From: Borislav Petkov <bp@suse.de>
To: Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>
Cc: qiaowei.ren@intel.com, luto@kernel.org,
adam.buchbinder@gmail.com, mst@redhat.com, mhiramat@kernel.org,
dave.hansen@linux.intel.com, mingo@kernel.org,
linux-kernel@vger.kernel.org, colin.king@canonical.com,
jslaby@suse.cz, pbonzini@redhat.com, cmetcalf@mellanox.com,
akpm@linux-foundation.org, vbabka@suse.cz, acme@redhat.com,
brgerst@gmail.com, shuah@kernel.org,
paul.gortmaker@windriver.com, lstoakes@gmail.com, hpa@zytor.com,
thgarnie@google.com, keescook@chromium.org,
adrian.hunter@intel.com, ricardo.neri-calderon@linux.intel.com,
ray.huang@amd.com, dvyukov@google.com, ravi.v.shankar@intel.com,
slaoub@gmail.com, tglx@linutronix.de, corbet@lwn.net,
linux-tip-commits@vger.kernel.org
Subject: Re: [tip:x86/mpx] x86/insn-eval: Add utility function to get segment descriptor
Date: Tue, 5 Dec 2017 19:14:56 +0100 [thread overview]
Message-ID: <20171205181456.akycirziiuhb7crw@pd.tnic> (raw)
In-Reply-To: <20171205174844.GM3165@worktop.lehotels.local>
On Tue, Dec 05, 2017 at 06:48:44PM +0100, Peter Zijlstra wrote:
> This is broken right? You unlock and then return @desc, which afaict can
> at that point get freed by free_ldt_struct().
>
> Something like the below ought to cure; although its not entirely
> pretty either.
Right.
Or, instead of introducing all the locking, we could also not do
anything because all that code runs inside fixup_umip_exception() so the
desc will be valid there.
But, if other code is going to use those functions - and I believe
that's the idea - otherwise they wouldn't be in arch/x86/lib/ - we
should convert all those functions to return directly the desc field
which is requested by the respective caller.
I.e., get_desc() will be called by a wrapper which returns desc base or
desc limit or whatever...
In the case where desc has been freed, it should return error, of
course.
How doed that sound?
--
Regards/Gruss,
Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--
next prev parent reply other threads:[~2017-12-05 18:15 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-27 20:25 [PATCH v10 00/18] x86: Add address resolution code for UMIP and MPX Ricardo Neri
2017-10-27 20:25 ` [PATCH v10 01/18] x86/mm: Relocate page fault error codes to traps.h Ricardo Neri
2017-11-01 20:55 ` [tip:x86/mpx] " tip-bot for Ricardo Neri
2017-10-27 20:25 ` [PATCH v10 02/18] x86/boot: Relocate definition of the initial state of CR0 Ricardo Neri
2017-10-27 20:25 ` Ricardo Neri
2017-10-27 20:25 ` Ricardo Neri
2017-11-01 20:55 ` [tip:x86/mpx] " tip-bot for Ricardo Neri
2017-10-27 20:25 ` [PATCH v10 03/18] ptrace,x86: Make user_64bit_mode() available to 32-bit builds Ricardo Neri
2017-11-01 20:55 ` [tip:x86/mpx] " tip-bot for Ricardo Neri
2017-10-27 20:25 ` [PATCH v10 04/18] uprobes/x86: Use existing definitions for segment override prefixes Ricardo Neri
2017-11-01 20:56 ` [tip:x86/mpx] " tip-bot for Ricardo Neri
2017-10-27 20:25 ` [PATCH v10 05/18] x86/mpx: Simplify handling of errors when computing linear addresses Ricardo Neri
2017-11-01 20:56 ` [tip:x86/mpx] " tip-bot for Ricardo Neri
2017-10-27 20:25 ` [PATCH v10 06/18] x86/mpx: Use signed variables to compute effective addresses Ricardo Neri
2017-11-01 20:57 ` [tip:x86/mpx] " tip-bot for Ricardo Neri
2017-10-27 20:25 ` [PATCH v10 07/18] x86/mpx: Do not use SIB.index if its value is 100b and ModRM.mod is not 11b Ricardo Neri
2017-11-01 20:57 ` [tip:x86/mpx] " tip-bot for Ricardo Neri
2017-10-27 20:25 ` [PATCH v10 08/18] x86/mpx: Do not use SIB.base if its value is 101b and ModRM.mod = 0 Ricardo Neri
2017-11-01 20:57 ` [tip:x86/mpx] " tip-bot for Ricardo Neri
2017-10-27 20:25 ` [PATCH v10 09/18] x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Ricardo Neri
2017-11-01 20:58 ` [tip:x86/mpx] " tip-bot for Ricardo Neri
2017-10-27 20:25 ` [PATCH v10 10/18] x86/insn-eval: Do not BUG on invalid register type Ricardo Neri
2017-11-01 20:58 ` [tip:x86/mpx] " tip-bot for Ricardo Neri
2017-10-27 20:25 ` [PATCH v10 11/18] x86/insn-eval: Add a utility function to get register offsets Ricardo Neri
2017-11-01 20:59 ` [tip:x86/mpx] " tip-bot for Ricardo Neri
2017-10-27 20:25 ` [PATCH v10 12/18] x86/insn-eval: Add utility function to identify string instructions Ricardo Neri
2017-11-01 20:59 ` [tip:x86/mpx] " tip-bot for Ricardo Neri
2017-10-27 20:25 ` [PATCH v10 13/18] x86/insn-eval: Add utility functions to get segment selector Ricardo Neri
2017-11-01 21:00 ` [tip:x86/mpx] " tip-bot for Ricardo Neri
2017-11-09 11:12 ` [PATCH v10 13/18] " Arnd Bergmann
2017-11-09 13:50 ` Ingo Molnar
2017-10-27 20:25 ` [PATCH v10 14/18] x86/insn-eval: Add utility function to get segment descriptor Ricardo Neri
2017-11-01 21:00 ` [tip:x86/mpx] " tip-bot for Ricardo Neri
2017-12-05 17:48 ` Peter Zijlstra
2017-12-05 18:14 ` Borislav Petkov [this message]
2017-12-05 18:38 ` Peter Zijlstra
2017-12-05 21:29 ` Borislav Petkov
2017-12-07 7:23 ` Ricardo Neri
2017-12-07 8:03 ` Borislav Petkov
2017-12-07 7:26 ` Ricardo Neri
2017-12-07 8:01 ` Borislav Petkov
2017-10-27 20:25 ` [PATCH v10 15/18] x86/insn-eval: Add utility functions to get segment descriptor base address and limit Ricardo Neri
2017-11-01 21:00 ` [tip:x86/mpx] " tip-bot for Ricardo Neri
2017-10-27 20:25 ` [PATCH v10 16/18] x86/insn-eval: Add function to get default params of code segment Ricardo Neri
2017-11-01 21:01 ` [tip:x86/mpx] " tip-bot for Ricardo Neri
2017-10-27 20:25 ` [PATCH v10 17/18] x86/insn-eval: Indicate a 32-bit displacement if ModRM.mod is 0 and ModRM.rm is 101b Ricardo Neri
2017-11-01 21:01 ` [tip:x86/mpx] " tip-bot for Ricardo Neri
2017-10-27 20:25 ` [PATCH v10 18/18] x86/insn-eval: Incorporate segment base in linear address computation Ricardo Neri
2017-11-01 17:56 ` Borislav Petkov
2017-11-01 19:08 ` Ricardo Neri
2017-11-01 21:02 ` [tip:x86/mpx] " tip-bot for Ricardo Neri
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