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| author |   David S. Miller <davem@davemloft.net> | 2013-01-29 15:32:13 -0500 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-01-29 15:32:13 -0500 |
| commit | f1e7b73acc26e8908af783bcd3a9900fd80688f5 (patch) | |
| tree | 9a9382fb7f12f1889020efb4bffa3f4a88589fc5 /arch/x86/kernel/step.c | |
| parent | ipv6: add anti-spoofing checks for 6to4 and 6rd (diff) | |
| parent | Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc (diff) | |
| download | linux-dev-f1e7b73acc26e8908af783bcd3a9900fd80688f5.tar.xz linux-dev-f1e7b73acc26e8908af783bcd3a9900fd80688f5.zip | |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Bring in the 'net' tree so that we can get some ipv4/ipv6 bug
fixes that some net-next work will build upon.
Signed-off-by: David S. Miller <davem@davemloft.net>
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(); |