1. 19 May, 2018 1 commit
    • Eric Dumazet's avatar
      llc: better deal with too small mtu · 1e22ffab
      Eric Dumazet authored
      [ Upstream commit 2c5d5b13 ]
      
      syzbot loves to set very small mtu on devices, since it brings joy.
      We must make llc_ui_sendmsg() fool proof.
      
      usercopy: Kernel memory overwrite attempt detected to wrapped address (offset 0, size 18446612139802320068)!
      
      kernel BUG at mm/usercopy.c:100!
      invalid opcode: 0000 [#1] SMP KASAN
      Dumping ftrace buffer:
         (ftrace buffer empty)
      Modules linked in:
      CPU: 0 PID: 17464 Comm: syz-executor1 Not tainted 4.17.0-rc3+ #36
      Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
      RIP: 0010:usercopy_abort+0xbb/0xbd mm/usercopy.c:88
      RSP: 0018:ffff8801868bf800 EFLAGS: 00010282
      RAX: 000000000000006c RBX: ffffffff87d2fb00 RCX: 0000000000000000
      RDX: 000000000000006c RSI: ffffffff81610731 RDI: ffffed0030d17ef6
      RBP: ffff8801868bf858 R08: ffff88018daa4200 R09: ffffed003b5c4fb0
      R10: ffffed003b5c4fb0 R11: ffff8801dae27d87 R12: ffffffff87d2f8e0
      R13: ffffffff87d2f7a0 R14: ffffffff87d2f7a0 R15: ffffffff87d2f7a0
      FS:  00007f56a14ac700(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
      CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      CR2: 0000001b2bc21000 CR3: 00000001abeb1000 CR4: 00000000001426f0
      DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
      DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000030602
      Call Trace:
       check_bogus_address mm/usercopy.c:153 [inline]
       __check_object_size+0x5d9/0x5d9 mm/usercopy.c:256
       check_object_size include/linux/thread_info.h:108 [inline]
       check_copy_size include/linux/thread_info.h:139 [inline]
       copy_from_iter_full include/linux/uio.h:121 [inline]
       memcpy_from_msg include/linux/skbuff.h:3305 [inline]
       llc_ui_sendmsg+0x4b1/0x1530 net/llc/af_llc.c:941
       sock_sendmsg_nosec net/socket.c:629 [inline]
       sock_sendmsg+0xd5/0x120 net/socket.c:639
       __sys_sendto+0x3d7/0x670 net/socket.c:1789
       __do_sys_sendto net/socket.c:1801 [inline]
       __se_sys_sendto net/socket.c:1797 [inline]
       __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1797
       do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
       entry_SYSCALL_64_after_hwframe+0x49/0xbe
      RIP: 0033:0x455979
      RSP: 002b:00007f56a14abc68 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
      RAX: ffffffffffffffda RBX: 00007f56a14ac6d4 RCX: 0000000000455979
      RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000018
      RBP: 000000000072bea0 R08: 00000000200012c0 R09: 0000000000000010
      R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
      R13: 0000000000000548 R14: 00000000006fbf60 R15: 0000000000000000
      Code: 55 c0 e8 c0 55 bb ff ff 75 c8 48 8b 55 c0 4d 89 f9 ff 75 d0 4d 89 e8 48 89 d9 4c 89 e6 41 56 48 c7 c7 80 fa d2 87 e8 a0 0b a3 ff <0f> 0b e8 95 55 bb ff e8 c0 a8 f7 ff 8b 95 14 ff ff ff 4d 89 e8
      RIP: usercopy_abort+0xbb/0xbd mm/usercopy.c:88 RSP: ffff8801868bf800
      
      Fixes: 1da177e4 ("Linux-2.6.12-rc2")
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Reported-by: default avatarsyzbot <syzkaller@googlegroups.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      1e22ffab
  2. 29 Apr, 2018 2 commits
    • Cong Wang's avatar
      llc: fix NULL pointer deref for SOCK_ZAPPED · 7814c479
      Cong Wang authored
      
      [ Upstream commit 3a04ce71 ]
      
      For SOCK_ZAPPED socket, we don't need to care about llc->sap,
      so we should just skip these refcount functions in this case.
      
      Fixes: f7e43672 ("llc: hold llc_sap before release_sock()")
      Reported-by: default avatarkernel test robot <lkp@intel.com>
      Signed-off-by: default avatarCong Wang <xiyou.wangcong@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      7814c479
    • Cong Wang's avatar
      llc: hold llc_sap before release_sock() · 543a6011
      Cong Wang authored
      
      [ Upstream commit f7e43672 ]
      
      syzbot reported we still access llc->sap in llc_backlog_rcv()
      after it is freed in llc_sap_remove_socket():
      
      Call Trace:
       __dump_stack lib/dump_stack.c:77 [inline]
       dump_stack+0x1b9/0x294 lib/dump_stack.c:113
       print_address_description+0x6c/0x20b mm/kasan/report.c:256
       kasan_report_error mm/kasan/report.c:354 [inline]
       kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
       __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430
       llc_conn_ac_send_sabme_cmd_p_set_x+0x3a8/0x460 net/llc/llc_c_ac.c:785
       llc_exec_conn_trans_actions net/llc/llc_conn.c:475 [inline]
       llc_conn_service net/llc/llc_conn.c:400 [inline]
       llc_conn_state_process+0x4e1/0x13a0 net/llc/llc_conn.c:75
       llc_backlog_rcv+0x195/0x1e0 net/llc/llc_conn.c:891
       sk_backlog_rcv include/net/sock.h:909 [inline]
       __release_sock+0x12f/0x3a0 net/core/sock.c:2335
       release_sock+0xa4/0x2b0 net/core/sock.c:2850
       llc_ui_release+0xc8/0x220 net/llc/af_llc.c:204
      
      llc->sap is refcount'ed and llc_sap_remove_socket() is paired
      with llc_sap_add_socket(). This can be amended by holding its refcount
      before llc_sap_remove_socket() and releasing it after release_sock().
      
      Reported-by: <syzbot+6e181fc95081c2cf9051@syzkaller.appspotmail.com>
      Signed-off-by: default avatarCong Wang <xiyou.wangcong@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      543a6011
  3. 26 May, 2017 1 commit
    • linzhang's avatar
      net: llc: add lock_sock in llc_ui_bind to avoid a race condition · 0908cf4d
      linzhang authored
      There is a race condition in llc_ui_bind if two or more processes/threads
      try to bind a same socket.
      
      If more processes/threads bind a same socket success that will lead to
      two problems, one is this action is not what we expected, another is
      will lead to kernel in unstable status or oops(in my simple test case,
      cause llc2.ko can't unload).
      
      The current code is test SOCK_ZAPPED bit to avoid a process to
      bind a same socket twice but that is can't avoid more processes/threads
      try to bind a same socket at the same time.
      
      So, add lock_sock in llc_ui_bind like others, such as llc_ui_connect.
      Signed-off-by: default avatarLin Zhang <xiaolou4617@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      0908cf4d
  4. 18 Apr, 2017 1 commit
    • Paul E. McKenney's avatar
      mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU · 5f0d5a3a
      Paul E. McKenney authored
      A group of Linux kernel hackers reported chasing a bug that resulted
      from their assumption that SLAB_DESTROY_BY_RCU provided an existence
      guarantee, that is, that no block from such a slab would be reallocated
      during an RCU read-side critical section.  Of course, that is not the
      case.  Instead, SLAB_DESTROY_BY_RCU only prevents freeing of an entire
      slab of blocks.
      
      However, there is a phrase for this, namely "type safety".  This commit
      therefore renames SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU in order
      to avoid future instances of this sort of confusion.
      Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      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: Andrew Morton <akpm@linux-foundation.org>
      Cc: <linux-mm@kvack.org>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      [ paulmck: Add comments mentioning the old name, as requested by Eric
        Dumazet, in order to help people familiar with the old name find
        the new one. ]
      Acked-by: default avatarDavid Rientjes <rientjes@google.com>
      5f0d5a3a
  5. 10 Mar, 2017 1 commit
    • David Howells's avatar
      net: Work around lockdep limitation in sockets that use sockets · cdfbabfb
      David Howells authored
      Lockdep issues a circular dependency warning when AFS issues an operation
      through AF_RXRPC from a context in which the VFS/VM holds the mmap_sem.
      
      The theory lockdep comes up with is as follows:
      
       (1) If the pagefault handler decides it needs to read pages from AFS, it
           calls AFS with mmap_sem held and AFS begins an AF_RXRPC call, but
           creating a call requires the socket lock:
      
      	mmap_sem must be taken before sk_lock-AF_RXRPC
      
       (2) afs_open_socket() opens an AF_RXRPC socket and binds it.  rxrpc_bind()
           binds the underlying UDP socket whilst holding its socket lock.
           inet_bind() takes its own socket lock:
      
      	sk_lock-AF_RXRPC must be taken before sk_lock-AF_INET
      
       (3) Reading from a TCP socket into a userspace buffer might cause a fault
           and thus cause the kernel to take the mmap_sem, but the TCP socket is
           locked whilst doing this:
      
      	sk_lock-AF_INET must be taken before mmap_sem
      
      However, lockdep's theory is wrong in this instance because it deals only
      with lock classes and not individual locks.  The AF_INET lock in (2) isn't
      really equivalent to the AF_INET lock in (3) as the former deals with a
      socket entirely internal to the kernel that never sees userspace.  This is
      a limitation in the design of lockdep.
      
      Fix the general case by:
      
       (1) Double up all the locking keys used in sockets so that one set are
           used if the socket is created by userspace and the other set is used
           if the socket is created by the kernel.
      
       (2) Store the kern parameter passed to sk_alloc() in a variable in the
           sock struct (sk_kern_sock).  This informs sock_lock_init(),
           sock_init_data() and sk_clone_lock() as to the lock keys to be used.
      
           Note that the child created by sk_clone_lock() inherits the parent's
           kern setting.
      
       (3) Add a 'kern' parameter to ->accept() that is analogous to the one
           passed in to ->create() that distinguishes whether kernel_accept() or
           sys_accept4() was the caller and can be passed to sk_alloc().
      
           Note that a lot of accept functions merely dequeue an already
           allocated socket.  I haven't touched these as the new socket already
           exists before we get the parameter.
      
           Note also that there are a couple of places where I've made the accepted
           socket unconditionally kernel-based:
      
      	irda_accept()
      	rds_rcp_accept_one()
      	tcp_accept_from_sock()
      
           because they follow a sock_create_kern() and accept off of that.
      
      Whilst creating this, I noticed that lustre and ocfs don't create sockets
      through sock_create_kern() and thus they aren't marked as for-kernel,
      though they appear to be internal.  I wonder if these should do that so
      that they use the new set of lock keys.
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      cdfbabfb
  6. 02 Mar, 2017 1 commit
  7. 14 Nov, 2016 1 commit
  8. 17 Sep, 2016 1 commit
  9. 04 May, 2016 1 commit
  10. 17 Feb, 2016 1 commit
  11. 27 Jul, 2015 1 commit
  12. 11 May, 2015 1 commit
  13. 02 Mar, 2015 1 commit
  14. 24 Nov, 2014 1 commit
  15. 05 Nov, 2014 1 commit
    • David S. Miller's avatar
      net: Add and use skb_copy_datagram_msg() helper. · 51f3d02b
      David S. Miller authored
      This encapsulates all of the skb_copy_datagram_iovec() callers
      with call argument signature "skb, offset, msghdr->msg_iov, length".
      
      When we move to iov_iters in the networking, the iov_iter object will
      sit in the msghdr.
      
      Having a helper like this means there will be less places to touch
      during that transformation.
      
      Based upon descriptions and patch from Al Viro.
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      51f3d02b
  16. 28 Sep, 2014 1 commit
  17. 19 Jan, 2014 1 commit
  18. 03 Jan, 2014 1 commit
    • Daniel Borkmann's avatar
      net: llc: fix use after free in llc_ui_recvmsg · 4d231b76
      Daniel Borkmann authored
      While commit 30a584d9 fixes datagram interface in LLC, a use
      after free bug has been introduced for SOCK_STREAM sockets that do
      not make use of MSG_PEEK.
      
      The flow is as follow ...
      
        if (!(flags & MSG_PEEK)) {
          ...
          sk_eat_skb(sk, skb, false);
          ...
        }
        ...
        if (used + offset < skb->len)
          continue;
      
      ... where sk_eat_skb() calls __kfree_skb(). Therefore, cache
      original length and work on skb_len to check partial reads.
      
      Fixes: 30a584d9 ("[LLX]: SOCK_DGRAM interface fixes")
      Signed-off-by: default avatarDaniel Borkmann <dborkman@redhat.com>
      Cc: Stephen Hemminger <stephen@networkplumber.org>
      Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      4d231b76
  19. 21 Nov, 2013 1 commit
    • Hannes Frederic Sowa's avatar
      net: rework recvmsg handler msg_name and msg_namelen logic · f3d33426
      Hannes Frederic Sowa authored
      This patch now always passes msg->msg_namelen as 0. recvmsg handlers must
      set msg_namelen to the proper size <= sizeof(struct sockaddr_storage)
      to return msg_name to the user.
      
      This prevents numerous uninitialized memory leaks we had in the
      recvmsg handlers and makes it harder for new code to accidentally leak
      uninitialized memory.
      
      Optimize for the case recvfrom is called with NULL as address. We don't
      need to copy the address at all, so set it to NULL before invoking the
      recvmsg handler. We can do so, because all the recvmsg handlers must
      cope with the case a plain read() is called on them. read() also sets
      msg_name to NULL.
      
      Also document these changes in include/linux/net.h as suggested by David
      Miller.
      
      Changes since RFC:
      
      Set msg->msg_name = NULL if user specified a NULL in msg_name but had a
      non-null msg_namelen in verify_iovec/verify_compat_iovec. This doesn't
      affect sendto as it would bail out earlier while trying to copy-in the
      address. It also more naturally reflects the logic by the callers of
      verify_iovec.
      
      With this change in place I could remove "
      if (!uaddr || msg_sys->msg_namelen == 0)
      	msg->msg_name = NULL
      ".
      
      This change does not alter the user visible error logic as we ignore
      msg_namelen as long as msg_name is NULL.
      
      Also remove two unnecessary curly brackets in ___sys_recvmsg and change
      comments to netdev style.
      
      Cc: David Miller <davem@davemloft.net>
      Suggested-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
      Signed-off-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      f3d33426
  20. 04 Sep, 2013 1 commit
  21. 07 Apr, 2013 1 commit
    • Mathias Krause's avatar
      llc: Fix missing msg_namelen update in llc_ui_recvmsg() · c77a4b9c
      Mathias Krause authored
      For stream sockets the code misses to update the msg_namelen member
      to 0 and therefore makes net/socket.c leak the local, uninitialized
      sockaddr_storage variable to userland -- 128 bytes of kernel stack
      memory. The msg_namelen update is also missing for datagram sockets
      in case the socket is shutting down during receive.
      
      Fix both issues by setting msg_namelen to 0 early. It will be
      updated later if we're going to fill the msg_name member.
      
      Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
      Signed-off-by: default avatarMathias Krause <minipli@googlemail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c77a4b9c
  22. 19 Nov, 2012 1 commit
    • Eric W. Biederman's avatar
      net: Allow userns root to control llc, netfilter, netlink, packet, and xfrm · df008c91
      Eric W. Biederman authored
      Allow an unpriviled user who has created a user namespace, and then
      created a network namespace to effectively use the new network
      namespace, by reducing capable(CAP_NET_ADMIN) and
      capable(CAP_NET_RAW) calls to be ns_capable(net->user_ns,
      CAP_NET_ADMIN), or capable(net->user_ns, CAP_NET_RAW) calls.
      
      Allow creation of af_key sockets.
      Allow creation of llc sockets.
      Allow creation of af_packet sockets.
      
      Allow sending xfrm netlink control messages.
      
      Allow binding to netlink multicast groups.
      Allow sending to netlink multicast groups.
      Allow adding and dropping netlink multicast groups.
      Allow sending to all netlink multicast groups and port ids.
      
      Allow reading the netfilter SO_IP_SET socket option.
      Allow sending netfilter netlink messages.
      Allow setting and getting ip_vs netfilter socket options.
      Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      df008c91
  23. 16 Aug, 2012 1 commit
    • Mathias Krause's avatar
      llc: fix info leak via getsockname() · 3592aaeb
      Mathias Krause authored
      The LLC code wrongly returns 0, i.e. "success", when the socket is
      zapped. Together with the uninitialized uaddrlen pointer argument from
      sys_getsockname this leads to an arbitrary memory leak of up to 128
      bytes kernel stack via the getsockname() syscall.
      
      Return an error instead when the socket is zapped to prevent the info
      leak. Also remove the unnecessary memset(0). We don't directly write to
      the memory pointed by uaddr but memcpy() a local structure at the end of
      the function that is properly initialized.
      Signed-off-by: default avatarMathias Krause <minipli@googlemail.com>
      Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      3592aaeb
  24. 14 Aug, 2012 1 commit
  25. 11 Jul, 2012 1 commit
  26. 17 May, 2012 1 commit
  27. 16 May, 2012 1 commit
    • Paul Gortmaker's avatar
      net: delete all instances of special processing for token ring · 211ed865
      Paul Gortmaker authored
      We are going to delete the Token ring support.  This removes any
      special processing in the core networking for token ring, (aside
      from net/tr.c itself), leaving the drivers and remaining tokenring
      support present but inert.
      
      The mass removal of the drivers and net/tr.c will be in a separate
      commit, so that the history of these files that we still care
      about won't have the giant deletion tied into their history.
      Signed-off-by: default avatarPaul Gortmaker <paul.gortmaker@windriver.com>
      211ed865
  28. 15 May, 2012 1 commit
  29. 15 Apr, 2012 1 commit
  30. 24 Jan, 2012 1 commit
  31. 19 Dec, 2011 1 commit
  32. 08 Dec, 2010 2 commits
    • Eric Dumazet's avatar
      net: RCU conversion of dev_getbyhwaddr() and arp_ioctl() · 941666c2
      Eric Dumazet authored
      Le dimanche 05 décembre 2010 à 09:19 +0100, Eric Dumazet a écrit :
      
      > Hmm..
      >
      > If somebody can explain why RTNL is held in arp_ioctl() (and therefore
      > in arp_req_delete()), we might first remove RTNL use in arp_ioctl() so
      > that your patch can be applied.
      >
      > Right now it is not good, because RTNL wont be necessarly held when you
      > are going to call arp_invalidate() ?
      
      While doing this analysis, I found a refcount bug in llc, I'll send a
      patch for net-2.6
      
      Meanwhile, here is the patch for net-next-2.6
      
      Your patch then can be applied after mine.
      
      Thanks
      
      [PATCH] net: RCU conversion of dev_getbyhwaddr() and arp_ioctl()
      
      dev_getbyhwaddr() was called under RTNL.
      
      Rename it to dev_getbyhwaddr_rcu() and change all its caller to now use
      RCU locking instead of RTNL.
      
      Change arp_ioctl() to use RCU instead of RTNL locking.
      
      Note: this fix a dev refcount bug in llc
      Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      941666c2
    • Eric Dumazet's avatar
      llc: fix a device refcount imbalance · 35d9b0c9
      Eric Dumazet authored
      Le dimanche 05 décembre 2010 à 12:23 +0100, Eric Dumazet a écrit :
      > Le dimanche 05 décembre 2010 à 09:19 +0100, Eric Dumazet a écrit :
      >
      > > Hmm..
      > >
      > > If somebody can explain why RTNL is held in arp_ioctl() (and therefore
      > > in arp_req_delete()), we might first remove RTNL use in arp_ioctl() so
      > > that your patch can be applied.
      > >
      > > Right now it is not good, because RTNL wont be necessarly held when you
      > > are going to call arp_invalidate() ?
      >
      > While doing this analysis, I found a refcount bug in llc, I'll send a
      > patch for net-2.6
      
      Oh well, of course I must first fix the bug in net-2.6, and wait David
      pull the fix in net-next-2.6 before sending this rcu conversion.
      
      Note: this patch should be sent to stable teams (2.6.34 and up)
      
      [PATCH net-2.6] llc: fix a device refcount imbalance
      
      commit abf9d537 (llc: add support for SO_BINDTODEVICE) added one
      refcount imbalance in llc_ui_bind(), because dev_getbyhwaddr() doesnt
      take a reference on device, while dev_get_by_index() does.
      
      Fix this using RCU locking. And since an RCU conversion will be done for
      2.6.38 for dev_getbyhwaddr(), put the rcu_read_lock/unlock exactly at
      their final place.
      Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
      Cc: stable@kernel.org
      Cc: Octavian Purdila <opurdila@ixiacom.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      35d9b0c9
  33. 13 Sep, 2010 1 commit
  34. 20 Apr, 2010 1 commit
  35. 30 Mar, 2010 1 commit
    • Tejun Heo's avatar
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking... · 5a0e3ad6
      Tejun Heo authored
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
      
      percpu.h is included by sched.h and module.h and thus ends up being
      included when building most .c files.  percpu.h includes slab.h which
      in turn includes gfp.h making everything defined by the two files
      universally available and complicating inclusion dependencies.
      
      percpu.h -> slab.h dependency is about to be removed.  Prepare for
      this change by updating users of gfp and slab facilities include those
      headers directly instead of assuming availability.  As this conversion
      needs to touch large number of source files, the following script is
      used as the basis of conversion.
      
        http://userweb.kernel.org/~tj/misc/slabh-sweep.py
      
      The script does the followings.
      
      * Scan files for gfp and slab usages and update includes such that
        only the necessary includes are there.  ie. if only gfp is used,
        gfp.h, if slab is used, slab.h.
      
      * When the script inserts a new include, it looks at the include
        blocks and try to put the new include such that its order conforms
        to its surrounding.  It's put in the include block which contains
        core kernel includes, in the same order that the rest are ordered -
        alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
        doesn't seem to be any matching order.
      
      * If the script can't find a place to put a new include (mostly
        because the file doesn't have fitting include block), it prints out
        an error message indicating which .h file needs to be added to the
        file.
      
      The conversion was done in the following steps.
      
      1. The initial automatic conversion of all .c files updated slightly
         over 4000 files, deleting around 700 includes and adding ~480 gfp.h
         and ~3000 slab.h inclusions.  The script emitted errors for ~400
         files.
      
      2. Each error was manually checked.  Some didn't need the inclusion,
         some needed manual addition while adding it to implementation .h or
         embedding .c file was more appropriate for others.  This step added
         inclusions to around 150 files.
      
      3. The script was run again and the output was compared to the edits
         from #2 to make sure no file was left behind.
      
      4. Several build tests were done and a couple of problems were fixed.
         e.g. lib/decompress_*.c used malloc/free() wrappers around slab
         APIs requiring slab.h to be added manually.
      
      5. The script was run on all .h files but without automatically
         editing them as sprinkling gfp.h and slab.h inclusions around .h
         files could easily lead to inclusion dependency hell.  Most gfp.h
         inclusion directives were ignored as stuff from gfp.h was usually
         wildly available and often used in preprocessor macros.  Each
         slab.h inclusion directive was examined and added manually as
         necessary.
      
      6. percpu.h was updated not to include slab.h.
      
      7. Build test were done on the following configurations and failures
         were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
         distributed build env didn't work with gcov compiles) and a few
         more options had to be turned off depending on archs to make things
         build (like ipr on powerpc/64 which failed due to missing writeq).
      
         * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
         * powerpc and powerpc64 SMP allmodconfig
         * sparc and sparc64 SMP allmodconfig
         * ia64 SMP allmodconfig
         * s390 SMP allmodconfig
         * alpha SMP allmodconfig
         * um on x86_64 SMP allmodconfig
      
      8. percpu.h modifications were reverted so that it could be applied as
         a separate patch and serve as bisection point.
      
      Given the fact that I had only a couple of failures from tests on step
      6, I'm fairly confident about the coverage of this conversion patch.
      If there is a breakage, it's likely to be something in one of the arch
      headers which should be easily discoverable easily on most builds of
      the specific arch.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Guess-its-ok-by: default avatarChristoph Lameter <cl@linux-foundation.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
      5a0e3ad6
  36. 27 Dec, 2009 3 commits