Messages in this thread Patch in this message | | | Date | Fri, 1 Apr 2011 20:13:01 +0200 | From | Oleg Nesterov <> | Subject | [PATCH 4/4] ptrace: ptrace_check_attach() should not do s/STOPPED/TRACED/ |
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After "ptrace: Clean transitions between TASK_STOPPED and TRACED" d79fdd6d96f46fabb779d86332e3677c6f5c2a4f, ptrace_check_attach() should never see a TASK_STOPPED tracee and s/STOPPED/TRACED/ is no longer legal. Add the warning.
Note: ptrace_check_attach() can be greatly simplified, in particular it doesn't need tasklist. But I'd prefer another patch for that.
Signed-off-by: Oleg Nesterov <oleg@redhat.com> ---
kernel/ptrace.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)
--- ptrace/kernel/ptrace.c~4_ck_attach_cant_be_stopped 2011-04-01 16:36:29.000000000 +0200 +++ ptrace/kernel/ptrace.c 2011-04-01 19:54:05.000000000 +0200 @@ -112,16 +112,14 @@ int ptrace_check_attach(struct task_stru */ read_lock(&tasklist_lock); if ((child->ptrace & PT_PTRACED) && child->parent == current) { - ret = 0; /* * child->sighand can't be NULL, release_task() * does ptrace_unlink() before __exit_signal(). */ spin_lock_irq(&child->sighand->siglock); - if (task_is_stopped(child)) - child->state = TASK_TRACED; - else if (!task_is_traced(child) && !kill) - ret = -ESRCH; + WARN_ON_ONCE(task_is_stopped(child)); + if (task_is_traced(child) || kill) + ret = 0; spin_unlock_irq(&child->sighand->siglock); } read_unlock(&tasklist_lock);
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