From: Dan Carpenter <dan.carpenter@oracle.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [PATCH] tracing: Fix an off by one in __next()
Date: Wed, 20 Jun 2018 14:08:00 +0300 [thread overview]
Message-ID: <20180620110758.crunhd5bfep7zuiz@kili.mountain> (raw)
The > should be >= to prevent an off by one bug.
From reviewing the code, it seems possible for
stack_trace_max.nr_entries to be set to .max_entries and in that case we
would be reading one element beyond the end of the stack_dump_trace[]
array. If it's not set to .max_entries then the bug doesn't affect
runtime.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 4237eba4ef20..6e3edd745c68 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -286,7 +286,7 @@ __next(struct seq_file *m, loff_t *pos)
{
long n = *pos - 1;
- if (n > stack_trace_max.nr_entries || stack_dump_trace[n] == ULONG_MAX)
+ if (n >= stack_trace_max.nr_entries || stack_dump_trace[n] == ULONG_MAX)
return NULL;
m->private = (void *)n;
next reply other threads:[~2018-06-20 11:08 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-20 11:08 Dan Carpenter [this message]
2018-11-27 18:44 ` [PATCH] tracing: Fix an off by one in __next() Steven Rostedt
2018-11-27 20:04 ` Dan Carpenter
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