From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 619D1149DFA for ; Thu, 8 Aug 2024 12:54:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723121693; cv=none; b=loK0ABtUvnx3NWANuEZPPkWXQvuvQ4F9/93Ypf7f89oRicaY49JCNcxRS+sztkCTydEvIbW9+zNXVankDT3ls5jF/80JcsO0qqH5H8neJgkKFbhKxz9Pw9TifjH1iXZUZ3ihllmSHYn07NxJF3EabANAFauWoHW7D5M6Pr10blE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723121693; c=relaxed/simple; bh=5uetXJ3+L+RhLKV5z8c9WyUlwsJduAkEGBQHl3zElLk=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=icukFHNreMQM8Od3q0AoyPqc8QUDwF/tEXe4L12VzCMdoeCPgTBvnlnvphOaeJmK3QTVAxEUfDtbX/9LAveFqOPpyWTjMxgzAS6k+7srOvv4OBeM9EOTX+jDiCiKllydI5serjW1JLLWLOsZf7a1flxWo2q7VhXOdAVqgE4dsyg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=h3SM1eXl; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="h3SM1eXl" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1723121690; 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=kkdFm8UYhX2wGq7WQBwF6R5jAWfsgP28pH4c5ptM2vc=; b=h3SM1eXlCrbC/oR+V8fYSS+pe+t0kPgZp9hL6udOUsiWK7bSFNZNycwkG4WBcWfvzsy6NT 3ZpetGYRi8d5TCjeihEx3zq+qkGETQihqCPYT5a2HSaQl/YFS7uavnaKnislwnoqKRvj7e 6/3ejfpvj/IfAasBdFh1v8Y/DXoytNw= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-572-QOiLiR0UNkmfzYsQ4Yd9pw-1; Thu, 08 Aug 2024 08:54:46 -0400 X-MC-Unique: QOiLiR0UNkmfzYsQ4Yd9pw-1 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 6B07C1944AA4; Thu, 8 Aug 2024 12:54:45 +0000 (UTC) Received: from llong.com (unknown [10.2.16.72]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id A4FD719560A3; Thu, 8 Aug 2024 12:54:43 +0000 (UTC) From: Waiman Long To: Andrew Morton , Andrey Ryabinin , Andrey Konovalov , Marco Elver , Dmitry Vyukov Cc: linux-kernel@vger.kernel.org, Waiman Long Subject: [PATCH v3] lib/stackdepot: Double DEPOT_POOLS_CAP if KASAN is enabled Date: Thu, 8 Aug 2024 08:54:30 -0400 Message-ID: <20240808125430.1172152-1-longman@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 As said in commit 02754e0a484a ("lib/stackdepot.c: bump stackdepot capacity from 16MB to 128MB"), KASAN uses stackdepot to memorize stacks for all kmalloc/kfree calls. So stackdepot capacity was increased 8 times to accommodate KASAN usage even thought it was claimed 4X should be enough at that time. With commit fc60e0caa94d ("lib/stackdepot: use fixed-sized slots for stack records"), all stackdepot records uses a fixed size with CONFIG_STACKDEPOT_MAX_FRAMES (default=64) entries. This is merged to support evictable KASAN stack records. Commit 31639fd6cebd ("stackdepot: use variable size records for non-evictable entries") re-enabled the use of variable size records for non-KASAN use cases, but KASAN (generic mode) still uses the large fixed size stack records. With the default CONFIG_STACKDEPOT_MAX_FRAMES of 64, KASAN use of stackdepot space had been more than double than before. Assuming an average stack frame size of 16, a KASAN stack record is almost 4X the size of a non-KASAN one. When a wide variety of workloads are run on a debug kernel with KASAN enabled, the following warning may sometimes be printed. [ 6818.650674] Stack depot reached limit capacity [ 6818.650730] WARNING: CPU: 1 PID: 272741 at lib/stackdepot.c:252 depot_alloc_stack+0x39e/0x3d0 : [ 6818.650907] Call Trace: [ 6818.650909] [<00047dd453d84b92>] depot_alloc_stack+0x3a2/0x3d0 [ 6818.650916] [<00047dd453d85254>] stack_depot_save_flags+0x4f4/0x5c0 [ 6818.650920] [<00047dd4535872c6>] kasan_save_stack+0x56/0x70 [ 6818.650924] [<00047dd453587328>] kasan_save_track+0x28/0x40 [ 6818.650927] [<00047dd45358a27a>] kasan_save_free_info+0x4a/0x70 [ 6818.650930] [<00047dd45358766a>] __kasan_slab_free+0x12a/0x1d0 [ 6818.650933] [<00047dd45350deb4>] kmem_cache_free+0x1b4/0x580 [ 6818.650938] [<00047dd452c520da>] __put_task_struct+0x24a/0x320 [ 6818.650945] [<00047dd452c6aee4>] delayed_put_task_struct+0x294/0x350 [ 6818.650949] [<00047dd452e9066a>] rcu_do_batch+0x6ea/0x2090 [ 6818.650953] [<00047dd452ea60f4>] rcu_core+0x474/0xa90 [ 6818.650956] [<00047dd452c780c0>] handle_softirqs+0x3c0/0xf90 [ 6818.650960] [<00047dd452c76fbe>] __irq_exit_rcu+0x35e/0x460 [ 6818.650963] [<00047dd452c79992>] irq_exit_rcu+0x22/0xb0 [ 6818.650966] [<00047dd454bd8128>] do_ext_irq+0xd8/0x120 [ 6818.650972] [<00047dd454c0ddd0>] ext_int_handler+0xb8/0xe8 [ 6818.650979] [<00047dd453589cf6>] kasan_check_range+0x236/0x2f0 [ 6818.650982] [<00047dd453378cf0>] filemap_get_pages+0x190/0xaa0 [ 6818.650986] [<00047dd453379940>] filemap_read+0x340/0xa70 [ 6818.650989] [<00047dd3d325d226>] xfs_file_buffered_read+0x2c6/0x400 [xfs] [ 6818.651431] [<00047dd3d325dfe2>] xfs_file_read_iter+0x2c2/0x550 [xfs] [ 6818.651663] [<00047dd45364710c>] vfs_read+0x64c/0x8c0 [ 6818.651669] [<00047dd453648ed8>] ksys_read+0x118/0x200 [ 6818.651672] [<00047dd452b6cf5a>] do_syscall+0x27a/0x380 [ 6818.651676] [<00047dd454bd7e74>] __do_syscall+0xf4/0x1a0 [ 6818.651680] [<00047dd454c0db58>] system_call+0x70/0x98 With all the recent changes in stackdepot to support new KASAN features, it is obvious that the current DEPOT_POOLS_CAP of 8192 may not be enough when KASAN is enabled. Fix this stackdepot capability issue by doubling DEPOT_POOLS_CAP if KASAN is enabled. With 4k pages, the maximum stackdepot capacity is doubled to 256 MB with KASAN enabled. Also use the MIN() macro for defining DEPOT_MAX_POOLS to clarify the intention. Fixes: fc60e0caa94d ("lib/stackdepot: use fixed-sized slots for stack records") Signed-off-by: Waiman Long --- lib/stackdepot.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) [v3] Include to avoid potential undefined macro problem. diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 5ed34cc963fc..1f1673b357b5 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -36,11 +37,12 @@ #include #include -#define DEPOT_POOLS_CAP 8192 +/* KASAN is a big user of stackdepot, double the cap if KASAN is enabled */ +#define DEPOT_POOLS_CAP (8192 * (IS_ENABLED(CONFIG_KASAN) ? 2 : 1)) + /* The pool_index is offset by 1 so the first record does not have a 0 handle. */ #define DEPOT_MAX_POOLS \ - (((1LL << (DEPOT_POOL_INDEX_BITS)) - 1 < DEPOT_POOLS_CAP) ? \ - (1LL << (DEPOT_POOL_INDEX_BITS)) - 1 : DEPOT_POOLS_CAP) + MIN((1LL << (DEPOT_POOL_INDEX_BITS)) - 1, DEPOT_POOLS_CAP) static bool stack_depot_disabled; static bool __stack_depot_early_init_requested __initdata = IS_ENABLED(CONFIG_STACKDEPOT_ALWAYS_INIT); -- 2.43.5