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=-5.7 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, 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 D35B9C61CE4 for ; Sat, 19 Jan 2019 11:32:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9C2F820821 for ; Sat, 19 Jan 2019 11:32:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727987AbfASLcF (ORCPT ); Sat, 19 Jan 2019 06:32:05 -0500 Received: from mail-it1-f199.google.com ([209.85.166.199]:60214 "EHLO mail-it1-f199.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id 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X-Received: by 2002:a5e:df44:: with SMTP id g4mr7868556ioq.0.1547897523973; Sat, 19 Jan 2019 03:32:03 -0800 (PST) Date: Sat, 19 Jan 2019 03:32:03 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <00000000000010b2fc057fcdfaba@google.com> Subject: INFO: rcu detected stall in sys_sendfile64 (2) From: syzbot To: akpm@linux-foundation.org, amir73il@gmail.com, darrick.wong@oracle.com, david@fromorbit.com, hannes@cmpxchg.org, hughd@google.com, jrdr.linux@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com, willy@infradead.org Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, syzbot found the following crash on: HEAD commit: 2339e91d0e66 Merge tag 'media/v5.0-1' of git://git.kernel... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=175f2638c00000 kernel config: https://syzkaller.appspot.com/x/.config?x=abc3dc9b7a900258 dashboard link: https://syzkaller.appspot.com/bug?extid=1505c80c74256c6118a5 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12c4dc28c00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15df4108c00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+1505c80c74256c6118a5@syzkaller.appspotmail.com audit: type=1400 audit(1547895693.874:36): avc: denied { map } for pid=8427 comm="syz-executor786" path="/root/syz-executor786610373" dev="sda1" ino=1426 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 hrtimer: interrupt took 42996 ns rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 0, t=10502 jiffies, g=6469, q=3) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295051508-4295041006), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor786 R running task 21544 8437 8433 0x00000000 Call Trace: sched_show_task kernel/sched/core.c:5293 [inline] sched_show_task.cold+0x273/0x2d5 kernel/sched/core.c:5268 print_other_cpu_stall.cold+0x7f2/0x8bb kernel/rcu/tree.c:1301 check_cpu_stall kernel/rcu/tree.c:1429 [inline] rcu_pending kernel/rcu/tree.c:3018 [inline] rcu_check_callbacks+0xf36/0x1380 kernel/rcu/tree.c:2521 update_process_times+0x32/0x80 kernel/time/timer.c:1635 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:161 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1271 __run_hrtimer kernel/time/hrtimer.c:1389 [inline] __hrtimer_run_queues+0x3a7/0x1050 kernel/time/hrtimer.c:1451 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1035 [inline] smp_apic_timer_interrupt+0x18d/0x760 arch/x86/kernel/apic/apic.c:1060 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:67 [inline] RIP: 0010:write_comp_data+0x9/0x70 kernel/kcov.c:122 Code: 12 00 00 8b 80 dc 12 00 00 48 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 5d c3 0f 1f 00 65 4c 8b 04 25 40 ee 01 00 <65> 8b 05 80 ee 7f 7e a9 00 01 1f 00 75 51 41 8b 80 d8 12 00 00 83 RSP: 0018:ffff888080466f58 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 000000000000226d RBX: ffff888080467140 RCX: ffffffff87f08bdf RDX: 0000000000000002 RSI: 0000000000000002 RDI: 0000000000000007 RBP: ffff888080466f60 R08: ffff888096338480 R09: ffffed1015cc5b90 R10: ffffed1015cc5b8f R11: ffff8880ae62dc7b R12: 1ffff1101008cdf0 R13: ffff888092b64102 R14: ffff888092b64102 R15: ffff888080467158 xa_is_node include/linux/xarray.h:946 [inline] xas_start+0x1cf/0x720 lib/xarray.c:183 xas_load+0x21/0x160 lib/xarray.c:227 find_get_entry+0x350/0x10a0 mm/filemap.c:1476 pagecache_get_page+0xe6/0x1020 mm/filemap.c:1579 find_get_page include/linux/pagemap.h:272 [inline] generic_file_buffered_read mm/filemap.c:2076 [inline] generic_file_read_iter+0x7b2/0x2d40 mm/filemap.c:2350 ext4_file_read_iter+0x180/0x3c0 fs/ext4/file.c:77 call_read_iter include/linux/fs.h:1856 [inline] generic_file_splice_read+0x5c4/0xa90 fs/splice.c:308 do_splice_to+0x12a/0x190 fs/splice.c:880 splice_direct_to_actor+0x31b/0x9d0 fs/splice.c:957 do_splice_direct+0x2c7/0x420 fs/splice.c:1066 do_sendfile+0x61a/0xe60 fs/read_write.c:1436 __do_sys_sendfile64 fs/read_write.c:1491 [inline] __se_sys_sendfile64 fs/read_write.c:1483 [inline] __x64_sys_sendfile64+0x15a/0x240 fs/read_write.c:1483 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x446a19 Code: e8 dc e6 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 4b 07 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f53e33cfda8 EFLAGS: 00000297 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00000000006dcc28 RCX: 0000000000446a19 RDX: 0000000020000380 RSI: 0000000000000003 RDI: 0000000000000003 RBP: 00000000006dcc20 R08: 0000000000000000 R09: 0000000000000000 R10: 00008080fffffffe R11: 0000000000000297 R12: 00000000006dcc2c R13: 00008080fffffffe R14: 00007f53e33d09c0 R15: 00000000006dcd2c rcu: rcu_preempt kthread starved for 10502 jiffies! g6469 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 26200 10 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x897/0x1e60 kernel/sched/core.c:3472 schedule+0xfe/0x350 kernel/sched/core.c:3516 schedule_timeout+0x14a/0x250 kernel/time/timer.c:1803 rcu_gp_fqs_loop+0x6ba/0x970 kernel/rcu/tree.c:1948 rcu_gp_kthread+0x2bb/0xc10 kernel/rcu/tree.c:2105 kthread+0x357/0x430 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 sched: RT throttling activated --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot. syzbot can test patches for this bug, for details see: https://goo.gl/tpsmEJ#testing-patches