• Zhang Xiaoxu's avatar
    cifs: Fix double add page to memcg when cifs_readpages · 5f7ca306
    Zhang Xiaoxu authored
    [ Upstream commit 95a3d8f3 ]
    
    When xfstests generic/451, there is an BUG at mm/memcontrol.c:
      page:ffffea000560f2c0 refcount:2 mapcount:0 mapping:000000008544e0ea
           index:0xf
      mapping->aops:cifs_addr_ops dentry name:"tst-aio-dio-cycle-write.451"
      flags: 0x2fffff80000001(locked)
      raw: 002fffff80000001 ffffc90002023c50 ffffea0005280088 ffff88815cda0210
      raw: 000000000000000f 0000000000000000 00000002ffffffff ffff88817287d000
      page dumped because: VM_BUG_ON_PAGE(page->mem_cgroup)
      page->mem_cgroup:ffff88817287d000
      ------------[ cut here ]------------
      kernel BUG at mm/memcontrol.c:2659!
      invalid opcode: 0000 [#1] SMP
      CPU: 2 PID: 2038 Comm: xfs_io Not tainted 5.8.0-rc1 #44
      Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_
        073836-buildvm-ppc64le-16.ppc.4
      RIP: 0010:commit_charge+0x35/0x50
      Code: 0d 48 83 05 54 b2 02 05 01 48 89 77 38 c3 48 c7
            c6 78 4a ea ba 48 83 05 38 b2 02 05 01 e8 63 0d9
      RSP: 0018:ffffc90002023a50 EFLAGS: 00010202
      RAX: 0000000000000000 RBX: ffff88817287d000 RCX: 0000000000000000
      RDX: 0000000000000000 RSI: ffff88817ac97ea0 RDI: ffff88817ac97ea0
      RBP: ffffea000560f2c0 R08: 0000000000000203 R09: 0000000000000005
      R10: 0000000000000030 R11: ffffc900020237a8 R12: 0000000000000000
      R13: 0000000000000001 R14: 0000000000000001 R15: ffff88815a1272c0
      FS:  00007f5071ab0800(0000) GS:ffff88817ac80000(0000) knlGS:0000000000000000
      CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      CR2: 000055efcd5ca000 CR3: 000000015d312000 CR4: 00000000000006e0
      DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
      DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
      Call Trace:
       mem_cgroup_charge+0x166/0x4f0
       __add_to_page_cache_locked+0x4a9/0x710
       add_to_page_cache_locked+0x15/0x20
       cifs_readpages+0x217/0x1270
       read_pages+0x29a/0x670
       page_cache_readahead_unbounded+0x24f/0x390
       __do_page_cache_readahead+0x3f/0x60
       ondemand_readahead+0x1f1/0x470
       page_cache_async_readahead+0x14c/0x170
       generic_file_buffered_read+0x5df/0x1100
       generic_file_read_iter+0x10c/0x1d0
       cifs_strict_readv+0x139/0x170
       new_sync_read+0x164/0x250
       __vfs_read+0x39/0x60
       vfs_read+0xb5/0x1e0
       ksys_pread64+0x85/0xf0
       __x64_sys_pread64+0x22/0x30
       do_syscall_64+0x69/0x150
       entry_SYSCALL_64_after_hwframe+0x44/0xa9
      RIP: 0033:0x7f5071fcb1af
      Code: Bad RIP value.
      RSP: 002b:00007ffde2cdb8e0 EFLAGS: 00000293 ORIG_RAX: 0000000000000011
      RAX: ffffffffffffffda RBX: 00007ffde2cdb990 RCX: 00007f5071fcb1af
      RDX: 0000000000001000 RSI: 000055efcd5ca000 RDI: 0000000000000003
      RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
      R10: 0000000000001000 R11: 0000000000000293 R12: 0000000000000001
      R13: 000000000009f000 R14: 0000000000000000 R15: 0000000000001000
      Modules linked in:
      ---[ end trace 725fa14a3e1af65c ]---
    
    Since commit 3fea5a49 ("mm: memcontrol: convert page cache to a new
    mem_cgroup_charge() API") not cancel the page charge, the pages maybe
    double add to pagecache:
    thread1                       | thread2
    cifs_readpages
    readpages_get_pages
     add_to_page_cache_locked(head,index=n)=0
                                  | readpages_get_pages
                                  | add_to_page_cache_locked(head,index=n+1)=0
     add_to_page_cache_locked(head, index=n+1)=-EEXIST
     then, will next loop with list head page's
     index=n+1 and the page->mapping not NULL
    readpages_get_pages
    add_to_page_cache_locked(head, index=n+1)
     commit_charge
      VM_BUG_ON_PAGE
    
    So, we should not do the next loop when any page add to page cache
    failed.
    Reported-by: default avatarHulk Robot <hulkci@huawei.com>
    Signed-off-by: default avatarZhang Xiaoxu <zhangxiaoxu5@huawei.com>
    Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
    Acked-by: default avatarRonnie Sahlberg <lsahlber@redhat.com>
    Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
    5f7ca306
file.c 109 KB