• Oleg Nesterov's avatar
    perf: perf_event_exit_task_context: s/rcu_dereference/rcu_dereference_raw/ · 806839b2
    Oleg Nesterov authored
    In theory, almost every user of task->child->perf_event_ctxp[]
    is wrong. find_get_context() can install the new context at any
    moment, we need read_barrier_depends().
    
    dbe08d82 "perf: Fix
    find_get_context() vs perf_event_exit_task() race" added
    rcu_dereference() into perf_event_exit_task_context() to make
    the precedent, but this makes __rcu_dereference_check() unhappy.
    Use rcu_dereference_raw() to shut up the warning.
    Reported-by: default avatarIngo Molnar <mingo@elte.hu>
    Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
    Cc: acme@redhat.com
    Cc: paulus@samba.org
    Cc: stern@rowland.harvard.edu
    Cc: a.p.zijlstra@chello.nl
    Cc: fweisbec@gmail.com
    Cc: roland@redhat.com
    Cc: prasad@linux.vnet.ibm.com
    Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
    LKML-Reference: <20110121174547.GA8796@redhat.com>
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    806839b2
perf_event.c 152 KB