From patchwork Mon Oct 23 16:22:31 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: andrey.konovalov@linux.dev X-Patchwork-Id: 13433180 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 81B04C001E0 for ; Mon, 23 Oct 2023 16:23:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D1E946B00F4; Mon, 23 Oct 2023 12:23:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CA7B76B00F5; Mon, 23 Oct 2023 12:23:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B48F96B00F6; Mon, 23 Oct 2023 12:23:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id A4E576B00F4 for ; Mon, 23 Oct 2023 12:23:01 -0400 (EDT) Received: from smtpin16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 7B5091203C6 for ; Mon, 23 Oct 2023 16:23:01 +0000 (UTC) X-FDA: 81377245362.16.34CC78A Received: from out-200.mta0.migadu.com (out-200.mta0.migadu.com [91.218.175.200]) by imf22.hostedemail.com (Postfix) with ESMTP id A2043C0013 for ; Mon, 23 Oct 2023 16:22:59 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=en6BEB2N; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf22.hostedemail.com: domain of andrey.konovalov@linux.dev designates 91.218.175.200 as permitted sender) smtp.mailfrom=andrey.konovalov@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1698078180; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:references:dkim-signature; bh=hE8/xihIXcLGI8uaU/L34q0MmNF0Ny3eNAOyLz5owLs=; b=FiZMEQ2qVYBh8a0/NpIDDlAVAUcgyuoaBg12InrZ7+fYbftLMUUwClD45QrWfbT+3DQmC9 zPqnNzMiL2yWGeTuy3IYA5HStC2B/CXpe2/hS1wDj42QD3FG4T83QNSxTcEw/XJ3MglCKt gol/zpR+AzmcE0IBl3w+dnFdD2UuovU= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=en6BEB2N; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf22.hostedemail.com: domain of andrey.konovalov@linux.dev designates 91.218.175.200 as permitted sender) smtp.mailfrom=andrey.konovalov@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1698078180; a=rsa-sha256; cv=none; b=bvRc38pOGpNv7ct7d5rn2qt5eY00ccUIilTR40HCn09nSbTukbZsHjT63g+H9m4XB1XA1n 5jDiTs5SqkCJIIwzcWt3kdLrzoZDQ5U6rri4UvLClD6zCDAyGzlaC5qhSKBWJy/l0Lj0gd OeAtyIkM3XLoOw31MrngsU5aIjnHGW4= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1698078177; 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=hE8/xihIXcLGI8uaU/L34q0MmNF0Ny3eNAOyLz5owLs=; b=en6BEB2NL2TkfIZ+o5d1ARfK4S/MJ2EVXaSRfOwcHIC+VIjAnj5g0Y6cuUN98kV9kwFDmT j7o0G98RL+sezKiMqYGkyZRIp0E/6tdKgsZRBac3ovUz5AAb1SmV8jOb1lrg5LGLAFU5an /uiVY0J+58ucGMH80sj+fzrZvHg1EoE= From: andrey.konovalov@linux.dev To: Marco Elver , Alexander Potapenko Cc: Andrey Konovalov , Dmitry Vyukov , Vlastimil Babka , kasan-dev@googlegroups.com, Evgenii Stepanov , Oscar Salvador , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH v3 00/19] stackdepot: allow evicting stack traces Date: Mon, 23 Oct 2023 18:22:31 +0200 Message-Id: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: A2043C0013 X-Stat-Signature: 7zrr4jwmwejxtyrtw1isuq19ynqzcxh8 X-HE-Tag: 1698078179-176120 X-HE-Meta: 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 Hx2aQbgW d6PXEZZqtAJ05fPOK4a+rZh0D6BM4qkm5iJEAm+64goxxf/QX0NmWhqc37BybqAvpWkr+2TXl46WKZSI3cZRwW9KcEwkxdTKabya3 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Andrey Konovalov Currently, the stack depot grows indefinitely until it reaches its capacity. Once that happens, the stack depot stops saving new stack traces. This creates a problem for using the stack depot for in-field testing and in production. For such uses, an ideal stack trace storage should: 1. Allow saving fresh stack traces on systems with a large uptime while limiting the amount of memory used to store the traces; 2. Have a low performance impact. Implementing #1 in the stack depot is impossible with the current keep-forever approach. This series targets to address that. Issue #2 is left to be addressed in a future series. This series changes the stack depot implementation to allow evicting unneeded stack traces from the stack depot. The users of the stack depot can do that via new stack_depot_save_flags(STACK_DEPOT_FLAG_GET) and stack_depot_put APIs. Internal changes to the stack depot code include: 1. Storing stack traces in fixed-frame-sized slots; the slot size is controlled via CONFIG_STACKDEPOT_MAX_FRAMES (vs precisely-sized slots in the current implementation); 2. Keeping available slots in a freelist (vs keeping an offset to the next free slot); 3. Using a read/write lock for synchronization (vs a lock-free approach combined with a spinlock). This series also integrates the eviction functionality in the tag-based KASAN modes. Despite wasting some space on rounding up the size of each stack record, with CONFIG_STACKDEPOT_MAX_FRAMES=32, the tag-based KASAN modes end up consuming ~5% less memory in stack depot during boot (with the default stack ring size of 32k entries). The reason for this is the eviction of irrelevant stack traces from the stack depot, which frees up space for other stack traces. For other tools that heavily rely on the stack depot, like Generic KASAN and KMSAN, this change leads to the stack depot capacity being reached sooner than before. However, as these tools are mainly used in fuzzing scenarios where the kernel is frequently rebooted, this outcome should be acceptable. There is no measurable boot time performance impact of these changes for KASAN on x86-64. I haven't done any tests for arm64 modes (the stack depot without performance optimizations is not suitable for intended use of those anyway), but I expect a similar result. Obtaining and copying stack trace frames when saving them into stack depot is what takes the most time. This series does not yet provide a way to configure the maximum size of the stack depot externally (e.g. via a command-line parameter). This will be added in a separate series, possibly together with the performance improvement changes. Tested-by: Anders Roxell Acked-by: Marco Elver --- Changes v2->v3: - Fix null-ptr-deref by using the proper number of entries for initializing the stack table when alloc_large_system_hash() auto-calculates the number (see patch #12). - Keep STACKDEPOT/STACKDEPOT_ALWAYS_INIT Kconfig options not configurable by users. - Use lockdep_assert_held_read annotation in depot_fetch_stack. - WARN_ON invalid flags in stack_depot_save_flags. - Moved "../slab.h" include in mm/kasan/report_tags.c in the right patch. - Various comment fixes. Changes v1->v2: - Rework API to stack_depot_save_flags(STACK_DEPOT_FLAG_GET) + stack_depot_put. - Add CONFIG_STACKDEPOT_MAX_FRAMES Kconfig option. - Switch stack depot to using list_head's. - Assorted minor changes, see the commit message for each path. Andrey Konovalov (19): lib/stackdepot: check disabled flag when fetching lib/stackdepot: simplify __stack_depot_save lib/stackdepot: drop valid bit from handles lib/stackdepot: add depot_fetch_stack helper lib/stackdepot: use fixed-sized slots for stack records lib/stackdepot: fix and clean-up atomic annotations lib/stackdepot: rework helpers for depot_alloc_stack lib/stackdepot: rename next_pool_required to new_pool_required lib/stackdepot: store next pool pointer in new_pool lib/stackdepot: store free stack records in a freelist lib/stackdepot: use read/write lock lib/stackdepot: use list_head for stack record links kmsan: use stack_depot_save instead of __stack_depot_save lib/stackdepot, kasan: add flags to __stack_depot_save and rename lib/stackdepot: add refcount for records lib/stackdepot: allow users to evict stack traces kasan: remove atomic accesses to stack ring entries kasan: check object_size in kasan_complete_mode_report_info kasan: use stack_depot_put for tag-based modes include/linux/stackdepot.h | 59 ++++-- lib/Kconfig | 10 + lib/stackdepot.c | 418 ++++++++++++++++++++++++------------- mm/kasan/common.c | 7 +- mm/kasan/generic.c | 9 +- mm/kasan/kasan.h | 2 +- mm/kasan/report_tags.c | 27 +-- mm/kasan/tags.c | 24 ++- mm/kmsan/core.c | 7 +- 9 files changed, 365 insertions(+), 198 deletions(-)