, thus
      protecting the rb_all_reps list.
      
      Fixes: b0b227f0 ("xprtrdma: Use an llist to manage free rpcrdma_reps")
      Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
      Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
      671c450b
    • Chuck Lever's avatar
      xprtrdma: Fix completion wait during device removal · 13cb886c
      Chuck Lever authored
      I've found that on occasion, "rmmod <dev>" will hang while if an NFS
      is under load.
      
      Ensure that ri_remove_done is initialized only just before the
      transport is woken up to force a close. This avoids the completion
      possibly getting initialized again while the CM event handler is
      waiting for a wake-up.
      
      Fixes: bebd0318 ("xprtrdma: Support unplugging an HCA from under an NFS mount")
      Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
      Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
      13cb886c
    • Chuck Lever's avatar
      xprtrdma: Fix create_qp crash on device unload · b32b9ed4
      Chuck Lever authored
      On device re-insertion, the RDMA device driver crashes trying to set
      up a new QP:
      
      Nov 27 16:32:06 manet kernel: BUG: kernel NULL pointer dereference, address: 00000000000001c0
      Nov 27 16:32:06 manet kernel: #PF: supervisor write access in kernel mode
      Nov 27 16:32:06 manet kernel: #PF: error_code(0x0002) - not-present page
      Nov 27 16:32:06 manet kernel: PGD 0 P4D 0
      Nov 27 16:32:06 manet kernel: Oops: 0002 [#1] SMP
      Nov 27 16:32:06 manet kernel: CPU: 1 PID: 345 Comm: kworker/u28:0 Tainted: G        W         5.4.0 #852
      Nov 27 16:32:06 manet kernel: Hardware name: Supermicro SYS-6028R-T/X10DRi, BIOS 1.1a 10/16/2015
      Nov 27 16:32:06 manet kernel: Workqueue: xprtiod xprt_rdma_connect_worker [rpcrdma]
      Nov 27 16:32:06 manet kernel: RIP: 0010:atomic_try_cmpxchg+0x2/0x12
      Nov 27 16:32:06 manet kernel: Code: ff ff 48 8b 04 24 5a c3 c6 07 00 0f 1f 40 00 c3 31 c0 48 81 ff 08 09 68 81 72 0c 31 c0 48 81 ff 83 0c 68 81 0f 92 c0 c3 8b 06 <f0> 0f b1 17 0f 94 c2 84 d2 75 02 89 06 88 d0 c3 53 ba 01 00 00 00
      Nov 27 16:32:06 manet kernel: RSP: 0018:ffffc900035abbf0 EFLAGS: 00010046
      Nov 27 16:32:06 manet kernel: RAX: 0000000000000000 RBX: 00000000000001c0 RCX: 0000000000000000
      Nov 27 16:32:06 manet kernel: RDX: 0000000000000001 RSI: ffffc900035abbfc RDI: 00000000000001c0
      Nov 27 16:32:06 manet kernel: RBP: ffffc900035abde0 R08: 000000000000000e R09: ffffffffffffc000
      Nov 27 16:32:06 manet kernel: R10: 0000000000000000 R11: 000000000002e800 R12: ffff88886169d9f8
      Nov 27 16:32:06 manet kernel: R13: ffff88886169d9f4 R14: 0000000000000246 R15: 0000000000000000
      Nov 27 16:32:06 manet kernel: FS:  0000000000000000(0000) GS:ffff88846fa40000(0000) knlGS:0000000000000000
      Nov 27 16:32:06 manet kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      Nov 27 16:32:06 manet kernel: CR2: 00000000000001c0 CR3: 0000000002009006 CR4: 00000000001606e0
      Nov 27 16:32:06 manet kernel: Call Trace:
      Nov 27 16:32:06 manet kernel: do_raw_spin_lock+0x2f/0x5a
      Nov 27 16:32:06 manet kernel: create_qp_common.isra.47+0x856/0xadf [mlx4_ib]
      Nov 27 16:32:06 manet kernel: ? slab_post_alloc_hook.isra.60+0xa/0x1a
      Nov 27 16:32:06 manet kernel: ? __kmalloc+0x125/0x139
      Nov 27 16:32:06 manet kernel: mlx4_ib_create_qp+0x57f/0x972 [mlx4_ib]
      
      The fix is to copy the qp_init_attr struct that was just created by
      rpcrdma_ep_create() instead of using the one from the previous
      connection instance.
      
      Fixes: 98ef77d1 ("xprtrdma: Send Queue size grows after a reconnect")
      Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
      Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
      b32b9ed4
    • Linus Torvalds's avatar
      Merge branch 'parisc-5.5-3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux · 452424cd
      Linus Torvalds authored
      Pull parisc fixes from Helge Deller:
       "A boot crash fix by Mike Rapoport and a printk fix by Krzysztof
        Kozlowski"
      
      * 'parisc-5.5-3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
        parisc: fix map_pages() to actually populate upper directory
        parisc: Use proper printk format for resource_size_t
      452424cd
    • Linus Torvalds's avatar
      Merge tag 'asm-generic-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground · 67373994
      Linus Torvalds authored
      Pull asm-generic fixes from Arnd Bergmann:
       "Here are two bugfixes from Mike Rapoport, both fixing compile-time
        errors for the nds32 architecture that were recently introduced"
      
      * tag 'asm-generic-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground:
        nds32: fix build failure caused by page table folding updates
        asm-generic/nds32: don't redefine cacheflush primitives
      67373994
    • Linus Torvalds's avatar
      Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi · c21ed4d9
      Linus Torvalds authored
      Pull SCSI fixes from James Bottomley:
       "Two simple fixes in the upper drivers (so both fairly core), one in
        enclosures, which fixes replugging a device into an enclosure slot and
        one in the disk driver which fixes revalidating a drive with
        protection information (PI) to make it a non-PI drive ... previously
        we were still remembering the old PI state.
      
        Both fixed issues are quite rare in the field"
      
      * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
        scsi: enclosure: Fix stale device oops with hot replug
        scsi: sd: Clear sdkp->protection_type if disk is reformatted without PI
      c21ed4d9
    • Linus Torvalds's avatar
      Merge branch 'dhowells' (patches from DavidH) · e033e7d4
      Linus Torvalds authored
      Merge misc fixes from David Howells.
      
      Two afs fixes and a key refcounting fix.
      
      * dhowells:
        afs: Fix afs_lookup() to not clobber the version on a new dentry
        afs: Fix use-after-loss-of-ref
        keys: Fix request_key() cache
      e033e7d4
    • David Howells's avatar
      afs: Fix afs_lookup() to not clobber the version on a new dentry · f52b83b0
      David Howells authored
      Fix afs_lookup() to not clobber the version set on a new dentry by
      afs_do_lookup() - especially as it's using the wrong version of the
      version (we need to use the one given to us by whatever op the dir
      contents correspond to rather than what's in the afs_vnode).
      
      Fixes: 9dd0b82e ("afs: Fix missing dentry data version updating")
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f52b83b0
    • David Howells's avatar
      afs: Fix use-after-loss-of-ref · 40a708bd
      David Howells authored
      afs_lookup() has a tracepoint to indicate the outcome of
      d_splice_alias(), passing it the inode to retrieve the fid from.
      However, the function gave up its ref on that inode when it called
      d_splice_alias(), which may have failed and dropped the inode.
      
      Fix this by caching the fid.
      
      Fixes: 80548b03 ("afs: Add more tracepoints")
      Reported-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      40a708bd
    • David Howells's avatar
      keys: Fix request_key() cache · 8379bb84
      David Howells authored
      When the key cached by request_key() and co.  is cleaned up on exit(),
      the code looks in the wrong task_struct, and so clears the wrong cache.
      This leads to anomalies in key refcounting when doing, say, a kernel
      build on an afs volume, that then trigger kasan to report a
      use-after-free when the key is viewed in /proc/keys.
      
      Fix this by making exit_creds() look in the passed-in task_struct rather
      than in current (the task_struct cleanup code is deferred by RCU and
      potentially run in another task).
      
      Fixes: 7743c48e ("keys: Cache result of request_key*() temporarily in task_struct")
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8379bb84
    • Linus Torvalds's avatar
      Merge branch 'akpm' (patches from Andrew) · 3f1f9a9b
      Linus Torvalds authored
      Merge misc fixes from Andrew Morton:
       "11 mm fixes"
      
      * emailed patches from Andrew Morton <akpm@linux-foundation.org>:
        mm: khugepaged: add trace status description for SCAN_PAGE_HAS_PRIVATE
        mm: memcg/slab: call flush_memcg_workqueue() only if memcg workqueue is valid
        mm/page-writeback.c: improve arithmetic divisions
        mm/page-writeback.c: use div64_ul() for u64-by-unsigned-long divide
        mm/page-writeback.c: avoid potential division by zero in wb_min_max_ratio()
        mm, debug_pagealloc: don't rely on static keys too early
        mm: memcg/slab: fix percpu slab vmstats flushing
        mm/shmem.c: thp, shmem: fix conflict of above-47bit hint address and PMD alignment
        mm/huge_memory.c: thp: fix conflict of above-47bit hint address and PMD alignment
        mm/memory_hotplug: don't free usage map when removing a re-added early section
        mm, thp: tweak reclaim/compaction effort of local-only and all-node allocations
      3f1f9a9b
    • Mike Rapoport's avatar
      parisc: fix map_pages() to actually populate upper directory · 8b7f938e
      Mike Rapoport authored
      The commit d96885e2 ("parisc: use pgtable-nopXd instead of
      4level-fixup") converted PA-RISC to use folded page tables, but it missed
      the conversion of pgd_populate() to pud_populate() in maps_pages()
      function. This caused the upper page table directory to remain empty and
      the system would crash as a result.
      
      Using pud_populate() that actually populates the page table instead of
      dummy pgd_populate() fixes the issue.
      
      Fixes: d96885e2 ("parisc: use pgtable-nopXd instead of 4level-fixup")
      Reported-by: default avatarMeelis Roos <mroos@linux.ee>
      Reported-by: default avatarJeroen Roovers <jer@gentoo.org>
      Reported-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Tested-by: default avatarJeroen Roovers <jer@gentoo.org>
      Tested-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Signed-off-by: default avatarMike Rapoport <rppt@linux.ibm.com>
      Signed-off-by: default avatarHelge Deller <deller@gmx.de>
      8b7f938e
    • Krzysztof Kozlowski's avatar
      parisc: Use proper printk format for resource_size_t · 4f80b70e
      Krzysztof Kozlowski authored
      resource_size_t should be printed with its own size-independent format
      to fix warnings when compiling on 64-bit platform (e.g. with
      COMPILE_TEST):
      
          arch/parisc/kernel/drivers.c: In function 'print_parisc_device':
          arch/parisc/kernel/drivers.c:892:9: warning:
              format '%p' expects argument of type 'void *',
              but argument 4 has type 'resource_size_t {aka unsigned int}' [-Wformat=]
      Signed-off-by: default avatarKrzysztof Kozlowski <krzk@kernel.org>
      Signed-off-by: default avatarHelge Deller <deller@gmx.de>
      4f80b70e
    • Linus Torvalds's avatar
      Merge tag 'Intel-CVE-2019-14615' from bundle by Akeem Abodunrin. · 63d264fe
      Linus Torvalds authored
      Merge Intel Gen9 graphics fix from Akeem Abodunrin:
       "Insufficient control flow in certain data structures for some Intel
        Processors with Intel Processor Graphics may allow an unauthenticated
        user to potentially enable information disclosure via local access
      
        This provides mitigation for Gen9 hardware. Note that Gen8 is not
        impacted due to a previously implemented workaround.
      
        The mitigation involves using an existing hardware feature to forcibly
        clear down all EU state at each context switch"
      
      * tag 'Intel-CVE-2019-14615' of emailed bundle from Akeem G Abodunrin <akeem.g.abodunrin@intel.com>:
        drm/i915/gen9: Clear residual context state on context switch
      63d264fe
    • Yang Shi's avatar
      mm: khugepaged: add trace status description for SCAN_PAGE_HAS_PRIVATE · 554913f6
      Yang Shi authored
      Commit 99cb0dbd ("mm,thp: add read-only THP support for (non-shmem)
      FS") introduced a new khugepaged scan result: SCAN_PAGE_HAS_PRIVATE, but
      the corresponding description for trace events were not added.
      
      Link: http://lkml.kernel.org/r/1574793844-2914-1-git-send-email-yang.shi@linux.alibaba.com
      Fixes: 99cb0dbd ("mm,thp: add read-only THP support for (non-shmem) FS")
      Signed-off-by: default avatarYang Shi <yang.shi@linux.alibaba.com>
      Cc: Song Liu <songliubraving@fb.com>
      Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Anshuman Khandual <anshuman.khandual@arm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      554913f6
    • Adrian Huang's avatar
      mm: memcg/slab: call flush_memcg_workqueue() only if memcg workqueue is valid · 2fe20210
      Adrian Huang authored
      When booting with amd_iommu=off, the following WARNING message
      appears:
      
        AMD-Vi: AMD IOMMU disabled on kernel command-line
        ------------[ cut here ]------------
        WARNING: CPU: 0 PID: 0 at kernel/workqueue.c:2772 flush_workqueue+0x42e/0x450
        Modules linked in:
        CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.5.0-rc3-amd-iommu #6
        Hardware name: Lenovo ThinkSystem SR655-2S/7D2WRCZ000, BIOS D8E101L-1.00 12/05/2019
        RIP: 0010:flush_workqueue+0x42e/0x450
        Code: ff 0f 0b e9 7a fd ff ff 4d 89 ef e9 33 fe ff ff 0f 0b e9 7f fd ff ff 0f 0b e9 bc fd ff ff 0f 0b e9 a8 fd ff ff e8 52 2c fe ff <0f> 0b 31 d2 48 c7 c6 e0 88 c5 95 48 c7 c7 d8 ad f0 95 e8 19 f5 04
        Call Trace:
         kmem_cache_destroy+0x69/0x260
         iommu_go_to_state+0x40c/0x5ab
         amd_iommu_prepare+0x16/0x2a
         irq_remapping_prepare+0x36/0x5f
         enable_IR_x2apic+0x21/0x172
         default_setup_apic_routing+0x12/0x6f
         apic_intr_mode_init+0x1a1/0x1f1
         x86_late_time_init+0x17/0x1c
         start_kernel+0x480/0x53f
         secondary_startup_64+0xb6/0xc0
        ---[ end trace 30894107c3749449 ]---
        x2apic: IRQ remapping doesn't support X2APIC mode
        x2apic disabled
      
      The warning is caused by the calling of 'kmem_cache_destroy()'
      in free_iommu_resources(). Here is the call path:
      
        free_iommu_resources
          kmem_cache_destroy
            flush_memcg_workqueue
              flush_workqueue
      
      The root cause is that the IOMMU subsystem runs before the workqueue
      subsystem, which the variable 'wq_online' is still 'false'.  This leads
      to the statement 'if (WARN_ON(!wq_online))' in flush_workqueue() is
      'true'.
      
      Since the variable 'memcg_kmem_cache_wq' is not allocated during the
      time, it is unnecessary to call flush_memcg_workqueue().  This prevents
      the WARNING message triggered by flush_workqueue().
      
      Link: http://lkml.kernel.org/r/20200103085503.1665-1-ahuang12@lenovo.com
      Fixes: 92ee383f ("mm: fix race between kmem_cache destroy, create and deactivate")
      Signed-off-by: default avatarAdrian Huang <ahuang12@lenovo.com>
      Reported-by: default avatarXiaochun Lee <lixc17@lenovo.com>
      Reviewed-by: default avatarShakeel Butt <shakeelb@google.com>
      Cc: Joerg Roedel <jroedel@suse.de>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Michal Hocko <mhocko@kernel.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2fe20210
    • Wen Yang's avatar
      mm/page-writeback.c: improve arithmetic divisions · 0a5d1a7f
      Wen Yang authored
      Use div64_ul() instead of do_div() if the divisor is unsigned long, to
      avoid truncation to 32-bit on 64-bit platforms.
      
      Link: http://lkml.kernel.org/r/20200102081442.8273-4-wenyang@linux.alibaba.comSigned-off-by: default avatarWen Yang <wenyang@linux.alibaba.com>
      Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Cc: Qian Cai <cai@lca.pw>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Jens Axboe <axboe@kernel.dk>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0a5d1a7f
    • Wen Yang's avatar
      mm/page-writeback.c: use div64_ul() for u64-by-unsigned-long divide · d3ac946e
      Wen Yang authored
      The two variables 'numerator' and 'denominator', though they are
      declared as long, they should actually be unsigned long (according to
      the implementation of the fprop_fraction_percpu() function)
      
      And do_div() does a 64-by-32 division, while the divisor 'denominator'
      is unsigned long, thus 64-bit on 64-bit platforms.  Hence the proper
      function to call is div64_ul().
      
      Link: http://lkml.kernel.org/r/20200102081442.8273-3-wenyang@linux.alibaba.comSigned-off-by: default avatarWen Yang <wenyang@linux.alibaba.com>
      Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Cc: Qian Cai <cai@lca.pw>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Jens Axboe <axboe@kernel.dk>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d3ac946e
    • Wen Yang's avatar
      mm/page-writeback.c: avoid potential division by zero in wb_min_max_ratio() · 6d9e8c65
      Wen Yang authored
      Patch series "use div64_ul() instead of div_u64() if the divisor is
      unsigned long".
      
      We were first inspired by commit b0ab99e7 ("sched: Fix possible divide
      by zero in avg_atom () calculation"), then refer to the recently analyzed
      mm code, we found this suspicious place.
      
       201                 if (min) {
       202                         min *= this_bw;
       203                         do_div(min, tot_bw);
       204                 }
      
      And we also disassembled and confirmed it:
      
        /usr/src/debug/kernel-4.9.168-016.ali3000/linux-4.9.168-016.ali3000.alios7.x86_64/mm/page-writeback.c: 201
        0xffffffff811c37da <__wb_calc_thresh+234>:      xor    %r10d,%r10d
        0xffffffff811c37dd <__wb_calc_thresh+237>:      test   %rax,%rax
        0xffffffff811c37e0 <__wb_calc_thresh+240>:      je 0xffffffff811c3800 <__wb_calc_thresh+272>
        /usr/src/debug/kernel-4.9.168-016.ali3000/linux-4.9.168-016.ali3000.alios7.x86_64/mm/page-writeback.c: 202
        0xffffffff811c37e2 <__wb_calc_thresh+242>:      imul   %r8,%rax
        /usr/src/debug/kernel-4.9.168-016.ali3000/linux-4.9.168-016.ali3000.alios7.x86_64/mm/page-writeback.c: 203
        0xffffffff811c37e6 <__wb_calc_thresh+246>:      mov    %r9d,%r10d    ---> truncates it to 32 bits here
        0xffffffff811c37e9 <__wb_calc_thresh+249>:      xor    %edx,%edx
        0xffffffff811c37eb <__wb_calc_thresh+251>:      div    %r10
        0xffffffff811c37ee <__wb_calc_thresh+254>:      imul   %rbx,%rax
        0xffffffff811c37f2 <__wb_calc_thresh+258>:      shr    $0x2,%rax
        0xffffffff811c37f6 <__wb_calc_thresh+262>:      mul    %rcx
        0xffffffff811c37f9 <__wb_calc_thresh+265>:      shr    $0x2,%rdx
        0xffffffff811c37fd <__wb_calc_thresh+269>:      mov    %rdx,%r10
      
      This series uses div64_ul() instead of div_u64() if the divisor is
      unsigned long, to avoid truncation to 32-bit on 64-bit platforms.
      
      This patch (of 3):
      
      The variables 'min' and 'max' are unsigned long and do_div truncates
      them to 32 bits, which means it can test non-zero and be truncated to
      zero for division.  Fix this issue by using div64_ul() instead.
      
      Link: http://lkml.kernel.org/r/20200102081442.8273-2-wenyang@linux.alibaba.com
      Fixes: 693108a8 ("writeback: make bdi->min/max_ratio handling cgroup writeback aware")
      Signed-off-by: default avatarWen Yang <wenyang@linux.alibaba.com>
      Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Cc: Qian Cai <cai@lca.pw>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Jens Axboe <axboe@kernel.dk>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      6d9e8c65
    • Vlastimil Babka's avatar
      mm, debug_pagealloc: don't rely on static keys too early · 8e57f8ac
      Vlastimil Babka authored
      Commit 96a2b03f ("mm, debug_pagelloc: use static keys to enable
      debugging") has introduced a static key to reduce overhead when
      debug_pagealloc is compiled in but not enabled.  It relied on the
      assumption that jump_label_init() is called before parse_early_param()
      as in start_kernel(), so when the "debug_pagealloc=on" option is parsed,
      it is safe to enable the static key.
      
      However, it turns out multiple architectures call parse_early_param()
      earlier from their setup_arch().  x86 also calls jump_label_init() even
      earlier, so no issue was found while testing the commit, but same is not
      true for e.g.  ppc64 and s390 where the kernel would not boot with
      debug_pagealloc=on as found by our QA.
      
      To fix this without tricky changes to init code of multiple
      architectures, this patch partially reverts the static key conversion
      from 96a2b03f.  Init-time and non-fastpath calls (such as in arch
      code) of debug_pagealloc_enabled() will again test a simple bool
      variable.  Fastpath mm code is converted to a new
      debug_pagealloc_enabled_static() variant that relies on the static key,
      which is enabled in a well-defined point in mm_init() where it's
      guaranteed that jump_label_init() has been called, regardless of
      architecture.
      
      [sfr@canb.auug.org.au: export _debug_pagealloc_enabled_early]
        Link: http://lkml.kernel.org/r/20200106164944.063ac07b@canb.auug.org.au
      Link: http://lkml.kernel.org/r/20191219130612.23171-1-vbabka@suse.cz
      Fixes: 96a2b03f ("mm, debug_pagelloc: use static keys to enable debugging")
      Signed-off-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
      Cc: Michal Hocko <mhocko@kernel.org>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Matthew Wilcox <willy@infradead.org>
      Cc: Mel Gorman <mgorman@techsingularity.net>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Qian Cai <cai@lca.pw>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8e57f8ac
    • Roman Gushchin's avatar
      mm: memcg/slab: fix percpu slab vmstats flushing · 4a87e2a2
      Roman Gushchin authored
      Currently slab percpu vmstats are flushed twice: during the memcg
      offlining and just before freeing the memcg structure.  Each time percpu
      counters are summed, added to the atomic counterparts and propagated up
      by the cgroup tree.
      
      The second flushing is required due to how recursive vmstats are
      implemented: counters are batched in percpu variables on a local level,
      and once a percpu value is crossing some predefined threshold, it spills
      over to atomic values on the local and each ascendant levels.  It means
      that without flushing some numbers cached in percpu variables will be
      dropped on floor each time a cgroup is destroyed.  And with uptime the
      error on upper levels might become noticeable.
      
      The first flushing aims to make counters on ancestor levels more
      precise.  Dying cgroups may resume in the dying state for a long time.
      After kmem_cache reparenting which is performed during the offlining
      slab counters of the dying cgroup don't have any chances to be updated,
      because any slab operations will be performed on the parent level.  It
      means that the inaccuracy caused by percpu batching will not decrease up
      to the final destruction of the cgroup.  By the original idea flushing
      slab counters during the offlining should minimize the visible
      inaccuracy of slab counters on the parent level.
      
      The problem is that percpu counters are not zeroed after the first
      flushing.  So every cached percpu value is summed twice.  It creates a
      small error (up to 32 pages per cpu, but usually less) which accumulates
      on parent cgroup level.  After creating and destroying of thousands of
      child cgroups, slab counter on parent level can be way off the real
      value.
      
      For now, let's just stop flushing slab counters on memcg offlining.  It
      can't be done correctly without scheduling a work on each cpu: reading
      and zeroing it during css offlining can race with an asynchronous
      update, which doesn't expect values to be changed underneath.
      
      With this change, slab counters on parent level will become eventually
      consistent.  Once all dying children are gone, values are correct.  And
      if not, the error is capped by 32 * NR_CPUS pages per dying cgroup.
      
      It's not perfect, as slab are reparented, so any updates after the
      reparenting will happen on the parent level.  It means that if a slab
      page was allocated, a counter on child level was bumped, then the page
      was reparented and freed, the annihilation of positive and negative
      counter values will not happen until the child cgroup is released.  It
      makes slab counters different from others, and it might want us to
      implement flushing in a correct form again.  But it's also a question of
      performance: scheduling a work on each cpu isn't free, and it's an open
      question if the benefit of having more accurate counters is worth it.
      
      We might also consider flushing all counters on offlining, not only slab
      counters.
      
      So let's fix the main problem now: make the slab counters eventually
      consistent, so at least the error won't grow with uptime (or more
      precisely the number of created and destroyed cgroups).  And think about
      the accuracy of counters separately.
      
      Link: http://lkml.kernel.org/r/20191220042728.1045881-1-guro@fb.com
      Fixes: bee07b33 ("mm: memcontrol: flush percpu slab vmstats on kmem offlining")
      Signed-off-by: default avatarRoman Gushchin <guro@fb.com>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Acked-by: default avatarMichal Hocko <mhocko@suse.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4a87e2a2
    • Kirill A. Shutemov's avatar
      mm/shmem.c: thp, shmem: fix conflict of above-47bit hint address and PMD alignment · 99158997
      Kirill A. Shutemov authored
      Shmem/tmpfs tries to provide THP-friendly mappings if huge pages are
      enabled.  But it doesn't work well with above-47bit hint address.
      
      Normally, the kernel doesn't create userspace mappings above 47-bit,
      even if the machine allows this (such as with 5-level paging on x86-64).
      Not all user space is ready to handle wide addresses.  It's known that
      at least some JIT compilers use higher bits in pointers to encode their
      information.
      
      Userspace can ask for allocation from full address space by specifying
      hint address (with or without MAP_FIXED) above 47-bits.  If the
      application doesn't need a particular address, but wants to allocate
      from whole address space it can specify -1 as a hint address.
      
      Unfortunately, this trick breaks THP alignment in shmem/tmp:
      shmem_get_unmapped_area() would not try to allocate PMD-aligned area if
      *any* hint address specified.
      
      This can be fixed by requesting the aligned area if the we failed to
      allocated at user-specified hint address.  The request with inflated
      length will also take the user-specified hint address.  This way we will
      not lose an allocation request from the full address space.
      
      [kirill@shutemov.name: fold in a fixup]
        Link: http://lkml.kernel.org/r/20191223231309.t6bh5hkbmokihpfu@box
      Link: http://lkml.kernel.org/r/20191220142548.7118-3-kirill.shutemov@linux.intel.com
      Fixes: b569bab7 ("x86/mm: Prepare to expose larger address space to userspace")
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: "Willhalm, Thomas" <thomas.willhalm@intel.com>
      Cc: Dan Williams <dan.j.williams@intel.com>
      Cc: "Bruggeman, Otto G" <otto.g.bruggeman@intel.com>
      Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      99158997
    • Kirill A. Shutemov's avatar
      mm/huge_memory.c: thp: fix conflict of above-47bit hint address and PMD alignment · 97d3d0f9
      Kirill A. Shutemov authored
      Patch series "Fix two above-47bit hint address vs.  THP bugs".
      
      The two get_unmapped_area() implementations have to be fixed to provide
      THP-friendly mappings if above-47bit hint address is specified.
      
      This patch (of 2):
      
      Filesystems use thp_get_unmapped_area() to provide THP-friendly
      mappings.  For DAX in particular.
      
      Normally, the kernel doesn't create userspace mappings above 47-bit,
      even if the machine allows this (such as with 5-level paging on x86-64).
      Not all user space is ready to handle wide addresses.  It's known that
      at least some JIT compilers use higher bits in pointers to encode their
      information.
      
      Userspace can ask for allocation from full address space by specifying
      hint address (with or without MAP_FIXED) above 47-bits.  If the
      application doesn't need a particular address, but wants to allocate
      from whole address space it can specify -1 as a hint address.
      
      Unfortunately, this trick breaks thp_get_unmapped_area(): the function
      would not try to allocate PMD-aligned area if *any* hint address
      specified.
      
      Modify the routine to handle it correctly:
      
       - Try to allocate the space at the specified hint address with length
         padding required for PMD alignment.
       - If failed, retry without length padding (but with the same hint
         address);
       - If the returned address matches the hint address return it.
       - Otherwise, align the address as required for THP and return.
      
      The user specified hint address is passed down to get_unmapped_area() so
      above-47bit hint address will be taken into account without breaking
      alignment requirements.
      
      Link: http://lkml.kernel.org/r/20191220142548.7118-2-kirill.shutemov@linux.intel.com
      Fixes: b569bab7 ("x86/mm: Prepare to expose larger address space to userspace")
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Reported-by: default avatarThomas Willhalm <thomas.willhalm@intel.com>
      Tested-by: default avatarDan Williams <dan.j.williams@intel.com>
      Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
      Cc: "Bruggeman, Otto G" <otto.g.bruggeman@intel.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      97d3d0f9