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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6D6CCC001DB for ; Sun, 3 Sep 2023 01:30:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235383AbjICBaw (ORCPT ); Sat, 2 Sep 2023 21:30:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46862 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231735AbjICBau (ORCPT ); Sat, 2 Sep 2023 21:30:50 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BC05FA2 for ; Sat, 2 Sep 2023 18:30:43 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 4A9C9B80AAF for ; Sun, 3 Sep 2023 01:30:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CB51EC433C8; Sun, 3 Sep 2023 01:30:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1693704640; bh=GMBQuILrFjCX71w1Y64s17b6M0xq1sKAkSumHrz4vx8=; h=Date:To:From:Subject:From; b=bSmxe5h0mmXzjCrBFcGw7WKx0KZmxfj2edInd2FcbCRZKOJ/28pBCZJlOvmAOwHHV agVmpX3jqpYzLyHpF5gX8KIwzYhx1jAC/Z7c5KCKgTfPCNC7bF6rZ8iahxpJs3dsEW 7ubhRw6ZYk3gVuoJOqeQwUd67lUfwWqGrI2bhiic= Date: Sat, 02 Sep 2023 18:30:40 -0700 To: mm-commits@vger.kernel.org, willy@infradead.org, thunder.leizhen@huaweicloud.com, qiang.zhang1211@gmail.com, paulmck@kernel.org, hch@infradead.org, joel@joelfernandes.org, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-vmalloc-add-a-safer-version-of-find_vm_area-for-debug.patch added to mm-unstable branch Message-Id: <20230903013040.CB51EC433C8@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm/vmalloc: add a safer version of find_vm_area() for debug has been added to the -mm mm-unstable branch. Its filename is mm-vmalloc-add-a-safer-version-of-find_vm_area-for-debug.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmalloc-add-a-safer-version-of-find_vm_area-for-debug.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: "Joel Fernandes (Google)" Subject: mm/vmalloc: add a safer version of find_vm_area() for debug Date: Wed, 30 Aug 2023 11:03:59 +0000 It is unsafe to dump vmalloc area information when trying to do so from some contexts. Add a safer trylock version of the same function to do a best-effort VMA finding and use it from vmalloc_dump_obj(). Link: https://lkml.kernel.org/r/20230830110402.386898-1-joel@joelfernandes.org Signed-off-by: Joel Fernandes (Google) Reported-by: Zhen Lei Reviewed-by: Matthew Wilcox (Oracle) Cc: Paul E. McKenney Cc: Zqiang Cc: Christoph Hellwig Signed-off-by: Andrew Morton --- mm/vmalloc.c | 35 ++++++++++++++++++++++++++++++++++- 1 file changed, 34 insertions(+), 1 deletion(-) --- a/mm/vmalloc.c~mm-vmalloc-add-a-safer-version-of-find_vm_area-for-debug +++ a/mm/vmalloc.c @@ -1865,6 +1865,18 @@ struct vmap_area *find_vmap_area(unsigne return va; } +static struct vmap_area *find_vmap_area_trylock(unsigned long addr) +{ + struct vmap_area *va; + + if (!spin_trylock(&vmap_area_lock)) + return NULL; + va = __find_vmap_area(addr, &vmap_area_root); + spin_unlock(&vmap_area_lock); + + return va; +} + static struct vmap_area *find_unlink_vmap_area(unsigned long addr) { struct vmap_area *va; @@ -2672,6 +2684,27 @@ struct vm_struct *find_vm_area(const voi } /** + * try_to_find_vm_area - find a continuous kernel virtual area + * @addr: base address + * + * This function is the same as find_vm_area() except that it is + * safe to call if vmap_area_lock is already held and returns NULL + * if it is. See comments in find_vmap_area() for other details. + * + * Return: the area descriptor on success or %NULL on failure. + */ +static struct vm_struct *try_to_find_vm_area(const void *addr) +{ + struct vmap_area *va; + + va = find_vmap_area_trylock((unsigned long)addr); + if (!va) + return NULL; + + return va->vm; +} + +/** * remove_vm_area - find and remove a continuous kernel virtual area * @addr: base address * @@ -4281,7 +4314,7 @@ bool vmalloc_dump_obj(void *object) struct vm_struct *vm; void *objp = (void *)PAGE_ALIGN((unsigned long)object); - vm = find_vm_area(objp); + vm = try_to_find_vm_area(objp); if (!vm) return false; pr_cont(" %u-page vmalloc region starting at %#lx allocated at %pS\n", _ Patches currently in -mm which might be from joel@joelfernandes.org are mm-vmalloc-add-a-safer-version-of-find_vm_area-for-debug.patch