From: Rick Edgecombe <rick.p.edgecombe@intel.com>
To: Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@redhat.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>, Nadav Amit <nadav.amit@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
linux_dti@icloud.com, linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org, akpm@linux-foundation.org,
kernel-hardening@lists.openwall.com, linux-mm@kvack.org,
will.deacon@arm.com, ard.biesheuvel@linaro.org,
kristen@linux.intel.com, deneen.t.dock@intel.com,
Nadav Amit <namit@vmware.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Rick Edgecombe <rick.p.edgecombe@intel.com>
Subject: [PATCH v2 20/20] x86/alternative: comment about module removal races
Date: Mon, 28 Jan 2019 16:34:22 -0800 [thread overview]
Message-ID: <20190129003422.9328-21-rick.p.edgecombe@intel.com> (raw)
In-Reply-To: <20190129003422.9328-1-rick.p.edgecombe@intel.com>
From: Nadav Amit <namit@vmware.com>
Add a comment to clarify that users of text_poke() must ensure that
no races with module removal take place.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/x86/kernel/alternative.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 81876e3ef3fd..cc3b6222857a 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -807,6 +807,11 @@ static void *__text_poke(void *addr, const void *opcode, size_t len)
* It means the size must be writable atomically and the address must be aligned
* in a way that permits an atomic write. It also makes sure we fit on a single
* page.
+ *
+ * Note that the caller must ensure that if the modified code is part of a
+ * module, the module would not be removed during poking. This can be achieved
+ * by registering a module notifier, and ordering module removal and patching
+ * trough a mutex.
*/
void *text_poke(void *addr, const void *opcode, size_t len)
{
--
2.17.1
prev parent reply other threads:[~2019-01-29 0:39 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-29 0:34 [PATCH v2 00/20] Merge text_poke fixes and executable lockdowns Rick Edgecombe
2019-01-29 0:34 ` [PATCH v2 01/20] Fix "x86/alternatives: Lockdep-enforce text_mutex in text_poke*()" Rick Edgecombe
2019-01-29 0:34 ` [PATCH v2 02/20] x86/jump_label: Use text_poke_early() during early init Rick Edgecombe
2019-01-29 0:34 ` [PATCH v2 03/20] x86/mm: temporary mm struct Rick Edgecombe
2019-01-31 11:29 ` Borislav Petkov
2019-01-31 22:19 ` Nadav Amit
2019-02-01 0:08 ` Borislav Petkov
2019-02-01 0:25 ` Nadav Amit
2019-02-04 14:28 ` Borislav Petkov
2019-01-29 0:34 ` [PATCH v2 04/20] fork: provide a function for copying init_mm Rick Edgecombe
2019-02-05 8:53 ` Borislav Petkov
2019-02-05 9:03 ` Nadav Amit
2019-01-29 0:34 ` [PATCH v2 05/20] x86/alternative: initializing temporary mm for patching Rick Edgecombe
2019-02-05 9:18 ` Borislav Petkov
2019-02-11 0:39 ` Nadav Amit
2019-02-11 5:18 ` Andy Lutomirski
2019-02-11 18:04 ` Nadav Amit
2019-02-11 19:07 ` Andy Lutomirski
2019-02-11 19:18 ` Nadav Amit
2019-02-11 22:47 ` Andy Lutomirski
2019-02-12 18:23 ` Nadav Amit
2019-01-29 0:34 ` [PATCH v2 06/20] x86/alternative: use temporary mm for text poking Rick Edgecombe
2019-02-05 9:58 ` Borislav Petkov
2019-02-05 11:31 ` Peter Zijlstra
2019-02-05 12:35 ` Borislav Petkov
2019-02-05 13:25 ` Peter Zijlstra
2019-02-05 17:54 ` Nadav Amit
2019-02-05 13:29 ` Peter Zijlstra
2019-01-29 0:34 ` [PATCH v2 07/20] x86/kgdb: avoid redundant comparison of patched code Rick Edgecombe
2019-01-29 0:34 ` [PATCH v2 08/20] x86/ftrace: set trampoline pages as executable Rick Edgecombe
2019-01-29 0:34 ` [PATCH v2 09/20] x86/kprobes: instruction pages initialization enhancements Rick Edgecombe
2019-02-11 18:22 ` Borislav Petkov
2019-02-11 19:36 ` Nadav Amit
2019-01-29 0:34 ` [PATCH v2 10/20] x86: avoid W^X being broken during modules loading Rick Edgecombe
2019-02-11 18:29 ` Borislav Petkov
2019-02-11 18:45 ` Nadav Amit
2019-02-11 19:01 ` Borislav Petkov
2019-02-11 19:09 ` Nadav Amit
2019-02-11 19:10 ` Borislav Petkov
2019-02-11 19:27 ` Nadav Amit
2019-02-11 19:42 ` Borislav Petkov
2019-02-11 20:32 ` Nadav Amit
2019-03-07 15:10 ` [PATCH] x86/cpufeature: Remove __pure attribute to _static_cpu_has() Borislav Petkov
2019-03-07 16:43 ` hpa
2019-03-07 17:02 ` Borislav Petkov
2019-03-29 18:22 ` [tip:x86/asm] " tip-bot for Borislav Petkov
2019-03-07 7:29 ` [PATCH v2 10/20] x86: avoid W^X being broken during modules loading Borislav Petkov
2019-03-07 16:53 ` hpa
2019-03-07 17:06 ` Borislav Petkov
2019-03-07 20:02 ` Andy Lutomirski
2019-03-07 20:25 ` Borislav Petkov
2019-01-29 0:34 ` [PATCH v2 11/20] x86/jump-label: remove support for custom poker Rick Edgecombe
2019-02-11 18:37 ` Borislav Petkov
2019-01-29 0:34 ` [PATCH v2 12/20] x86/alternative: Remove the return value of text_poke_*() Rick Edgecombe
2019-01-29 0:34 ` [PATCH v2 13/20] Add set_alias_ function and x86 implementation Rick Edgecombe
2019-02-11 19:09 ` Borislav Petkov
2019-02-11 19:27 ` Edgecombe, Rick P
2019-02-11 22:59 ` Andy Lutomirski
2019-02-12 0:01 ` Edgecombe, Rick P
2019-01-29 0:34 ` [PATCH v2 14/20] mm: Make hibernate handle unmapped pages Rick Edgecombe
2019-02-19 11:04 ` Borislav Petkov
2019-02-19 21:28 ` Edgecombe, Rick P
2019-02-20 16:07 ` Borislav Petkov
2019-01-29 0:34 ` [PATCH v2 15/20] vmalloc: New flags for safe vfree on special perms Rick Edgecombe
2019-02-19 12:48 ` Borislav Petkov
2019-02-19 19:42 ` Edgecombe, Rick P
2019-02-20 16:14 ` Borislav Petkov
2019-01-29 0:34 ` [PATCH v2 16/20] modules: Use vmalloc special flag Rick Edgecombe
2019-01-29 0:34 ` [PATCH v2 17/20] bpf: " Rick Edgecombe
2019-01-29 0:34 ` [PATCH v2 18/20] x86/ftrace: " Rick Edgecombe
2019-01-29 0:34 ` [PATCH v2 19/20] x86/kprobes: " Rick Edgecombe
2019-01-29 0:34 ` Rick Edgecombe [this message]
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