From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Chris J Arges <chris.j.arges@canonical.com>
Cc: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org,
jikos@kernel.org, pmladek@suse.com, mbenes@suse.cz,
jeyu@redhat.com
Subject: Re: [PATCH 0/3 v9] livepatch: disambiguate symbols with the same name
Date: Thu, 3 Dec 2015 11:59:53 -0600 [thread overview]
Message-ID: <20151203175953.GE11394@treble.redhat.com> (raw)
In-Reply-To: <1449024076-16034-1-git-send-email-chris.j.arges@canonical.com>
On Tue, Dec 01, 2015 at 08:40:53PM -0600, Chris J Arges wrote:
> Currently, patching objects with duplicate symbol names fail because the
> creation of the sysfs function directory collides with the previous
> attempt. Appending old_addr to the function name is problematic as it
> reveals the address of the function being patch to a normal user. Using
> the symbol's occurrence in kallsyms to postfix the function name in the
> sysfs directory solves the issue of having consistent unique names and
> ensuring that the address is not exposed to a normal user.
>
> In addition, using the symbol position as the user's method to disambiguate
> symbols instead of addr allows for disambiguating symbols in modules as
> well for both function addresses and for relocs. This also simplifies much
> of the code. Special handling for kASLR is no longer needed and can be
> removed. The klp_find_verify_func_addr function can be replaced by
> klp_find_object_symbol, and klp_verify_vmlinux_symbol and its callback can
> be removed completely.
>
> The following set of patches use symbol positioning instead of old
> addresses to disambiguate symbols that have the same name in a given
> object. This is necessary in order to be able to patch symbols with the
> same name within the same object. This requires modifications to the
> klp_func and klp_reloc structures to add an additional element. In addition
> the scheme used for the func directory in sysfs is modified to append the
> symbols occurrence in kallsyms.
>
> In addition, I've tested this patchset against a modified kpatch. I
> modified the kpatch livepatch scaffolding to set lreloc->sympos = 0, and
> lfunc->old_sympos to the nth occurrence of the symbol for that object in
> kallsyms. I was able to patch the same test patch as described here:
> https://github.com/dynup/kpatch/issues/493
> I've also tested this with sample livepatch code to test if the various
> old_sympos values work for unique and duplicate functions.
>
> v9:
> - use mod->name instead of mod->obj->name for klp_find_object_symbol in
> klp_write_object_relocations
> - rebase on current master
> - tested with kpatch
For the series:
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
--
Josh
next prev parent reply other threads:[~2015-12-03 17:59 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-02 17:58 [PATCH] livepatch: old_name.number scheme in livepatch sysfs directory Chris J Arges
2015-11-02 19:15 ` Jessica Yu
2015-11-02 19:52 ` [PATCH] " Josh Poimboeuf
2015-11-02 20:16 ` Chris J Arges
2015-11-02 20:32 ` Josh Poimboeuf
2015-11-02 22:59 ` [PATCH v2] " Chris J Arges
2015-11-03 9:50 ` Miroslav Benes
2015-11-03 15:03 ` Josh Poimboeuf
2015-11-03 10:52 ` Miroslav Benes
2015-11-03 12:44 ` Petr Mladek
2015-11-03 15:03 ` Josh Poimboeuf
2015-11-03 19:57 ` Jiri Kosina
2015-11-03 20:06 ` Josh Poimboeuf
[not found] ` <1447259366-7055-1-git-send-email-chris.j.arges@canonical.com>
2015-11-11 16:28 ` [PATCH 1/3 v4] livepatch: add old_sympos as disambiguator field to klp_func Chris J Arges
2015-11-11 17:43 ` Josh Poimboeuf
2015-11-12 10:22 ` Miroslav Benes
2015-11-11 16:29 ` [PATCH 2/3 v4] livepatch: add old_sympos as disambiguator field to klp_reloc Chris J Arges
2015-11-11 16:39 ` Chris J Arges
2015-11-11 17:57 ` Josh Poimboeuf
2015-11-12 14:31 ` Petr Mladek
2015-11-12 19:19 ` Josh Poimboeuf
2015-11-13 13:54 ` Petr Mladek
2015-11-13 16:59 ` Josh Poimboeuf
2015-11-16 12:11 ` Petr Mladek
2015-11-12 10:23 ` Miroslav Benes
2015-11-11 16:29 ` [PATCH 3/3 v4] livepatch: old_name,number scheme in livepatch sysfs directory Chris J Arges
2015-11-11 18:01 ` Josh Poimboeuf
[not found] ` <1447347595-30728-1-git-send-email-chris.j.arges@canonical.com>
2015-11-12 16:59 ` [PATCH 1/4 v5] livepatch: add old_sympos as disambiguator field to klp_func Chris J Arges
2015-11-12 19:45 ` Josh Poimboeuf
2015-11-13 9:56 ` Jiri Kosina
2015-11-13 10:14 ` Miroslav Benes
2015-11-13 16:27 ` Petr Mladek
2015-11-12 16:59 ` [PATCH 2/4 v5] livepatch: Simplify code for relocated external symbols Chris J Arges
2015-11-13 10:24 ` Miroslav Benes
2015-11-13 13:55 ` Petr Mladek
2015-11-12 16:59 ` [PATCH 3/4 v5] livepatch: add sympos as disambiguator field to klp_reloc Chris J Arges
2015-11-12 19:50 ` Josh Poimboeuf
2015-11-13 16:42 ` Petr Mladek
2015-11-12 16:59 ` [PATCH 4/4 v5] livepatch: function,sympos scheme in livepatch sysfs directory Chris J Arges
[not found] ` <1447431804-18786-1-git-send-email-chris.j.arges@canonical.com>
2015-11-13 16:23 ` [PATCH 1/3 v6] livepatch: add old_sympos as disambiguator field to klp_func Chris J Arges
2015-11-13 16:23 ` [PATCH 2/3 v6] livepatch: add sympos as disambiguator field to klp_reloc Chris J Arges
2015-11-13 16:23 ` [PATCH 3/3 v6] livepatch: function,sympos scheme in livepatch sysfs directory Chris J Arges
[not found] ` <1447693391-10065-1-git-send-email-chris.j.arges@canonical.com>
2015-11-16 17:03 ` [PATCH 1/3 v7] livepatch: add old_sympos as disambiguator field to klp_func Chris J Arges
2015-11-16 21:59 ` Jiri Kosina
2015-11-17 14:29 ` Chris J Arges
2015-11-19 10:02 ` Jiri Kosina
2015-11-16 17:03 ` [PATCH 2/3 v7] livepatch: add sympos as disambiguator field to klp_reloc Chris J Arges
2015-11-18 9:56 ` Miroslav Benes
2015-11-18 14:01 ` Josh Poimboeuf
2015-11-18 16:47 ` Petr Mladek
2015-11-18 16:37 ` Petr Mladek
2015-11-18 16:39 ` Chris J Arges
2015-11-18 16:55 ` Petr Mladek
2015-11-18 20:34 ` Jiri Kosina
2015-11-16 17:03 ` [PATCH 3/3 v7] livepatch: function,sympos scheme in livepatch sysfs directory Chris J Arges
2015-11-20 17:25 ` [PATCH 0/3 v8] livepatch: disambiguate symbols with the same name Chris J Arges
2015-11-20 17:25 ` [PATCH 1/3 v8] livepatch: add old_sympos as disambiguator field to klp_func Chris J Arges
2015-11-23 9:47 ` Miroslav Benes
2015-11-20 17:25 ` [PATCH 2/3 v8] livepatch: add sympos as disambiguator field to klp_reloc Chris J Arges
2015-11-23 9:52 ` Miroslav Benes
2015-11-30 20:46 ` Chris J Arges
2015-12-01 1:17 ` Josh Poimboeuf
2015-11-20 17:25 ` [PATCH 3/3 v8] livepatch: function,sympos scheme in livepatch sysfs directory Chris J Arges
2015-11-23 9:47 ` Miroslav Benes
2015-12-02 2:40 ` [PATCH 0/3 v9] livepatch: disambiguate symbols with the same name Chris J Arges
2015-12-02 2:40 ` [PATCH 1/3 v9] livepatch: add old_sympos as disambiguator field to klp_func Chris J Arges
2015-12-02 2:40 ` [PATCH 2/3 v9] livepatch: add sympos as disambiguator field to klp_reloc Chris J Arges
2015-12-14 12:45 ` Miroslav Benes
2015-12-02 2:40 ` [PATCH 3/3 v9] livepatch: function,sympos scheme in livepatch sysfs directory Chris J Arges
2015-12-02 15:28 ` [PATCH 0/3 v9] livepatch: disambiguate symbols with the same name Petr Mladek
2015-12-03 17:59 ` Josh Poimboeuf [this message]
2015-12-03 22:04 ` Jiri Kosina
2015-11-03 14:58 ` [PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory Josh Poimboeuf
2015-11-03 16:09 ` Miroslav Benes
2015-11-03 16:50 ` Josh Poimboeuf
2015-11-03 20:42 ` Chris J Arges
2015-11-04 9:52 ` Miroslav Benes
2015-11-04 16:03 ` Josh Poimboeuf
2015-11-04 16:17 ` Chris J Arges
2015-11-05 15:18 ` Miroslav Benes
2015-11-05 15:56 ` Josh Poimboeuf
2015-11-05 16:07 ` Chris J Arges
2015-11-09 16:16 ` [PATCH v3] livepatch: old_name,number " Chris J Arges
2015-11-09 20:56 ` Josh Poimboeuf
2015-11-09 23:01 ` Chris J Arges
2015-11-10 4:54 ` Josh Poimboeuf
2015-11-10 8:49 ` Miroslav Benes
2015-11-10 13:40 ` Josh Poimboeuf
2015-11-10 9:02 ` Miroslav Benes
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