Willy Tarreau <w...@1wt.eu> writes: > 2.6.32-longterm review patch. If anyone has any objections, please let me > know. > > ------------------ > race with SIGKILL > > From: Oleg Nesterov <o...@redhat.com> > > ptrace: ensure arch_ptrace/ptrace_request can never race with SIGKILL >
This patch actually introduce a regression in the Ubuntu kernel. You may want to include the fix below. http://kernel.ubuntu.com/git?p=ubuntu/ubuntu-lucid.git;a=commit;h=d06bbd59e5c7a0e0525af764a897028d6d352c36 Cheers, -- Luis >From d06bbd59e5c7a0e0525af764a897028d6d352c36 Mon Sep 17 00:00:00 2001 From: John Johansen <john.johan...@canonical.com> Date: Thu, 21 Mar 2013 13:57:18 -0700 Subject: [PATCH] Fix ptrace when task is in task_is_stopped(), state >From d6a1da349c76ac2ebe4774d1da9fb7e660df01d3 Mon Sep 17 00:00:00 2001 From: John Johansen <john.johan...@canonical.com> Date: Thu, 21 Mar 2013 05:04:13 -0700 Subject: [PATCH] UBUNTU: SAUCE: Fix ptrace when task is in task_is_stopped() state This patch fixes a regression in ptrace, introduced by commit 9e74eb39 (backport of 9899d11f) which makes assumptions about ptrace behavior which are not true in the 2.6.32 kernel. BugLink: http://bugs.launchpad.net/bugs/1145234 9899d11f makes the assumption that task_is_stopped() is not a valid state in ptrace because it is built on top of a series of patches which change how the TASK_STOPPED state is tracked (321fb561 which requires d79fdd6d and several other patches). Because Lucid does not have the set of patches that make task_is_stopped() an invalid state in ptrace_check_attach, partially revert 9e74eb39 so that ptrace_check_attach() correctly handles task_is_stopped(). However we must replace the assignment of TASK_TRACED with __TASK_TRACED to ensure TASK_WAKEKILL is cleared. Signed-off-by: John Johansen <john.johan...@canonical.com> Acked-by: Colin King <colin.k...@canonical.com> Acked-by: Stefan Bader <stefan.ba...@canonical.com> Acked-by: Luis Henriques <luis.henriq...@canonical.com> Signed-off-by: Tim Gardner <tim.gard...@canonical.com> --- kernel/ptrace.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/kernel/ptrace.c b/kernel/ptrace.c index d0036f0..d9c8c47 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -81,14 +81,18 @@ void __ptrace_unlink(struct task_struct *child) } /* Ensure that nothing can wake it up, even SIGKILL */ -static bool ptrace_freeze_traced(struct task_struct *task) +static bool ptrace_freeze_traced(struct task_struct *task, int kill) { - bool ret = false; + bool ret = true; spin_lock_irq(&task->sighand->siglock); - if (task_is_traced(task) && !__fatal_signal_pending(task)) { + if (task_is_stopped(task) && !__fatal_signal_pending(task)) task->state = __TASK_TRACED; - ret = true; + else if (!kill) { + if (task_is_traced(task) && !__fatal_signal_pending(task)) + task->state = __TASK_TRACED; + else + ret = false; } spin_unlock_irq(&task->sighand->siglock); @@ -131,7 +135,7 @@ int ptrace_check_attach(struct task_struct *child, int kill) * child->sighand can't be NULL, release_task() * does ptrace_unlink() before __exit_signal(). */ - if (kill || ptrace_freeze_traced(child)) + if (ptrace_freeze_traced(child, kill)) ret = 0; } read_unlock(&tasklist_lock); -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
