Unwinding a running task has proven problematic.
In one instance, the running task was attempting to unwind itself and
received an interrupt between when get_wchan allocated local variables on
the stack and when unw_init_from_blocked_task was called which resulted
in unw_init_frame_info to place this tasks task_struct pointer over the
switch stack's ar_bspstore entry.
Signed-off-by: Robin Holt <[EMAIL PROTECTED]>
Index: linux-tot-20070517/arch/ia64/kernel/process.c
===================================================================
--- linux-tot-20070517.orig/arch/ia64/kernel/process.c 2007-05-18
10:14:45.485516967 -0500
+++ linux-tot-20070517/arch/ia64/kernel/process.c 2007-05-18
10:15:10.340573728 -0500
@@ -763,6 +763,9 @@ get_wchan (struct task_struct *p)
unsigned long ip;
int count = 0;
+ if (!p || p == current || p->state == TASK_RUNNING)
+ return 0;
+
/*
* Note: p may not be a blocked task (it could be current or
* another process running on some other CPU. Rather than
@@ -773,6 +776,8 @@ get_wchan (struct task_struct *p)
*/
unw_init_from_blocked_task(&info, p);
do {
+ if (p->state == TASK_RUNNING)
+ return 0;
if (unw_unwind(&info) < 0)
return 0;
unw_get_ip(&info, &ip);
-
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