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 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 index 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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