From: Steven Rostedt <rostedt@goodmis.org>
To: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Cc: <catalin.marinas@arm.com>, <linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>,
<linux-mediatek@lists.infradead.org>, <matthias.bgg@gmail.com>,
<mingo@redhat.com>, <will@kernel.org>, <yj.chiang@mediatek.com>
Subject: Re: [PATCH] arm64: ftrace: don't dereference a probably invalid address
Date: Mon, 7 Jun 2021 10:52:17 -0400 [thread overview]
Message-ID: <20210607105217.772214e5@oasis.local.home> (raw)
In-Reply-To: <20210607141522.3281-1-mark-pk.tsai@mediatek.com>
On Mon, 7 Jun 2021 22:15:22 +0800
Mark-PK Tsai <mark-pk.tsai@mediatek.com> wrote:
> And the crash is becuase kernel trying to read *rec->ip in print_ip_ins() if
> ftrace_bug() get error code -EINVAL.
Right, so the actual fix should be something like this:
[ not tested, nor even compiled ]
-- Steve
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 2e8a3fde7104..72ef4dccbcc4 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1967,12 +1967,18 @@ static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
static void print_ip_ins(const char *fmt, const unsigned char *p)
{
+ char ins[MCOUNT_INSN_SIZE];
int i;
+ if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) {
+ printk(KERN_CONT "%s[FAULT](%px)", fmt, p);
+ return;
+ }
+
printk(KERN_CONT "%s", fmt);
for (i = 0; i < MCOUNT_INSN_SIZE; i++)
- printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
+ printk(KERN_CONT "%s%02x", i ? ":" : "", ins[i]);
}
enum ftrace_bug_type ftrace_bug_type;
next prev parent reply other threads:[~2021-06-07 14:52 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-07 3:23 Mark-PK Tsai
2021-06-07 13:55 ` Steven Rostedt
2021-06-07 14:15 ` Mark-PK Tsai
2021-06-07 14:36 ` Mark-PK Tsai
2021-06-07 14:52 ` Steven Rostedt [this message]
2021-06-07 18:14 ` Mark-PK Tsai
2021-06-07 18:50 ` Steven Rostedt
2021-06-08 0:52 ` Mark-PK Tsai
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