From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67D7DC433ED for ; Sat, 8 May 2021 22:39:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4960261415 for ; Sat, 8 May 2021 22:39:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229609AbhEHWkU (ORCPT ); Sat, 8 May 2021 18:40:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:43284 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229620AbhEHWkR (ORCPT ); Sat, 8 May 2021 18:40:17 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 88C4061402; Sat, 8 May 2021 22:39:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1620513555; bh=ywjewyhGcwzH9+ixPmAs+T1RNj92Qm+n+z738tkvswg=; h=Date:From:To:Subject:From; b=umnXnCGkzU23tm7sDvr2klmufSddLbe1xBb2rsDJfivUwtxKIxNBUREReDQSz7pkc ULsO4iw5uQSw2K8q3k6acjB24KxHjYwv+TnxOOJD96K0eqm5d2M20GLC+027jAT6z+ CHo/z9ApE6gA44l9DUQRmF/lJ/qdvmQCS+BsLfpA= Date: Sat, 08 May 2021 15:39:15 -0700 From: akpm@linux-foundation.org To: mm-commits@vger.kernel.org, slyfox@gentoo.org Subject: [merged] ia64-module-fix-symbolizer-crash-on-fdescr.patch removed from -mm tree Message-ID: <20210508223915.M6SP88xou%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: ia64: module: fix symbolizer crash on fdescr has been removed from the -mm tree. Its filename was ia64-module-fix-symbolizer-crash-on-fdescr.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Sergei Trofimovich Subject: ia64: module: fix symbolizer crash on fdescr Noticed failure as a crash on ia64 when tried to symbolize all backtraces collected by page_owner=on: $ cat /sys/kernel/debug/page_owner CPU: 1 PID: 2074 Comm: cat Not tainted 5.12.0-rc4 #226 Hardware name: hp server rx3600, BIOS 04.03 04/08/2008 ip is at dereference_module_function_descriptor+0x41/0x100 Crash happens at dereference_module_function_descriptor() due to use-after-free when dereferencing ".opd" section header. All section headers are already freed after module is laoded successfully. To keep symbolizer working the change stores ".opd" address and size after module is relocated to a new place and before section headers are discarded. To make similar errors less obscure module_finalize() now zeroes out all variables relevant to module loading only. Link: https://lkml.kernel.org/r/20210403074803.3309096-1-slyfox@gentoo.org Signed-off-by: Sergei Trofimovich Signed-off-by: Andrew Morton --- arch/ia64/include/asm/module.h | 6 +++++- arch/ia64/kernel/module.c | 29 +++++++++++++++++++++++++---- 2 files changed, 30 insertions(+), 5 deletions(-) --- a/arch/ia64/include/asm/module.h~ia64-module-fix-symbolizer-crash-on-fdescr +++ a/arch/ia64/include/asm/module.h @@ -14,16 +14,20 @@ struct elf64_shdr; /* forward declration */ struct mod_arch_specific { + /* Used only at module load time. */ struct elf64_shdr *core_plt; /* core PLT section */ struct elf64_shdr *init_plt; /* init PLT section */ struct elf64_shdr *got; /* global offset table */ struct elf64_shdr *opd; /* official procedure descriptors */ struct elf64_shdr *unwind; /* unwind-table section */ unsigned long gp; /* global-pointer for module */ + unsigned int next_got_entry; /* index of next available got entry */ + /* Used at module run and cleanup time. */ void *core_unw_table; /* core unwind-table cookie returned by unwinder */ void *init_unw_table; /* init unwind-table cookie returned by unwinder */ - unsigned int next_got_entry; /* index of next available got entry */ + void *opd_addr; /* symbolize uses .opd to get to actual function */ + unsigned long opd_size; }; #define ARCH_SHF_SMALL SHF_IA_64_SHORT --- a/arch/ia64/kernel/module.c~ia64-module-fix-symbolizer-crash-on-fdescr +++ a/arch/ia64/kernel/module.c @@ -905,9 +905,31 @@ register_unwind_table (struct module *mo int module_finalize (const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, struct module *mod) { + struct mod_arch_specific *mas = &mod->arch; + DEBUGP("%s: init: entry=%p\n", __func__, mod->init); - if (mod->arch.unwind) + if (mas->unwind) register_unwind_table(mod); + + /* + * ".opd" was already relocated to the final destination. Store + * it's address for use in symbolizer. + */ + mas->opd_addr = (void *)mas->opd->sh_addr; + mas->opd_size = mas->opd->sh_size; + + /* + * Module relocation was already done at this point. Section + * headers are about to be deleted. Wipe out load-time context. + */ + mas->core_plt = NULL; + mas->init_plt = NULL; + mas->got = NULL; + mas->opd = NULL; + mas->unwind = NULL; + mas->gp = 0; + mas->next_got_entry = 0; + return 0; } @@ -926,10 +948,9 @@ module_arch_cleanup (struct module *mod) void *dereference_module_function_descriptor(struct module *mod, void *ptr) { - Elf64_Shdr *opd = mod->arch.opd; + struct mod_arch_specific *mas = &mod->arch; - if (ptr < (void *)opd->sh_addr || - ptr >= (void *)(opd->sh_addr + opd->sh_size)) + if (ptr < mas->opd_addr || ptr >= mas->opd_addr + mas->opd_size) return ptr; return dereference_function_descriptor(ptr); _ Patches currently in -mm which might be from slyfox@gentoo.org are