From: Kees Cook <keescook@chromium.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Kees Cook" <keescook@chromium.org>,
"Qi Zheng" <zhengqi.arch@bytedance.com>,
"kernel test robot" <oliver.sang@intel.com>,
"Vito Caputo" <vcaputo@pengaru.com>,
"Jann Horn" <jannh@google.com>, "Ingo Molnar" <mingo@redhat.com>,
"Juri Lelli" <juri.lelli@redhat.com>,
"Vincent Guittot" <vincent.guittot@linaro.org>,
"Dietmar Eggemann" <dietmar.eggemann@arm.com>,
"Steven Rostedt" <rostedt@goodmis.org>,
"Ben Segall" <bsegall@google.com>, "Mel Gorman" <mgorman@suse.de>,
"Daniel Bristot de Oliveira" <bristot@redhat.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Christian Brauner" <christian.brauner@ubuntu.com>,
"Anand K Mistry" <amistry@google.com>,
"Kenta.Tada@sony.com" <Kenta.Tada@sony.com>,
"Alexey Gladkov" <legion@kernel.org>,
"Michael Weiß" <michael.weiss@aisec.fraunhofer.de>,
"Michal Hocko" <mhocko@suse.com>, "Helge Deller" <deller@gmx.de>,
"Tobin C. Harding" <me@tobin.cc>,
"Tycho Andersen" <tycho@tycho.pizza>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Borislav Petkov" <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
"Mark Rutland" <mark.rutland@arm.com>,
"Jens Axboe" <axboe@kernel.dk>,
"Stefan Metzmacher" <metze@samba.org>,
"Lai Jiangshan" <laijs@linux.alibaba.com>,
"Andy Lutomirski" <luto@kernel.org>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
"Ohhoon Kwon" <ohoono.kwon@samsung.com>,
"Kalesh Singh" <kaleshsingh@google.com>,
"YiFei Zhu" <yifeifz2@illinois.edu>,
"Josh Poimboeuf" <jpoimboe@redhat.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-hardening@vger.kernel.org, x86@kernel.org
Subject: [PATCH v2 5/6] x86: Fix get_wchan() to support the ORC unwinder
Date: Wed, 29 Sep 2021 15:02:17 -0700 [thread overview]
Message-ID: <20210929220218.691419-6-keescook@chromium.org> (raw)
In-Reply-To: <20210929220218.691419-1-keescook@chromium.org>
From: Qi Zheng <zhengqi.arch@bytedance.com>
Currently, the kernel CONFIG_UNWINDER_ORC option is enabled by default
on x86, but the implementation of get_wchan() is still based on the frame
pointer unwinder, so the /proc/<pid>/wchan usually returned 0 regardless
of whether the task <pid> is running.
Reimplement get_wchan() by calling stack_trace_save_tsk(), which is
adapted to the ORC and frame pointer unwinders.
Fixes: ee9f8fce9964 ("x86/unwind: Add the ORC unwinder")
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210831083625.59554-1-zhengqi.arch@bytedance.com
---
arch/x86/kernel/process.c | 51 +++------------------------------------
1 file changed, 3 insertions(+), 48 deletions(-)
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 1d9463e3096b..e645925f9f02 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -944,58 +944,13 @@ unsigned long arch_randomize_brk(struct mm_struct *mm)
*/
unsigned long get_wchan(struct task_struct *p)
{
- unsigned long start, bottom, top, sp, fp, ip, ret = 0;
- int count = 0;
+ unsigned long entry = 0;
if (p == current || task_is_running(p))
return 0;
- if (!try_get_task_stack(p))
- return 0;
-
- start = (unsigned long)task_stack_page(p);
- if (!start)
- goto out;
-
- /*
- * Layout of the stack page:
- *
- * ----------- topmax = start + THREAD_SIZE - sizeof(unsigned long)
- * PADDING
- * ----------- top = topmax - TOP_OF_KERNEL_STACK_PADDING
- * stack
- * ----------- bottom = start
- *
- * The tasks stack pointer points at the location where the
- * framepointer is stored. The data on the stack is:
- * ... IP FP ... IP FP
- *
- * We need to read FP and IP, so we need to adjust the upper
- * bound by another unsigned long.
- */
- top = start + THREAD_SIZE - TOP_OF_KERNEL_STACK_PADDING;
- top -= 2 * sizeof(unsigned long);
- bottom = start;
-
- sp = READ_ONCE(p->thread.sp);
- if (sp < bottom || sp > top)
- goto out;
-
- fp = READ_ONCE_NOCHECK(((struct inactive_task_frame *)sp)->bp);
- do {
- if (fp < bottom || fp > top)
- goto out;
- ip = READ_ONCE_NOCHECK(*(unsigned long *)(fp + sizeof(unsigned long)));
- if (!in_sched_functions(ip)) {
- ret = ip;
- goto out;
- }
- fp = READ_ONCE_NOCHECK(*(unsigned long *)fp);
- } while (count++ < 16 && !task_is_running(p));
-
-out:
- put_task_stack(p);
- return ret;
+ stack_trace_save_tsk(p, &entry, 1, 0);
+ return entry;
}
long do_arch_prctl_common(struct task_struct *task, int option,
--
2.30.2
next prev parent reply other threads:[~2021-09-29 22:03 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-29 22:02 [PATCH v2 0/6] wchan: Fix ORC support and leaky fallback Kees Cook
2021-09-29 22:02 ` [PATCH v2 1/6] Revert "proc/wchan: use printk format instead of lookup_symbol_name()" Kees Cook
2021-09-29 22:02 ` [PATCH v2 2/6] sched: Add wrapper for get_wchan() to keep task blocked Kees Cook
2021-09-30 8:27 ` Peter Zijlstra
2021-09-30 8:28 ` Peter Zijlstra
2021-09-30 8:29 ` Peter Zijlstra
2021-09-29 22:02 ` [PATCH v2 3/6] proc: Use task_is_running() for wchan in /proc/$pid/stat Kees Cook
2021-09-29 22:02 ` [PATCH v2 4/6] proc: Only report /proc/$pid/wchan when process is blocked Kees Cook
2021-09-29 22:02 ` Kees Cook [this message]
2021-09-29 22:02 ` [PATCH v2 6/6] leaking_addresses: Always print a trailing newline Kees Cook
2021-09-30 14:37 ` Tycho Andersen
2021-09-30 1:01 ` [PATCH v2 0/6] wchan: Fix ORC support and leaky fallback Josh Poimboeuf
2021-09-30 8:40 ` Peter Zijlstra
2021-09-30 15:18 ` Kees Cook
2021-09-30 18:39 ` Peter Zijlstra
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=20210929220218.691419-6-keescook@chromium.org \
--to=keescook@chromium.org \
--cc=Kenta.Tada@sony.com \
--cc=akpm@linux-foundation.org \
--cc=amistry@google.com \
--cc=axboe@kernel.dk \
--cc=bp@alien8.de \
--cc=bristot@redhat.com \
--cc=bsegall@google.com \
--cc=christian.brauner@ubuntu.com \
--cc=dave.hansen@linux.intel.com \
--cc=deller@gmx.de \
--cc=dietmar.eggemann@arm.com \
--cc=ebiederm@xmission.com \
--cc=hpa@zytor.com \
--cc=jannh@google.com \
--cc=jpoimboe@redhat.com \
--cc=juri.lelli@redhat.com \
--cc=kaleshsingh@google.com \
--cc=laijs@linux.alibaba.com \
--cc=legion@kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-hardening@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mark.rutland@arm.com \
--cc=me@tobin.cc \
--cc=metze@samba.org \
--cc=mgorman@suse.de \
--cc=mhocko@suse.com \
--cc=michael.weiss@aisec.fraunhofer.de \
--cc=mingo@redhat.com \
--cc=ohoono.kwon@samsung.com \
--cc=oliver.sang@intel.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
--cc=tycho@tycho.pizza \
--cc=vcaputo@pengaru.com \
--cc=vincent.guittot@linaro.org \
--cc=x86@kernel.org \
--cc=yifeifz2@illinois.edu \
--cc=zhengqi.arch@bytedance.com \
/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).