From: Peter Zijlstra <peterz@infradead.org>
To: Vegard Nossum <vegard.nossum@oracle.com>
Cc: tglx@linutronix.de, bp@alien8.de, mingo@kernel.org,
rostedt@goodmis.org, luto@kernel.org,
torvalds@linux-foundation.org, hpa@zytor.com,
dave.hansen@linux.intel.com, jgross@suse.com,
linux-kernel@vger.kernel.org, zhe.he@windriver.com,
joel@joelfernandes.org, devel@etsukata.com
Subject: [PATCH] stacktrace: Force USER_DS for stack_trace_save_user()
Date: Thu, 18 Jul 2019 10:57:54 +0200 [thread overview]
Message-ID: <20190718085754.GM3402@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <b0a3406c-5de7-20e0-0f09-dbb7222426e2@oracle.com>
On Wed, Jul 17, 2019 at 10:09:45AM +0200, Vegard Nossum wrote:
> On 7/17/19 10:07 AM, Peter Zijlstra wrote:
> > Does something like the below help?
> Yes.
Thanks!
---
Subject: stacktrace: Force USER_DS for stack_trace_save_user()
From: Peter Zijlstra <peterz@infradead.org>
Date: Thu Jul 18 10:47:47 CEST 2019
When walking userspace stacks, we should set USER_DS, otherwise
access_ok() will not function as expected.
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Tested-by: Vegard Nossum <vegard.nossum@oracle.com>
Reported-by: Eiichi Tsukata <devel@etsukata.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -226,12 +226,17 @@ unsigned int stack_trace_save_user(unsig
.store = store,
.size = size,
};
+ mm_segment_t fs;
/* Trace user stack if not a kernel thread */
if (current->flags & PF_KTHREAD)
return 0;
+ fs = get_fs();
+ set_fs(USER_DS);
arch_stack_walk_user(consume_entry, &c, task_pt_regs(current));
+ set_fs(fs);
+
return c.len;
}
#endif
next prev parent reply other threads:[~2019-07-18 8:58 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-11 11:40 [PATCH v3 0/6] Tracing vs CR2 Peter Zijlstra
2019-07-11 11:40 ` [PATCH v3 1/6] x86/paravirt: Make read_cr2() CALLEE_SAVE Peter Zijlstra
2019-07-17 21:22 ` [tip:x86/urgent] " tip-bot for Peter Zijlstra
2019-07-11 11:40 ` [PATCH v3 2/6] x86/entry/32: Simplify common_exception Peter Zijlstra
2019-07-17 21:23 ` [tip:x86/urgent] " tip-bot for Peter Zijlstra
2019-07-11 11:40 ` [PATCH v3 3/6] x86/entry/64: Simplify idtentry a little Peter Zijlstra
2019-07-17 21:24 ` [tip:x86/urgent] " tip-bot for Peter Zijlstra
2019-07-11 11:40 ` [PATCH v3 4/6] x86/entry/64: Update comments and sanity tests for create_gap Peter Zijlstra
2019-07-17 21:25 ` [tip:x86/urgent] " tip-bot for Peter Zijlstra
2019-07-11 11:40 ` [PATCH v3 5/6] x86/mm, tracing: Fix CR2 corruption Peter Zijlstra
2019-07-17 21:25 ` [tip:x86/urgent] " tip-bot for Peter Zijlstra
2019-07-11 11:41 ` [PATCH v3 6/6] x86/entry/64: Remove TRACE_IRQS_*_DEBUG Peter Zijlstra
2019-07-11 14:45 ` Andy Lutomirski
2019-07-11 18:28 ` Peter Zijlstra
2019-07-16 19:33 ` [PATCH v3 0/6] Tracing vs CR2 Vegard Nossum
2019-07-16 21:51 ` Vegard Nossum
2019-07-17 1:02 ` Andy Lutomirski
2019-07-17 7:46 ` Vegard Nossum
2019-07-17 7:47 ` Peter Zijlstra
2019-07-17 9:37 ` Eiichi Tsukata
2019-07-18 20:27 ` Andy Lutomirski
2019-07-20 3:59 ` Eiichi Tsukata
2019-07-20 12:49 ` Andy Lutomirski
2019-07-20 14:23 ` Eiichi Tsukata
2019-07-17 8:07 ` Peter Zijlstra
2019-07-17 8:09 ` Vegard Nossum
2019-07-18 8:57 ` Peter Zijlstra [this message]
2019-07-18 13:21 ` [PATCH] stacktrace: Force USER_DS for stack_trace_save_user() Joel Fernandes
2019-07-18 14:52 ` [tip:core/urgent] " tip-bot for Peter Zijlstra
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