From nobody Thu Sep 24 12:50:44 2026 Received: from mta0.migadu.com (out-250.mta0.migadu.com [91.218.175.250]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C61262931C4 for ; Thu, 24 Sep 2026 08:51:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.250 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790239919; cv=none; b=sJdniSflj6oEMHSsucKwtekB22NQFrS3J4ZyAI46VY0ebgFnYypmdml7be4ckzPvPKl7khx+n4HJ7fhdH4P3Z4RoNBAEhLqtlKWhK6NAXHznk1ZYgb1r9o4rTgZjillbw0XTz5z/svLQ9jC+T1lcDAhOv/FtuDiUcoV2sSo/7Ig= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790239919; c=relaxed/simple; bh=VMcXVA6Q//nucy9IuPEO+cpUVY2addflHX+2AAjGN8s=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=aCY4vR4IhV4ehJqhIIZT57Y/dr3wXt26bwmqesVbkTtafiH+bx1Q5m1swY7YQJL/wgZ5VgUd9w/XETrhke9YECc+wnXRMVcSMrpGi7KUpVTcB9kuAq0W+z6u+1puGWY0VyTHrKrjSYb3JWfLz9MYzhNlBH5QNGBXWopRjAhxm0M= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=JFPj+/Ww; arc=none smtp.client-ip=91.218.175.250 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="JFPj+/Ww" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=VMcXVA6Q//nucy9IuPEO+cpUVY2addflHX+2AAjGN8s=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1790239915; v=1; x=1790844715; b=JFPj+/WwpV+GK99lpdLKQNokzmXaHwqhfi6/luOa64C8H60i3R+Qa191jjlNu20k1qnI39Y0 WHiu1ekU4wCvBFHf8hW0Gj9/eNhlFb1Og2nab8guypD+hx7z1Q2/Aj/uHhc2fBeZvej83b1lNB5 0egrPQHSkJQ2cPlcFwlbe7p4= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 4de7b20785afd569; Thu, 24 Sep 2026 08:51:52 +0000 X-Mizu-Trace-ID: 4de7b20785afd569 X-Migadu-Flow: FLOW_OUT From: Ye Liu Date: Thu, 24 Sep 2026 16:51:39 +0800 Subject: [PATCH v3 1/2] mm/vmalloc: fix vmalloc_dump_obj address alignment for last-page lookups Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260924-vmalloc_dump_obj-v3-1-5bdee3da37b3@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 From: Ye Liu vmalloc_dump_obj() uses PAGE_ALIGN() to normalize the input address before looking it up in the per-node busy tree. PAGE_ALIGN() rounds up, which can push an address in the last page of a vmalloc allocation to va_end -- outside the [va_start, va_end) range that __find_vmap_area() searches. This causes the lookup to miss the VA and return false, degrading diagnostic output in OOM dumps and KASAN reports to the less informative "vmalloc memory" fallback. The upward alignment can also change the addr_to_node() mapping when the page boundary crosses a vmap zone boundary, causing the search to hit the wrong node entirely. Use PAGE_ALIGN_DOWN() instead, which rounds down to the page containing the address. This keeps the address within the VA range and preserves the correct node mapping. Signed-off-by: Ye Liu Reviewed-by: Uladzislau Rezki (Sony) --- mm/vmalloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 859e6d2d57a3..df42d8a6f058 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -5277,7 +5277,7 @@ bool vmalloc_dump_obj(void *object) unsigned long addr; unsigned long nr_pages; =20 - addr =3D PAGE_ALIGN((unsigned long) object); + addr =3D PAGE_ALIGN_DOWN((unsigned long) object); vn =3D addr_to_node(addr); =20 if (!spin_trylock(&vn->busy.lock)) --=20 2.25.1 From nobody Thu Sep 24 12:50:44 2026 Received: from mta0.migadu.com (out-252.mta0.migadu.com [91.218.175.252]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5A5523E5594 for ; Thu, 24 Sep 2026 08:51:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.252 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790239922; cv=none; b=pmuuVI9fh/Dx1WVCMJdPCmg0M8DqbImMZCuAJCww/Uzgupp8+aaB1e3RjBkLx1B76taPaXwhIe5L3xAD2kqonhlYwU3F2xlfFkMOoMjnYaQiM6NUGzauHC0LksIO/Oep5QUiJDt14vpqAH81eBNycVSnd9XebhHFD0OF3LrlhmM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790239922; c=relaxed/simple; bh=SSX9xIAupprnWjWqUwH2oYEZRlvMUWqzHUN8lhagogw=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=PxI/AqThnAxmrShCudv0wJQVk3e5Oud51O8MXOUUCjU/lrkbm0+sI5Z4msuEPqi/T/t0tstjBzOzRyphvRdBGN6D9bG/O/wsPBB9Eqlc9RzIB3NUm4vK7rDe2n7P7Azzs+wLa824cT55Mx0FklgdLpby+bfecZLYv9KGdFWMEzc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=BhFgSU6x; arc=none smtp.client-ip=91.218.175.252 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="BhFgSU6x" X-Envelope-To: linux-kernel@vger.kernel.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-kernel@vger.kernel.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 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable 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 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); } =20 -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; =20 - if (unlikely(!vmap_initialized)) + if (unlikely(!vmap_initialized)) { + *locked_vn =3D NULL; return NULL; + } =20 - /* - * 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 =3D j =3D addr_to_node_id(addr); do { vn =3D &vmap_nodes[i]; =20 - spin_lock(&vn->busy.lock); + if (mode =3D=3D VMAP_LOCK) { + spin_lock(&vn->busy.lock); + } else { + if (!spin_trylock(&vn->busy.lock)) + continue; + } + va =3D __find_vmap_area(addr, &vn->busy.root); + if (va) { + *locked_vn =3D vn; + return va; + } + spin_unlock(&vn->busy.lock); + } while ((i =3D next_vmap_node_id(i)) !=3D j); =20 - if (va) - return va; - } while ((i =3D (i + nr_vmap_nodes - 1) % nr_vmap_nodes) !=3D j); + *locked_vn =3D NULL; + return NULL; +} + +struct vmap_area *find_vmap_area(unsigned long addr) +{ + struct vmap_node *vn; + struct vmap_area *va; + + va =3D find_vmap_area_lock(addr, &vn, VMAP_LOCK); + if (va) { + spin_unlock(&vn->busy.lock); + return va; + } =20 return NULL; } @@ -2558,26 +2600,14 @@ static struct vmap_area *find_unlink_vmap_area(unsi= gned 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 =3D j =3D addr_to_node_id(addr); - do { - vn =3D &vmap_nodes[i]; =20 - spin_lock(&vn->busy.lock); - va =3D __find_vmap_area(addr, &vn->busy.root); - if (va) - unlink_va(va, &vn->busy.root); + va =3D find_vmap_area_lock(addr, &vn, VMAP_LOCK); + if (va) { + unlink_va(va, &vn->busy.root); spin_unlock(&vn->busy.lock); + } =20 - if (va) - return va; - } while ((i =3D (i + nr_vmap_nodes - 1) % nr_vmap_nodes) !=3D j); - - return NULL; + return va; } =20 /*** Per cpu kva allocator ***/ @@ -5278,14 +5308,11 @@ bool vmalloc_dump_obj(void *object) unsigned long nr_pages; =20 addr =3D PAGE_ALIGN_DOWN((unsigned long) object); - vn =3D addr_to_node(addr); - - if (!spin_trylock(&vn->busy.lock)) - return false; =20 - va =3D __find_vmap_area(addr, &vn->busy.root); + va =3D 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; } =20 --=20 2.25.1