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  1. 11 6月, 2009 18 次提交
  3. 10 6月, 2009 1 次提交
  5. 05 6月, 2009 1 次提交
    • S
      drivers/char/mem.c: avoid OOM lockup during large reads from /dev/zero · 730c586a
      由 Salman Qazi 提交于 
      While running 20 parallel instances of dd as follows:

  #!/bin/bash
  for i in `seq 1 20`; do
           dd if=/dev/zero of=/export/hda3/dd_$i bs=1073741824 count=1 &
  done
  wait

on a 16G machine, we noticed that rather than just killing the processes,
the entire kernel went down.  Stracing dd reveals that it first does an
mmap2, which makes 1GB worth of zero page mappings.  Then it performs a
read on those pages from /dev/zero, and finally it performs a write.

The machine died during the reads.  Looking at the code, it was noticed
that /dev/zero's read operation had been changed by
557ed1fa ("remove ZERO_PAGE") from giving
zero page mappings to actually zeroing the page.

The zeroing of the pages causes physical pages to be allocated to the
process.  But, when the process exhausts all the memory that it can, the
kernel cannot kill it, as it is still in the kernel mode allocating more
memory.  Consequently, the kernel eventually crashes.

To fix this, I propose that when a fatal signal is pending during
/dev/zero read operation, we simply return and let the user process die.
Signed-off-by: NSalman Qazi <sqazi@google.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
[ Modified error return and comment trivially.  - Linus]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      730c586a
  7. 22 5月, 2009 1 次提交
    • C
      ipmi: fix ipmi_si modprobe hang · 9a2845c4
      由 Corey Minyard 提交于 
      Instead of queuing IPMB messages before channel initialization, just
throw them away.  Nobody will be listening for them at this point,
anyway, and they will clog up the queue and nothing will be delivered
if we queue them.

Also set the current channel to the number of channels, as this value
is used to tell if the channel information has been initialized.
Signed-off-by: NCorey Minyard <cminyard@mvista.com>
Cc: Ferenc Wagner <wferi@niif.hu>
Cc: Dan Frazier <dannf@hp.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      9a2845c4
  9. 20 5月, 2009 2 次提交
    • E
      TPM: get_event_name stack corruption · fbaa5869
      由 Eric Paris 提交于 
      get_event_name uses sprintf to fill a buffer declared on the stack.  It fills
the buffer 2 bytes at a time.  What the code doesn't take into account is that
sprintf(buf, "%02x", data) actually writes 3 bytes.  2 bytes for the data and
then it nul terminates the string.  Since we declare buf to be 40 characters
long and then we write 40 bytes of data into buf sprintf is going to write 41
characters.  The fix is to leave room in buf for the nul terminator.
Signed-off-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NJames Morris <jmorris@namei.org>
      fbaa5869
    • L
      Avoid ICE in get_random_int() with gcc-3.4.5 · 26a9a418
      由 Linus Torvalds 提交于 
      Martin Knoblauch reports that trying to build 2.6.30-rc6-git3 with
RHEL4.3 userspace (gcc (GCC) 3.4.5 20051201 (Red Hat 3.4.5-2)) causes an
internal compiler error (ICE):

    drivers/char/random.c: In function `get_random_int':
    drivers/char/random.c:1672: error: unrecognizable insn:
    (insn 202 148 150 0 /scratch/build/linux-2.6.30-rc6-git3/arch/x86/include/asm/tsc.h:23 (set (reg:SI 0 ax [91])
            (subreg:SI (plus:DI (plus:DI (reg:DI 0 ax [88])
                        (subreg:DI (reg:SI 6 bp) 0))
                    (const_int -4 [0xfffffffffffffffc])) 0)) -1 (nil)
        (nil))
    drivers/char/random.c:1672: internal compiler error: in extract_insn, at recog.c:2083

and after some debugging it turns out that it's due to the code trying
to figure out the rough value of the current stack pointer by taking an
address of an uninitialized variable and casting that to an integer.

This is clearly a compiler bug, but it's not worth fighting - while the
current stack kernel pointer might be somewhat hard to predict in user
space, it's also not generally going to change for a lot of the call
chains for a particular process.

So just drop it, and mumble some incoherent curses at the compiler.
Tested-by: NMartin Knoblauch <spamtrap@knobisoft.de>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      26a9a418
  11. 15 5月, 2009 1 次提交
  13. 08 5月, 2009 1 次提交
    • L
      random: make get_random_int() more random · 8a0a9bd4
      由 Linus Torvalds 提交于 
      It's a really simple patch that basically just open-codes the current
"secure_ip_id()" call, but when open-coding it we now use a _static_
hashing area, so that it gets updated every time.

And to make sure somebody can't just start from the same original seed of
all-zeroes, and then do the "half_md4_transform()" over and over until
they get the same sequence as the kernel has, each iteration also mixes in
the same old "current->pid + jiffies" we used - so we should now have a
regular strong pseudo-number generator, but we also have one that doesn't
have a single seed.

Note: the "pid + jiffies" is just meant to be a tiny tiny bit of noise. It
has no real meaning. It could be anything. I just picked the previous
seed, it's just that now we keep the state in between calls and that will
feed into the next result, and that should make all the difference.

I made that hash be a per-cpu data just to avoid cache-line ping-pong:
having multiple CPU's write to the same data would be fine for randomness,
and add yet another layer of chaos to it, but since get_random_int() is
supposed to be a fast interface I did it that way instead. I considered
using "__raw_get_cpu_var()" to avoid any preemption overhead while still
getting the hash be _mostly_ ping-pong free, but in the end good taste won
out.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      8a0a9bd4
  15. 07 5月, 2009 1 次提交
  17. 25 4月, 2009 1 次提交
  19. 22 4月, 2009 5 次提交
  21. 20 4月, 2009 2 次提交
  23. 14 4月, 2009 2 次提交
  25. 10 4月, 2009 1 次提交
  27. 07 4月, 2009 3 次提交