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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 92052C7115B for ; Thu, 19 Jun 2025 18:32:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B95296B009D; Thu, 19 Jun 2025 14:32:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B45BC6B009F; Thu, 19 Jun 2025 14:32:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A83076B00A0; Thu, 19 Jun 2025 14:32:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 96A8F6B009D for ; Thu, 19 Jun 2025 14:32:51 -0400 (EDT) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 3B22E1608DD for ; Thu, 19 Jun 2025 18:32:51 +0000 (UTC) X-FDA: 83572996542.04.EECBF27 Received: from out-182.mta0.migadu.com (out-182.mta0.migadu.com [91.218.175.182]) by imf07.hostedemail.com (Postfix) with ESMTP id 80FDA40009 for ; Thu, 19 Jun 2025 18:32:49 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=avh9Op8b; spf=pass (imf07.hostedemail.com: domain of hao.ge@linux.dev designates 91.218.175.182 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=1750357969; 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:references:dkim-signature; bh=rk1XrNVw6kdosuxgoceVk/dfJwPjANKclVJ6ABpWvlQ=; b=tsou63OFyv/IlOrEXOvKyhfyk2SGyL06/aVFIhYTc4kLx+r07t4t3uwlLIEeOuFQg6DmmE VTjx5SW8PTdojcU5HMeD1tmnOSBC8AzPEyMHoGhJqgyb8Zqh4smaH4xbKD7ih85ONutud2 exgO4EVWLJX+b+0xU6ZIMfsdFwCOT4c= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=avh9Op8b; spf=pass (imf07.hostedemail.com: domain of hao.ge@linux.dev designates 91.218.175.182 as permitted sender) smtp.mailfrom=hao.ge@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1750357969; a=rsa-sha256; cv=none; b=musRstlC2bMBfT9oValBtjRIuR7q3ETT7d53kP3tFZQmcQxwQ20C8LYKHAXaN2mZL5CzhN Mfm5/xR6iV8KBcAnEpuf4CL20yVJARR0ibGkMwPyID2AI9UBJbw16tAptui4BpauasXbC0 sYeX2ByCGBky1uhGy8q6+OVrB21GGkM= 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=1750357967; 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; bh=rk1XrNVw6kdosuxgoceVk/dfJwPjANKclVJ6ABpWvlQ=; b=avh9Op8bICMJcNtHFIZwcOnF785QKsjRPMk8Q+1lsy5MlLYulrMbQbpJKjzG7/9DtEmSpT D6XgLm54Q8rwZLmNbWxPXJpctlEDsSvaxLZ8HgrUcm6a2lzkUPu4QD1yhnCLAFAnNCtfWq Vkak6YJWUiCZ/bUkZLg/4Hihog9VLw8= From: Hao Ge To: Catalin Marinas , Suren Baghdasaryan , Kent Overstreet , Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Hao Ge , Hao Ge Subject: [PATCH] mm/alloc_tag: Fix the kmemleak false positive issue in the allocation of the percpu variable tag->counters Date: Fri, 20 Jun 2025 02:31:54 +0800 Message-Id: <20250619183154.2122608-1-hao.ge@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Queue-Id: 80FDA40009 X-Rspamd-Server: rspam01 X-Stat-Signature: ao6fnq8z9o8zgxgw6yrizhnse6tejb59 X-HE-Tag: 1750357969-416173 X-HE-Meta: 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 LHkfE349 3Oj48JhKb/5Jg4UFd4VxuSvYkMUhVN3hIXUKk4gOxcwQgCRAtfQKhZuID7siAdxvEvuZeA3JIvVlJzM5AM0xbyft5SHnbe0+4Ot+EH/PzPIMG3cEVV4pn3hjzHo2jH0xD5LhkNvwYecd9yJDnisIxG3bpqQUeEmOi6KBRgqiTzdyswKEqPvnokTIKBdGlirX/lCLIY+g2JKPkis1VmySdRUf/NFgby+3JarO1xljO/jVyrtLFZ83wWTkl1lzso12/QxxKs4noOaz39HwYhDOoib+7g1dnVAsr83rG X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Hao Ge When loading a module, as long as the module has memory allocation operations, kmemleak produces a false positive report that resembles the following: unreferenced object (percpu) 0x7dfd232a1650 (size 16): comm "modprobe", pid 1301, jiffies 4294940249 hex dump (first 16 bytes on cpu 2): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace (crc 0): kmemleak_alloc_percpu+0xb4/0xd0 pcpu_alloc_noprof+0x700/0x1098 load_module+0xd4/0x348 codetag_module_init+0x20c/0x450 codetag_load_module+0x70/0xb8 load_module+0xef8/0x1608 init_module_from_file+0xec/0x158 idempotent_init_module+0x354/0x608 __arm64_sys_finit_module+0xbc/0x150 invoke_syscall+0xd4/0x258 el0_svc_common.constprop.0+0xb4/0x240 do_el0_svc+0x48/0x68 el0_svc+0x40/0xf8 el0t_64_sync_handler+0x10c/0x138 el0t_64_sync+0x1ac/0x1b0 This is because the module can only indirectly reference alloc_tag_counters through the alloc_tag section, which misleads kmemleak. However, we don't have a kmemleak ignore interface for percpu allocations yet. So let's create one and invoke it for tag->counters. Fixes: 12ca42c23775 ("alloc_tag: allocate percpu counters for module tags dynamically") Signed-off-by: Hao Ge --- include/linux/kmemleak.h | 1 + lib/alloc_tag.c | 8 +++++++- mm/kmemleak.c | 14 ++++++++++++++ 3 files changed, 22 insertions(+), 1 deletion(-) diff --git a/include/linux/kmemleak.h b/include/linux/kmemleak.h index 93a73c076d16..2ea8e66bf689 100644 --- a/include/linux/kmemleak.h +++ b/include/linux/kmemleak.h @@ -28,6 +28,7 @@ extern void kmemleak_update_trace(const void *ptr) __ref; extern void kmemleak_not_leak(const void *ptr) __ref; extern void kmemleak_transient_leak(const void *ptr) __ref; extern void kmemleak_ignore(const void *ptr) __ref; +extern void kmemleak_igonore_percpu(const void __percpu *ptr) __ref; extern void kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp) __ref; extern void kmemleak_no_scan(const void *ptr) __ref; extern void kmemleak_alloc_phys(phys_addr_t phys, size_t size, diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c index d48b80f3f007..de6dcf4ea0f5 100644 --- a/lib/alloc_tag.c +++ b/lib/alloc_tag.c @@ -10,6 +10,7 @@ #include #include #include +#include #define ALLOCINFO_FILE_NAME "allocinfo" #define MODULE_ALLOC_TAG_VMAP_SIZE (100000UL * sizeof(struct alloc_tag)) @@ -632,8 +633,13 @@ static int load_module(struct module *mod, struct codetag *start, struct codetag mod->name); return -ENOMEM; } - } + /* + * Avoid a kmemleak false positive. The pointer to the counters is stored + * in the alloc_tag section of the module and cannot be directly accessed. + */ + kmemleak_igonore_percpu(tag->counters); + } return 0; } diff --git a/mm/kmemleak.c b/mm/kmemleak.c index da9cee34ee1b..8797fe88861e 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -1246,6 +1246,20 @@ void __ref kmemleak_transient_leak(const void *ptr) } EXPORT_SYMBOL(kmemleak_transient_leak); +/** + * kmemleak_ignore_phys - similar to kmemleak_ignore but taking a percpu + * address argument + * @ptr: percpu address of the object + */ +void __ref kmemleak_igonore_percpu(const void __percpu *ptr) +{ + pr_debug("%s(0x%px)\n", __func__, ptr); + + if (kmemleak_enabled && ptr && !IS_ERR_PCPU(ptr)) + make_black_object((unsigned long)ptr, OBJECT_PERCPU); +} +EXPORT_SYMBOL_GPL(kmemleak_igonore_percpu); + /** * kmemleak_ignore - ignore an allocated object * @ptr: pointer to beginning of the object -- 2.25.1