diff options
| author | John Johansen <john.johansen@canonical.com> | 2013-03-21 05:04:13 -0700 |
|---|---|---|
| committer | Willy Tarreau <w@1wt.eu> | 2013-06-10 11:42:20 +0200 |
| commit | 96ec5658179a39389e482d4d8e31d1aeeea9c539 (patch) | |
| tree | 2a95692b242dd352cfe1aa815f9cef543872b7eb /kernel | |
| parent | 062bdcb3e5d3e9892c91eff5950dac767af71fae (diff) | |
ptrace: 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.johansen@canonical.com>
Acked-by: Colin King <colin.king@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Luis Henriques <luis.henriques@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/ptrace.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c index d0036f09e6c1..d9c8c47ec994 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); |