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authorMichal Marek <mmarek@suse.cz>2010-10-12 17:09:06 +0400
committerMichal Marek <mmarek@suse.cz>2010-10-12 17:09:06 +0400
commit239060b93bb30a4ad55f1ecaa512464a035cc5ba (patch)
tree77f79810e57d4fc24356eca0cd6db463e8994128 /kernel/ptrace.c
parent1408b15b98635a13bad2e2a50b3c2ae2ccdf625b (diff)
parente9203c988234aa512bd45ca32b52e21c7bbfc414 (diff)
downloadlinux-239060b93bb30a4ad55f1ecaa512464a035cc5ba.tar.xz
Merge branch 'kbuild/rc-fixes' into kbuild/kconfig
We need to revert the temporary hack in 71ebc01, hence the merge.
Diffstat (limited to 'kernel/ptrace.c')
-rw-r--r--kernel/ptrace.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 74a3d693c196..f34d798ef4a2 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -324,26 +324,32 @@ int ptrace_detach(struct task_struct *child, unsigned int data)
}
/*
- * Detach all tasks we were using ptrace on.
+ * Detach all tasks we were using ptrace on. Called with tasklist held
+ * for writing, and returns with it held too. But note it can release
+ * and reacquire the lock.
*/
void exit_ptrace(struct task_struct *tracer)
{
struct task_struct *p, *n;
LIST_HEAD(ptrace_dead);
- write_lock_irq(&tasklist_lock);
+ if (likely(list_empty(&tracer->ptraced)))
+ return;
+
list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
if (__ptrace_detach(tracer, p))
list_add(&p->ptrace_entry, &ptrace_dead);
}
- write_unlock_irq(&tasklist_lock);
+ write_unlock_irq(&tasklist_lock);
BUG_ON(!list_empty(&tracer->ptraced));
list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) {
list_del_init(&p->ptrace_entry);
release_task(p);
}
+
+ write_lock_irq(&tasklist_lock);
}
int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)