1. 02 May, 2013 1 commit
  2. 01 May, 2013 17 commits
  3. 30 Apr, 2013 22 commits
    • zhangwei(Jovi)'s avatar
      kernel/relay.c: move FIX_SIZE macro into relay.c · 536b39ec
      zhangwei(Jovi) authored
      
      
      It's better to place FIX_SIZE macro in relay.c, instead of relay.h
      Signed-off-by: default avatarzhangwei(Jovi) <jovi.zhangwei@huawei.com>
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Eric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      536b39ec
    • Raphael S.Carvalho's avatar
      pid_namespace.c/.h: simplify defines · 5cc54451
      Raphael S.Carvalho authored
      
      
      Move BITS_PER_PAGE from pid_namespace.c to pid_namespace.h, since we can
      simplify the define PID_MAP_ENTRIES by using the BITS_PER_PAGE.
      
      [akpm@linux-foundation.org: kernel/pid.c:54:1: warning: "BITS_PER_PAGE" redefined]
      Signed-off-by: default avatarRaphael S.Carvalho <raphael.scarv@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      5cc54451
    • Oleg Nesterov's avatar
      exec: do not abuse ->cred_guard_mutex in threadgroup_lock() · e56fb287
      Oleg Nesterov authored
      
      
      threadgroup_lock() takes signal->cred_guard_mutex to ensure that
      thread_group_leader() is stable.  This doesn't look nice, the scope of
      this lock in do_execve() is huge.
      
      And as Dave pointed out this can lead to deadlock, we have the
      following dependencies:
      
      	do_execve:		cred_guard_mutex -> i_mutex
      	cgroup_mount:		i_mutex -> cgroup_mutex
      	attach_task_by_pid:	cgroup_mutex -> cred_guard_mutex
      
      Change de_thread() to take threadgroup_change_begin() around the
      switch-the-leader code and change threadgroup_lock() to avoid
      ->cred_guard_mutex.
      
      Note that de_thread() can't sleep with ->group_rwsem held, this can
      obviously deadlock with the exiting leader if the writer is active, so it
      does threadgroup_change_end() before schedule().
      Reported-by: default avatarDave Jones <davej@redhat.com>
      Acked-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.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>
      e56fb287
    • Oleg Nesterov's avatar
      coredump: only SIGKILL should interrupt the coredumping task · 403bad72
      Oleg Nesterov authored
      
      
      There are 2 well known and ancient problems with coredump/signals, and a
      lot of related bug reports:
      
      - do_coredump() clears TIF_SIGPENDING but of course this can't help
        if, say, SIGCHLD comes after that.
      
        In this case the coredump can fail unexpectedly. See for example
        wait_for_dump_helper()->signal_pending() check but there are other
        reasons.
      
      - At the same time, dumping a huge core on the slow media can take a
        lot of time/resources and there is no way to kill the coredumping
        task reliably. In particular this is not oom_kill-friendly.
      
      This patch tries to fix the 1st problem, and makes the preparation for the
      next changes.
      
      We add the new SIGNAL_GROUP_COREDUMP flag set by zap_threads() to indicate
      that this process dumps the core.  prepare_signal() checks this flag and
      nacks any signal except SIGKILL.
      
      Note that this check tries to be conservative, in the long term we should
      probably treat the SIGNAL_GROUP_EXIT case equally but this needs more
      discussion.  See marc.info/?l=linux-kernel&m=120508897917439
      
      Notes:
      	- recalc_sigpending() doesn't check SIGNAL_GROUP_COREDUMP.
      	  The patch assumes that dump_write/etc paths should never
      	  call it, but we can change it as well.
      
      	- There is another source of TIF_SIGPENDING, freezer. This
      	  will be addressed separately.
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Tested-by: default avatarMandeep Singh Baines <msb@chromium.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Neil Horman <nhorman@redhat.com>
      Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
      Cc: Roland McGrath <roland@hack.frob.com>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      403bad72
    • Lucas De Marchi's avatar
      kmod: remove call_usermodehelper_fns() · 66e5b7e1
      Lucas De Marchi authored
      
      
      This function suffers from not being able to determine if the cleanup is
      called in case it returns -ENOMEM.  Nobody is using it anymore, so let's
      remove it.
      Signed-off-by: default avatarLucas De Marchi <lucas.demarchi@profusion.mobi>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: David Howells <dhowells@redhat.com>
      Cc: James Morris <james.l.morris@oracle.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      66e5b7e1
    • Lucas De Marchi's avatar
      usermodehelper: export call_usermodehelper_exec() and call_usermodehelper_setup() · 938e4b22
      Lucas De Marchi authored
      
      
      call_usermodehelper_setup() + call_usermodehelper_exec() need to be
      called instead of call_usermodehelper_fns() when the cleanup function
      needs to be called even when an ENOMEM error occurs.  In this case using
      call_usermodehelper_fns() the user can't distinguish if the cleanup
      function was called or not.
      
      [akpm@linux-foundation.org: export call_usermodehelper_setup() to modules]
      Signed-off-by: default avatarLucas De Marchi <lucas.demarchi@profusion.mobi>
      Reviewed-by: default avatarOleg Nesterov <oleg@redhat.com>
      Cc: David Howells <dhowells@redhat.com>
      Cc: James Morris <james.l.morris@oracle.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      938e4b22
    • Stephen Rothwell's avatar
      kernel/compat.c: make do_sysinfo() static · 1a0df594
      Stephen Rothwell authored
      
      
      The only use outside of kernel/timer.c was in kernel/compat.c, so move
      compat_sys_sysinfo() next to sys_sysinfo() in kernel/timer.c.
      Signed-off-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Guenter Roeck <linux@roeck-us.net>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      1a0df594
    • Andy Shevchenko's avatar
      lib/string_helpers: introduce generic string_unescape · 16c7fa05
      Andy Shevchenko authored
      
      
      There are several places in kernel where modules unescapes input to convert
      C-Style Escape Sequences into byte codes.
      
      The patch provides generic implementation of such approach. Test cases are
      also included into the patch.
      
      [akpm@linux-foundation.org: clarify comment]
      [akpm@linux-foundation.org: export get_random_int() to modules]
      Signed-off-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
      Cc: Samuel Thibault <samuel.thibault@ens-lyon.org>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: Jason Baron <jbaron@redhat.com>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: William Hubbs <w.d.hubbs@gmail.com>
      Cc: Chris Brannon <chris@the-brannons.com>
      Cc: Kirk Reiser <kirk@braille.uwo.ca>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      16c7fa05
    • Fan Du's avatar
      include/linux/fs.h: disable preempt when acquire i_size_seqcount write lock · 74e3d1e1
      Fan Du authored
      
      
      Two rt tasks bind to one CPU core.
      
      The higher priority rt task A preempts a lower priority rt task B which
      has already taken the write seq lock, and then the higher priority rt
      task A try to acquire read seq lock, it's doomed to lockup.
      
      rt task A with lower priority: call write
      i_size_write                                        rt task B with higher priority: call sync, and preempt task A
        write_seqcount_begin(&inode->i_size_seqcount);    i_size_read
        inode->i_size = i_size;                             read_seqcount_begin <-- lockup here...
      
      So disable preempt when acquiring every i_size_seqcount *write* lock will
      cure the problem.
      Signed-off-by: default avatarFan Du <fan.du@windriver.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      74e3d1e1
    • liguang's avatar
      kernel/smp.c: remove 'priv' of call_single_data · 3440a1ca
      liguang authored
      
      
      The 'priv' field is redundant; we can pass data via 'info'.
      Signed-off-by: default avatarliguang <lig.fnst@cn.fujitsu.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3440a1ca
    • Tejun Heo's avatar
      workqueue: include workqueue info when printing debug dump of a worker task · 3d1cb205
      Tejun Heo authored
      
      
      One of the problems that arise when converting dedicated custom
      threadpool to workqueue is that the shared worker pool used by workqueue
      anonimizes each worker making it more difficult to identify what the
      worker was doing on which target from the output of sysrq-t or debug
      dump from oops, BUG() and friends.
      
      This patch implements set_worker_desc() which can be called from any
      workqueue work function to set its description.  When the worker task is
      dumped for whatever reason - sysrq-t, WARN, BUG, oops, lockdep assertion
      and so on - the description will be printed out together with the
      workqueue name and the worker function pointer.
      
      The printing side is implemented by print_worker_info() which is called
      from functions in task dump paths - sched_show_task() and
      dump_stack_print_info().  print_worker_info() can be safely called on
      any task in any state as long as the task struct itself is accessible.
      It uses probe_*() functions to access worker fields.  It may print
      garbage if something went very wrong, but it wouldn't cause (another)
      oops.
      
      The description is currently limited to 24bytes including the
      terminating \0.  worker->desc_valid and workder->desc[] are added and
      the 64 bytes marker which was already incorrect before adding the new
      fields is moved to the correct position.
      
      Here's an example dump with writeback updated to set the bdi name as
      worker desc.
      
       Hardware name: Bochs
       Modules linked in:
       Pid: 7, comm: kworker/u9:0 Not tainted 3.9.0-rc1-work+ #1
       Workqueue: writeback bdi_writeback_workfn (flush-8:0)
        ffffffff820a3ab0 ffff88000f6e9cb8 ffffffff81c61845 ffff88000f6e9cf8
        ffffffff8108f50f 0000000000000000 0000000000000000 ffff88000cde16b0
        ffff88000cde1aa8 ffff88001ee19240 ffff88000f6e9fd8 ffff88000f6e9d08
       Call Trace:
        [<ffffffff81c61845>] dump_stack+0x19/0x1b
        [<ffffffff8108f50f>] warn_slowpath_common+0x7f/0xc0
        [<ffffffff8108f56a>] warn_slowpath_null+0x1a/0x20
        [<ffffffff81200150>] bdi_writeback_workfn+0x2a0/0x3b0
       ...
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Acked-by: default avatarJan Kara <jack@suse.cz>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: Dave Chinner <david@fromorbit.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3d1cb205
    • Tejun Heo's avatar
      kthread: implement probe_kthread_data() · cd42d559
      Tejun Heo authored
      
      
      One of the problems that arise when converting dedicated custom threadpool
      to workqueue is that the shared worker pool used by workqueue anonimizes
      each worker making it more difficult to identify what the worker was doing
      on which target from the output of sysrq-t or debug dump from oops, BUG()
      and friends.
      
      For example, after writeback is converted to use workqueue instead of
      priviate thread pool, there's no easy to tell which backing device a
      writeback work item was working on at the time of task dump, which,
      according to our writeback brethren, is important in tracking down issues
      with a lot of mounted file systems on a lot of different devices.
      
      This patchset implements a way for a work function to mark its execution
      instance so that task dump of the worker task includes information to
      indicate what the work item was doing.
      
      An example WARN dump would look like the following.
      
       WARNING: at fs/fs-writeback.c:1015 bdi_writeback_workfn+0x2b4/0x3c0()
       Modules linked in:
       CPU: 0 Pid: 28 Comm: kworker/u18:0 Not tainted 3.9.0-rc1-work+ #24
       Hardware name: empty empty/S3992, BIOS 080011  10/26/2007
       Workqueue: writeback bdi_writeback_workfn (flush-8:16)
        ffffffff820a3a98 ffff88015b927cb8 ffffffff81c61855 ffff88015b927cf8
        ffffffff8108f500 0000000000000000 ffff88007a171948 ffff88007a1716b0
        ffff88015b49df00 ffff88015b8d3940 0000000000000000 ffff88015b927d08
       Call Trace:
        [<ffffffff81c61855>] dump_stack+0x19/0x1b
        [<ffffffff8108f500>] warn_slowpath_common+0x70/0xa0
        ...
      
      This patch:
      
      Implement probe_kthread_data() which returns kthread_data if accessible.
      The function is equivalent to kthread_data() except that the specified
      @task may not be a kthread or its vfork_done is already cleared rendering
      struct kthread inaccessible.  In the former case, probe_kthread_data() may
      return any value.  In the latter, NULL.
      
      This will be used to safely print debug information without affecting
      synchronization in the normal paths.  Workqueue debug info printing on
      dump_stack() and friends will make use of it.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Acked-by: default avatarJan Kara <jack@suse.cz>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      cd42d559
    • Tejun Heo's avatar
      dump_stack: unify debug information printed by show_regs() · a43cb95d
      Tejun Heo authored
      
      
      show_regs() is inherently arch-dependent but it does make sense to print
      generic debug information and some archs already do albeit in slightly
      different forms.  This patch introduces a generic function to print debug
      information from show_regs() so that different archs print out the same
      information and it's much easier to modify what's printed.
      
      show_regs_print_info() prints out the same debug info as dump_stack()
      does plus task and thread_info pointers.
      
      * Archs which didn't print debug info now do.
      
        alpha, arc, blackfin, c6x, cris, frv, h8300, hexagon, ia64, m32r,
        metag, microblaze, mn10300, openrisc, parisc, score, sh64, sparc,
        um, xtensa
      
      * Already prints debug info.  Replaced with show_regs_print_info().
        The printed information is superset of what used to be there.
      
        arm, arm64, avr32, mips, powerpc, sh32, tile, unicore32, x86
      
      * s390 is special in that it used to print arch-specific information
        along with generic debug info.  Heiko and Martin think that the
        arch-specific extra isn't worth keeping s390 specfic implementation.
        Converted to use the generic version.
      
      Note that now all archs print the debug info before actual register
      dumps.
      
      An example BUG() dump follows.
      
       kernel BUG at /work/os/work/kernel/workqueue.c:4841!
       invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
       Modules linked in:
       CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.9.0-rc1-work+ #7
       Hardware name: empty empty/S3992, BIOS 080011  10/26/2007
       task: ffff88007c85e040 ti: ffff88007c860000 task.ti: ffff88007c860000
       RIP: 0010:[<ffffffff8234a07e>]  [<ffffffff8234a07e>] init_workqueues+0x4/0x6
       RSP: 0000:ffff88007c861ec8  EFLAGS: 00010246
       RAX: ffff88007c861fd8 RBX: ffffffff824466a8 RCX: 0000000000000001
       RDX: 0000000000000046 RSI: 0000000000000001 RDI: ffffffff8234a07a
       RBP: ffff88007c861ec8 R08: 0000000000000000 R09: 0000000000000000
       R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff8234a07a
       R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
       FS:  0000000000000000(0000) GS:ffff88007dc00000(0000) knlGS:0000000000000000
       CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
       CR2: ffff88015f7ff000 CR3: 00000000021f1000 CR4: 00000000000007f0
       DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
       DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
       Stack:
        ffff88007c861ef8 ffffffff81000312 ffffffff824466a8 ffff88007c85e650
        0000000000000003 0000000000000000 ffff88007c861f38 ffffffff82335e5d
        ffff88007c862080 ffffffff8223d8c0 ffff88007c862080 ffffffff81c47760
       Call Trace:
        [<ffffffff81000312>] do_one_initcall+0x122/0x170
        [<ffffffff82335e5d>] kernel_init_freeable+0x9b/0x1c8
        [<ffffffff81c47760>] ? rest_init+0x140/0x140
        [<ffffffff81c4776e>] kernel_init+0xe/0xf0
        [<ffffffff81c6be9c>] ret_from_fork+0x7c/0xb0
        [<ffffffff81c47760>] ? rest_init+0x140/0x140
        ...
      
      v2: Typo fix in x86-32.
      
      v3: CPU number dropped from show_regs_print_info() as
          dump_stack_print_info() has been updated to print it.  s390
          specific implementation dropped as requested by s390 maintainers.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
      Acked-by: default avatarJesper Nilsson <jesper.nilsson@axis.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Bjorn Helgaas <bhelgaas@google.com>
      Cc: Fengguang Wu <fengguang.wu@intel.com>
      Cc: Mike Frysinger <vapier@gentoo.org>
      Cc: Vineet Gupta <vgupta@synopsys.com>
      Cc: Sam Ravnborg <sam@ravnborg.org>
      Acked-by: Chris Metcalf <cmetcalf@tilera.com>		[tile bits]
      Acked-by: Richard Kuo <rkuo@codeaurora.org>		[hexagon bits]
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a43cb95d
    • Tejun Heo's avatar
      dump_stack: implement arch-specific hardware description in task dumps · 98e5e1bf
      Tejun Heo authored
      
      
      x86 and ia64 can acquire extra hardware identification information
      from DMI and print it along with task dumps; however, the usage isn't
      consistent.
      
      * x86 show_regs() collects vendor, product and board strings and print
        them out with PID, comm and utsname.  Some of the information is
        printed again later in the same dump.
      
      * warn_slowpath_common() explicitly accesses the DMI board and prints
        it out with "Hardware name:" label.  This applies to both x86 and
        ia64 but is irrelevant on all other archs.
      
      * ia64 doesn't show DMI information on other non-WARN dumps.
      
      This patch introduces arch-specific hardware description used by
      dump_stack().  It can be set by calling dump_stack_set_arch_desc()
      during boot and, if exists, printed out in a separate line with
      "Hardware name:" label.
      
      dmi_set_dump_stack_arch_desc() is added which sets arch-specific
      description from DMI data.  It uses dmi_ids_string[] which is set from
      dmi_present() used for DMI debug message.  It is superset of the
      information x86 show_regs() is using.  The function is called from x86
      and ia64 boot code right after dmi_scan_machine().
      
      This makes the explicit DMI handling in warn_slowpath_common()
      unnecessary.  Removed.
      
      show_regs() isn't yet converted to use generic debug information
      printing and this patch doesn't remove the duplicate DMI handling in
      x86 show_regs().  The next patch will unify show_regs() handling and
      remove the duplication.
      
      An example WARN dump follows.
      
       WARNING: at kernel/workqueue.c:4841 init_workqueues+0x35/0x505()
       Modules linked in:
       CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.9.0-rc1-work+ #3
       Hardware name: empty empty/S3992, BIOS 080011  10/26/2007
        0000000000000009 ffff88007c861e08 ffffffff81c614dc ffff88007c861e48
        ffffffff8108f500 ffffffff82228240 0000000000000040 ffffffff8234a08e
        0000000000000000 0000000000000000 0000000000000000 ffff88007c861e58
       Call Trace:
        [<ffffffff81c614dc>] dump_stack+0x19/0x1b
        [<ffffffff8108f500>] warn_slowpath_common+0x70/0xa0
        [<ffffffff8108f54a>] warn_slowpath_null+0x1a/0x20
        [<ffffffff8234a0c3>] init_workqueues+0x35/0x505
        ...
      
      v2: Use the same string as the debug message from dmi_present() which
          also contains BIOS information.  Move hardware name into its own
          line as warn_slowpath_common() did.  This change was suggested by
          Bjorn Helgaas.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Bjorn Helgaas <bhelgaas@google.com>
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Fengguang Wu <fengguang.wu@intel.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: Jesper Nilsson <jesper.nilsson@axis.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Mike Frysinger <vapier@gentoo.org>
      Cc: Vineet Gupta <vgupta@synopsys.com>
      Cc: Sam Ravnborg <sam@ravnborg.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      98e5e1bf
    • Tejun Heo's avatar
      dump_stack: consolidate dump_stack() implementations and unify their behaviors · 196779b9
      Tejun Heo authored
      
      
      Both dump_stack() and show_stack() are currently implemented by each
      architecture.  show_stack(NULL, NULL) dumps the backtrace for the
      current task as does dump_stack().  On some archs, dump_stack() prints
      extra information - pid, utsname and so on - in addition to the
      backtrace while the two are identical on other archs.
      
      The usages in arch-independent code of the two functions indicate
      show_stack(NULL, NULL) should print out bare backtrace while
      dump_stack() is used for debugging purposes when something went wrong,
      so it does make sense to print additional information on the task which
      triggered dump_stack().
      
      There's no reason to require archs to implement two separate but mostly
      identical functions.  It leads to unnecessary subtle information.
      
      This patch expands the dummy fallback dump_stack() implementation in
      lib/dump_stack.c such that it prints out debug information (taken from
      x86) and invokes show_stack(NULL, NULL) and drops arch-specific
      dump_stack() implementations in all archs except blackfin.  Blackfin's
      dump_stack() does something wonky that I don't understand.
      
      Debug information can be printed separately by calling
      dump_stack_print_info() so that arch-specific dump_stack()
      implementation can still emit the same debug information.  This is used
      in blackfin.
      
      This patch brings the following behavior changes.
      
      * On some archs, an extra level in backtrace for show_stack() could be
        printed.  This is because the top frame was determined in
        dump_stack() on those archs while generic dump_stack() can't do that
        reliably.  It can be compensated by inlining dump_stack() but not
        sure whether that'd be necessary.
      
      * Most archs didn't use to print debug info on dump_stack().  They do
        now.
      
      An example WARN dump follows.
      
       WARNING: at kernel/workqueue.c:4841 init_workqueues+0x35/0x505()
       Hardware name: empty
       Modules linked in:
       CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.9.0-rc1-work+ #9
        0000000000000009 ffff88007c861e08 ffffffff81c614dc ffff88007c861e48
        ffffffff8108f50f ffffffff82228240 0000000000000040 ffffffff8234a03c
        0000000000000000 0000000000000000 0000000000000000 ffff88007c861e58
       Call Trace:
        [<ffffffff81c614dc>] dump_stack+0x19/0x1b
        [<ffffffff8108f50f>] warn_slowpath_common+0x7f/0xc0
        [<ffffffff8108f56a>] warn_slowpath_null+0x1a/0x20
        [<ffffffff8234a071>] init_workqueues+0x35/0x505
        ...
      
      v2: CPU number added to the generic debug info as requested by s390
          folks and dropped the s390 specific dump_stack().  This loses %ksp
          from the debug message which the maintainers think isn't important
          enough to keep the s390-specific dump_stack() implementation.
      
          dump_stack_print_info() is moved to kernel/printk.c from
          lib/dump_stack.c.  Because linkage is per objecct file,
          dump_stack_print_info() living in the same lib file as generic
          dump_stack() means that archs which implement custom dump_stack()
          - at this point, only blackfin - can't use dump_stack_print_info()
          as that will bring in the generic version of dump_stack() too.  v1
          The v1 patch broke build on blackfin due to this issue.  The build
          breakage was reported by Fengguang Wu.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
      Acked-by: default avatarVineet Gupta <vgupta@synopsys.com>
      Acked-by: default avatarJesper Nilsson <jesper.nilsson@axis.com>
      Acked-by: default avatarVineet Gupta <vgupta@synopsys.com>
      Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>	[s390 bits]
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: Mike Frysinger <vapier@gentoo.org>
      Cc: Fengguang Wu <fengguang.wu@intel.com>
      Cc: Bjorn Helgaas <bhelgaas@google.com>
      Cc: Sam Ravnborg <sam@ravnborg.org>
      Acked-by: Richard Kuo <rkuo@codeaurora.org>		[hexagon bits]
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      196779b9
    • Bob Liu's avatar
      mm: cleancache: clean up cleancache_enabled · ff610a1d
      Bob Liu authored
      
      
      cleancache_ops is used to decide whether backend is registered.
      So now cleancache_enabled is always true if defined CONFIG_CLEANCACHE.
      Signed-off-by: default avatarBob Liu <lliubbo@gmail.com>
      Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
      Cc: Andor Daam <andor.daam@googlemail.com>
      Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
      Cc: Florian Schmaus <fschmaus@gmail.com>
      Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Stefan Hengelein <ilendir@googlemail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ff610a1d
    • Konrad Rzeszutek Wilk's avatar
      cleancache: Make cleancache_init use a pointer for the ops · 833f8662
      Konrad Rzeszutek Wilk authored
      
      
      Instead of using a backend_registered to determine whether a backend is
      enabled.  This allows us to remove the backend_register check and just
      do 'if (cleancache_ops)'
      
      [v1: Rebase on top of b97c4b430b0a (ramster->zcache move]
      Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      Signed-off-by: default avatarBob Liu <lliubbo@gmail.com>
      Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
      Cc: Andor Daam <andor.daam@googlemail.com>
      Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
      Cc: Florian Schmaus <fschmaus@gmail.com>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Stefan Hengelein <ilendir@googlemail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      833f8662
    • Minchan Kim's avatar
      frontswap: get rid of swap_lock dependency · 4f89849d
      Minchan Kim authored
      
      
      Frontswap initialization routine depends on swap_lock, which want to be
      atomic about frontswap's first appearance.  IOW, frontswap is not present
      and will fail all calls OR frontswap is fully functional but if new
      swap_info_struct isn't registered by enable_swap_info, swap subsystem
      doesn't start I/O so there is no race between init procedure and page I/O
      working on frontswap.
      
      So let's remove unnecessary swap_lock dependency.
      
      Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
      Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
      [v1: Rebased on my branch, reworked to work with backends loading late]
      [v2: Added a check for !map]
      [v3: Made the invalidate path follow the init path]
      [v4: Address comments by Wanpeng Li <liwanp@linux.vnet.ibm.com>]
      Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad@darnok.org>
      Signed-off-by: default avatarBob Liu <lliubbo@gmail.com>
      Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
      Cc: Andor Daam <andor.daam@googlemail.com>
      Cc: Florian Schmaus <fschmaus@gmail.com>
      Cc: Stefan Hengelein <ilendir@googlemail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4f89849d
    • Bob Liu's avatar
      mm: frontswap: cleanup code · f066ea23
      Bob Liu authored
      
      
      After allowing tmem backends to build/run as modules, frontswap_enabled
      always true if defined CONFIG_FRONTSWAP.  But frontswap_test() depends on
      whether backend is registered, mv it into frontswap.c using fronstswap_ops
      to make the decision.
      
      frontswap_set/clear are not used outside frontswap, so don't export them.
      Signed-off-by: default avatarBob Liu <lliubbo@gmail.com>
      Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
      Cc: Andor Daam <andor.daam@googlemail.com>
      Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
      Cc: Florian Schmaus <fschmaus@gmail.com>
      Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Stefan Hengelein <ilendir@googlemail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f066ea23
    • Konrad Rzeszutek Wilk's avatar
      frontswap: make frontswap_init use a pointer for the ops · 1e01c968
      Konrad Rzeszutek Wilk authored
      This simplifies the code in the frontswap - we can get rid of the
      'backend_registered' test and instead check against frontswap_ops.
      
      [v1: Rebase on top of 703ba7fe
      
       (ramster->zcache move]
      Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      Signed-off-by: default avatarBob Liu <lliubbo@gmail.com>
      Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
      Cc: Andor Daam <andor.daam@googlemail.com>
      Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
      Cc: Florian Schmaus <fschmaus@gmail.com>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Stefan Hengelein <ilendir@googlemail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      1e01c968
    • Vincent Stehlé's avatar
      memory hotplug: fix warnings · ace6128d
      Vincent Stehlé authored
      
      
      Fix the following compilation warnings:
      
        mm/slab.c: In function `kmem_cache_init_late':
        mm/slab.c:1778:2: warning: statement with no effect [-Wunused-value]
      
        mm/page_cgroup.c: In function `page_cgroup_init':
        mm/page_cgroup.c:305:2: warning: statement with no effect [-Wunused-value]
      Signed-off-by: default avatarVincent Stehlé <vincent.stehle@laposte.net>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ace6128d
    • Matt Fleming's avatar
      efi, pstore: Read data from variable store before memcpy() · 8a415b8c
      Matt Fleming authored
      
      
      Seiji reported getting empty dmesg-* files, because the data was never
      actually read in efi_pstore_read_func(), and so the memcpy() was copying
      garbage data.
      
      This patch necessitated adding __efivar_entry_get() which is callable
      between efivar_entry_iter_{begin,end}(). We can also delete
      __efivar_entry_size() because efi_pstore_read_func() was the only
      caller.
      Reported-by: default avatarSeiji Aguchi <seiji.aguchi@hds.com>
      Tested-by: default avatarSeiji Aguchi <seiji.aguchi@hds.com>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: Matthew Garrett <matthew.garrett@nebula.com>
      Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
      8a415b8c