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authorVineet Gupta <vgupta@synopsys.com>2020-10-27 15:01:17 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-11-10 12:37:33 +0100
commitfbfca92c7840db5f4a980b111789ab0a7af745ef (patch)
treec46889fb89f22d503673ecc1d6cd74317a0f12f3 /arch/arc
parentd61edc06002f6448b863bfa8d164c5fbc64de509 (diff)
ARC: stack unwinding: avoid indefinite looping
commit 328d2168ca524d501fc4b133d6be076142bd305c upstream. Currently stack unwinder is a while(1) loop which relies on the dwarf unwinder to signal termination, which in turn relies on dwarf info to do so. This in theory could cause an infinite loop if the dwarf info was somehow messed up or the register contents were etc. This fix thus detects the excessive looping and breaks the loop. | Mem: 26184K used, 1009136K free, 0K shrd, 0K buff, 14416K cached | CPU: 0.0% usr 72.8% sys 0.0% nic 27.1% idle 0.0% io 0.0% irq 0.0% sirq | Load average: 4.33 2.60 1.11 2/74 139 | PID PPID USER STAT VSZ %VSZ CPU %CPU COMMAND | 133 2 root SWN 0 0.0 3 22.9 [rcu_torture_rea] | 132 2 root SWN 0 0.0 0 22.0 [rcu_torture_rea] | 131 2 root SWN 0 0.0 3 21.5 [rcu_torture_rea] | 126 2 root RW 0 0.0 2 5.4 [rcu_torture_wri] | 129 2 root SWN 0 0.0 0 0.2 [rcu_torture_fak] | 137 2 root SW 0 0.0 0 0.2 [rcu_torture_cbf] | 127 2 root SWN 0 0.0 0 0.1 [rcu_torture_fak] | 138 115 root R 1464 0.1 2 0.1 top | 130 2 root SWN 0 0.0 0 0.1 [rcu_torture_fak] | 128 2 root SWN 0 0.0 0 0.1 [rcu_torture_fak] | 115 1 root S 1472 0.1 1 0.0 -/bin/sh | 104 1 root S 1464 0.1 0 0.0 inetd | 1 0 root S 1456 0.1 2 0.0 init | 78 1 root S 1456 0.1 0 0.0 syslogd -O /var/log/messages | 134 2 root SW 0 0.0 2 0.0 [rcu_torture_sta] | 10 2 root IW 0 0.0 1 0.0 [rcu_preempt] | 88 2 root IW 0 0.0 1 0.0 [kworker/1:1-eve] | 66 2 root IW 0 0.0 2 0.0 [kworker/2:2-eve] | 39 2 root IW 0 0.0 2 0.0 [kworker/2:1-eve] | unwinder looping too long, aborting ! Cc: <stable@vger.kernel.org> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/arc')
-rw-r--r--arch/arc/kernel/stacktrace.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/arc/kernel/stacktrace.c b/arch/arc/kernel/stacktrace.c
index 1e440bbfa876..fc65d2921e3b 100644
--- a/arch/arc/kernel/stacktrace.c
+++ b/arch/arc/kernel/stacktrace.c
@@ -112,7 +112,7 @@ arc_unwind_core(struct task_struct *tsk, struct pt_regs *regs,
int (*consumer_fn) (unsigned int, void *), void *arg)
{
#ifdef CONFIG_ARC_DW2_UNWIND
- int ret = 0;
+ int ret = 0, cnt = 0;
unsigned int address;
struct unwind_frame_info frame_info;
@@ -132,6 +132,11 @@ arc_unwind_core(struct task_struct *tsk, struct pt_regs *regs,
break;
frame_info.regs.r63 = frame_info.regs.r31;
+
+ if (cnt++ > 128) {
+ printk("unwinder looping too long, aborting !\n");
+ return 0;
+ }
}
return address; /* return the last address it saw */