From: Robin Holt Date: Fri, 18 May 2007 18:46:52 +0000 (-0500) Subject: [IA64] Only unwind non-running tasks. X-Git-Tag: v2.6.22-rc3~96^2~1 X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=6ae384884d936cb39ab20238af34689933e44525;p=linux-2.6-omap-h63xx.git [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 Signed-off-by: Tony Luck --- 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);