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  1. 06 Mar, 2012 2 commits
    • Masami Hiramatsu's avatar
      x86/kprobes: Fix a bug which can modify kernel code permanently · 46484688
      Masami Hiramatsu authored 
      Fix a bug in kprobes which can modify kernel code
permanently at run-time. In the result, kernel can
crash when it executes the modified code.

This bug can happen when we put two probes enough near
and the first probe is optimized. When the second probe
is set up, it copies a byte which is already modified
by the first probe, and executes it when the probe is hit.
Even worse, the first probe and the second probe are removed
respectively, the second probe writes back the copied
(modified) instruction.

To fix this bug, kprobes always recovers the original
code and copies the first byte from recovered instruction.
Signed-off-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: yrl.pp-manager.tt@hitachi.com
Cc: systemtap@sourceware.org
Cc: anderson@redhat.com
Link: http://lkml.kernel.org/r/20120305133215.5982.31991.stgit@localhost.localdomainSigned-off-by: default avatarIngo Molnar <mingo@elte.hu>
      46484688
    • Masami Hiramatsu's avatar
      x86/kprobes: Fix instruction recovery on optimized path · 86b4ce31
      Masami Hiramatsu authored 
      Current probed-instruction recovery expects that only breakpoint
instruction modifies instruction. However, since kprobes jump
optimization can replace original instructions with a jump,
that expectation is not enough. And it may cause instruction
decoding failure on the function where an optimized probe
already exists.

This bug can reproduce easily as below:

1) find a target function address (any kprobe-able function is OK)

 $ grep __secure_computing /proc/kallsyms
   ffffffff810c19d0 T __secure_computing

2) decode the function
   $ objdump -d vmlinux --start-address=0xffffffff810c19d0 --stop-address=0xffffffff810c19eb

  vmlinux:     file format elf64-x86-64

Disassembly of section .text:

ffffffff810c19d0 <__secure_computing>:
ffffffff810c19d0:       55                      push   %rbp
ffffffff810c19d1:       48 89 e5                mov    %rsp,%rbp
ffffffff810c19d4:       e8 67 8f 72 00          callq
ffffffff817ea940 <mcount>
ffffffff810c19d9:       65 48 8b 04 25 40 b8    mov    %gs:0xb840,%rax
ffffffff810c19e0:       00 00
ffffffff810c19e2:       83 b8 88 05 00 00 01    cmpl $0x1,0x588(%rax)
ffffffff810c19e9:       74 05                   je     ffffffff810c19f0 <__secure_computing+0x20>

3) put a kprobe-event at an optimize-able place, where no
 call/jump places within the 5 bytes.
 $ su -
 # cd /sys/kernel/debug/tracing
 # echo p __secure_computing+0x9 > kprobe_events

4) enable it and check it is optimized.
 # echo 1 > events/kprobes/p___secure_computing_9/enable
 # cat ../kprobes/list
 ffffffff810c19d9  k  __secure_computing+0x9    [OPTIMIZED]

5) put another kprobe on an instruction after previous probe in
  the same function.
 # echo p __secure_computing+0x12 >> kprobe_events
 bash: echo: write error: Invalid argument
 # dmesg | tail -n 1
 [ 1666.500016] Probing address(0xffffffff810c19e2) is not an instruction boundary.

6) however, if the kprobes optimization is disabled, it works.
 # echo 0 > /proc/sys/debug/kprobes-optimization
 # cat ../kprobes/list
 ffffffff810c19d9  k  __secure_computing+0x9
 # echo p __secure_computing+0x12 >> kprobe_events
 (no error)

This is because kprobes doesn't recover the instruction
which is overwritten with a relative jump by another kprobe
when finding instruction boundary.
It only recovers the breakpoint instruction.

This patch fixes kprobes to recover such instructions.

With this fix:

 # echo p __secure_computing+0x9 > kprobe_events
 # echo 1 > events/kprobes/p___secure_computing_9/enable
 # cat ../kprobes/list
 ffffffff810c1aa9  k  __secure_computing+0x9    [OPTIMIZED]
 # echo p __secure_computing+0x12 >> kprobe_events
 # cat ../kprobes/list
 ffffffff810c1aa9  k  __secure_computing+0x9    [OPTIMIZED]
 ffffffff810c1ab2  k  __secure_computing+0x12    [DISABLED]

Changes in v4:
 - Fix a bug to ensure optimized probe is really optimized
   by jump.
 - Remove kprobe_optready() dependency.
 - Cleanup code for preparing optprobe separation.

Changes in v3:
 - Fix a build error when CONFIG_OPTPROBE=n. (Thanks, Ingo!)
   To fix the error, split optprobe instruction recovering
   path from kprobes path.
 - Cleanup comments/styles.

Changes in v2:
 - Fix a bug to recover original instruction address in
   RIP-relative instruction fixup.
 - Moved on tip/master.
Signed-off-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: yrl.pp-manager.tt@hitachi.com
Cc: systemtap@sourceware.org
Cc: anderson@redhat.com
Link: http://lkml.kernel.org/r/20120305133209.5982.36568.stgit@localhost.localdomainSigned-off-by: default avatarIngo Molnar <mingo@elte.hu>
      86b4ce31
  3. 05 Mar, 2012 10 commits
  5. 03 Mar, 2012 3 commits
  7. 02 Mar, 2012 2 commits
  9. 29 Feb, 2012 4 commits
  11. 28 Feb, 2012 3 commits
  13. 27 Feb, 2012 11 commits
  15. 26 Feb, 2012 3 commits
    • Andreas Bießmann's avatar
      mod/file2alias: make modpost compile on darwin again · dd2a3aca
      Andreas Bießmann authored 
      commit e49ce141 breaks cross compiling
the linux kernel on darwin hosts.
This fix introduce some minimal glue to adopt linker section handling
for darwin hosts.
Signed-off-by: default avatarAndreas Bießmann <andreas@biessmann.de>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: Jochen Friedrich <jochen@scram.de>
CC: Samuel Ortiz <sameo@linux.intel.com>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Tested-by: default avatarBernhard Walle <bernhard@bwalle.de>
      dd2a3aca
    • Linus Torvalds's avatar
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net · 203738e5
      Linus Torvalds authored 
      1) ICMP sockets leave err uninitialized but we try to return it for the
   unsupported MSG_OOB case, reported by Dave Jones.

2) Add new Zaurus device ID entries, from Dave Jones.

3) Pointer calculation in hso driver memset is wrong, from Dan
   Carpenter.

4) ks8851_probe() checks unsigned value as negative, fix also from Dan
   Carpenter.

5) Fix crashes in atl1c driver due to TX queue handling, from Eric
   Dumazet.  I anticipate some TX side locking fixes coming in the near
   future for this driver as well.

6) The inline directive fix in Bluetooth which was breaking the build
   only with very new versions of GCC, from Johan Hedberg.

7) Fix crashes in the ATP CLIP code due to ARP cleanups this merge
   window, reported by Meelis Roos and fixed by Eric Dumazet.

8) JME driver doesn't flush RX FIFO correctly, from Guo-Fu Tseng.

9) Some ip6_route_output() callers test the return value for NULL, but
   this never happens as the convention is to return a dst entry with
   dst->error set.  Fixes from RonQing Li.

10) Logitech Harmony 900 should be handled by zaurus driver not
   cdc_ether, update white lists and black lists accordingly.  From
   Scott Talbert.

11) Receiving from certain kinds of devices there won't be a MAC header,
   so there is no MAC header to fixup in the IPSEC code, and if we try
   to do it we'll crash.  Fix from Eric Dumazet.

12) Port type array indexing off-by-one in mlx4 driver, fix from Yevgeny
   Petrilin.

13) Fix regression in link-down handling in davinci_emac which causes
   all RX descriptors to be freed up and therefore RX to wedge
   completely, from Christian Riesch.

14) It took two attempts, but ctnetlink soft lockups seem to be
   cured now, from Pablo Neira Ayuso.

15) Endianness bug fix in ENIC driver, from Santosh Nayak.

16) The long ago conversion of the PPP fragmentation code over to
   abstracted SKB list handling wasn't perfect, once we get an
   out of sequence SKB we don't flush the rest of them like we
   should.  From Ben McKeegan.

17) Fix regression of ->ip_summed initialization in sfc driver.
   From Ben Hutchings.

18) Bluetooth timeout mistakenly using msecs instead of jiffies,
   from Andrzej Kaczmarek.

19) Using _sync variant of work cancellation results in deadlocks,
   use the non _sync variants instead.  From Andre Guedes.

20) Bluetooth rfcomm code had reference counting problems leading
   to crashes, fix from Octavian Purdila.

21) The conversion of netem over to classful qdisc handling added
   two bugs to netem_dequeue(), fixes from Eric Dumazet.

22) Missing pci_iounmap() in ATM Solos driver.  Fix from Julia Lawall.

23) b44_pci_exit() should not have __exit tag since it's invoked from
   non-__exit code.  From Nikola Pajkovsky.

24) The conversion of the neighbour hash tables over to RCU added a
   race, fixed here by adding the necessary reread of tbl->nht, fix
   from Michel Machado.

25) When we added VF (virtual function) attributes for network device
   dumps, this potentially bloats up the size of the dump of one
   network device such that the dump size is too large for the buffer
   allocated by properly written netlink applications.

   In particular, if you add 255 VFs to a network device, parts of
   GLIBC stop working.

   To fix this, we add an attribute that is used to turn on these
   extended portions of the network device dump.  Sophisticaed
   applications like 'ip' that want to see this stuff  will be changed
   to set the attribute, whereas things like GLIBC that don't care
   about VFs simply will not, and therefore won't be busted by the
   mere presence of VFs on a network device.

   Thanks to the tireless work of Greg Rose on this fix.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (53 commits)
  sfc: Fix assignment of ip_summed for pre-allocated skbs
  ppp: fix 'ppp_mp_reconstruct bad seq' errors
  enic: Fix endianness bug.
  gre: fix spelling in comments
  netfilter: ctnetlink: fix soft lockup when netlink adds new entries (v2)
  Revert "netfilter: ctnetlink: fix soft lockup when netlink adds new entries"
  davinci_emac: Do not free all rx dma descriptors during init
  mlx4_core: Fixing array indexes when setting port types
  phy: IC+101G and PHY_HAS_INTERRUPT flag
  netdev/phy/icplus: Correct broken phy_init code
  ipsec: be careful of non existing mac headers
  Move Logitech Harmony 900 from cdc_ether to zaurus
  hso: memsetting wrong data in hso_get_count()
  netfilter: ip6_route_output() never returns NULL.
  ethernet/broadcom: ip6_route_output() never returns NULL.
  ipv6: ip6_route_output() never returns NULL.
  jme: Fix FIFO flush issue
  atm: clip: remove clip_tbl
  ipv4: ping: Fix recvmsg MSG_OOB error handling.
  rtnetlink: Fix problem with buffer allocation
  ...
      203738e5
    • Linus Torvalds's avatar
      Fix autofs compile without CONFIG_COMPAT · 3c761ea0
      Linus Torvalds authored 
      The autofs compat handling fix caused a compile failure when
CONFIG_COMPAT isn't defined.

Instead of adding random #ifdef'fery in autofs, let's just make the
compat helpers earlier to use: without CONFIG_COMPAT, is_compat_task()
just hardcodes to zero.

We could probably do something similar for a number of other cases where
we have #ifdef's in code, but this is the low-hanging fruit.
Reported-and-tested-by: default avatarAndreas Schwab <schwab@linux-m68k.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3c761ea0
  17. 25 Feb, 2012 2 commits
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