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| author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-01-25 12:34:27 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-01-25 12:34:27 -0800 |
| commit | 74790147fb4e9b71083a62a525ab283a275d63b7 (patch) | |
| tree | 2805293e7f1806ce2fd804255f868ab94edeae88 /arch/x86/kernel/step.c | |
| parent | f6dcf8e747a0723ace5275334bacfcd88ab39333 (diff) | |
| parent | 949db153b6466c6f7cad5a427ecea94985927311 (diff) | |
Merge 3.8-rc5 into char-misc-next
This pulls in all of the 3.8-rc5 fixes into this branch so we can test easier.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/kernel/step.c')
| -rw-r--r-- | arch/x86/kernel/step.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c index cd3b2438a980..9b4d51d0c0d0 100644 --- a/arch/x86/kernel/step.c +++ b/arch/x86/kernel/step.c @@ -165,10 +165,11 @@ void set_task_blockstep(struct task_struct *task, bool on) * Ensure irq/preemption can't change debugctl in between. * Note also that both TIF_BLOCKSTEP and debugctl should * be changed atomically wrt preemption. - * FIXME: this means that set/clear TIF_BLOCKSTEP is simply - * wrong if task != current, SIGKILL can wakeup the stopped - * tracee and set/clear can play with the running task, this - * can confuse the next __switch_to_xtra(). + * + * NOTE: this means that set/clear TIF_BLOCKSTEP is only safe if + * task is current or it can't be running, otherwise we can race + * with __switch_to_xtra(). We rely on ptrace_freeze_traced() but + * PTRACE_KILL is not safe. */ local_irq_disable(); debugctl = get_debugctlmsr(); |