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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E6B8AC5B567 for ; Wed, 12 Aug 2026 05:41:11 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A2AB26B0096; Wed, 12 Aug 2026 01:41:10 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9DB446B0098; Wed, 12 Aug 2026 01:41:10 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8A2B86B0099; Wed, 12 Aug 2026 01:41:10 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 597AF6B0096 for ; Wed, 12 Aug 2026 01:41:10 -0400 (EDT) Received: from smtpin29.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id CCD081C0E8A for ; Wed, 12 Aug 2026 05:41:09 +0000 (UTC) X-FDA: 85091519058.29.7F2F307 Received: from out-186.mta1.migadu.com (mta1.migadu.com [37.59.57.117]) by imf31.hostedemail.com (Postfix) with ESMTP id 0519720004 for ; Wed, 12 Aug 2026 05:41:07 +0000 (UTC) Authentication-Results: imf31.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=Whpnxh9p; spf=pass (imf31.hostedemail.com: domain of hao.ge@linux.dev designates 37.59.57.117 as permitted sender) smtp.mailfrom=hao.ge@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1786513268; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=TJw8Kb7KYo62APlX8MEZxvAZlhH4o0ziACenqfJhSwk=; b=BgZSurqADTWIVFtI5hrNyPdNXtwyN2W7A0QWkaEwuWVAATwhOZjb2ASb/LSsxe6JlAGk3t Dwwa/26P9FWJkKKDcUCUF+u8Q4/gfmMBI6Un60M8gTqAqMopoaz9vyH5mSi0WDZDsc9RR6 PfBy9u05q/xXAoD7uodVTZyQPoYuPgU= ARC-Authentication-Results: i=1; imf31.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=Whpnxh9p; spf=pass (imf31.hostedemail.com: domain of hao.ge@linux.dev designates 37.59.57.117 as permitted sender) smtp.mailfrom=hao.ge@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1786513268; b=M0xtbBKo61Ma94x3dP8jwDNUb5yFkMUOkB/3U2wTCvQj40ec2bZD93X4/6VWYMaSNAkOAW lblwzihRMfieW923/hWcNOxrzRAfQLdvU5rldTre4tJvnzhUDtx0qRrwVCzW1tTGJAGSIY /g+5AxhM9zdwDjgYBpygImfYZQykD0w= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1786513266; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TJw8Kb7KYo62APlX8MEZxvAZlhH4o0ziACenqfJhSwk=; b=Whpnxh9pXp2+bTxNYX9GyGV2YNWyFmEhiFLBxTHM1emfN+vJjElCcTotxQwVy3X1umLo6t yiTOJm0OqPnobb7aV185QEy//Yh3hnbhvUFaABU9uMRD6FwBkggx2YIhowltCfc/AyM1lq HTTnFTnQdY/3c7KPSiV2czkyKaweldU= From: Hao Ge To: Suren Baghdasaryan , Andrew Morton , Luis Chamberlain , Petr Pavlu , Daniel Gomez , Sami Tolvanen , Aaron Tomlin Cc: linux-modules@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Hao Ge , stable@vger.kernel.org Subject: [PATCH v5 2/2] alloc_tag: fix undetected compressed tag overflow when profiling is disabled Date: Wed, 12 Aug 2026 13:41:05 +0800 Message-Id: <20260812054105.102637-3-hao.ge@linux.dev> In-Reply-To: <20260812054105.102637-1-hao.ge@linux.dev> References: <20260812054105.102637-1-hao.ge@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 0519720004 X-Stat-Signature: yaqfwo5ji6m9zhxuz9m1hyju5hwa6e9o X-Rspam-User: X-HE-Tag: 1786513267-264500 X-HE-Meta: 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 oka9IJfT 5BjWP+Vzf5CHTVhHWx3Vw9pn7rWoPiUz1fPOtE+xWUG/2zlxpo59zarjzRTIZDierdPYPoDKQsAGtB2dLceJIsxyvKneor5vVB91F+9yHIJcK+wAqcy8XolD5cv76aDTRdnUhRyBHAYRu6JHF0oK/rv0ZibVBGwNTxHehv4QiqAhqctHnqtXfqvdrVAv+pe6KK39J5LK3O8zHVngaksb/ue2tahHBnB6NdDE+X9kwZ0pkgCzuCoeS4IAYkdckLahfx9/F Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: In reserve_module_tags(), the tag overflow check is gated on mem_alloc_profiling_enabled(): if (mem_alloc_profiling_enabled() && !tags_addressable()) If profiling is toggled off at runtime and a module is loaded whose tags exceed the compressed-mode limit, shutdown_mem_profiling() is skipped. vm_module_tags_populate() still maps memory for the tags and the module loads successfully, but the total tag count now exceeds what NR_UNUSED_PAGEFLAG_BITS can address. Once profiling is re-enabled, ref_to_idx() computes each tag's index as its position in the alloc_tag array. update_page_tag_ref() masks it to alloc_tag_ref_mask before storing in page->flags. Indices beyond the mask are truncated and idx_to_ref() resolves them to wrong tags. This silently corrupts /proc/allocinfo: allocated pages get attributed to the wrong call sites, so the statistics it reports are wrong. mem_alloc_profiling_enabled() and mem_profiling_compressed are independent. Once compressed mode is established at boot, it stays active regardless of runtime toggles of mem_profiling. Remove the mem_alloc_profiling_enabled() guard. On overflow, shut down profiling, release the reservation, and return -EAGAIN so that layout_and_allocate() retries with profiling disabled: codetag sections are then placed as regular module data and the module loads without profiling rather than being rejected entirely. Fixes: 4835f747d3ed ("alloc_tag: support for page allocation tag compression") Cc: stable@vger.kernel.org Suggested-by: Suren Baghdasaryan Signed-off-by: Hao Ge --- kernel/module/main.c | 25 +++++++++++++++++++++++-- mm/alloc_tag.c | 8 +++++--- 2 files changed, 28 insertions(+), 5 deletions(-) diff --git a/kernel/module/main.c b/kernel/module/main.c index 46dd8d25a605..ed26f167be84 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -2944,6 +2944,7 @@ static struct module *layout_and_allocate(struct load_info *info, int flags) { struct module *mod; int err; + unsigned long frob_size[MOD_MEM_NUM_TYPES]; /* Allow arches to frob section contents and sizes. */ err = module_frob_arch_sections(info->hdr, info->sechdrs, @@ -2966,18 +2967,38 @@ static struct module *layout_and_allocate(struct load_info *info, int flags) */ module_mark_ro_after_init(info->hdr, info->sechdrs, info->secstrings); + /* + * Save the sizes reserved by module_frob_arch_sections() so they can + * be restored if we retry below. + */ + for_each_mod_mem_type(type) + frob_size[type] = info->mod->mem[type].size; + /* * Determine total sizes, and put offsets in sh_entsize. For now * this is done generically; there doesn't appear to be any * special cases for the architectures. */ +retry: layout_sections(info->mod, info); layout_symtab(info->mod, info); /* Allocate and move to the final place */ err = move_module(info->mod, info); - if (err) - return ERR_PTR(err); + if (err) { + if (err != -EAGAIN) + return ERR_PTR(err); + /* + * -EAGAIN means profiling was disabled but the module + * can still load without it. Reset state and retry. + */ + rewrite_section_headers(info, flags); + for_each_mod_mem_type(type) + info->mod->mem[type].size = frob_size[type]; + info->sechdrs[info->index.sym].sh_flags &= ~(unsigned long)SHF_ALLOC; + info->sechdrs[info->index.str].sh_flags &= ~(unsigned long)SHF_ALLOC; + goto retry; + } /* Module has been copied to its final place now: return it. */ mod = (void *)info->sechdrs[info->index.mod].sh_addr; diff --git a/mm/alloc_tag.c b/mm/alloc_tag.c index af44f90379f2..0a7b657fe2de 100644 --- a/mm/alloc_tag.c +++ b/mm/alloc_tag.c @@ -950,10 +950,12 @@ static void *reserve_module_tags(struct module *mod, unsigned long size, int grow_res; module_tags.size = offset + size; - if (mem_alloc_profiling_enabled() && !tags_addressable()) { + if (!tags_addressable()) { shutdown_mem_profiling(true); - pr_warn("With module %s there are too many tags to fit in %d page flag bits. Memory allocation profiling is disabled!\n", - mod->name, NR_UNUSED_PAGEFLAG_BITS); + pr_warn_once("With module %s there are too many tags to fit in %d page flag bits. Memory allocation profiling is disabled!\n", + mod->name, NR_UNUSED_PAGEFLAG_BITS); + release_module_tags(mod, false); + return ERR_PTR(-EAGAIN); } grow_res = vm_module_tags_populate(); -- 2.25.1