summaryrefslogtreecommitdiff
path: root/kernel/smp.c
diff options
context:
space:
mode:
authorDavid Howells <dhowells@redhat.com>2010-10-27 17:28:35 +0100
committerDavid Howells <dhowells@redhat.com>2010-10-27 17:28:35 +0100
commit3b950de9c94b4b9fde4f1340358ab52ce0f34be0 (patch)
tree724923f90b0d12bd6e0374b73e8fd06d8d8787e1 /kernel/smp.c
parentdcd42ed3ea829aa99cf00d34c61e082ce575b193 (diff)
MN10300: Prevent cnt32_to_63() from being preempted in sched_clock()
Prevent cnt32_to_63() from being preempted in sched_clock() because it may read its internal counter, get preempted, get delayed for more than the half period of the 'TSC' and then write the internal counter, thus corrupting it. Whilst some callers of sched_clock() have interrupts disabled or hold spinlocks, not all do, and so preemption must be held here. Note that sched_clock() is called from lockdep, but that shouldn't be a problem because although preempt_disable() calls into lockdep, lockdep has a recursion counter to deal with this. Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'kernel/smp.c')
0 files changed, 0 insertions, 0 deletions