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  1. 06 9月, 2008 1 次提交
  3. 14 8月, 2008 1 次提交
  5. 01 8月, 2008 1 次提交
  7. 31 7月, 2008 3 次提交
  9. 27 7月, 2008 3 次提交
  11. 26 7月, 2008 1 次提交
    • S
      x64, fpu: fix possible FPU leakage in error conditions · 6ffac1e9
      由 Suresh Siddha 提交于 
      On Thu, Jul 24, 2008 at 03:43:44PM -0700, Linus Torvalds wrote:
> So how about this patch as a starting point? This is the RightThing(tm) to
> do regardless, and if it then makes it easier to do some other cleanups,
> we should do it first. What do you think?

restore_fpu_checking() calls init_fpu() in error conditions.

While this is wrong(as our main intention is to clear the fpu state of
the thread), this was benign before commit 92d140e2 ("x86: fix taking
DNA during 64bit sigreturn").

Post commit 92d140e2, live FPU registers may not belong to this
process at this error scenario.

In the error condition for restore_fpu_checking() (especially during the
64bit signal return), we are doing init_fpu(), which saves the live FPU
register state (possibly belonging to some other process context) into
the thread struct (through unlazy_fpu() in init_fpu()). This is wrong
and can leak the FPU data.

For the signal handler restore error condition in restore_i387(), clear
the fpu state present in the thread struct(before ultimately sending a
SIGSEGV for badframe).

For the paranoid error condition check in math_state_restore(), send a
SIGSEGV, if we fail to restore the state.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: <stable@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      6ffac1e9
  13. 25 7月, 2008 1 次提交
    • L
      x86-64: Clean up 'save/restore_i387()' usage · b30f3ae5
      由 Linus Torvalds 提交于 
      Suresh Siddha wants to fix a possible FPU leakage in error conditions,
but the fact that save/restore_i387() are inlines in a header file makes
that harder to do than necessary.  So start off with an obvious cleanup.

This just moves the x86-64 version of save/restore_i387() out of the
header file, and moves it to the only file that it is actually used in:
arch/x86/kernel/signal_64.c.  So exposing it in a header file was wrong
to begin with.

[ Side note: I'd like to fix up some of the games we play with the
  32-bit version of these functions too, but that's a separate
  matter.  The 32-bit versions are shared - under different names
  at that! - by both the native x86-32 code and the x86-64 32-bit
  compatibility code ]
Acked-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      b30f3ae5
  15. 22 7月, 2008 1 次提交
  17. 20 7月, 2008 1 次提交
    • P
      sched, x86: clean up hrtick implementation · 31656519
      由 Peter Zijlstra 提交于 
      random uvesafb failures were reported against Gentoo:

  http://bugs.gentoo.org/show_bug.cgi?id=222799

and Mihai Moldovan bisected it back to:

> 8f4d37ec is first bad commit
> commit 8f4d37ec
> Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Date:   Fri Jan 25 21:08:29 2008 +0100
>
>    sched: high-res preemption tick

Linus suspected it to be hrtick + vm86 interaction and observed:

> Btw, Peter, Ingo: I think that commit is doing bad things. They aren't
> _incorrect_ per se, but they are definitely bad.
>
> Why?
>
> Using random _TIF_WORK_MASK flags is really impolite for doing
> "scheduling" work. There's a reason that arch/x86/kernel/entry_32.S
> special-cases the _TIF_NEED_RESCHED flag: we don't want to exit out of
> vm86 mode unnecessarily.
>
> See the "work_notifysig_v86" label, and how it does that
> "save_v86_state()" thing etc etc.

Right, I never liked having to fiddle with those TIF flags. Initially I
needed it because the hrtimer base lock could not nest in the rq lock.
That however is fixed these days.

Currently the only reason left to fiddle with the TIF flags is remote
wakeups. We cannot program a remote cpu's hrtimer. I've been thinking
about using the new and improved IPI function call stuff to implement
hrtimer_start_on().

However that does require that smp_call_function_single(.wait=0) works
from interrupt context - /me looks at the latest series from Jens - Yes
that does seem to be supported, good.

Here's a stab at cleaning this stuff up ...

Mihai reported test success as well.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: NMihai Moldovan <ionic@ionic.de>
Cc: Michal Januszewski <spock@gentoo.org>
Cc: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      31656519
  19. 17 7月, 2008 1 次提交
    • R
      x86 ptrace: unify TIF_SINGLESTEP · 64f09733
      由 Roland McGrath 提交于 
      This unifies the treatment of TIF_SINGLESTEP on i386 and x86_64.
The bit is now excluded from _TIF_WORK_MASK on i386 as it has been
on x86_64.  This means the do_notify_resume() path using it is never
used, so TIF_SINGLESTEP is not cleared on returning to user mode.

Both now leave TIF_SINGLESTEP set when returning to user, so that
it's already set on an int $0x80 system call entry.  This removes
the need for testing TF on the system_call path.  Doing it this way
fixes the regression for PTRACE_SINGLESTEP into a sigreturn syscall,
introduced by commit 1e2e99f0.

The clear_TF_reenable case that sets TIF_SINGLESTEP can only happen
on a non-exception kernel entry, i.e. sysenter/syscall instruction.
That will always get to the syscall exit tracing path.
Signed-off-by: NRoland McGrath <roland@redhat.com>
      64f09733
  21. 30 4月, 2008 1 次提交
  23. 26 4月, 2008 2 次提交
  25. 17 4月, 2008 7 次提交
  27. 12 3月, 2008 1 次提交
    • R
      x86: ia32 syscall restart fix · 40f0933d
      由 Roland McGrath 提交于 
      The code to restart syscalls after signals depends on checking for a
negative orig_ax, and for particular negative -ERESTART* values in ax.
These fields are 64 bits and for a 32-bit task they get zero-extended.
The syscall restart behavior is lost, a regression from a native 32-bit
kernel and from 64-bit tasks' behavior.

This patch fixes the problem by doing sign-extension where it matters.

For orig_ax, the only time the value should be -1 but winds up as
0x0ffffffff is via a 32-bit ptrace call. So the patch changes ptrace to
sign-extend the 32-bit orig_eax value when it's stored; it doesn't
change the checks on orig_ax, though it uses the new current_syscall()
inline to better document the subtle importance of the used of
signedness there.

The ax value is stored a lot of ways and it seems hard to get them all
sign-extended at their origins. So for that, we use the
current_syscall_ret() to sign-extend it only for 32-bit tasks at the
time of the -ERESTART* comparisons.
Signed-off-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      40f0933d
  29. 07 3月, 2008 1 次提交
  31. 30 1月, 2008 5 次提交
  33. 26 1月, 2008 1 次提交
    • P
      sched: high-res preemption tick · 8f4d37ec
      由 Peter Zijlstra 提交于 
      Use HR-timers (when available) to deliver an accurate preemption tick.

The regular scheduler tick that runs at 1/HZ can be too coarse when nice
level are used. The fairness system will still keep the cpu utilisation 'fair'
by then delaying the task that got an excessive amount of CPU time but try to
minimize this by delivering preemption points spot-on.

The average frequency of this extra interrupt is sched_latency / nr_latency.
Which need not be higher than 1/HZ, its just that the distribution within the
sched_latency period is important.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      8f4d37ec
  35. 20 10月, 2007 1 次提交
  37. 14 10月, 2007 1 次提交
    • D
      Delete filenames in comments. · 835c34a1
      由 Dave Jones 提交于 
      Since the x86 merge, lots of files that referenced their own filenames
are no longer correct.  Rather than keep them up to date, just delete
them, as they add no real value.

Additionally:
- fix up comment formatting in scx200_32.c
- Remove a credit from myself in setup_64.c from a time when we had no SCM
- remove longwinded history from tsc_32.c which can be figured out from
  git.
Signed-off-by: NDave Jones <davej@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      835c34a1
  39. 11 10月, 2007 2 次提交
  41. 23 7月, 2007 1 次提交
    • M
      x86: i386-show-unhandled-signals-v3 · abd4f750
      由 Masoud Asgharifard Sharbiani 提交于 
      This patch makes the i386 behave the same way that x86_64 does when a
segfault happens.  A line gets printed to the kernel log so that tools
that need to check for failures can behave more uniformly between
debug.show_unhandled_signals sysctl variable to 0 (or by doing echo 0 >
/proc/sys/debug/exception-trace)

Also, all of the lines being printed are now using printk_ratelimit() to
deny the ability of DoS from a local user with a program like the
following:

main()
{
       while (1)
               if (!fork()) *(int *)0 = 0;
}

This new revision also includes the fix that Andrew did which got rid of
new sysctl that was added to the system in earlier versions of this.
Also, 'show-unhandled-signals' sysctl has been renamed back to the old
'exception-trace' to avoid breakage of people's scripts.

AK: Enabling by default for i386 will be likely controversal, but let's see what happens
AK: Really folks, before complaining just fix your segfaults
AK: I bet this will find a lot of silent issues
Signed-off-by: NMasoud Sharbiani <masouds@google.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
[ Personally, I've found the complaints useful on x86-64, so I'm all for
  this. That said, I wonder if we could do it more prettily..   -Linus ]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      abd4f750
  43. 22 7月, 2007 1 次提交
    • T
      x86_64: support poll() on /dev/mcelog · e02e68d3
      由 Tim Hockin 提交于 
      Background:
 /dev/mcelog is typically polled manually.  This is less than optimal for
 situations where accurate accounting of MCEs is important.  Calling
 poll() on /dev/mcelog does not work.

Description:
 This patch adds support for poll() to /dev/mcelog.  This results in
 immediate wakeup of user apps whenever the poller finds MCEs.  Because
 the exception handler can not take any locks, it can not call the wakeup
 itself.  Instead, it uses a thread_info flag (TIF_MCE_NOTIFY) which is
 caught at the next return from interrupt or exit from idle, calling the
 mce_user_notify() routine.  This patch also disables the "fake panic"
 path of the mce_panic(), because it results in printk()s in the exception
 handler and crashy systems.

 This patch also does some small cleanup for essentially unused variables,
 and moves the user notification into the body of the poller, so it is
 only called once per poll, rather than once per CPU.

Result:
 Applications can now poll() on /dev/mcelog.  When an error is logged
 (whether through the poller or through an exception) the applications are
 woken up promptly.  This should not affect any previous behaviors.  If no
 MCEs are being logged, there is no overhead.

Alternatives:
 I considered simply supporting poll() through the poller and not using
 TIF_MCE_NOTIFY at all.  However, the time between an uncorrectable error
 happening and the user application being notified is *the*most* critical
 window for us.  Many uncorrectable errors can be logged to the network if
 given a chance.

 I also considered doing the MCE poll directly from the idle notifier, but
 decided that was overkill.

Testing:
 I used an error-injecting DIMM to create lots of correctable DRAM errors
 and verified that my user app is woken up in sync with the polling interval.
 I also used the northbridge to inject uncorrectable ECC errors, and
 verified (printk() to the rescue) that the notify routine is called and the
 user app does wake up.  I built with PREEMPT on and off, and verified
 that my machine survives MCEs.

[wli@holomorphy.com: build fix]
Signed-off-by: NTim Hockin <thockin@google.com>
Signed-off-by: NWilliam Irwin <bill.irwin@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      e02e68d3
  45. 09 5月, 2007 1 次提交
  47. 03 5月, 2007 1 次提交