From patchwork Tue Nov 8 03:52:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qi Zheng X-Patchwork-Id: 13035785 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5A6F4C43219 for ; Tue, 8 Nov 2022 03:52:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233158AbiKHDwv (ORCPT ); Mon, 7 Nov 2022 22:52:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34648 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232464AbiKHDwt (ORCPT ); Mon, 7 Nov 2022 22:52:49 -0500 Received: from mail-pj1-x102c.google.com (mail-pj1-x102c.google.com [IPv6:2607:f8b0:4864:20::102c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 03DAA2F38D for ; Mon, 7 Nov 2022 19:52:48 -0800 (PST) Received: by mail-pj1-x102c.google.com with SMTP id h14so12605377pjv.4 for ; Mon, 07 Nov 2022 19:52:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=uCbnVcwfxaz8WtuNm+dEU4u6g06+3FeMUHVI5XHFQX8=; b=cH6oIK+cRiM9JP04nwl7ycPUaaFryhc7fuPf6QP2unzym9OFAXM3cj8P8q3Z0l3UQ8 fO3U06Wogr7GIymltQYsOZuNGuYI//al0ILagvi/IcuJqE9MF2CgpTnuhq6WqH9wiOyG qReEY6Rsb8gmlJCnoeUw0FhBsSb5Vva9ClovzmEC0LwLA/lm6QMwgSYzVLZk9YocVoiI JBcvCRjM7ySOzjPeDYoVALfidXKJr19nhTCgMx+U62h9DE2xcd+mJXN2Ba31pwvuWrdw PPsE/lL/0eLznOpdC0R8JnZZ2271DQnHEOtNmF6wz5/OU9sDZQhZ6EAS1/VC0+2FLA8f 14PA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=uCbnVcwfxaz8WtuNm+dEU4u6g06+3FeMUHVI5XHFQX8=; b=utau/eaM78y1ZvqtswpjJHRS+9bX/Huy72r8txFvN6KASnrg5wflg3R67I7dfhE5S8 EgNrDuCbk8Y83c+Wa93fCKsxoN6xh6Qo2gPPZ8vUNuIIkCFqQu4a3XT7eKjPu4Q5vntj su5CGNQTGEVwwLhnuFkB29WUKF8solHwR8KOxEh2Hh3FY7Ko4DtgdhxJzOZOf9NLDXaL 7003tbNS3V+dDYx04a7/XuUvptnOElprVcn8P8s0tOGBuyl5O3syCaD3C5+Lp4z/LVAv hgbTTC3x9P7co9/vDI/FOUPeDtLc6/78G45RWPtLFQQOOOKofN3TEEl39lsEWCVqJQxp 7qzw== X-Gm-Message-State: ANoB5pnCsbVRaTtY/NqE5rVDJydaCfla71tuQdAfLqoT5RR4v9QSUET0 bxzzAX8hFZ/lcgwMaZZj7/XqIw== X-Google-Smtp-Source: AA0mqf7NI1yJdV5umCgvPMvxA3wJbCU2bY2T2ObWSHagxwnHwoIDEjY5taSByd88BDmJQitnYIpiMA== X-Received: by 2002:a17:902:e5cc:b0:188:712f:df78 with SMTP id u12-20020a170902e5cc00b00188712fdf78mr17567320plf.106.1667879567491; Mon, 07 Nov 2022 19:52:47 -0800 (PST) Received: from C02DW0BEMD6R.bytedance.net ([139.177.225.251]) by smtp.gmail.com with ESMTPSA id x6-20020a170902a38600b0018685257c0dsm5747418pla.58.2022.11.07.19.52.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Nov 2022 19:52:46 -0800 (PST) From: Qi Zheng To: dvyukov@google.com, jgg@nvidia.com, willy@infradead.org, akinobu.mita@gmail.com Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Qi Zheng , stable@vger.kernel.org Subject: [PATCH v2] mm: fix unexpected changes to {failslab|fail_page_alloc}.attr Date: Tue, 8 Nov 2022 11:52:32 +0800 Message-Id: <20221108035232.87180-1-zhengqi.arch@bytedance.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org When we specify __GFP_NOWARN, we only expect that no warnings will be issued for current caller. But in the __should_failslab() and __should_fail_alloc_page(), the local GFP flags alter the global {failslab|fail_page_alloc}.attr, which is persistent and shared by all tasks. This is not what we expected, let's fix it. Cc: stable@vger.kernel.org Fixes: 3f913fc5f974 ("mm: fix missing handler for __GFP_NOWARN") Reported-by: Dmitry Vyukov Signed-off-by: Qi Zheng Reviewed-by: Akinobu Mita --- v1: https://lore.kernel.org/lkml/20221107033109.59709-1-zhengqi.arch@bytedance.com/ Changelog in v1 -> v2: - add comment for __should_failslab() and __should_fail_alloc_page() (suggested by Jason) include/linux/fault-inject.h | 7 +++++-- lib/fault-inject.c | 14 +++++++++----- mm/failslab.c | 12 ++++++++++-- mm/page_alloc.c | 7 +++++-- 4 files changed, 29 insertions(+), 11 deletions(-) diff --git a/include/linux/fault-inject.h b/include/linux/fault-inject.h index 9f6e25467844..444236dadcf0 100644 --- a/include/linux/fault-inject.h +++ b/include/linux/fault-inject.h @@ -20,7 +20,6 @@ struct fault_attr { atomic_t space; unsigned long verbose; bool task_filter; - bool no_warn; unsigned long stacktrace_depth; unsigned long require_start; unsigned long require_end; @@ -32,6 +31,10 @@ struct fault_attr { struct dentry *dname; }; +enum fault_flags { + FAULT_NOWARN = 1 << 0, +}; + #define FAULT_ATTR_INITIALIZER { \ .interval = 1, \ .times = ATOMIC_INIT(1), \ @@ -40,11 +43,11 @@ struct fault_attr { .ratelimit_state = RATELIMIT_STATE_INIT_DISABLED, \ .verbose = 2, \ .dname = NULL, \ - .no_warn = false, \ } #define DECLARE_FAULT_ATTR(name) struct fault_attr name = FAULT_ATTR_INITIALIZER int setup_fault_attr(struct fault_attr *attr, char *str); +bool should_fail_ex(struct fault_attr *attr, ssize_t size, int flags); bool should_fail(struct fault_attr *attr, ssize_t size); #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS diff --git a/lib/fault-inject.c b/lib/fault-inject.c index 4b8fafce415c..5971f7c3e49e 100644 --- a/lib/fault-inject.c +++ b/lib/fault-inject.c @@ -41,9 +41,6 @@ EXPORT_SYMBOL_GPL(setup_fault_attr); static void fail_dump(struct fault_attr *attr) { - if (attr->no_warn) - return; - if (attr->verbose > 0 && __ratelimit(&attr->ratelimit_state)) { printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure.\n" "name %pd, interval %lu, probability %lu, " @@ -103,7 +100,7 @@ static inline bool fail_stacktrace(struct fault_attr *attr) * http://www.nongnu.org/failmalloc/ */ -bool should_fail(struct fault_attr *attr, ssize_t size) +bool should_fail_ex(struct fault_attr *attr, ssize_t size, int flags) { bool stack_checked = false; @@ -152,13 +149,20 @@ bool should_fail(struct fault_attr *attr, ssize_t size) return false; fail: - fail_dump(attr); + if (!(flags & FAULT_NOWARN)) + fail_dump(attr); if (atomic_read(&attr->times) != -1) atomic_dec_not_zero(&attr->times); return true; } +EXPORT_SYMBOL_GPL(should_fail_ex); + +bool should_fail(struct fault_attr *attr, ssize_t size) +{ + return should_fail_ex(attr, size, 0); +} EXPORT_SYMBOL_GPL(should_fail); #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS diff --git a/mm/failslab.c b/mm/failslab.c index 58df9789f1d2..ffc420c0e767 100644 --- a/mm/failslab.c +++ b/mm/failslab.c @@ -16,6 +16,8 @@ static struct { bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags) { + int flags = 0; + /* No fault-injection for bootstrap cache */ if (unlikely(s == kmem_cache)) return false; @@ -30,10 +32,16 @@ bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags) if (failslab.cache_filter && !(s->flags & SLAB_FAILSLAB)) return false; + /* + * In some cases, it expects to specify __GFP_NOWARN + * to avoid printing any information(not just a warning), + * thus avoiding deadlocks. See commit 6b9dbedbe349 for + * details. + */ if (gfpflags & __GFP_NOWARN) - failslab.attr.no_warn = true; + flags |= FAULT_NOWARN; - return should_fail(&failslab.attr, s->object_size); + return should_fail_ex(&failslab.attr, s->object_size, flags); } static int __init setup_failslab(char *str) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 7192ded44ad0..cb6fe715d983 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3902,6 +3902,8 @@ __setup("fail_page_alloc=", setup_fail_page_alloc); static bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order) { + int flags = 0; + if (order < fail_page_alloc.min_order) return false; if (gfp_mask & __GFP_NOFAIL) @@ -3912,10 +3914,11 @@ static bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order) (gfp_mask & __GFP_DIRECT_RECLAIM)) return false; + /* See comment in __should_failslab() */ if (gfp_mask & __GFP_NOWARN) - fail_page_alloc.attr.no_warn = true; + flags |= FAULT_NOWARN; - return should_fail(&fail_page_alloc.attr, 1 << order); + return should_fail_ex(&fail_page_alloc.attr, 1 << order, flags); } #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS