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=-0.4 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 D7B28C2D0C0 for ; Thu, 26 Dec 2019 21:25:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AFFF720838 for ; Thu, 26 Dec 2019 21:25:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727016AbfLZVZL (ORCPT ); Thu, 26 Dec 2019 16:25:11 -0500 Received: from mail-io1-f71.google.com ([209.85.166.71]:56204 "EHLO mail-io1-f71.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726827AbfLZVZK (ORCPT ); Thu, 26 Dec 2019 16:25:10 -0500 Received: by mail-io1-f71.google.com with SMTP id z21so17550510iob.22 for ; Thu, 26 Dec 2019 13:25:10 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:message-id:subject:from:to; bh=ZKQ8t0LgRq3eSEQ30gZDP+qRt7+3uldP2yAu+ovI0lM=; b=pMM+dHxzZViQ6KANRjU9kUEPNZezPuqT0PoThW0OfX3La0L0KwdRuyrI3nQQyPhj39 Wjy2HgFhjNwEHel+e4AG95Iq1nfplPXmzx64y3OEC2gq88FxKNdOmQiEIPTzFWIsX30/ 4+Pnuq1YwmoKmHxD8p5w0zq2vUYjR2TIL5x++2i0+dPlFmFEdy1pmG6JcwEiBcs2aaHe VaGZcDrAuVX3CE66SsqnFr/MYLXeiXsZ6ou8K5NNMy/4WoRnoO9/xteAUjXISvqqwIQH SetTF6KXXCTn+F7Nf9oxPiHKau/v0pxLgREbPGbKYzVND2Ozw95hSVREQjI9LPpp9O05 0oEA== X-Gm-Message-State: APjAAAVxZbr0/NJ0dwCt4uD6b/FEw65PcmZ7AzuxUcX+Bq8/4rXBReFk 2YunRqiT5SVleGEQoNjonwYiuI63OQZff+Rsh5WAaJv+dUBX X-Google-Smtp-Source: APXvYqySw3c5SYTM6WDiwD4RYyo/I1NRODtqLrRrqlDXUw9CGt3QivfVdV9pGcz2LrRCJChL1rfewTyX7Bb2B4uEEkIVNSco22P1 MIME-Version: 1.0 X-Received: by 2002:a5d:8901:: with SMTP id b1mr30764167ion.246.1577395509730; Thu, 26 Dec 2019 13:25:09 -0800 (PST) Date: Thu, 26 Dec 2019 13:25:09 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000072c55059aa2033b@google.com> Subject: possible deadlock in uart_write From: syzbot To: gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-serial-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org Hello, syzbot found the following crash on: HEAD commit: 46cf053e Linux 5.5-rc3 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=17295351e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=ed9d672709340e35 dashboard link: https://syzkaller.appspot.com/bug?extid=b0e376d3731cd5e82bb7 compiler: gcc (GCC) 9.0.0 20181231 (experimental) userspace arch: i386 Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+b0e376d3731cd5e82bb7@syzkaller.appspotmail.com ============================================ WARNING: possible recursive locking detected 5.5.0-rc3-syzkaller #0 Not tainted -------------------------------------------- syz-executor.2/25003 is trying to acquire lock: ffffffff8c103048 (&port_lock_key){-.-.}, at: uart_write+0x1e1/0x6f0 drivers/tty/serial/serial_core.c:592 but task is already holding lock: ffffffff8c103048 (&port_lock_key){-.-.}, at: serial8250_handle_irq.part.0+0x24/0x330 drivers/tty/serial/8250/8250_port.c:1823 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&port_lock_key); lock(&port_lock_key); *** DEADLOCK *** May be due to missing lock nesting notation 5 locks held by syz-executor.2/25003: #0: ffff8880942de858 (&(ptlock_ptr(page))->rlock#2){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline] #0: ffff8880942de858 (&(ptlock_ptr(page))->rlock#2){+.+.}, at: zap_pte_range mm/memory.c:1038 [inline] #0: ffff8880942de858 (&(ptlock_ptr(page))->rlock#2){+.+.}, at: zap_pmd_range mm/memory.c:1184 [inline] #0: ffff8880942de858 (&(ptlock_ptr(page))->rlock#2){+.+.}, at: zap_pud_range mm/memory.c:1213 [inline] #0: ffff8880942de858 (&(ptlock_ptr(page))->rlock#2){+.+.}, at: zap_p4d_range mm/memory.c:1234 [inline] #0: ffff8880942de858 (&(ptlock_ptr(page))->rlock#2){+.+.}, at: unmap_page_range+0x885/0x28a0 mm/memory.c:1255 #1: ffffffff899a5680 (rcu_read_lock){....}, at: lock_page_memcg+0x0/0x240 include/linux/cgroup.h:491 #2: ffff88809ed05430 (&(&i->lock)->rlock){-.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] #2: ffff88809ed05430 (&(&i->lock)->rlock){-.-.}, at: serial8250_interrupt+0x2d/0x1a0 drivers/tty/serial/8250/8250_core.c:116 #3: ffffffff8c103048 (&port_lock_key){-.-.}, at: serial8250_handle_irq.part.0+0x24/0x330 drivers/tty/serial/8250/8250_port.c:1823 #4: ffff88808c386090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref+0x22/0x90 drivers/tty/tty_ldisc.c:288 stack backtrace: CPU: 1 PID: 25003 Comm: syz-executor.2 Not tainted 5.5.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_deadlock_bug kernel/locking/lockdep.c:2371 [inline] check_deadlock kernel/locking/lockdep.c:2412 [inline] validate_chain kernel/locking/lockdep.c:2955 [inline] __lock_acquire.cold+0x15d/0x385 kernel/locking/lockdep.c:3955 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:159 uart_write+0x1e1/0x6f0 drivers/tty/serial/serial_core.c:592 n_hdlc_send_frames+0x29a/0x480 drivers/tty/n_hdlc.c:403 n_hdlc_tty_wakeup+0xc0/0xe0 drivers/tty/n_hdlc.c:479 tty_wakeup+0xe9/0x120 drivers/tty/tty_io.c:536 tty_port_default_wakeup+0x2b/0x40 drivers/tty/tty_port.c:50 tty_port_tty_wakeup+0x57/0x70 drivers/tty/tty_port.c:388 uart_write_wakeup+0x46/0x70 drivers/tty/serial/serial_core.c:104 serial8250_tx_chars+0x495/0xaf0 drivers/tty/serial/8250/8250_port.c:1761 serial8250_handle_irq.part.0+0x2a2/0x330 drivers/tty/serial/8250/8250_port.c:1834 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1820 [inline] serial8250_default_handle_irq+0xc0/0x150 drivers/tty/serial/8250/8250_port.c:1850 serial8250_interrupt+0xf1/0x1a0 drivers/tty/serial/8250/8250_core.c:126 __handle_irq_event_percpu+0x15d/0x970 kernel/irq/handle.c:149 handle_irq_event_percpu+0x74/0x160 kernel/irq/handle.c:189 handle_irq_event+0xa7/0x134 kernel/irq/handle.c:206 handle_edge_irq+0x25e/0x8d0 kernel/irq/chip.c:830 generic_handle_irq_desc include/linux/irqdesc.h:156 [inline] do_IRQ+0xde/0x280 arch/x86/kernel/irq.c:250 common_interrupt+0xf/0xf arch/x86/entry/entry_64.S:607 RIP: 0010:check_memory_region_inline mm/kasan/generic.c:174 [inline] RIP: 0010:check_memory_region+0x105/0x1a0 mm/kasan/generic.c:192 Code: eb 0c 49 83 c0 01 4c 89 c8 4d 39 c8 74 10 41 80 38 00 74 ee 4b 8d 44 25 00 4d 85 c0 75 31 49 89 d9 49 29 c1 e9 68 ff ff ff 5b 01 00 00 00 41 5c 41 5d 5d c3 4d 85 c9 74 ef 4d 01 e1 eb 09 48 RSP: 0018:ffffc9000749f8a0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffda RAX: ffffed1015d2703d RBX: ffff8880ae938100 RCX: ffffffff8162ae44 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8880ae9381e0 RBP: ffffc9000749f8b0 R08: 1ffff11015d2703c R09: ffffed1015d2703d R10: ffffed1015d2703c R11: ffff8880ae9381e3 R12: ffffed1015d2703c R13: 0000000000000000 R14: ffffea0001b62008 R15: dead000000000100 __kasan_check_read+0x11/0x20 mm/kasan/common.c:95 atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 kernel/rcu/tree.c:301 rcu_is_watching+0x10/0x30 kernel/rcu/tree.c:922 rcu_read_unlock include/linux/rcupdate.h:667 [inline] __unlock_page_memcg+0x73/0x100 mm/memcontrol.c:2019 unlock_page_memcg+0x2c/0x40 mm/memcontrol.c:2028 page_remove_file_rmap mm/rmap.c:1273 [inline] page_remove_rmap+0x60c/0x11d0 mm/rmap.c:1330 zap_pte_range mm/memory.c:1080 [inline] zap_pmd_range mm/memory.c:1184 [inline] zap_pud_range mm/memory.c:1213 [inline] zap_p4d_range mm/memory.c:1234 [inline] unmap_page_range+0xde0/0x28a0 mm/memory.c:1255 unmap_single_vma+0x19d/0x300 mm/memory.c:1300 unmap_vmas+0x184/0x2f0 mm/memory.c:1332 exit_mmap+0x2ba/0x530 mm/mmap.c:3140 __mmput kernel/fork.c:1082 [inline] mmput+0x179/0x4d0 kernel/fork.c:1103 exit_mm kernel/exit.c:485 [inline] do_exit+0x806/0x2ef0 kernel/exit.c:784 do_group_exit+0x135/0x360 kernel/exit.c:895 __do_sys_exit_group kernel/exit.c:906 [inline] __se_sys_exit_group kernel/exit.c:904 [inline] __ia32_sys_exit_group+0x44/0x50 kernel/exit.c:904 do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline] do_fast_syscall_32+0x27b/0xe16 arch/x86/entry/common.c:408 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f32a39 Code: 00 00 00 89 d3 5b 5e 5f 5d c3 b8 80 96 98 00 eb c4 8b 04 24 c3 8b 1c 24 c3 8b 34 24 c3 8b 3c 24 c3 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:000000000848fd7c EFLAGS: 00000202 ORIG_RAX: 00000000000000fc RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000080589db RBP: 00000000fffffff7 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 --- 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#status for how to communicate with syzbot.