Messages in this thread Patch in this message | | | From | pmeda@akamai ... | Date | Fri, 19 Nov 2004 19:09:26 -0800 | Subject | [PATCH] ptrace: locked accesss to ptrace last_siginfo |
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ptrace_setsiginfo/ptrace_getsiginfo need to do locked access to last_siginfo. ptrace_notify()/ptrace_stop() sets the current->last_siginfo and sleeps on schedule(). It can be waked up by kill signal from signal_wake_up before debugger wakes it up. On return from schedule(), the current->last_siginfo is reset.
Signed-off-by: Prasanna Meda <pmeda@akamai.com>
--- a/kernel/ptrace.c Fri Nov 19 18:27:26 2004 +++ b/kernel/ptrace.c Fri Nov 19 18:52:52 2004 @@ -303,18 +303,33 @@ static int ptrace_getsiginfo(struct task_struct *child, siginfo_t __user * data) { - if (child->last_siginfo == NULL) - return -EINVAL; - return copy_siginfo_to_user(data, child->last_siginfo); + siginfo_t lastinfo; + + spin_lock_irq(&child->sighand->siglock); + if (likely(child->last_siginfo != NULL)) { + memcpy(&lastinfo, child->last_siginfo, sizeof (siginfo_t)); + spin_unlock_irq(&child->sighand->siglock); + return copy_siginfo_to_user(data, &lastinfo); + } + spin_unlock_irq(&child->sighand->siglock); + return -EINVAL; } static int ptrace_setsiginfo(struct task_struct *child, siginfo_t __user * data) { - if (child->last_siginfo == NULL) - return -EINVAL; - if (copy_from_user(child->last_siginfo, data, sizeof (siginfo_t)) != 0) + siginfo_t newinfo; + + if (copy_from_user(&newinfo, data, sizeof (siginfo_t)) != 0) return -EFAULT; - return 0; + + spin_lock_irq(&child->sighand->siglock); + if (likely(child->last_siginfo != NULL)) { + memcpy(child->last_siginfo, &newinfo, sizeof (siginfo_t)); + spin_unlock_irq(&child->sighand->siglock); + return 0; + } + spin_unlock_irq(&child->sighand->siglock); + return -EINVAL; } int ptrace_request(struct task_struct *child, long request, - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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