From patchwork Wed May 11 06:19:50 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qi Zheng X-Patchwork-Id: 12845829 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 58756C433F5 for ; Wed, 11 May 2022 06:20:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 97BE98D0001; Wed, 11 May 2022 02:20:12 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 92B916B0075; Wed, 11 May 2022 02:20:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7F2AD8D0001; Wed, 11 May 2022 02:20:12 -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 713AF6B0073 for ; Wed, 11 May 2022 02:20:12 -0400 (EDT) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay11.hostedemail.com (Postfix) with ESMTP id 4CFCC81D94 for ; Wed, 11 May 2022 06:20:12 +0000 (UTC) X-FDA: 79452462264.30.EF91C49 Received: from mail-pg1-f181.google.com (mail-pg1-f181.google.com [209.85.215.181]) by imf13.hostedemail.com (Postfix) with ESMTP id F249A200A7 for ; Wed, 11 May 2022 06:19:53 +0000 (UTC) Received: by mail-pg1-f181.google.com with SMTP id q76so917393pgq.10 for ; Tue, 10 May 2022 23:20:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=RBCTXkaBUfUOeTfxKhpY9jDR1ijlEmdERD1cfMUNmSA=; b=OGrTnYkDNUCJeelwKaqgYK2IzIhLtD2WG4QWzXdcIL1G2x24+914SHBAcrrGHg6+wj y3W5eWqbn+Si8zcWIPzbEA22upwORacffRy59qMHsWYQjbFfnXGQY8vmxqgS/E38sc4X Vov7vJB5+1fXRchhjlzu6UHd1oYOQK/sBXwse2tIz8mOkHeLfmaAW7r7+LqHUiHf47el MBJI/kogaNUebG1EfNQQOUKF4NRqWVxBHK2gf2Tl3bUZlorRCDvpzPxqgAxCm6XASS7H F5vOThJvh1mcUeDbjLLVEhwOqWpAXsa4GMAA/zqW86N6TR5L52eeND4CEqPFcGP2URa+ g8HQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=RBCTXkaBUfUOeTfxKhpY9jDR1ijlEmdERD1cfMUNmSA=; b=yghdPjfqO57CMalh94Sa/+cfPcsrMy+jOURMXzKP3FDetlIPVTtxO2BaYl1HMv0QvC dStpBA7hipM9ZkjRIFI5R1xOrj2EObVS6EdlbLO0d8rAr8pYjnOysHay82MiD+fExbms 88TofL00JRm8qa9JJ71h40gZLOLf8cH0z+4g7IhcddeA2FwWUKz1wdkaFGx+Lwf8ApVb B9czJkiBt/mmq+AgNYg/UQfOhI3fOS8Ygr20+OJwvzz7isK9MH2Ow2aEfq/JLKM8zdJG FRP9tLjUdUv5sb6Mzrk9f2wZ+m4YYeRcVkWmeZNeNPiLEU5jY2DOe1XfgAXnnEzS1Ljt WY7g== X-Gm-Message-State: AOAM530fvYX6kPtm7Pnc0jqDmJ56jRe2JXP/t1+WCKjECDB/LzJUqPLL gavWla4HRIJ6sANcbi8XnM5Dbw== X-Google-Smtp-Source: ABdhPJxoZdtoGcwCeoQXfgXydgTLFLm7LSjfdlvo1hIasxB0k3gl79CsDovlh8jZ6leJ+7mwqqmI2g== X-Received: by 2002:a63:d1b:0:b0:3db:1faa:a473 with SMTP id c27-20020a630d1b000000b003db1faaa473mr1833277pgl.555.1652250010085; Tue, 10 May 2022 23:20:10 -0700 (PDT) Received: from C02DW0BEMD6R.bytedance.net ([139.177.225.242]) by smtp.gmail.com with ESMTPSA id be12-20020a170902aa0c00b0015e8d4eb1e4sm771500plb.46.2022.05.10.23.20.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 May 2022 23:20:09 -0700 (PDT) From: Qi Zheng To: akpm@linux-foundation.org, jirislaby@kernel.org, akinobu.mita@gmail.com, vbabka@suse.cz, gregkh@linuxfoundation.org, rostedt@goodmis.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Qi Zheng Subject: [PATCH v2 1/2] mm: fix missing handler for __GFP_NOWARN Date: Wed, 11 May 2022 14:19:50 +0800 Message-Id: <20220511061951.1114-1-zhengqi.arch@bytedance.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) MIME-Version: 1.0 Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=bytedance-com.20210112.gappssmtp.com header.s=20210112 header.b=OGrTnYkD; dmarc=pass (policy=none) header.from=bytedance.com; spf=pass (imf13.hostedemail.com: domain of zhengqi.arch@bytedance.com designates 209.85.215.181 as permitted sender) smtp.mailfrom=zhengqi.arch@bytedance.com X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: F249A200A7 X-Rspam-User: X-Stat-Signature: sz1m4qfccdtotzwq9zg8irwf7ojhnekg X-HE-Tag: 1652249993-441839 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: We expect no warnings to be issued when we specify __GFP_NOWARN, but currently in paths like alloc_pages() and kmalloc(), there are still some warnings printed, fix it. But for some warnings that report usage problems, we don't deal with them. If such warnings are printed, then we should fix the usage problems. Such as the following case: WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1)); Signed-off-by: Qi Zheng --- include/linux/fault-inject.h | 2 ++ lib/fault-inject.c | 3 +++ mm/failslab.c | 3 +++ mm/internal.h | 15 +++++++++++++++ mm/page_alloc.c | 18 ++++++++++-------- 5 files changed, 33 insertions(+), 8 deletions(-) diff --git a/include/linux/fault-inject.h b/include/linux/fault-inject.h index 2d04f6448cde..9f6e25467844 100644 --- a/include/linux/fault-inject.h +++ b/include/linux/fault-inject.h @@ -20,6 +20,7 @@ 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; @@ -39,6 +40,7 @@ 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 diff --git a/lib/fault-inject.c b/lib/fault-inject.c index ce12621b4275..423784d9c058 100644 --- a/lib/fault-inject.c +++ b/lib/fault-inject.c @@ -41,6 +41,9 @@ 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, " diff --git a/mm/failslab.c b/mm/failslab.c index f92fed91ac23..58df9789f1d2 100644 --- a/mm/failslab.c +++ b/mm/failslab.c @@ -30,6 +30,9 @@ bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags) if (failslab.cache_filter && !(s->flags & SLAB_FAILSLAB)) return false; + if (gfpflags & __GFP_NOWARN) + failslab.attr.no_warn = true; + return should_fail(&failslab.attr, s->object_size); } diff --git a/mm/internal.h b/mm/internal.h index e3e50af20706..34fdedb9986f 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -35,6 +35,21 @@ struct folio_batch; /* Do not use these with a slab allocator */ #define GFP_SLAB_BUG_MASK (__GFP_DMA32|__GFP_HIGHMEM|~__GFP_BITS_MASK) +/* + * Different from WARN_ON_ONCE(), no warning will be issued + * when we specify __GFP_NOWARN. + */ +#define WARN_ON_ONCE_GFP(cond, gfp) ({ \ + static bool __section(".data.once") __warned; \ + int __ret_warn_once = !!(cond); \ + \ + if (unlikely(!(gfp & __GFP_NOWARN) && __ret_warn_once && !__warned)) { \ + __warned = true; \ + WARN_ON(1); \ + } \ + unlikely(__ret_warn_once); \ +}) + void page_writeback_init(void); static inline void *folio_raw_mapping(struct folio *folio) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 65f892af1d4f..f9f329403d76 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3789,6 +3789,9 @@ static bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order) (gfp_mask & __GFP_DIRECT_RECLAIM)) return false; + if (gfp_mask & __GFP_NOWARN) + fail_page_alloc.attr.no_warn = true; + return should_fail(&fail_page_alloc.attr, 1 << order); } @@ -4337,7 +4340,8 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order, */ /* Exhausted what can be done so it's blame time */ - if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) { + if (out_of_memory(&oc) || + WARN_ON_ONCE_GFP(gfp_mask & __GFP_NOFAIL, gfp_mask)) { *did_some_progress = 1; /* @@ -5103,7 +5107,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, * All existing users of the __GFP_NOFAIL are blockable, so warn * of any new users that actually require GFP_NOWAIT */ - if (WARN_ON_ONCE(!can_direct_reclaim)) + if (WARN_ON_ONCE_GFP(!can_direct_reclaim, gfp_mask)) goto fail; /* @@ -5111,7 +5115,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, * because we cannot reclaim anything and only can loop waiting * for somebody to do a work for us */ - WARN_ON_ONCE(current->flags & PF_MEMALLOC); + WARN_ON_ONCE_GFP(current->flags & PF_MEMALLOC, gfp_mask); /* * non failing costly orders are a hard requirement which we @@ -5119,7 +5123,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, * so that we can identify them and convert them to something * else. */ - WARN_ON_ONCE(order > PAGE_ALLOC_COSTLY_ORDER); + WARN_ON_ONCE_GFP(order > PAGE_ALLOC_COSTLY_ORDER, gfp_mask); /* * Help non-failing allocations by giving them access to memory @@ -5365,10 +5369,8 @@ struct page *__alloc_pages(gfp_t gfp, unsigned int order, int preferred_nid, * There are several places where we assume that the order value is sane * so bail out early if the request is out of bound. */ - if (unlikely(order >= MAX_ORDER)) { - WARN_ON_ONCE(!(gfp & __GFP_NOWARN)); + if (WARN_ON_ONCE_GFP(order >= MAX_ORDER, gfp)) return NULL; - } gfp &= gfp_allowed_mask; /* @@ -9020,7 +9022,7 @@ int __alloc_contig_migrate_range(struct compact_control *cc, lru_cache_enable(); if (ret < 0) { - if (ret == -EBUSY) + if (!(cc->gfp_mask & __GFP_NOWARN) && ret == -EBUSY) alloc_contig_dump_pages(&cc->migratepages); putback_movable_pages(&cc->migratepages); return ret; From patchwork Wed May 11 06:19:51 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qi Zheng X-Patchwork-Id: 12845830 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 8699EC433EF for ; Wed, 11 May 2022 06:20:16 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0F2176B0073; Wed, 11 May 2022 02:20:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 09FBD8D0002; Wed, 11 May 2022 02:20:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E83DB6B007D; Wed, 11 May 2022 02:20:15 -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 DC1336B0073 for ; Wed, 11 May 2022 02:20:15 -0400 (EDT) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id C04B3322C2 for ; Wed, 11 May 2022 06:20:15 +0000 (UTC) X-FDA: 79452462390.26.6D04EE8 Received: from mail-pg1-f175.google.com (mail-pg1-f175.google.com [209.85.215.175]) by imf15.hostedemail.com (Postfix) with ESMTP id 2CAB5A009A for ; Wed, 11 May 2022 06:20:03 +0000 (UTC) Received: by mail-pg1-f175.google.com with SMTP id 7so914045pga.12 for ; Tue, 10 May 2022 23:20:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=P6VNAwCH3n0ix/X7qN1lMdQqsfuBwClntHRvqIjUObk=; b=TWy8cyml379D9laFnVPycgxdVd2TTLlXmCcqmId+QI2tzj4kUZHMdFsHw73Xh/+MlQ uPoZIIF9qAD+Iy7mN73nKAxSP/ZRtyp6YLUmJaZ39zkudrUVv0kUL8b1nhjkFKjk+6vl 6orErtugJO4H1+Gy3ji1Fk2ICNy+LAWsm2v3sQYFL3L3IoGRtdwCW6HsbXBi9I2TEdwa ChF+xMVYEooN/85OtqwPVR/Nb82CVe8JJwgPOAoxFHC9oXb3aeVv0bfNlNsaytuCJRHI pCKEPjppXWU2vgzkZ7UnD2eJGlo/o4Wg1BPfXOJO5YxGm1oHhHBaYnV2s1CrMFBOc854 1GYQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=P6VNAwCH3n0ix/X7qN1lMdQqsfuBwClntHRvqIjUObk=; b=O/VqBaCeEv4gjgYjqmX1N1aGqc3R+YWjcO6V6GggMSA/dWbdX5rJfgYN62pFZboXzp bV1a1LateNawKKNqdUjuosoRnoHJtajyJ/GelAtDntS2vicJmydU7XFo+8aqBQGDEhlK Crgi4LG7uLT7b6vzBC2QSRFyXr1vlOdYuvQEOHbE9YM11hXIEA1EbEAD66CzrtX5zAU1 l2TcWVL48gFpbgiVjaFcE7fmoKx01AtX92jS5jEqW9Mg93SE2YxRxg9fdLE3lnFMwPW8 BSOWR0H4NEvuH8SrXasMdWcgBUNXYCpp1Zh4KHXE7w1LBkDPhbnk4UVTp5El4aIy0llV wsag== X-Gm-Message-State: AOAM531On7e0+RWZ7jgJaoj2LHWblacnVRADbuV0gZloW1EJcgBWSIot pa+y9Hy5JRp/ee47vM9FqOYiim2fTJcvsg== X-Google-Smtp-Source: ABdhPJyyDckfPI4haYh0t1Eo1lwNryAkpm9KBeuy7gA6mj5GpQeczY+jgQs0trOIfRO6E3LmQG9J7g== X-Received: by 2002:a62:1490:0:b0:4cc:3c7d:4dec with SMTP id 138-20020a621490000000b004cc3c7d4decmr5258576pfu.32.1652250014402; Tue, 10 May 2022 23:20:14 -0700 (PDT) Received: from C02DW0BEMD6R.bytedance.net ([139.177.225.242]) by smtp.gmail.com with ESMTPSA id be12-20020a170902aa0c00b0015e8d4eb1e4sm771500plb.46.2022.05.10.23.20.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 May 2022 23:20:13 -0700 (PDT) From: Qi Zheng To: akpm@linux-foundation.org, jirislaby@kernel.org, akinobu.mita@gmail.com, vbabka@suse.cz, gregkh@linuxfoundation.org, rostedt@goodmis.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Qi Zheng Subject: [PATCH v2 2/2] tty: fix deadlock caused by calling printk() under tty_port->lock Date: Wed, 11 May 2022 14:19:51 +0800 Message-Id: <20220511061951.1114-2-zhengqi.arch@bytedance.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: <20220511061951.1114-1-zhengqi.arch@bytedance.com> References: <20220511061951.1114-1-zhengqi.arch@bytedance.com> MIME-Version: 1.0 X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 2CAB5A009A Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=bytedance-com.20210112.gappssmtp.com header.s=20210112 header.b=TWy8cyml; spf=pass (imf15.hostedemail.com: domain of zhengqi.arch@bytedance.com designates 209.85.215.175 as permitted sender) smtp.mailfrom=zhengqi.arch@bytedance.com; dmarc=pass (policy=none) header.from=bytedance.com X-Rspam-User: X-Stat-Signature: 3ssq6qbcfoca6gj3ue8xrm6mb88eo5mw X-HE-Tag: 1652250003-471967 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: The pty_write() invokes kmalloc() which may invoke a normal printk() to print failure message. This can cause a deadlock in the scenario reported by syz-bot below: CPU0 CPU1 CPU2 ---- ---- ---- lock(console_owner); lock(&port_lock_key); lock(&port->lock); lock(&port_lock_key); lock(&port->lock); lock(console_owner); As commit dbdda842fe96 ("printk: Add console owner and waiter logic to load balance console writes") said, such deadlock can be prevented by using printk_deferred() in kmalloc() (which is invoked in the section guarded by the port->lock). But there are too many printk() on the kmalloc() path, and kmalloc() can be called from anywhere, so changing printk() to printk_deferred() is too complicated and inelegant. Therefore, this patch chooses to specify __GFP_NOWARN to kmalloc(), so that printk() will not be called, and this deadlock problem can be avoided. Syz-bot reported the following lockdep error: ====================================================== WARNING: possible circular locking dependency detected 5.4.143-00237-g08ccc19a-dirty #10 Not tainted ------------------------------------------------------ syz-executor.4/29420 is trying to acquire lock: ffffffff8aedb2a0 (console_owner){....}-{0:0}, at: console_trylock_spinning kernel/printk/printk.c:1752 [inline] ffffffff8aedb2a0 (console_owner){....}-{0:0}, at: vprintk_emit+0x2ca/0x470 kernel/printk/printk.c:2023 but task is already holding lock: ffff8880119c9158 (&port->lock){-.-.}-{2:2}, at: pty_write+0xf4/0x1f0 drivers/tty/pty.c:120 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&port->lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x35/0x50 kernel/locking/spinlock.c:159 tty_port_tty_get drivers/tty/tty_port.c:288 [inline] <-- lock(&port->lock); tty_port_default_wakeup+0x1d/0xb0 drivers/tty/tty_port.c:47 serial8250_tx_chars+0x530/0xa80 drivers/tty/serial/8250/8250_port.c:1767 serial8250_handle_irq.part.0+0x31f/0x3d0 drivers/tty/serial/8250/8250_port.c:1854 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1827 [inline] <-- lock(&port_lock_key); serial8250_default_handle_irq+0xb2/0x220 drivers/tty/serial/8250/8250_port.c:1870 serial8250_interrupt+0xfd/0x200 drivers/tty/serial/8250/8250_core.c:126 __handle_irq_event_percpu+0x109/0xa50 kernel/irq/handle.c:156 [...] -> #1 (&port_lock_key){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x35/0x50 kernel/locking/spinlock.c:159 serial8250_console_write+0x184/0xa40 drivers/tty/serial/8250/8250_port.c:3198 <-- lock(&port_lock_key); call_console_drivers kernel/printk/printk.c:1819 [inline] console_unlock+0x8cb/0xd00 kernel/printk/printk.c:2504 vprintk_emit+0x1b5/0x470 kernel/printk/printk.c:2024 <-- lock(console_owner); vprintk_func+0x8d/0x250 kernel/printk/printk_safe.c:394 printk+0xba/0xed kernel/printk/printk.c:2084 register_console+0x8b3/0xc10 kernel/printk/printk.c:2829 univ8250_console_init+0x3a/0x46 drivers/tty/serial/8250/8250_core.c:681 console_init+0x49d/0x6d3 kernel/printk/printk.c:2915 start_kernel+0x5e9/0x879 init/main.c:713 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241 -> #0 (console_owner){....}-{0:0}: [...] lock_acquire+0x127/0x340 kernel/locking/lockdep.c:4734 console_trylock_spinning kernel/printk/printk.c:1773 [inline] <-- lock(console_owner); vprintk_emit+0x307/0x470 kernel/printk/printk.c:2023 vprintk_func+0x8d/0x250 kernel/printk/printk_safe.c:394 printk+0xba/0xed kernel/printk/printk.c:2084 fail_dump lib/fault-inject.c:45 [inline] should_fail+0x67b/0x7c0 lib/fault-inject.c:144 __should_failslab+0x152/0x1c0 mm/failslab.c:33 should_failslab+0x5/0x10 mm/slab_common.c:1224 slab_pre_alloc_hook mm/slab.h:468 [inline] slab_alloc_node mm/slub.c:2723 [inline] slab_alloc mm/slub.c:2807 [inline] __kmalloc+0x72/0x300 mm/slub.c:3871 kmalloc include/linux/slab.h:582 [inline] tty_buffer_alloc+0x23f/0x2a0 drivers/tty/tty_buffer.c:175 __tty_buffer_request_room+0x156/0x2a0 drivers/tty/tty_buffer.c:273 tty_insert_flip_string_fixed_flag+0x93/0x250 drivers/tty/tty_buffer.c:318 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x126/0x1f0 drivers/tty/pty.c:122 <-- lock(&port->lock); n_tty_write+0xa7a/0xfc0 drivers/tty/n_tty.c:2356 do_tty_write drivers/tty/tty_io.c:961 [inline] tty_write+0x512/0x930 drivers/tty/tty_io.c:1045 __vfs_write+0x76/0x100 fs/read_write.c:494 [...] other info that might help us debug this: Chain exists of: console_owner --> &port_lock_key --> &port->lock Fixes: b6da31b2c07c ("tty: Fix data race in tty_insert_flip_string_fixed_flag") Signed-off-by: Qi Zheng Acked-by: Jiri Slaby Acked-by: Greg Kroah-Hartman --- drivers/tty/tty_buffer.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 646510476c30..bfa431a8e690 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -175,7 +175,8 @@ static struct tty_buffer *tty_buffer_alloc(struct tty_port *port, size_t size) */ if (atomic_read(&port->buf.mem_used) > port->buf.mem_limit) return NULL; - p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC); + p = kmalloc(sizeof(struct tty_buffer) + 2 * size, + GFP_ATOMIC | __GFP_NOWARN); if (p == NULL) return NULL;