From nobody Sun Jun 28 00:14:40 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DDEA1C433F5 for ; Thu, 17 Feb 2022 08:50:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238180AbiBQIui (ORCPT ); Thu, 17 Feb 2022 03:50:38 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:49660 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238114AbiBQIub (ORCPT ); Thu, 17 Feb 2022 03:50:31 -0500 Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2E49F2A229A; Thu, 17 Feb 2022 00:50:17 -0800 (PST) Received: from localhost (mailhub3.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4JzpS71R4gz9sSn; Thu, 17 Feb 2022 09:50:15 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Zp3kcSnZ9IwF; Thu, 17 Feb 2022 09:50:15 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4JzpS424nDz9sSZ; Thu, 17 Feb 2022 09:50:12 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 366678B77A; Thu, 17 Feb 2022 09:50:12 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id ntk_fVf6iUkT; Thu, 17 Feb 2022 09:50:12 +0100 (CET) Received: from PO20335.IDSI0.si.c-s.fr (unknown [192.168.6.225]) by messagerie.si.c-s.fr (Postfix) with ESMTP id E760B8B763; Thu, 17 Feb 2022 09:50:11 +0100 (CET) Received: from PO20335.IDSI0.si.c-s.fr (localhost [127.0.0.1]) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.16.1) with ESMTPS id 21H8o20x345518 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Thu, 17 Feb 2022 09:50:02 +0100 Received: (from chleroy@localhost) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.17.1/Submit) id 21H8o0Ew345517; Thu, 17 Feb 2022 09:50:00 +0100 X-Authentication-Warning: PO20335.IDSI0.si.c-s.fr: chleroy set sender to christophe.leroy@csgroup.eu using -f From: Christophe Leroy To: Petr Mladek , Steven Rostedt , Sergey Senozhatsky , Andy Shevchenko , Rasmus Villemoes , Jonathan Corbet Cc: Christophe Leroy , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org Subject: [PATCH v2] vsprintf: Fix %pK with kptr_restrict == 0 Date: Thu, 17 Feb 2022 09:49:59 +0100 Message-Id: <107476128e59bff11a309b5bf7579a1753a41aca.1645087605.git.christophe.leroy@csgroup.eu> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1645087798; l=4466; s=20211009; h=from:subject:message-id; bh=dLHQV1fFbxDzziI+jHDqlL7hJXcffZqPNoUQg+RXCaE=; b=RdE0988bpb7eoHvBctHTt7Ru8x9D9fQ3HjQYdmRhvuWi7m6yJjHUuh7V0DqMYUifRQrvveemrNJh 9gp6rlrPCUuFHTCKqA8XbR4Wzl/HmLOlT4BC8GcOS9d+L5eSZREJ X-Developer-Key: i=christophe.leroy@csgroup.eu; a=ed25519; pk=HIzTzUj91asvincQGOFx6+ZF5AoUuP9GdOtQChs7Mm0= Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Although kptr_restrict is set to 0 and the kernel is booted with no_hash_pointers parameter, the content of /proc/vmallocinfo is lacking the real addresses. / # cat /proc/vmallocinfo 0x(ptrval)-0x(ptrval) 8192 load_module+0xc0c/0x2c0c pages=3D1 vmalloc 0x(ptrval)-0x(ptrval) 12288 start_kernel+0x4e0/0x690 pages=3D2 vmalloc 0x(ptrval)-0x(ptrval) 12288 start_kernel+0x4e0/0x690 pages=3D2 vmalloc 0x(ptrval)-0x(ptrval) 8192 _mpic_map_mmio.constprop.0+0x20/0x44 phys= =3D0x80041000 ioremap 0x(ptrval)-0x(ptrval) 12288 _mpic_map_mmio.constprop.0+0x20/0x44 phys= =3D0x80041000 ioremap ... According to the documentation for /proc/sys/kernel/, %pK is equivalent to %p when kptr_restrict is set to 0. Fixes: 5ead723a20e0 ("lib/vsprintf: no_hash_pointers prints all addresses a= s unhashed") Signed-off-by: Christophe Leroy Reviewed-by: Petr Mladek --- v2: Refactor %p default handling into default_pointer() --- .../admin-guide/kernel-parameters.txt | 3 +- lib/vsprintf.c | 36 +++++++++++-------- 2 files changed, 22 insertions(+), 17 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentatio= n/admin-guide/kernel-parameters.txt index f5a27f067db9..c3133f97aa42 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3485,8 +3485,7 @@ difficult since unequal pointers can no longer be compared. However, if this command-line option is specified, then all normal pointers will have their true - value printed. Pointers printed via %pK may still be - hashed. This option should only be specified when + value printed. This option should only be specified when debugging the kernel. Please do not use on production kernels. =20 diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 3b8129dd374c..7003c9ff787b 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -53,6 +53,10 @@ #include #include "kstrtox.h" =20 +/* Disable pointer hashing if requested */ +bool no_hash_pointers __ro_after_init; +EXPORT_SYMBOL_GPL(no_hash_pointers); + static noinline unsigned long long simple_strntoull(const char *startp, si= ze_t max_chars, char **endp, unsigned int base) { const char *cp; @@ -848,6 +852,19 @@ static char *ptr_to_id(char *buf, char *end, const voi= d *ptr, return pointer_string(buf, end, (const void *)hashval, spec); } =20 +static char *default_pointer(char *buf, char *end, const void *ptr, + struct printf_spec spec) +{ + /* + * default is to _not_ leak addresses, so hash before printing, + * unless no_hash_pointers is specified on the command line. + */ + if (unlikely(no_hash_pointers)) + return pointer_string(buf, end, ptr, spec); + + return ptr_to_id(buf, end, ptr, spec); +} + int kptr_restrict __read_mostly; =20 static noinline_for_stack @@ -857,7 +874,7 @@ char *restricted_pointer(char *buf, char *end, const vo= id *ptr, switch (kptr_restrict) { case 0: /* Handle as %p, hash and do _not_ leak addresses. */ - return ptr_to_id(buf, end, ptr, spec); + return default_pointer(buf, end, ptr, spec); case 1: { const struct cred *cred; =20 @@ -2223,10 +2240,6 @@ char *fwnode_string(char *buf, char *end, struct fwn= ode_handle *fwnode, return widen_string(buf, buf - buf_start, end, spec); } =20 -/* Disable pointer hashing if requested */ -bool no_hash_pointers __ro_after_init; -EXPORT_SYMBOL_GPL(no_hash_pointers); - int __init no_hash_pointers_enable(char *str) { if (no_hash_pointers) @@ -2455,7 +2468,7 @@ char *pointer(const char *fmt, char *buf, char *end, = void *ptr, case 'e': /* %pe with a non-ERR_PTR gets treated as plain %p */ if (!IS_ERR(ptr)) - break; + return default_pointer(buf, end, ptr, spec); return err_ptr(buf, end, ptr, spec); case 'u': case 'k': @@ -2465,16 +2478,9 @@ char *pointer(const char *fmt, char *buf, char *end,= void *ptr, default: return error_string(buf, end, "(einval)", spec); } + default: + return default_pointer(buf, end, ptr, spec); } - - /* - * default is to _not_ leak addresses, so hash before printing, - * unless no_hash_pointers is specified on the command line. - */ - if (unlikely(no_hash_pointers)) - return pointer_string(buf, end, ptr, spec); - else - return ptr_to_id(buf, end, ptr, spec); } =20 /* --=20 2.34.1