From: Vineet Gupta <Vineet.Gupta1@synopsys.com>
To: linux-snps-arc@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, Alexey.Brodkin@synopsys.com,
Eugeniy.Paltsev@synopsys.com, Igor.Guryanov@synopsys.com,
Vineet Gupta <Vineet.Gupta1@synopsys.com>
Subject: [PATCH] ARC: stack unwinding: avoid indefinite looping
Date: Tue, 27 Oct 2020 15:32:33 -0700 [thread overview]
Message-ID: <20201027223233.3199386-1-vgupta@synopsys.com> (raw)
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.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
arch/arc/kernel/stacktrace.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/arc/kernel/stacktrace.c b/arch/arc/kernel/stacktrace.c
index bf40e06f3fb8..0fed32b95923 100644
--- a/arch/arc/kernel/stacktrace.c
+++ b/arch/arc/kernel/stacktrace.c
@@ -115,7 +115,7 @@ 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;
@@ -135,6 +135,11 @@ 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 */
--
2.25.1
reply other threads:[~2020-10-27 22:32 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201027223233.3199386-1-vgupta@synopsys.com \
--to=vineet.gupta1@synopsys.com \
--cc=Alexey.Brodkin@synopsys.com \
--cc=Eugeniy.Paltsev@synopsys.com \
--cc=Igor.Guryanov@synopsys.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-snps-arc@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).