1. 14 Nov, 2020 12 commits
    • Mike Kravetz's avatar
      hugetlbfs: fix anon huge page migration race · 336bf30e
      Mike Kravetz authored
      Qian Cai reported the following BUG in [1]
      
        LTP: starting move_pages12
        BUG: unable to handle page fault for address: ffffffffffffffe0
        ...
        RIP: 0010:anon_vma_interval_tree_iter_first+0xa2/0x170 avc_start_pgoff at mm/interval_tree.c:63
        Call Trace:
          rmap_walk_anon+0x141/0xa30 rmap_walk_anon at mm/rmap.c:1864
          try_to_unmap+0x209/0x2d0 try_to_unmap at mm/rmap.c:1763
          migrate_pages+0x1005/0x1fb0
          move_pages_and_store_status.isra.47+0xd7/0x1a0
          __x64_sys_move_pages+0xa5c/0x1100
          do_syscall_64+0x5f/0x310
          entry_SYSCALL_64_after_hwframe+0x44/0xa9
      
      Hugh Dickins diagnosed this as a migration bug caused by code introduced
      to use i_mmap_rwsem for pmd sharing synchronization.  Specifically, the
      routine unmap_and_move_huge_page() is always passing the TTU_RMAP_LOCKED
      flag to try_to_unmap() while holding i_mmap_rwsem.  This is wrong for
      anon pages as the anon_vma_lock should be held in this case.  Further
      analysis suggested that i_mmap_rwsem was not required to he held at all
      when calling try_to_unmap for anon pages as an anon page could never be
      part of a shared pmd mapping.
      
      Discussion also revealed that the hack in hugetlb_page_mapping_lock_write
      to drop page lock and acquire i_mmap_rwsem is wrong.  There is no way to
      keep mapping valid while dropping page lock.
      
      This patch does the following:
      
       - Do not take i_mmap_rwsem and set TTU_RMAP_LOCKED for anon pages when
         calling try_to_unmap.
      
       - Remove the hacky code in hugetlb_page_mapping_lock_write. The routine
         will now simply do a 'trylock' while still holding the page lock. If
         the trylock fails, it will return NULL. This could impact the
         callers:
      
          - migration calling code will receive -EAGAIN and retry up to the
            hard coded limit (10).
      
          - memory error code will treat the page as BUSY. This will force
            killing (SIGKILL) instead of SIGBUS any mapping tasks.
      
         Do note that this change in behavior only happens when there is a
         race. None of the standard kernel testing suites actually hit this
         race, but it is possible.
      
      [1] https://lore.kernel.org/lkml/20200708012044.GC992@lca.pw/
      [2] https://lore.kernel.org/linux-mm/alpine.LSU.2.11.2010071833100.2214@eggly.anvils/
      
      Fixes: c0d0381a ("hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization")
      Reported-by: default avatarQian Cai <cai@lca.pw>
      Suggested-by: default avatarHugh Dickins <hughd@google.com>
      Signed-off-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Acked-by: default avatarNaoya Horiguchi <naoya.horiguchi@nec.com>
      Cc: <stable@vger.kernel.org>
      Link: https://lkml.kernel.org/r/20201105195058.78401-1-mike.kravetz@oracle.comSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      336bf30e
    • Muchun Song's avatar
      mm: memcontrol: fix missing wakeup polling thread · 8b21ca02
      Muchun Song authored
      When we poll the swap.events, we can miss being woken up when the swap
      event occurs.  Because we didn't notify.
      
      Fixes: f3a53a3a ("mm, memcontrol: implement memory.swap.events")
      Signed-off-by: default avatarMuchun Song <songmuchun@bytedance.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Reviewed-by: default avatarShakeel Butt <shakeelb@google.com>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Cc: Roman Gushchin <guro@fb.com>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: Yafang Shao <laoar.shao@gmail.com>
      Cc: Chris Down <chris@chrisdown.name>
      Cc: Tejun Heo <tj@kernel.org>
      Link: https://lkml.kernel.org/r/20201105161936.98312-1-songmuchun@bytedance.comSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8b21ca02
    • Santosh Sivaraj's avatar
      kernel/watchdog: fix watchdog_allowed_mask not used warning · e7e04615
      Santosh Sivaraj authored
      Define watchdog_allowed_mask only when SOFTLOCKUP_DETECTOR is enabled.
      
      Fixes: 7feeb9cd ("watchdog/sysctl: Clean up sysctl variable name space")
      Signed-off-by: default avatarSantosh Sivaraj <santosh@fossix.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Reviewed-by: default avatarPetr Mladek <pmladek@suse.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: https://lkml.kernel.org/r/20201106015025.1281561-1-santosh@fossix.orgSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e7e04615
    • Matteo Croce's avatar
      reboot: fix overflow parsing reboot cpu number · df5b0ab3
      Matteo Croce authored
      Limit the CPU number to num_possible_cpus(), because setting it to a
      value lower than INT_MAX but higher than NR_CPUS produces the following
      error on reboot and shutdown:
      
          BUG: unable to handle page fault for address: ffffffff90ab1bb0
          #PF: supervisor read access in kernel mode
          #PF: error_code(0x0000) - not-present page
          PGD 1c09067 P4D 1c09067 PUD 1c0a063 PMD 0
          Oops: 0000 [#1] SMP
          CPU: 1 PID: 1 Comm: systemd-shutdow Not tainted 5.9.0-rc8-kvm #110
          Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
          RIP: 0010:migrate_to_reboot_cpu+0xe/0x60
          Code: ea ea 00 48 89 fa 48 c7 c7 30 57 f1 81 e9 fa ef ff ff 66 2e 0f 1f 84 00 00 00 00 00 53 8b 1d d5 ea ea 00 e8 14 33 fe ff 89 da <48> 0f a3 15 ea fc bd 00 48 89 d0 73 29 89 c2 c1 e8 06 65 48 8b 3c
          RSP: 0018:ffffc90000013e08 EFLAGS: 00010246
          RAX: ffff88801f0a0000 RBX: 0000000077359400 RCX: 0000000000000000
          RDX: 0000000077359400 RSI: 0000000000000002 RDI: ffffffff81c199e0
          RBP: ffffffff81c1e3c0 R08: ffff88801f41f000 R09: ffffffff81c1e348
          R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
          R13: 00007f32bedf8830 R14: 00000000fee1dead R15: 0000000000000000
          FS:  00007f32bedf8980(0000) GS:ffff88801f480000(0000) knlGS:0000000000000000
          CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
          CR2: ffffffff90ab1bb0 CR3: 000000001d057000 CR4: 00000000000006a0
          DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
          DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
          Call Trace:
            __do_sys_reboot.cold+0x34/0x5b
            do_syscall_64+0x2d/0x40
      
      Fixes: 1b3a5d02 ("reboot: move arch/x86 reboot= handling to generic kernel")
      Signed-off-by: default avatarMatteo Croce <mcroce@microsoft.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Fabian Frederick <fabf@skynet.be>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: Guenter Roeck <linux@roeck-us.net>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Mike Rapoport <rppt@kernel.org>
      Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
      Cc: Petr Mladek <pmladek@suse.com>
      Cc: Robin Holt <robinmholt@gmail.com>
      Cc: <stable@vger.kernel.org>
      Link: https://lkml.kernel.org/r/20201103214025.116799-3-mcroce@linux.microsoft.comSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      df5b0ab3
    • Matteo Croce's avatar
      Revert "kernel/reboot.c: convert simple_strtoul to kstrtoint" · 8b92c4ff
      Matteo Croce authored
      Patch series "fix parsing of reboot= cmdline", v3.
      
      The parsing of the reboot= cmdline has two major errors:
      
       - a missing bound check can crash the system on reboot
      
       - parsing of the cpu number only works if specified last
      
      Fix both.
      
      This patch (of 2):
      
      This reverts commit 616feab7.
      
      kstrtoint() and simple_strtoul() have a subtle difference which makes
      them non interchangeable: if a non digit character is found amid the
      parsing, the former will return an error, while the latter will just
      stop parsing, e.g.  simple_strtoul("123xyx") = 123.
      
      The kernel cmdline reboot= argument allows to specify the CPU used for
      rebooting, with the syntax `s####` among the other flags, e.g.
      "reboot=warm,s31,force", so if this flag is not the last given, it's
      silently ignored as well as the subsequent ones.
      
      Fixes: 616feab7 ("kernel/reboot.c: convert simple_strtoul to kstrtoint")
      Signed-off-by: default avatarMatteo Croce <mcroce@microsoft.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Cc: Guenter Roeck <linux@roeck-us.net>
      Cc: Petr Mladek <pmladek@suse.com>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Mike Rapoport <rppt@kernel.org>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
      Cc: Robin Holt <robinmholt@gmail.com>
      Cc: Fabian Frederick <fabf@skynet.be>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: <stable@vger.kernel.org>
      Link: https://lkml.kernel.org/r/20201103214025.116799-2-mcroce@linux.microsoft.comSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8b92c4ff
    • Arvind Sankar's avatar
      compiler.h: fix barrier_data() on clang · 3347acc6
      Arvind Sankar authored
      Commit 815f0ddb ("include/linux/compiler*.h: make compiler-*.h
      mutually exclusive") neglected to copy barrier_data() from
      compiler-gcc.h into compiler-clang.h.
      
      The definition in compiler-gcc.h was really to work around clang's more
      aggressive optimization, so this broke barrier_data() on clang, and
      consequently memzero_explicit() as well.
      
      For example, this results in at least the memzero_explicit() call in
      lib/crypto/sha256.c:sha256_transform() being optimized away by clang.
      
      Fix this by moving the definition of barrier_data() into compiler.h.
      
      Also move the gcc/clang definition of barrier() into compiler.h,
      __memory_barrier() is icc-specific (and barrier() is already defined
      using it in compiler-intel.h) and doesn't belong in compiler.h.
      
      [rdunlap@infradead.org: fix ALPHA builds when SMP is not enabled]
      
      Link: https://lkml.kernel.org/r/20201101231835.4589-1-rdunlap@infradead.org
      Fixes: 815f0ddb ("include/linux/compiler*.h: make compiler-*.h mutually exclusive")
      Signed-off-by: default avatarArvind Sankar <nivedita@alum.mit.edu>
      Signed-off-by: default avatarRandy Dunlap <rdunlap@infradead.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Tested-by: default avatarNick Desaulniers <ndesaulniers@google.com>
      Reviewed-by: default avatarNick Desaulniers <ndesaulniers@google.com>
      Reviewed-by: default avatarKees Cook <keescook@chromium.org>
      Cc: <stable@vger.kernel.org>
      Link: https://lkml.kernel.org/r/20201014212631.207844-1-nivedita@alum.mit.eduSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3347acc6
    • Jason Gunthorpe's avatar
      mm/gup: use unpin_user_pages() in __gup_longterm_locked() · 96e1fac1
      Jason Gunthorpe authored
      When FOLL_PIN is passed to __get_user_pages() the page list must be put
      back using unpin_user_pages() otherwise the page pin reference persists
      in a corrupted state.
      
      There are two places in the unwind of __gup_longterm_locked() that put
      the pages back without checking.  Normally on error this function would
      return the partial page list making this the caller's responsibility,
      but in these two cases the caller is not allowed to see these pages at
      all.
      
      Fixes: 3faa52c0 ("mm/gup: track FOLL_PIN pages")
      Reported-by: default avatarIra Weiny <ira.weiny@intel.com>
      Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Reviewed-by: default avatarIra Weiny <ira.weiny@intel.com>
      Reviewed-by: default avatarJohn Hubbard <jhubbard@nvidia.com>
      Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
      Cc: Dan Williams <dan.j.williams@intel.com>
      Cc: <stable@vger.kernel.org>
      Link: https://lkml.kernel.org/r/0-v2-3ae7d9d162e2+2a7-gup_cma_fix_jgg@nvidia.comSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      96e1fac1
    • Laurent Dufour's avatar
      mm/slub: fix panic in slab_alloc_node() · 22e4663e
      Laurent Dufour authored
      While doing memory hot-unplug operation on a PowerPC VM running 1024 CPUs
      with 11TB of ram, I hit the following panic:
      
          BUG: Kernel NULL pointer dereference on read at 0x00000007
          Faulting instruction address: 0xc000000000456048
          Oops: Kernel access of bad area, sig: 11 [#2]
          LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS= 2048 NUMA pSeries
          Modules linked in: rpadlpar_io rpaphp
          CPU: 160 PID: 1 Comm: systemd Tainted: G      D           5.9.0 #1
          NIP:  c000000000456048 LR: c000000000455fd4 CTR: c00000000047b350
          REGS: c00006028d1b77a0 TRAP: 0300   Tainted: G      D            (5.9.0)
          MSR:  8000000000009033 <SF,EE,ME,IR,DR,RI,LE>  CR: 24004228  XER: 00000000
          CFAR: c00000000000f1b0 DAR: 0000000000000007 DSISR: 40000000 IRQMASK: 0
          GPR00: c000000000455fd4 c00006028d1b7a30 c000000001bec800 0000000000000000
          GPR04: 0000000000000dc0 0000000000000000 00000000000374ef c00007c53df99320
          GPR08: 000007c53c980000 0000000000000000 000007c53c980000 0000000000000000
          GPR12: 0000000000004400 c00000001e8e4400 0000000000000000 0000000000000f6a
          GPR16: 0000000000000000 c000000001c25930 c000000001d62528 00000000000000c1
          GPR20: c000000001d62538 c00006be469e9000 0000000fffffffe0 c0000000003c0ff8
          GPR24: 0000000000000018 0000000000000000 0000000000000dc0 0000000000000000
          GPR28: c00007c513755700 c000000001c236a4 c00007bc4001f800 0000000000000001
          NIP [c000000000456048] __kmalloc_node+0x108/0x790
          LR [c000000000455fd4] __kmalloc_node+0x94/0x790
          Call Trace:
            kvmalloc_node+0x58/0x110
            mem_cgroup_css_online+0x10c/0x270
            online_css+0x48/0xd0
            cgroup_apply_control_enable+0x2c4/0x470
            cgroup_mkdir+0x408/0x5f0
            kernfs_iop_mkdir+0x90/0x100
            vfs_mkdir+0x138/0x250
            do_mkdirat+0x154/0x1c0
            system_call_exception+0xf8/0x200
            system_call_common+0xf0/0x27c
          Instruction dump:
          e93e0000 e90d0030 39290008 7cc9402a e94d0030 e93e0000 7ce95214 7f89502a
          2fbc0000 419e0018 41920230 e9270010 <89290007> 7f994800 419e0220 7ee6bb78
      
      This pointing to the following code:
      
          mm/slub.c:2851
                  if (unlikely(!object || !node_match(page, node))) {
          c000000000456038:       00 00 bc 2f     cmpdi   cr7,r28,0
          c00000000045603c:       18 00 9e 41     beq     cr7,c000000000456054 <__kmalloc_node+0x114>
          node_match():
          mm/slub.c:2491
                  if (node != NUMA_NO_NODE && page_to_nid(page) != node)
          c000000000456040:       30 02 92 41     beq     cr4,c000000000456270 <__kmalloc_node+0x330>
          page_to_nid():
          include/linux/mm.h:1294
          c000000000456044:       10 00 27 e9     ld      r9,16(r7)
          c000000000456048:       07 00 29 89     lbz     r9,7(r9)	<<<< r9 = NULL
          node_match():
          mm/slub.c:2491
          c00000000045604c:       00 48 99 7f     cmpw    cr7,r25,r9
          c000000000456050:       20 02 9e 41     beq     cr7,c000000000456270 <__kmalloc_node+0x330>
      
      The panic occurred in slab_alloc_node() when checking for the page's node:
      
      	object = c->freelist;
      	page = c->page;
      	if (unlikely(!object || !node_match(page, node))) {
      		object = __slab_alloc(s, gfpflags, node, addr, c);
      		stat(s, ALLOC_SLOWPATH);
      
      The issue is that object is not NULL while page is NULL which is odd but
      may happen if the cache flush happened after loading object but before
      loading page.  Thus checking for the page pointer is required too.
      
      The cache flush is done through an inter processor interrupt when a
      piece of memory is off-lined.  That interrupt is triggered when a memory
      hot-unplug operation is initiated and offline_pages() is calling the
      slub's MEM_GOING_OFFLINE callback slab_mem_going_offline_callback()
      which is calling flush_cpu_slab().  If that interrupt is caught between
      the reading of c->freelist and the reading of c->page, this could lead
      to such a situation.  That situation is expected and the later call to
      this_cpu_cmpxchg_double() will detect the change to c->freelist and redo
      the whole operation.
      
      In commit 6159d0f5 ("mm/slub.c: page is always non-NULL in
      node_match()") check on the page pointer has been removed assuming that
      page is always valid when it is called.  It happens that this is not
      true in that particular case, so check for page before calling
      node_match() here.
      
      Fixes: 6159d0f5 ("mm/slub.c: page is always non-NULL in node_match()")
      Signed-off-by: default avatarLaurent Dufour <ldufour@linux.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Acked-by: default avatarChristoph Lameter <cl@linux.com>
      Cc: Wei Yang <richard.weiyang@gmail.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Nathan Lynch <nathanl@linux.ibm.com>
      Cc: Scott Cheloha <cheloha@linux.ibm.com>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: <stable@vger.kernel.org>
      Link: https://lkml.kernel.org/r/20201027190406.33283-1-ldufour@linux.ibm.comSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      22e4663e
    • Dmitry Baryshkov's avatar
      mailmap: fix entry for Dmitry Baryshkov/Eremin-Solenikov · 044747e9
      Dmitry Baryshkov authored
      Change back surname to new (old) one.  Dmitry Baryshkov -> Dmitry
      Eremin-Solenikov -> Dmitry Baryshkov.  Map several odd entries to main
      identity.
      Signed-off-by: default avatarDmitry Baryshkov <dbaryshkov@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Link: https://lkml.kernel.org/r/20201103005158.1181426-1-dmitry.baryshkov@linaro.orgSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      044747e9
    • Nicholas Piggin's avatar
      mm/vmscan: fix NR_ISOLATED_FILE corruption on 64-bit · 2da9f630
      Nicholas Piggin authored
      Previously the negated unsigned long would be cast back to signed long
      which would have the correct negative value.  After commit 730ec8c0
      ("mm/vmscan.c: change prototype for shrink_page_list"), the large
      unsigned int converts to a large positive signed long.
      
      Symptoms include CMA allocations hanging forever holding the cma_mutex
      due to alloc_contig_range->...->isolate_migratepages_block waiting
      forever in "while (unlikely(too_many_isolated(pgdat)))".
      
      [akpm@linux-foundation.org: fix -stat.nr_lazyfree_fail as well, per Michal]
      
      Fixes: 730ec8c0 ("mm/vmscan.c: change prototype for shrink_page_list")
      Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Acked-by: default avatarMichal Hocko <mhocko@suse.com>
      Cc: Vaneet Narang <v.narang@samsung.com>
      Cc: Maninder Singh <maninder1.s@samsung.com>
      Cc: Amit Sahrawat <a.sahrawat@samsung.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: <stable@vger.kernel.org>
      Link: https://lkml.kernel.org/r/20201029032320.1448441-1-npiggin@gmail.comSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2da9f630
    • Zi Yan's avatar
      mm/compaction: stop isolation if too many pages are isolated and we have pages to migrate · d20bdd57
      Zi Yan authored
      In isolate_migratepages_block, if we have too many isolated pages and
      nr_migratepages is not zero, we should try to migrate what we have
      without wasting time on isolating.
      
      In theory it's possible that multiple parallel compactions will cause
      too_many_isolated() to become true even if each has isolated less than
      COMPACT_CLUSTER_MAX, and loop forever in the while loop.  Bailing
      immediately prevents that.
      
      [vbabka@suse.cz: changelog addition]
      
      Fixes: 1da2f328 (“mm,thp,compaction,cma: allow THP migration for CMA allocations”)
      Suggested-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarZi Yan <ziy@nvidia.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Cc: <stable@vger.kernel.org>
      Cc: Mel Gorman <mgorman@techsingularity.net>
      Cc: Michal Hocko <mhocko@kernel.org>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: Yang Shi <shy828301@gmail.com>
      Link: https://lkml.kernel.org/r/20201030183809.3616803-2-zi.yan@sent.comSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d20bdd57
    • Zi Yan's avatar
      mm/compaction: count pages and stop correctly during page isolation · 38935861
      Zi Yan authored
      In isolate_migratepages_block, when cc->alloc_contig is true, we are
      able to isolate compound pages.  But nr_migratepages and nr_isolated did
      not count compound pages correctly, causing us to isolate more pages
      than we thought.
      
      So count compound pages as the number of base pages they contain.
      Otherwise, we might be trapped in too_many_isolated while loop, since
      the actual isolated pages can go up to COMPACT_CLUSTER_MAX*512=16384,
      where COMPACT_CLUSTER_MAX is 32, since we stop isolation after
      cc->nr_migratepages reaches to COMPACT_CLUSTER_MAX.
      
      In addition, after we fix the issue above, cc->nr_migratepages could
      never be equal to COMPACT_CLUSTER_MAX if compound pages are isolated,
      thus page isolation could not stop as we intended.  Change the isolation
      stop condition to '>='.
      
      The issue can be triggered as follows:
      
      In a system with 16GB memory and an 8GB CMA region reserved by
      hugetlb_cma, if we first allocate 10GB THPs and mlock them (so some THPs
      are allocated in the CMA region and mlocked), reserving 6 1GB hugetlb
      pages via /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages will
      get stuck (looping in too_many_isolated function) until we kill either
      task.  With the patch applied, oom will kill the application with 10GB
      THPs and let hugetlb page reservation finish.
      
      [ziy@nvidia.com: v3]
      
      Link: https://lkml.kernel.org/r/20201030183809.3616803-1-zi.yan@sent.com
      Fixes: 1da2f328 ("cmm,thp,compaction,cma: allow THP migration for CMA allocations")
      Signed-off-by: default avatarZi Yan <ziy@nvidia.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Reviewed-by: default avatarYang Shi <shy828301@gmail.com>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: Michal Hocko <mhocko@kernel.org>
      Cc: Mel Gorman <mgorman@techsingularity.net>
      Cc: <stable@vger.kernel.org>
      Link: https://lkml.kernel.org/r/20201029200435.3386066-1-zi.yan@sent.comSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      38935861
  2. 13 Nov, 2020 27 commits
  3. 12 Nov, 2020 1 commit
    • Linus Torvalds's avatar
      Merge tag 'net-5.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net · db7c9535
      Linus Torvalds authored
      Pull networking fixes from Jakub Kicinski:
       "Current release - regressions:
      
         - arm64: dts: fsl-ls1028a-kontron-sl28: specify in-band mode for
           ENETC
      
        Current release - bugs in new features:
      
         - mptcp: provide rmem[0] limit offset to fix oops
      
        Previous release - regressions:
      
         - IPv6: Set SIT tunnel hard_header_len to zero to fix path MTU
           calculations
      
         - lan743x: correctly handle chips with internal PHY
      
         - bpf: Don't rely on GCC __attribute__((optimize)) to disable GCSE
      
         - mlx5e: Fix VXLAN port table synchronization after function reload
      
        Previous release - always broken:
      
         - bpf: Zero-fill re-used per-cpu map element
      
         - fix out-of-order UDP packets when forwarding with UDP GSO fraglists
           turned on:
             - fix UDP header access on Fast/frag0 UDP GRO
             - fix IP header access and skb lookup on Fast/frag0 UDP GRO
      
         - ethtool: netlink: add missing netdev_features_change() call
      
         - net: Update window_clamp if SOCK_RCVBUF is set
      
         - igc: Fix returning wrong statistics
      
         - ch_ktls: fix multiple leaks and corner cases in Chelsio TLS offload
      
         - tunnels: Fix off-by-one in lower MTU bounds for ICMP/ICMPv6 replies
      
         - r8169: disable hw csum for short packets on all chip versions
      
         - vrf: Fix fast path output packet handling with async Netfilter
           rules"
      
      * tag 'net-5.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (65 commits)
        lan743x: fix use of uninitialized variable
        net: udp: fix IP header access and skb lookup on Fast/frag0 UDP GRO
        net: udp: fix UDP header access on Fast/frag0 UDP GRO
        devlink: Avoid overwriting port attributes of registered port
        vrf: Fix fast path output packet handling with async Netfilter rules
        cosa: Add missing kfree in error path of cosa_write
        net: switch to the kernel.org patchwork instance
        ch_ktls: stop the txq if reaches threshold
        ch_ktls: tcb update fails sometimes
        ch_ktls/cxgb4: handle partial tag alone SKBs
        ch_ktls: don't free skb before sending FIN
        ch_ktls: packet handling prior to start marker
        ch_ktls: Correction in middle record handling
        ch_ktls: missing handling of header alone
        ch_ktls: Correction in trimmed_len calculation
        cxgb4/ch_ktls: creating skbs causes panic
        ch_ktls: Update cheksum information
        ch_ktls: Correction in finding correct length
        cxgb4/ch_ktls: decrypted bit is not enough
        net/x25: Fix null-ptr-deref in x25_connect
        ...
      db7c9535