From: Prasanna Meda <pmeda@akamai.com>
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>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/kernel/ptrace.c | 29 ++++++++++++++++++++++-------
1 files changed, 22 insertions(+), 7 deletions(-)
diff -puN kernel/ptrace.c~ptrace-locked-accesss-to-ptrace-last_siginfo kernel/ptrace.c
--- 25/kernel/ptrace.c~ptrace-locked-accesss-to-ptrace-last_siginfo 2004-11-21 15:52:10.490855832 -0800
+++ 25-akpm/kernel/ptrace.c 2004-11-21 15:52:10.494855224 -0800
@@ -319,18 +319,33 @@ static int ptrace_setoptions(struct task
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,
_