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authorRobin Holt <holt@sgi.com>2007-05-18 13:46:52 -0500
committerTony Luck <tony.luck@intel.com>2007-05-22 10:16:07 -0700
commit6ae384884d936cb39ab20238af34689933e44525 (patch)
tree41fdde5596919fb7f987f637a4578792ef39ea4e /arch/ia64
parente2e6fe7bb6e30621ad4e8a3acb1e711815c239bd (diff)
downloadlinux-2.6.34-ux500-6ae384884d936cb39ab20238af34689933e44525.tar.gz
[IA64] Only unwind non-running tasks.
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 <holt@sgi.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64')
-rw-r--r--arch/ia64/kernel/process.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index d1c3ed9943e..af73b8dfde2 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -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);