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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 01C33C9833E for ; Mon, 28 Sep 2026 08:16:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:In-Reply-To:References:Message-Id :MIME-Version:Subject:Date:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=aXKEWvGvIIDs5EfgfJPKJqKShgpEL8YezAmV56jMwKw=; b=TIlOKNM6VS4ro3 it6lZ4sh/oQE35HA3k5+Ul0fPwlIgWsGPEVABoZa4x5zadQemuKSTh7K5v+P22yOr35Iojb2KApC1 8XX79R1ZYgLdElSla/bp10LOdzl/OoEOyv5BUDv/uecH9XpVWIrbic+9JI9Szh7nvJq8fu6Tr14mB jGijllfLOs9S6AzDHvvhfkpu7oeVAM5AS6jeOP15zqtQ7rhTzMVIuHqK4OLWM0Onfhu3XF1TFWNgi b7QZrJ81DUFHIO8DaeJR6Q7auUPh73pLtynu/vQNOG33hrmImU1ugq3ANqogxjkFKlXzCIOmP2Q2U Ko2r3fZcrq0eXjtnLpww==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xB6X6-000000003Gc-2YND; Mon, 28 Sep 2026 08:16:20 +0000 Received: from out-74.mta1.migadu.com ([2001:41d0:203:375::4a] helo=mta1.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xB6X3-000000003F3-3Aul for linux-riscv@lists.infradead.org; Mon, 28 Sep 2026 08:16:19 +0000 X-Envelope-To: linux-riscv@lists.infradead.org DKIM-Signature: a=rsa-sha256; bh=K5Q3pCElJ1kYWoQWSMWmJuaeilGdZ97iIqv2nF2D+kg=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1790583375; v=1; x=1791188175; b=GqVC5/8uTYJZtNOWdI+aXaf2zHD0scZdxMkOrdPgugWTIzBdZ1cyEgQ3uToLkslkz6AY6vpX 76vnilVWgDAZMqp2aYAYUr7finyuV9+Ej12qGJBEZMGA3Ucm5zeUrW/pLTa6Me8KYkE0sd4FG19 blL8X5kbSO1G0sxMlOubppFo= X-Envelope-To: linux-riscv@lists.infradead.org Received: by smtp.migadu.com with ESMTPS id ef3d12d70e3ed8e3; Mon, 28 Sep 2026 08:16:15 +0000 X-Mizu-Trace-ID: ef3d12d70e3ed8e3 X-Migadu-Flow: FLOW_OUT From: Ye Liu Date: Mon, 28 Sep 2026 16:15:55 +0800 Subject: [PATCH v4 2/2] mm/vmalloc: fix vmalloc_dump_obj cross-zone VA lookup MIME-Version: 1.0 Message-Id: <20260928-vmalloc_dump_obj-v4-2-6f288a431edc@linux.dev> References: <20260928-vmalloc_dump_obj-v4-0-6f288a431edc@linux.dev> In-Reply-To: <20260928-vmalloc_dump_obj-v4-0-6f288a431edc@linux.dev> To: Andrew Morton , Uladzislau Rezki , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Ye Liu X-Mailer: b4 0.14.3 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260928_011617_956306_A88EB636 X-CRM114-Status: GOOD ( 19.03 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org From: Ye Liu vmalloc_dump_obj() searches only one vmap node (addr_to_node(addr)), but a vmalloc allocation may span multiple vmap zones. The VA is stored in only one node's rb-tree (addr_to_node(va_start)), so an object pointer in a different zone than va_start maps to a different node and the search misses. This affects any allocation larger than vmap_zone_size (64 KiB) on multi-CPU systems. Extract find_vmap_area_lock() from find_vmap_area() to share the cross-node iteration logic. The helper supports both spin_lock and spin_trylock, the latter for atomic dump contexts (OOM, KASAN, RCU). Signed-off-by: Ye Liu --- mm/vmalloc.c | 108 ++++++++++++++++++++++++++++++++++++----------------------- 1 file changed, 66 insertions(+), 42 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index df42d8a6f058..4f4d7453962f 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2517,67 +2517,94 @@ static void free_unmap_vmap_area(struct vmap_area *va) free_vmap_area_noflush(va); } -struct vmap_area *find_vmap_area(unsigned long addr) +static inline int next_vmap_node_id(int i) +{ + return (i + nr_vmap_nodes - 1) % nr_vmap_nodes; +} + +enum vmap_lock_mode { + VMAP_LOCK, + VMAP_TRYLOCK, +}; + +/* + * Search for a vmap_area at @addr across all vmap nodes. An + * addr_to_node_id(addr) converts an address to a node index where + * a VA is located. If VA spans several zones and passed addr is not + * the same as va->va_start, what is not common, we may need to scan + * extra nodes. See an example: + * + * <----va----> + * -|-----|-----|-----|-----|- + * 1 2 0 1 + * + * VA resides in node 1 whereas it spans 1, 2 an 0. If passed addr + * is within 2 or 0 nodes we should do extra work. + * + * Returns the VA with @locked_vn->busy.lock held; the caller must + * release it. If @mode is VMAP_TRYLOCK, nodes that cannot be locked + * are skipped. + */ +static struct vmap_area * +find_vmap_area_lock(unsigned long addr, struct vmap_node **locked_vn, + enum vmap_lock_mode mode) { struct vmap_node *vn; struct vmap_area *va; int i, j; + *locked_vn = NULL; + if (unlikely(!vmap_initialized)) return NULL; - /* - * An addr_to_node_id(addr) converts an address to a node index - * where a VA is located. If VA spans several zones and passed - * addr is not the same as va->va_start, what is not common, we - * may need to scan extra nodes. See an example: - * - * <----va----> - * -|-----|-----|-----|-----|- - * 1 2 0 1 - * - * VA resides in node 1 whereas it spans 1, 2 an 0. If passed - * addr is within 2 or 0 nodes we should do extra work. - */ i = j = addr_to_node_id(addr); do { vn = &vmap_nodes[i]; - spin_lock(&vn->busy.lock); - va = __find_vmap_area(addr, &vn->busy.root); - spin_unlock(&vn->busy.lock); + if (mode == VMAP_LOCK) { + spin_lock(&vn->busy.lock); + } else { + if (!spin_trylock(&vn->busy.lock)) + continue; + } - if (va) + va = __find_vmap_area(addr, &vn->busy.root); + if (va) { + *locked_vn = vn; return va; - } while ((i = (i + nr_vmap_nodes - 1) % nr_vmap_nodes) != j); + } + + spin_unlock(&vn->busy.lock); + } while ((i = next_vmap_node_id(i)) != j); return NULL; } -static struct vmap_area *find_unlink_vmap_area(unsigned long addr) +struct vmap_area *find_vmap_area(unsigned long addr) { struct vmap_node *vn; struct vmap_area *va; - int i, j; - - /* - * Check the comment in the find_vmap_area() about the loop. - */ - i = j = addr_to_node_id(addr); - do { - vn = &vmap_nodes[i]; - spin_lock(&vn->busy.lock); - va = __find_vmap_area(addr, &vn->busy.root); - if (va) - unlink_va(va, &vn->busy.root); + va = find_vmap_area_lock(addr, &vn, VMAP_LOCK); + if (va) spin_unlock(&vn->busy.lock); - if (va) - return va; - } while ((i = (i + nr_vmap_nodes - 1) % nr_vmap_nodes) != j); + return va; +} - return NULL; +static struct vmap_area *find_unlink_vmap_area(unsigned long addr) +{ + struct vmap_node *vn; + struct vmap_area *va; + + va = find_vmap_area_lock(addr, &vn, VMAP_LOCK); + if (va) { + unlink_va(va, &vn->busy.root); + spin_unlock(&vn->busy.lock); + } + + return va; } /*** Per cpu kva allocator ***/ @@ -5278,14 +5305,11 @@ bool vmalloc_dump_obj(void *object) unsigned long nr_pages; addr = PAGE_ALIGN_DOWN((unsigned long) object); - vn = addr_to_node(addr); - - if (!spin_trylock(&vn->busy.lock)) - return false; - va = __find_vmap_area(addr, &vn->busy.root); + va = find_vmap_area_lock(addr, &vn, VMAP_TRYLOCK); if (!va || !va->vm) { - spin_unlock(&vn->busy.lock); + if (va) + spin_unlock(&vn->busy.lock); return false; } -- 2.25.1 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv