From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CEB6FC433C1 for ; Tue, 30 Mar 2021 09:26:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 74DCB61989 for ; Tue, 30 Mar 2021 09:26:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231752AbhC3JZb (ORCPT ); Tue, 30 Mar 2021 05:25:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35822 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231779AbhC3JZF (ORCPT ); Tue, 30 Mar 2021 05:25:05 -0400 Received: from mail-ed1-x535.google.com (mail-ed1-x535.google.com [IPv6:2a00:1450:4864:20::535]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8B131C061762 for ; Tue, 30 Mar 2021 02:25:04 -0700 (PDT) Received: by mail-ed1-x535.google.com with SMTP id e7so17330810edu.10 for ; Tue, 30 Mar 2021 02:25:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=iozylAVUn40DswvE7F5Csv/HFc0KYvTsB9WmzHP7DYI=; b=VY0BxsS6yI9+6W6VS901o5TRH1lMcM+M0wo4wI2CA7tRaPLveWGYtpUL9AER/qgedJ zhKnS45nTFEsAiMKaG9o+gsF2sK53jUWeuVxMlHtNkrny0oSpB3pEDMiv+18pDS+Uh2V vTh4sTau5YMDObnT+3rWJiXCdDiKQHanWNP3ue5rjVJy++d+Ihq3mbtyyDCbkpAzOuYg m4M70E1bgujx9CxecD7uWtmztYzwW8+xovCJMIVyuF28RZPSMIS0sgtPaVsHv0V0ovjE gu2xyBHDYVwIhXS1WsAX8sZyTqISKAQaj5BBHaOUoDPozdgVn+rGZiDWRQIhSerzv/Ip qi4w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=iozylAVUn40DswvE7F5Csv/HFc0KYvTsB9WmzHP7DYI=; b=M+4ASd9JQLAxn4CarabLXauZ5JTBpglcqUeib9KlIWzWMrp6a4ad7N8/sbEnhK9ClB fB5lmJE6eYOWO4jEbhLFwa6FvujkWU9dDCHnfyrhGZqZ1iXUutDQdoNhTg0g5bU36Ub+ SVM8ldlHHYVoQaoqbNJkDclzGYd+rajhs8K60qjXFS8zXorsQBSM44+YAsieBII7Q+Ov tpNtpgzypLSxe1Y8zDo6Q6MVPXuwAJEdbW5KmT82/3CZMD/aroDPFHz/VnPkUDODeBQ1 dhnsEpAjKgNidZlUunj4rVqUkjotV1KhzMAjHTOozUwam9pzBDkPyuZ4FKE3297Ycmk5 WyMA== X-Gm-Message-State: AOAM5326hq2I+VVLCWGmAFPSTOvzUuAKmCKwpT9BMDTiIxC4y9j+2Z1p 71gT5nSLvxkFMm0cH2XW1rc= X-Google-Smtp-Source: ABdhPJwmLkVtHtUufeMkZd6fQrycKVl+HV3fxXOlhRMp4wFD8/53LS07Nl+4qJfA9viMh9xpvPWITQ== X-Received: by 2002:a05:6402:9:: with SMTP id d9mr32389643edu.67.1617096303157; Tue, 30 Mar 2021 02:25:03 -0700 (PDT) Received: from smtpclient.apple ([178.254.237.20]) by smtp.gmail.com with ESMTPSA id gb4sm9565888ejc.122.2021.03.30.02.25.02 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 30 Mar 2021 02:25:02 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.80.0.2.10\)) Subject: Re: [PATCH net v4] net: fix race between napi kthread mode and busy poll From: Martin Zaharinov In-Reply-To: Date: Tue, 30 Mar 2021 12:25:01 +0300 Cc: Wei Wang , "David S . Miller" , Jakub Kicinski , netdev , Alexander Duyck , Paolo Abeni , Hannes Frederic Sowa Content-Transfer-Encoding: quoted-printable Message-Id: References: <20210316223647.4080796-1-weiwan@google.com> <6AF20AA6-07E7-4DDD-8A9E-BE093FC03802@gmail.com> To: Eric Dumazet X-Mailer: Apple Mail (2.3654.80.0.2.10) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Eric and Wei Please check this log : 1584288.951272] napi/eth0-523: page allocation failure: order:0, = mode:0x40a20(GFP_ATOMIC|__GFP_COMP), nodemask=3D(null) [1584289.003674] CPU: 4 PID: 3179 Comm: napi/eth0-523 Tainted: G = O 5.11.4 #1 [1584289.055545] Hardware name: Supermicro SYS-5038MR-H8TRF/X10SRD-F, = BIOS 3.2 11/22/2019 [1584289.107263] Call Trace: [1584289.107266] dump_stack+0x58/0x6b [1584289.209562] warn_alloc.cold+0x70/0xd4 [1584289.209569] __alloc_pages_slowpath.constprop.0+0xd57/0xfb0 [1584289.209574] __alloc_pages_nodemask+0x15a/0x180 [1584289.474009] allocate_slab+0x272/0x450 [1584289.496731] ___slab_alloc.constprop.0+0x41e/0x4d0 [1584289.519147] kmem_cache_alloc+0x110/0x120 [1584289.541416] build_skb+0x1a/0x200 [1584289.563121] ixgbe_clean_rx_irq+0x5fc/0xa10 [ixgbe] [1584289.584618] ixgbe_poll+0xeb/0x2a0 [ixgbe] [1584289.605528] __napi_poll+0x1f/0x130 [1584289.625842] napi_threaded_poll+0x110/0x160 [1584289.646110] ? __napi_poll+0x130/0x130 [1584289.665810] kthread+0xea/0x120 [1584289.684836] ? kthread_park+0x80/0x80 [1584289.703440] ret_from_fork+0x1f/0x30 [1584289.721616] Mem-Info: [1584289.739066] active_anon:8157 inactive_anon:2100191 isolated_anon:0 active_file:17408 inactive_file:149 isolated_file:32 unevictable:1440359 dirty:17500 writeback:0 slab_reclaimable:43368 slab_unreclaimable:155124 mapped:817431 shmem:7650 pagetables:32093 bounce:0 free:17832 free_pcp:113 free_cma:0 [1584289.842614] Node 0 active_anon:32628kB inactive_anon:8400764kB = active_file:69312kB inactive_file:880kB unevictable:5761436kB = isolated(anon):0kB isolated(file):128kB mapped:3269724kB dirty:69740kB = writeback:0kB shmem:30600kB writeback_tmp:0kB kernel_stack:5376kB = pagetables:128372kB all_unreclaimable? no [1584289.913793] Node 0 DMA free:13836kB min:12kB low:24kB high:36kB = reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB = active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB = present:15968kB managed:15884kB mlocked:0kB bounce:0kB free_pcp:0kB = local_pcp:0kB free_cma:0kB [1584289.986882] lowmem_reserve[]: 0 1741 15726 15726 [1584290.005519] Node 0 DMA32 free:54448kB min:9780kB low:11560kB = high:13340kB reserved_highatomic:24576KB active_anon:5104kB = inactive_anon:760844kB active_file:51532kB inactive_file:388kB = unevictable:885428kB writepending:51744kB present:1965124kB = managed:1899588kB mlocked:0kB bounce:0kB free_pcp:684kB local_pcp:0kB = free_cma:0kB [1584290.104980] lowmem_reserve[]: 0 0 13985 13985 [1584290.125807] Node 0 Normal free:2288kB min:78608kB low:92928kB = high:107248kB reserved_highatomic:32768KB active_anon:27524kB = inactive_anon:7639920kB active_file:17776kB inactive_file:1304kB = unevictable:4876016kB writepending:17736kB present:14680064kB = managed:14326620kB mlocked:0kB bounce:0kB free_pcp:288kB local_pcp:28kB = free_cma:0kB [1584290.237051] lowmem_reserve[]: 0 0 0 0 [1584290.260423] Node 0 DMA: 1*4kB (U) 1*8kB (U) 0*16kB 0*32kB 2*64kB = (U) 1*128kB (U) 1*256kB (U) 0*512kB 1*1024kB (U) 0*2048kB 3*4096kB (M) =3D= 13836kB [1584290.308847] Node 0 DMA32: 12500*4kB (UMEH) 553*8kB (MH) 0*16kB = 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB =3D = 54424kB [1584290.358363] Node 0 Normal: 0*4kB 25*8kB (H) 0*16kB 5*32kB (H) = 1*64kB (H) 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB =3D 424kB [1584290.409087] 1465768 total pagecache pages [1584290.434531] 4165289 pages RAM [1584290.459616] 0 pages HighMem/MovableOnly [1584290.484480] 104766 pages reserved [1584290.508709] 0 pages hwpoisoned [1584301.710231] team0: Failed to send options change via netlink (err = -105) [1584302.635731] telegraf invoked oom-killer: = gfp_mask=3D0x400dc0(GFP_KERNEL_ACCOUNT|__GFP_ZERO), order=3D1, = oom_score_adj=3D0 [1584302.682874] CPU: 0 PID: 3494492 Comm: telegraf Tainted: G = O 5.11.4 #1 [1584302.729535] Hardware name: Supermicro SYS-5038MR-H8TRF/X10SRD-F, = BIOS 3.2 11/22/2019 [1584302.776532] Call Trace: [1584302.799361] dump_stack+0x58/0x6b [1584302.821791] dump_header+0x4c/0x2e6 [1584302.843580] oom_kill_process.cold+0xb/0x10 [1584302.865223] out_of_memory.part.0+0x125/0x5f0 [1584302.886641] out_of_memory+0x54/0xa0 [1584302.907302] __alloc_pages_slowpath.constprop.0+0xb03/0xfb0 [1584302.927913] __alloc_pages_nodemask+0x15a/0x180 [1584302.947874] __get_free_pages+0x8/0x30 [1584302.967246] pgd_alloc+0x21/0x180 [1584302.986355] mm_alloc+0x1af/0x250 [1584303.005085] alloc_bprm+0x80/0x2a0 [1584303.023328] do_execveat_common+0x8b/0x330 [1584303.041181] __x64_sys_execve+0x2b/0x40 [1584303.058513] do_syscall_64+0x2d/0x40 [1584303.075281] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [1584303.091891] RIP: 0033:0x488376 [1584303.108045] Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc = cc cc cc cc 48 8b 7c 24 10 48 8b 74 24 18 48 8b 54 24 20 48 8b 44 24 08 = 0f 05 <48> 3d 01 f0 ff ff 76 1b 48 c7 44 24 28 ff ff ff ff 48 c7 44 24 = 30 [1584303.159632] RSP: 002b:000000c001108528 EFLAGS: 00000206 ORIG_RAX: = 000000000000003b [1584303.195446] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: = 0000000000488376 [1584303.231451] RDX: 000000c002b1a080 RSI: 000000c0028432e0 RDI: = 000000c000cae660 [1584303.267407] RBP: 000000c0011086c8 R08: 0000000000000018 R09: = 0000000000000000 [1584303.303594] R10: 0000000000000008 R11: 0000000000000206 R12: = 000000000047f258 [1584303.340218] R13: 000000000000000e R14: 000000000000000d R15: = 0000000000000100 [1584303.379094] Mem-Info: [1584303.398713] active_anon:8159 inactive_anon:2138194 isolated_anon:0 active_file:12975 inactive_file:168 isolated_file:32 unevictable:909709 dirty:12864 writeback:10 slab_reclaimable:42415 slab_unreclaimable:154783 mapped:39825 shmem:14744 pagetables:26041 bounce:0 free:537002 free_pcp:1813 free_cma:0 [1584303.547011] Node 0 active_anon:32636kB inactive_anon:8552776kB = active_file:51476kB inactive_file:1112kB unevictable:3638836kB = isolated(anon):0kB isolated(file):128kB mapped:159480kB dirty:51024kB = writeback:28kB shmem:58976kB writeback_tmp:0kB kernel_stack:5392kB = pagetables:104164kB all_unreclaimable? no [1584303.640025] Node 0 DMA free:13428kB min:12kB low:24kB high:36kB = reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB = active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB = present:15968kB managed:15884kB mlocked:0kB bounce:0kB free_pcp:0kB = local_pcp:0kB free_cma:0kB [1584303.739414] lowmem_reserve[]: 0 1741 15726 15726 [1584303.764535] Node 0 DMA32 free:121320kB min:5872kB low:7652kB = high:9432kB reserved_highatomic:24576KB active_anon:5104kB = inactive_anon:761140kB active_file:37160kB inactive_file:772kB = unevictable:885428kB writepending:37672kB present:1965124kB = managed:1899588kB mlocked:0kB bounce:0kB free_pcp:1448kB local_pcp:0kB = free_cma:0kB [1584303.888935] lowmem_reserve[]: 0 0 13985 13985 [1584303.913532] Node 0 Normal free:1970692kB min:78608kB low:92928kB = high:107248kB reserved_highatomic:126976KB active_anon:27524kB = inactive_anon:7812248kB active_file:13664kB inactive_file:1528kB = unevictable:2753408kB writepending:12888kB present:14680064kB = managed:14326620kB mlocked:0kB bounce:0kB free_pcp:4076kB local_pcp:0kB = free_cma:0kB [1584304.036531] lowmem_reserve[]: 0 0 0 0 [1584304.060733] Node 0 DMA: 1*4kB (U) 40*8kB (U) 37*16kB (U) 32*32kB = (U) 24*64kB (U) 14*128kB (U) 8*256kB (U) 2*512kB (U) 1*1024kB (U) = 0*2048kB 1*4096kB (M) =3D 13460kB [1584304.134551] Node 0 DMA32: 15098*4kB (UMEH) 6204*8kB (UMEH) 662*16kB = (UMEH) 20*32kB (UMEH) 1*64kB (U) 0*128kB 0*256kB 0*512kB 0*1024kB = 0*2048kB 0*4096kB =3D 121320kB [1584304.209349] Node 0 Normal: 1038*4kB (UEH) 392*8kB (EH) 56*16kB = (UEH) 28*32kB (UEH) 14*64kB (MEH) 25*128kB (MEH) 6*256kB (MH) 3*512kB = (UMH) 3*1024kB (MH) 5*2048kB (UMH) 472*4096kB (U) =3D 1962872kB [1584304.287094] 933871 total pagecache pages [1584304.312815] 4165289 pages RAM [1584304.337915] 0 pages HighMem/MovableOnly [1584304.362522] 104766 pages reserved [1584304.386516] 0 pages hwpoisoned > On 20 Mar 2021, at 11:55, Eric Dumazet wrote: >=20 > On Sat, Mar 20, 2021 at 9:45 AM Martin Zaharinov = wrote: >>=20 >> Hi Wei >> Check this: >>=20 >> [ 39.706567] ------------[ cut here ]------------ >> [ 39.706568] RTNL: assertion failed at net/ipv4/udp_tunnel_nic.c = (557) >> [ 39.706585] WARNING: CPU: 0 PID: 429 at = net/ipv4/udp_tunnel_nic.c:557 __udp_tunnel_nic_reset_ntf+0xea/0x100 >=20 > Probably more relevant to Intel maintainers than Wei :/ >=20 >> [ 39.706594] Modules linked in: i40e(+) nf_nat_sip nf_conntrack_sip = nf_nat_pptp nf_conntrack_pptp nf_nat_tftp nf_conntrack_tftp nf_nat_ftp = nf_conntrack_ftp nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 = acpi_ipmi ipmi_si ipmi_devintf ipmi_msghandler rtc_cmos megaraid_sas >> [ 39.706614] CPU: 0 PID: 429 Comm: kworker/0:2 Tainted: G = O 5.11.7 #1 >> [ 39.706618] Hardware name: Supermicro X11DPi-N(T)/X11DPi-NT, BIOS = 3.4 11/23/2020 >> [ 39.706619] Workqueue: events work_for_cpu_fn >> [ 39.706627] RIP: 0010:__udp_tunnel_nic_reset_ntf+0xea/0x100 >> [ 39.706631] Code: c0 79 f1 00 00 0f 85 4e ff ff ff ba 2d 02 00 00 = 48 c7 c6 45 3c 3a 93 48 c7 c7 40 de 39 93 c6 05 a0 79 f1 00 01 e8 f5 ad = 0c 00 <0f> 0b e9 28 ff ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 = 00 >> [ 39.706634] RSP: 0018:ffffa8390d9b3b38 EFLAGS: 00010292 >> [ 39.706637] RAX: 0000000000000039 RBX: ffff8e02630b2768 RCX: = 00000000ffdfffff >> [ 39.706639] RDX: 00000000ffdfffff RSI: ffff8e80ad400000 RDI: = 0000000000000001 >> [ 39.706641] RBP: ffff8e025df72000 R08: ffff8e80bb3fffe8 R09: = 00000000ffffffea >> [ 39.706643] R10: 00000000ffdfffff R11: 80000000ffe00000 R12: = ffff8e02630b2008 >> [ 39.706645] R13: 0000000000000000 R14: ffff8e024a88ba00 R15: = 0000000000000000 >> [ 39.706646] FS: 0000000000000000(0000) GS:ffff8e40bf800000(0000) = knlGS:0000000000000000 >> [ 39.706649] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> [ 39.706651] CR2: 00000000004d8f40 CR3: 0000002ca140a002 CR4: = 00000000001706f0 >> [ 39.706652] DR0: 0000000000000000 DR1: 0000000000000000 DR2: = 0000000000000000 >> [ 39.706654] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: = 0000000000000400 >> [ 39.706656] Call Trace: >> [ 39.706658] i40e_setup_pf_switch+0x617/0xf80 [i40e] >> [ 39.706683] i40e_probe.part.0.cold+0x8dc/0x109e [i40e] >> [ 39.706708] ? acpi_ns_check_object_type+0xd4/0x193 >> [ 39.706713] ? acpi_ns_check_package_list+0xfd/0x205 >> [ 39.706716] ? __kmalloc+0x37/0x160 >> [ 39.706720] ? kmem_cache_alloc+0xcb/0x120 >> [ 39.706723] ? irq_get_irq_data+0x5/0x20 >> [ 39.706726] ? mp_check_pin_attr+0xe/0xf0 >> [ 39.706729] ? irq_get_irq_data+0x5/0x20 >> [ 39.706731] ? mp_map_pin_to_irq+0xb7/0x2c0 >> [ 39.706735] ? acpi_register_gsi_ioapic+0x86/0x150 >> [ 39.706739] ? pci_conf1_read+0x9f/0xf0 >> [ 39.706743] ? pci_bus_read_config_word+0x2e/0x40 >> [ 39.706746] local_pci_probe+0x1b/0x40 >> [ 39.706750] work_for_cpu_fn+0xb/0x20 >> [ 39.706754] process_one_work+0x1ec/0x350 >> [ 39.706758] worker_thread+0x24b/0x4d0 >> [ 39.706760] ? process_one_work+0x350/0x350 >> [ 39.706762] kthread+0xea/0x120 >> [ 39.706766] ? kthread_park+0x80/0x80 >> [ 39.706770] ret_from_fork+0x1f/0x30 >> [ 39.706774] ---[ end trace 7a203f3ec972a377 ]--- >>=20 >> Martin >>=20 >>=20 >>> On 17 Mar 2021, at 0:36, Wei Wang wrote: >>>=20 >>> Currently, napi_thread_wait() checks for NAPI_STATE_SCHED bit to >>> determine if the kthread owns this napi and could call napi->poll() = on >>> it. However, if socket busy poll is enabled, it is possible that the >>> busy poll thread grabs this SCHED bit (after the previous = napi->poll() >>> invokes napi_complete_done() and clears SCHED bit) and tries to poll >>> on the same napi. napi_disable() could grab the SCHED bit as well. >>> This patch tries to fix this race by adding a new bit >>> NAPI_STATE_SCHED_THREADED in napi->state. This bit gets set in >>> ____napi_schedule() if the threaded mode is enabled, and gets = cleared >>> in napi_complete_done(), and we only poll the napi in kthread if = this >>> bit is set. This helps distinguish the ownership of the napi between >>> kthread and other scenarios and fixes the race issue. >>>=20 >>> Fixes: 29863d41bb6e ("net: implement threaded-able napi poll loop = support") >>> Reported-by: Martin Zaharinov >>> Suggested-by: Jakub Kicinski >>> Signed-off-by: Wei Wang >>> Cc: Alexander Duyck >>> Cc: Eric Dumazet >>> Cc: Paolo Abeni >>> Cc: Hannes Frederic Sowa >>> --- >>> Change since v3: >>> - Add READ_ONCE() for thread->state and add comments in >>> ____napi_schedule(). >>>=20 >>> include/linux/netdevice.h | 2 ++ >>> net/core/dev.c | 19 ++++++++++++++++++- >>> 2 files changed, 20 insertions(+), 1 deletion(-) >>>=20 >>> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h >>> index 5b67ea89d5f2..87a5d186faff 100644 >>> --- a/include/linux/netdevice.h >>> +++ b/include/linux/netdevice.h >>> @@ -360,6 +360,7 @@ enum { >>> NAPI_STATE_IN_BUSY_POLL, /* sk_busy_loop() owns this = NAPI */ >>> NAPI_STATE_PREFER_BUSY_POLL, /* prefer busy-polling over = softirq processing*/ >>> NAPI_STATE_THREADED, /* The poll is performed inside = its own thread*/ >>> + NAPI_STATE_SCHED_THREADED, /* Napi is currently scheduled = in threaded mode */ >>> }; >>>=20 >>> enum { >>> @@ -372,6 +373,7 @@ enum { >>> NAPIF_STATE_IN_BUSY_POLL =3D = BIT(NAPI_STATE_IN_BUSY_POLL), >>> NAPIF_STATE_PREFER_BUSY_POLL =3D = BIT(NAPI_STATE_PREFER_BUSY_POLL), >>> NAPIF_STATE_THREADED =3D BIT(NAPI_STATE_THREADED), >>> + NAPIF_STATE_SCHED_THREADED =3D = BIT(NAPI_STATE_SCHED_THREADED), >>> }; >>>=20 >>> enum gro_result { >>> diff --git a/net/core/dev.c b/net/core/dev.c >>> index 6c5967e80132..d3195a95f30e 100644 >>> --- a/net/core/dev.c >>> +++ b/net/core/dev.c >>> @@ -4294,6 +4294,13 @@ static inline void ____napi_schedule(struct = softnet_data *sd, >>> */ >>> thread =3D READ_ONCE(napi->thread); >>> if (thread) { >>> + /* Avoid doing set_bit() if the thread is in >>> + * INTERRUPTIBLE state, cause = napi_thread_wait() >>> + * makes sure to proceed with napi polling >>> + * if the thread is explicitly woken from = here. >>> + */ >>> + if (READ_ONCE(thread->state) !=3D = TASK_INTERRUPTIBLE) >>> + set_bit(NAPI_STATE_SCHED_THREADED, = &napi->state); >>> wake_up_process(thread); >>> return; >>> } >>> @@ -6486,6 +6493,7 @@ bool napi_complete_done(struct napi_struct *n, = int work_done) >>> WARN_ON_ONCE(!(val & NAPIF_STATE_SCHED)); >>>=20 >>> new =3D val & ~(NAPIF_STATE_MISSED | NAPIF_STATE_SCHED = | >>> + NAPIF_STATE_SCHED_THREADED | >>> NAPIF_STATE_PREFER_BUSY_POLL); >>>=20 >>> /* If STATE_MISSED was set, leave STATE_SCHED set, >>> @@ -6968,16 +6976,25 @@ static int napi_poll(struct napi_struct *n, = struct list_head *repoll) >>>=20 >>> static int napi_thread_wait(struct napi_struct *napi) >>> { >>> + bool woken =3D false; >>> + >>> set_current_state(TASK_INTERRUPTIBLE); >>>=20 >>> while (!kthread_should_stop() && !napi_disable_pending(napi)) { >>> - if (test_bit(NAPI_STATE_SCHED, &napi->state)) { >>> + /* Testing SCHED_THREADED bit here to make sure the = current >>> + * kthread owns this napi and could poll on this napi. >>> + * Testing SCHED bit is not enough because SCHED bit = might be >>> + * set by some other busy poll thread or by = napi_disable(). >>> + */ >>> + if (test_bit(NAPI_STATE_SCHED_THREADED, &napi->state) = || woken) { >>> WARN_ON(!list_empty(&napi->poll_list)); >>> __set_current_state(TASK_RUNNING); >>> return 0; >>> } >>>=20 >>> schedule(); >>> + /* woken being true indicates this thread owns this = napi. */ >>> + woken =3D true; >>> set_current_state(TASK_INTERRUPTIBLE); >>> } >>> __set_current_state(TASK_RUNNING); >>> -- >>> 2.31.0.rc2.261.g7f71774620-goog >>>=20 >>=20