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 AB93AC98311 for ; Thu, 24 Sep 2026 08:52:16 +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=dpXWjQcrFSVT//yT0BjXy2ofojqMt59v7qcYFKfPQb8=; b=3B2Z7ZzhVRBJNf VESOsoQUQK9VgUseCDlIZ8I7XeS9E+onKw7o0LFz6C9bAnGmA/PgvqZRcGBAcGDCY7dh9hew11fGM sHeu/j2zCtS+QvQHhVKwR6aRthJ0xlnLMUDZbkJCmPuxrwUBwmHxqoBBv65PutDCcbHOq2WyhAcZq 4/FJ8LBRv2n5GLDu6eQ27JMSLqjvGxiWxO/V+PQIn36lnX5JWk2gRfHuYQHBassy+B7b9N+/Esawj ByBhuhC9mCZ7W+L3F/OgeGHZW+f1yPK1dR2xrnVVCy9EvRKVShHEouX/WsLGzARzIefoDb5RzeyOb caeAn9yRh72uy60wdnNw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x9fBS-0000000AV2w-1G0r; Thu, 24 Sep 2026 08:52:02 +0000 Received: from out-34.mta1.migadu.com ([95.215.58.34] helo=mta1.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x9fBP-0000000AV0k-2wHN for linux-riscv@lists.infradead.org; Thu, 24 Sep 2026 08:52:01 +0000 X-Envelope-To: linux-riscv@lists.infradead.org DKIM-Signature: a=rsa-sha256; bh=SSX9xIAupprnWjWqUwH2oYEZRlvMUWqzHUN8lhagogw=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1790239918; v=1; x=1790844718; b=BhFgSU6x72wnDos1k2qf6Fd9lM1UlkPIf4CIWWmHLJt7j/fJqj6dWrgEuE72JmEnf9OHrR+F kEukD5SkxDpC607CU2XjUQygInZipl9G3Gbx5Zo3kT7RiwH0sI79Z++bonMUUDKAiDkyUmMbN31 VCGxdOzEQoiTuFnDpxkCzjco= X-Envelope-To: linux-riscv@lists.infradead.org Received: by smtp.migadu.com with ESMTPS id bf2fbf69d3d2174c; Thu, 24 Sep 2026 08:51:57 +0000 X-Mizu-Trace-ID: bf2fbf69d3d2174c X-Migadu-Flow: FLOW_OUT From: Ye Liu Date: Thu, 24 Sep 2026 16:51:40 +0800 Subject: [PATCH v3 2/2] mm/vmalloc: fix vmalloc_dump_obj cross-zone VA lookup MIME-Version: 1.0 Message-Id: <20260924-vmalloc_dump_obj-v3-2-5bdee3da37b3@linux.dev> References: <20260924-vmalloc_dump_obj-v3-0-5bdee3da37b3@linux.dev> In-Reply-To: <20260924-vmalloc_dump_obj-v3-0-5bdee3da37b3@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-20260924_015159_903992_13B5C2E5 X-CRM114-Status: GOOD ( 19.34 ) 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 | 111 +++++++++++++++++++++++++++++++++++++---------------------- 1 file changed, 69 insertions(+), 42 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index df42d8a6f058..e5b465de1559 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2517,39 +2517,81 @@ 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; - if (unlikely(!vmap_initialized)) + if (unlikely(!vmap_initialized)) { + *locked_vn = NULL; 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); + if (mode == VMAP_LOCK) { + spin_lock(&vn->busy.lock); + } else { + if (!spin_trylock(&vn->busy.lock)) + continue; + } + va = __find_vmap_area(addr, &vn->busy.root); + if (va) { + *locked_vn = vn; + return va; + } + spin_unlock(&vn->busy.lock); + } while ((i = next_vmap_node_id(i)) != j); - if (va) - return va; - } while ((i = (i + nr_vmap_nodes - 1) % nr_vmap_nodes) != j); + *locked_vn = NULL; + return NULL; +} + +struct vmap_area *find_vmap_area(unsigned long addr) +{ + struct vmap_node *vn; + struct vmap_area *va; + + va = find_vmap_area_lock(addr, &vn, VMAP_LOCK); + if (va) { + spin_unlock(&vn->busy.lock); + return va; + } return NULL; } @@ -2558,26 +2600,14 @@ static struct vmap_area *find_unlink_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) { + unlink_va(va, &vn->busy.root); spin_unlock(&vn->busy.lock); + } - if (va) - return va; - } while ((i = (i + nr_vmap_nodes - 1) % nr_vmap_nodes) != j); - - return NULL; + return va; } /*** Per cpu kva allocator ***/ @@ -5278,14 +5308,11 @@ 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