linux-toradex.git/kernel/posix-timers.c, branch v3.2.48

posix-timer: Don't call idr_find() with out-of-range ID

2013-03-06T03:24:09+00:00

commit e182bb38d7db7494fa5dcd82da17fe0dedf60ecf upstream.

When idr_find() was fed a negative ID, it used to look up the ID
ignoring the sign bit before recent ("idr: remove MAX_IDR_MASK and
move left MAX_IDR_* into idr.c") patch. Now a negative ID triggers
a WARN_ON_ONCE().

__lock_timer() feeds timer_id from userland directly to idr_find()
without sanitizing it which can trigger the above malfunctions.  Add a
range check on @timer_id before invoking idr_find() in __lock_timer().

While timer_t is defined as int by all archs at the moment, Andrew
worries that it may be defined as a larger type later on.  Make the
test cover larger integers too so that it at least is guaranteed to
not return the wrong timer.

Note that WARN_ON_ONCE() in idr_find() on id < 0 is transitional
precaution while moving away from ignoring MSB.  Once it's gone we can
remove the guard as long as timer_t isn't larger than int.

Signed-off-by: Tejun Heo nnn
Reported-by: Sasha Levin 
Cc: Andrew Morton 
Link: http://lkml.kernel.org/r/20130220232412.GL3570@htj.dyndns.org
Signed-off-by: Thomas Gleixner 
Signed-off-by: Ben Hutchings

kernel: Map most files to use export.h instead of module.h

2011-10-31T13:20:12+00:00

The changed files were only including linux/module.h for the
EXPORT_SYMBOL infrastructure, and nothing else.  Revector them
onto the isolated export header for faster compile times.

Nothing to see here but a whole lot of instances of:

  -#include 
  +#include 

This commit is only changing the kernel dir; next targets
will probably be mm, fs, the arch dirs, etc.

Signed-off-by: Paul Gortmaker

posix-timers: RCU conversion

2011-05-24T10:10:51+00:00

Ben Nagy reported a scalability problem with KVM/QEMU that hit very hard
a single spinlock (idr_lock) in posix-timers code, on its 48 core
machine.

Even on a 16 cpu machine (2x4x2), a single test can show 98% of cpu time
used in ticket_spin_lock, from lock_timer

Ref: http://www.spinics.net/lists/kvm/msg51526.html

Switching to RCU is quite easy, IDR being already RCU ready. idr_lock
should be locked only for an insert/delete, not a lookup.

Benchmark on a 2x4x2 machine, 16 processes calling timer_gettime().

Before :

real    1m18.669s
user    0m1.346s
sys     1m17.180s

After :

real    0m3.296s
user    0m1.366s
sys     0m1.926s

Reported-by: Ben Nagy 
Signed-off-by: Eric Dumazet 
Tested-by: Ben Nagy 
Cc: Oleg Nesterov 
Cc: Avi Kivity 
Cc: John Stultz 
Cc: Richard Cochran 
Cc: Paul E. McKenney 
Cc: Andrew Morton 
Signed-off-by: Thomas Gleixner

hrtimers: Avoid touching inactive timer bases

2011-05-23T11:59:54+00:00

Instead of iterating over all possible timer bases avoid it by marking
the active bases in the cpu base.

Signed-off-by: Thomas Gleixner 
Reviewed-by: Peter Zijlstra

Fix common misspellings

2011-03-31T14:26:23+00:00

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi

timers: Export CLOCK_BOOTTIME via the posix timers interface

2011-02-21T20:53:09+00:00

This patch exports CLOCK_BOOTTIME through the posix timers interface

CC: Jamie Lokier 
CC: Thomas Gleixner 
CC: Alexander Shishkin 
CC: Arve Hjønnevåg 
Signed-off-by: John Stultz

posix clocks: Introduce dynamic clocks

2011-02-02T14:28:20+00:00

This patch adds support for adding and removing posix clocks. The
clock lifetime cycle is patterned after usb devices. Each clock is
represented by a standard character device. In addition, the driver
may optionally implement custom character device operations.

The posix clock and timer system calls listed below now work with
dynamic posix clocks, as well as the traditional static clocks.
The following system calls are affected:

   - clock_adjtime (brand new syscall)
   - clock_gettime
   - clock_getres
   - clock_settime
   - timer_create
   - timer_delete
   - timer_gettime
   - timer_settime

[ tglx: Adapted to the posix-timer cleanup. Moved clock_posix_dynamic
  	to posix-clock.c and made all referenced functions static ]

Signed-off-by: Richard Cochran 
Acked-by: John Stultz 
LKML-Reference: <20110201134420.164172635@linutronix.de>
Signed-off-by: Thomas Gleixner

posix-timers: Cleanup namespace

2011-02-02T14:28:19+00:00

Rename register_posix_clock() to posix_timers_register_clock(). That's
what the function really does. As a side effect this cleans up the
posix_clock namespace for the upcoming dynamic posix_clock
infrastructure.

Signed-off-by: Thomas Gleixner 
Tested-by: Richard Cochran 
Cc: John Stultz 
LKML-Reference:

posix-timers: Add support for fd based clocks

2011-02-02T14:28:19+00:00

Extend the negative clockids which are currently used by posix cpu
timers to encode the PID with a file descriptor based type which
encodes the fd in the upper bits.

Originally-from: Richard Cochran 
Signed-off-by: Thomas Gleixner 
Acked-by: John Stultz 
LKML-Reference: <20110201134420.062860200@linutronix.de>

posix-timers: Introduce a syscall for clock tuning.

2011-02-02T14:28:19+00:00

A new syscall is introduced that allows tuning of a POSIX clock. The
new call, clock_adjtime, takes two parameters, the clock ID and a
pointer to a struct timex. Any ADJTIMEX(2) operation may be requested
via this system call, but various POSIX clocks may or may not support
tuning.

[ tglx: Adapted to the posix-timer cleanup series. Avoid copy_to_user
  	in the error case ]

Signed-off-by: Richard Cochran 
Acked-by: John Stultz 
LKML-Reference: <20110201134419.869804645@linutronix.de>
Signed-off-by: Thomas Gleixner