Skip to content

L
linux
Switch branch/tag
  1. 08 Apr, 2008 6 commits
  3. 05 Apr, 2008 4 commits
  5. 04 Apr, 2008 3 commits
  7. 03 Apr, 2008 24 commits
  9. 02 Apr, 2008 3 commits
    • Linus Torvalds's avatar
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6 · 9597362d
      Linus Torvalds authored 
      * git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6:
  USB: ohci: fix 2 timers to fire at jiffies + 1s
  USB: Allow initialization of broken keyspan serial adapters.
  USB: fix bug in sg initialization in usbtest
  USB: serial: fix regression in Visor/Palm OS module for kernels >= 2.6.24
  USB: cp2101: Add identifiers for the Telegesys ETRX2USB
  USB: serial: ti_usb_3410_5052: Correct TUSB3410 endpoint requirements.
  USB: another ehci_iaa_watchdog fix
      9597362d
    • Andrew Morton's avatar
      alpha: get_current(): don't add zero to current_thread_info()->task · 06f11f37
      Andrew Morton authored 
      A nasty compile error:

In file included from security/keys/internal.h:16,
                 from security/keys/sysctl.c:14:
include/linux/key-ui.h: In function 'key_permission':
include/linux/key-ui.h:51: error: invalid use of undefined type 'struct task_struct'

apparently the compiler has decided that it needs to know sizeof(task_struct)
so that it can add zero to a task_struct* (which is rather dumb of it).

Getting task_struct in scope in these deeply-nested headers is scary-looking,
so let's just remove the "+ 0".

Cc: David Howells <dhowells@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      06f11f37
    • Mathieu Desnoyers's avatar
      markers: use synchronize_sched() · 6496968e
      Mathieu Desnoyers authored 
      Markers do not mix well with CONFIG_PREEMPT_RCU because it uses
preempt_disable/enable() and not rcu_read_lock/unlock for minimal
intrusiveness.  We would need call_sched and sched_barrier primitives.

Currently, the modification (connection and disconnection) of probes
from markers requires changes to the data structure done in RCU-style :
a new data structure is created, the pointer is changed atomically, a
quiescent state is reached and then the old data structure is freed.

The quiescent state is reached once all the currently running
preempt_disable regions are done running.  We use the call_rcu mechanism
to execute kfree() after such quiescent state has been reached.
However, the new CONFIG_PREEMPT_RCU version of call_rcu and rcu_barrier
does not guarantee that all preempt_disable code regions have finished,
hence the race.

The "proper" way to do this is to use rcu_read_lock/unlock, but we don't
want to use it to minimize intrusiveness on the traced system.  (we do
not want the marker code to call into much of the OS code, because it
would quickly restrict what can and cannot be instrumented, such as the
scheduler).

The temporary fix, until we get call_rcu_sched and rcu_barrier_sched in
mainline, is to use synchronize_sched before each call_rcu calls, so we
wait for the quiescent state in the system call code path.  It will slow
down batch marker enable/disable, but will make sure the race is gone.
Signed-off-by: default avatarMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      6496968e
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7