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  1. Jul 01, 2011
    • Arnd Bergmann's avatar
      6pack,mkiss: fix lock inconsistency · 6e4e2f81
      Arnd Bergmann authored
      
      Lockdep found a locking inconsistency in the mkiss_close function:
      
      > kernel: [ INFO: inconsistent lock state ]
      > kernel: 2.6.39.1 #3
      > kernel: ---------------------------------
      > kernel: inconsistent {IN-SOFTIRQ-R} -> {SOFTIRQ-ON-W} usage.
      > kernel: ax25ipd/2813 [HC0[0]:SC0[0]:HE1:SE1] takes:
      > kernel: (disc_data_lock){+++?.-}, at: [<ffffffffa018552b>] mkiss_close+0x1b/0x90 [mkiss]
      > kernel: {IN-SOFTIRQ-R} state was registered at:
      
      The message hints that disc_data_lock is aquired with softirqs disabled,
      but does not itself disable softirqs, which can in rare circumstances
      lead to a deadlock. 
      The same problem is present in the 6pack driver, this patch fixes both
      by using write_lock_bh instead of write_lock.
      
      Reported-by: default avatarBernard F6BVP <f6bvp@free.fr>
      Tested-by: default avatarBernard F6BVP <f6bvp@free.fr>
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      Acked-by: default avatarRalf <Baechle&lt;ralf@linux-mips.org>
      Cc: stable@kernel.org
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      6e4e2f81
  2. Jun 06, 2011
  3. Jun 03, 2011
    • Linus Torvalds's avatar
      Revert "tty: make receive_buf() return the amout of bytes received" · 55db4c64
      Linus Torvalds authored
      
      This reverts commit b1c43f82.
      
      It was broken in so many ways, and results in random odd pty issues.
      
      It re-introduced the buggy schedule_work() in flush_to_ldisc() that can
      cause endless work-loops (see commit a5660b41: "tty: fix endless
      work loop when the buffer fills up").
      
      It also used an "unsigned int" return value fo the ->receive_buf()
      function, but then made multiple functions return a negative error code,
      and didn't actually check for the error in the caller.
      
      And it didn't actually work at all.  BenH bisected down odd tty behavior
      to it:
        "It looks like the patch is causing some major malfunctions of the X
         server for me, possibly related to PTYs.  For example, cat'ing a
         large file in a gnome terminal hangs the kernel for -minutes- in a
         loop of what looks like flush_to_ldisc/workqueue code, (some ftrace
         data in the quoted bits further down).
      
         ...
      
         Some more data: It -looks- like what happens is that the
         flush_to_ldisc work queue entry constantly re-queues itself (because
         the PTY is full ?) and the workqueue thread will basically loop
         forver calling it without ever scheduling, thus starving the consumer
         process that could have emptied the PTY."
      
      which is pretty much exactly the problem we fixed in a5660b41.
      
      Milton Miller pointed out the 'unsigned int' issue.
      
      Reported-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      Reported-by: default avatarMilton Miller <miltonm@bga.com>
      Cc: Stefan Bigler <stefan.bigler@keymile.com>
      Cc: Toby Gray <toby.gray@realvnc.com>
      Cc: Felipe Balbi <balbi@ti.com>
      Cc: Greg Kroah-Hartman <gregkh@suse.de>
      Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      55db4c64
  4. May 25, 2011
  5. May 05, 2011
  6. Apr 22, 2011
  7. Mar 31, 2011
  8. Jan 27, 2011
  9. Jan 09, 2011
  10. Oct 18, 2010
  11. Oct 12, 2010
  12. Sep 26, 2010
  13. Aug 16, 2010
  14. May 28, 2010
  15. May 14, 2010
    • Joe Perches's avatar
      drivers/net: Remove unnecessary returns from void function()s · a4b77097
      Joe Perches authored
      
      This patch removes from drivers/net/ all the unnecessary
      return; statements that precede the last closing brace of
      void functions.
      
      It does not remove the returns that are immediately
      preceded by a label as gcc doesn't like that.
      
      It also does not remove null void functions with return.
      
      Done via:
      $ grep -rP --include=*.[ch] -l "return;\n}" net/ | \
        xargs perl -i -e 'local $/ ; while (<>) { s/\n[ \t\n]+return;\n}/\n}/g; print; }'
      
      with some cleanups by hand.
      
      Compile tested x86 allmodconfig only.
      
      Signed-off-by: default avatarJoe Perches <joe@perches.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      a4b77097
  16. Mar 30, 2010
    • 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
  17. Mar 24, 2010
  18. Jan 03, 2010
  19. Dec 04, 2009
  20. Dec 03, 2009
  21. Nov 25, 2009
  22. Nov 15, 2009
  23. Nov 06, 2009
    • Arnd Bergmann's avatar
      net, compat_ioctl: handle socket ioctl abuses in tty drivers · 9646e7ce
      Arnd Bergmann authored
      
      Slip and a few other drivers use the same ioctl numbers on
      tty devices that are normally meant for sockets. This causes
      problems with our compat_ioctl handling that tries to convert
      the data structures in a different format.
      
      Fortunately, these five drivers all use 32 bit compatible
      data structures in the ioctl numbers, so we can just add
      a trivial compat_ioctl conversion function to each of them.
      
      SIOCSIFENCAP and SIOCGIFENCAP do not need to live in
      fs/compat_ioctl.c after this any more, and they are not
      used on any sockets.
      
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      9646e7ce
  24. Oct 14, 2009
  25. Oct 13, 2009
  26. Oct 11, 2009
  27. Oct 01, 2009
  28. Sep 03, 2009
    • Ralf Baechle's avatar
      NET: Fix possible corruption in bpqether driver · 3eb00275
      Ralf Baechle authored
      
      The bpq ether driver is modifying the data art of the skb by first
      dropping the KISS byte (a command byte for the radio) then prepending the
      length + 4 of the remaining AX.25 packet to be transmitted as a little
      endian 16-bit number.  If the high byte of the length has a different
      value than the dropped KISS byte users of clones of the skb may observe
      this as corruption.  This was observed with by running listen(8) -a which
      uses a packet socket which clones transmit packets.  The corruption will
      then typically be displayed for as a KISS "TX Delay" command for AX.25
      packets in the range of 252..508 bytes or any other KISS command for
      yet larger packets.
      
      Fixed by using skb_cow to create a private copy should the skb be cloned.
      Using skb_cow also allows us to cleanup the old logic to ensure sufficient
      headroom in the skb.
      
      While at it, replace a return of 0 from bpq_xmit with the proper constant
      NETDEV_TX_OK which is now being used everywhere else in this function.
      
      Affected: all 2.2, 2.4 and 2.6 kernels.
      
      Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      Reported-by: default avatarJann Traschewski <jann@gmx.de>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      3eb00275
  29. Sep 01, 2009
  30. Jul 17, 2009
  31. Jul 14, 2009
  32. Jul 12, 2009
    • Ralf Baechle's avatar
      NET: Fix locking issues in PPP, 6pack, mkiss and strip line disciplines. · adeab1af
      Ralf Baechle authored
      Guido Trentalancia reports:
      
      I am trying to use the kiss driver in the Linux kernel that is being
      shipped with Fedora 10 but unfortunately I get the following oops:
      
      mkiss: AX.25 Multikiss, Hans Albas PE1AYX
      mkiss: ax0: crc mode is auto.
      ADDRCONF(NETDEV_CHANGE): ax0: link becomes ready
      ------------[ cut here ]------------
      WARNING: at kernel/softirq.c:77 __local_bh_disable+0x2f/0x83() (Not
      tainted)
      [...]
      unloaded: microcode]
      Pid: 0, comm: swapper Not tainted 2.6.27.25-170.2.72.fc10.i686 #1
       [<c042ddfb>] warn_on_slowpath+0x65/0x8b
       [<c06ab62b>] ? _spin_unlock_irqrestore+0x22/0x38
       [<c04228b4>] ? __enqueue_entity+0xe3/0xeb
       [<c042431e>] ? enqueue_entity+0x203/0x20b
       [<c0424361>] ? enqueue_task_fair+0x3b/0x3f
       [<c041f88c>] ? resched_task+0x3a/0x6e
       [<c06ab62b>] ? _spin_unlock_irqrestore+0x22/0x38
       [<c06ab4e2>] ? _spin_lock_bh+0xb/0x16
       [<c043255b>] __local_bh_disable+0x2f/0x83
       [<c04325ba>] local_bh_disable+0xb/0xd
       [<c06ab4e2>] _spin_lock_bh+0xb/0x16
       [<f8b6f600>] mkiss_receive_buf+0x2fb/0x3a6 [mkiss]
       [<c0572a30>] flush_to_ldisc+0xf7/0x198
       [<c0572b12>] tty_flip_buffer_push+0x41/0x51
       [<f89477f2>] ftdi_process_read+0x375/0x4ad [ftdi_sio]
       [<f8947a5a>] ftdi_read_bulk_callback+0x130/0x138 [ftdi_sio]
       [<c05d4bec>] usb_hcd_giveback_urb+0x63/0x93
       [<c05ea290>] uhci_giveback_urb+0xe5/0x15f
       [<c05eaabf>] uhci_scan_schedule+0x52e/0x767
       [<c05f6288>] ? psmouse_handle_byte+0xc/0xe5
       [<c054df78>] ? acpi_ev_gpe_detect+0xd6/0xe1
       [<c05ec5b0>] uhci_irq+0x110/0x125
       [<c05d4834>] usb_hcd_irq+0x40/0xa3
       [<c0465313>] handle_IRQ_event+0x2f/0x64
       [<c046642b>] handle_level_irq+0x74/0xbe
       [<c04663b7>] ? handle_level_irq+0x0/0xbe
       [<c0406e6e>] do_IRQ+0xc7/0xfe
       [<c0405668>] common_interrupt+0x28/0x30
       [<c056821a>] ? acpi_idle_enter_simple+0x162/0x19d
       [<c0617f52>] cpuidle_idle_call+0x60/0x92
       [<c0403c61>] cpu_idle+0x101/0x134
       [<c069b1ba>] rest_init+0x4e/0x50
       =======================
      ---[ end trace b7cc8076093467ad ]---
      ------------[ cut here ]------------
      WARNING: at kernel/softirq.c:136 _local_bh_enable_ip+0x3d/0xc4()
      [...]
      Pid: 0, comm: swapper Tainted: G        W 2.6.27.25-170.2.72.fc10.i686
       [<c042ddfb>] warn_on_slowpath+0x65/0x8b
       [<c06ab62b>] ? _spin_unlock_irqrestore+0x22/0x38
       [<c04228b4>] ? __enqueue_entity+0xe3/0xeb
       [<c042431e>] ? enqueue_entity+0x203/0x20b
       [<c0424361>] ? enqueue_task_fair+0x3b/0x3f
       [<c041f88c>] ? resched_task+0x3a/0x6e
       [<c06ab62b>] ? _spin_unlock_irqrestore+0x22/0x38
       [<c06ab4e2>] ? _spin_lock_bh+0xb/0x16
       [<f8b6f642>] ? mkiss_receive_buf+0x33d/0x3a6 [mkiss]
       [<c04325f9>] _local_bh_enable_ip+0x3d/0xc4
       [<c0432688>] local_bh_enable_ip+0x8/0xa
       [<c06ab54d>] _spin_unlock_bh+0x11/0x13
       [<f8b6f642>] mkiss_receive_buf+0x33d/0x3a6 [mkiss]
       [<c0572a30>] flush_to_ldisc+0xf7/0x198
       [<c0572b12>] tty_flip_buffer_push+0x41/0x51
       [<f89477f2>] ftdi_process_read+0x375/0x4ad [ftdi_sio]
       [<f8947a5a>] ftdi_read_bulk_callback+0x130/0x138 [ftdi_sio]
       [<c05d4bec>] usb_hcd_giveback_urb+0x63/0x93
       [<c05ea290>] uhci_giveback_urb+0xe5/0x15f
       [<c05eaabf>] uhci_scan_schedule+0x52e/0x767
       [<c05f6288>] ? psmouse_handle_byte+0xc/0xe5
       [<c054df78>] ? acpi_ev_gpe_detect+0xd6/0xe1
       [<c05ec5b0>] uhci_irq+0x110/0x125
       [<c05d4834>] usb_hcd_irq+0x40/0xa3
       [<c0465313>] handle_IRQ_event+0x2f/0x64
       [<c046642b>] handle_level_irq+0x74/0xbe
       [<c04663b7>] ? handle_level_irq+0x0/0xbe
       [<c0406e6e>] do_IRQ+0xc7/0xfe
       [<c0405668>] common_interrupt+0x28/0x30
       [<c056821a>] ? acpi_idle_enter_simple+0x162/0x19d
       [<c0617f52>] cpuidle_idle_call+0x60/0x92
       [<c0403c61>] cpu_idle+0x101/0x134
       [<c069b1ba>] rest_init+0x4e/0x50
       =======================
      ---[ end trace b7cc8076093467ad ]---
      mkiss: ax0: Trying crc-smack
      mkiss: ax0: Trying crc-flexnet
      
      The issue was, that the locking code in mkiss was assuming it was only
      ever being called in process or bh context.  Fixed by converting the
      involved locking code to use irq-safe locks.
      
      Review of other networking line disciplines shows that 6pack, both sync
      and async PPP and STRIP have similar issues.  The ppp_async one is the
      most interesting one as it sorts out half of the issue as far back as
      2004 in commit http://git.kernel.org/?p=linux/kernel/git/tglx/history.git;a=commitdiff;h=2996d8deaeddd01820691a872550dc0cfba0c37d
      
      
      
      Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      Reported-by: default avatarGuido Trentalancia <guido@trentalancia.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      adeab1af
  33. Jul 08, 2009
  34. Jul 05, 2009
  35. Jun 17, 2009
  36. Jun 13, 2009
  37. Mar 30, 2009
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