From mboxrd@z Thu Jan 1 00:00:00 1970 From: syzbot Date: Thu, 12 Dec 2019 10:37:09 +0000 Subject: INFO: task hung in fb_compat_ioctl Message-Id: <000000000000d424a205997f53bd@google.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: b.zolnierkie@samsung.com, daniel.vetter@ffwll.ch, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, maarten.lankhorst@linux.intel.com, peda@axentia.se, sam@ravnborg.org, syzkaller-bugs@googlegroups.com Hello, syzbot found the following crash on: HEAD commit: 687dec9b Merge tag 'erofs-for-5.5-rc2-fixes' of git://git... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x979cfae00000 kernel config: https://syzkaller.appspot.com/x/.config?xyf79de2a27d3e3d dashboard link: https://syzkaller.appspot.com/bug?extid1df5e46ec99b40552c 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+061df5e46ec99b40552c@syzkaller.appspotmail.com INFO: task syz-executor.2:25386 blocked for more than 143 seconds. Not tainted 5.5.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D29712 25386 9095 0x20020004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1036 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1106 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1121 lock_fb_info include/linux/fb.h:637 [inline] fb_get_fscreeninfo drivers/video/fbdev/core/fbmem.c:1283 [inline] fb_compat_ioctl+0x6ed/0xc50 drivers/video/fbdev/core/fbmem.c:1314 __do_compat_sys_ioctl fs/compat_ioctl.c:214 [inline] __se_compat_sys_ioctl fs/compat_ioctl.c:142 [inline] __ia32_compat_sys_ioctl+0x233/0x610 fs/compat_ioctl.c:142 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: 0023:0xf7f41a39 Code: Bad RIP value. RSP: 002b:00000000f5d1c0cc EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000004602 RDX: 0000000020000080 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 INFO: task syz-executor.2:25392 blocked for more than 143 seconds. Not tainted 5.5.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28520 25392 9095 0x20020004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1036 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1106 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1121 lock_fb_info include/linux/fb.h:637 [inline] fb_open+0xd7/0x450 drivers/video/fbdev/core/fbmem.c:1406 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3420 [inline] path_openat+0x10df/0x4500 fs/namei.c:3537 do_filp_open+0x1a1/0x280 fs/namei.c:3567 do_sys_open+0x3fe/0x5d0 fs/open.c:1097 __do_compat_sys_openat fs/open.c:1143 [inline] __se_compat_sys_openat fs/open.c:1141 [inline] __ia32_compat_sys_openat+0x98/0xf0 fs/open.c:1141 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: 0023:0xf7f41a39 Code: Bad RIP value. RSP: 002b:00000000f5cda0cc EFLAGS: 00000296 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00000000ffffff9c RCX: 0000000020000180 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/1113: #0: ffffffff899a56c0 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5334 1 lock held by rsyslogd/8960: #0: ffff88808c2640e0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/9050: #0: ffff88809b3bf090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900017cb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9051: #0: ffff888095020090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000184b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9052: #0: ffff8880a322a090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000182b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9053: #0: ffff88809a312090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000183b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9054: #0: ffff8880935fc090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900017eb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9055: #0: ffff88809edd6090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000181b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9056: #0: ffff8880959b2090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000178b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.2/25382: 1 lock held by syz-executor.2/25386: #0: ffff888218cbf070 (&fb_info->lock){+.+.}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff888218cbf070 (&fb_info->lock){+.+.}, at: fb_get_fscreeninfo drivers/video/fbdev/core/fbmem.c:1283 [inline] #0: ffff888218cbf070 (&fb_info->lock){+.+.}, at: fb_compat_ioctl+0x6ed/0xc50 drivers/video/fbdev/core/fbmem.c:1314 1 lock held by syz-executor.2/25392: #0: ffff888218cbf070 (&fb_info->lock){+.+.}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff888218cbf070 (&fb_info->lock){+.+.}, at: fb_open+0xd7/0x450 drivers/video/fbdev/core/fbmem.c:1406 ====================== NMI backtrace for cpu 0 CPU: 0 PID: 1113 Comm: khungtaskd Not tainted 5.5.0-rc1-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 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xb11/0x10c0 kernel/hung_task.c:289 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 25382 Comm: syz-executor.2 Not tainted 5.5.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__writeq arch/x86/include/asm/io.h:98 [inline] RIP: 0010:bitfill_aligned drivers/video/fbdev/core/cfbfillrect.c:50 [inline] RIP: 0010:bitfill_aligned+0xaa/0x210 drivers/video/fbdev/core/cfbfillrect.c:35 Code: 31 ff 4c 89 fe e8 46 9b c0 fd 4d 85 ff 74 09 e8 9c 99 c0 fd 4c 21 7d d0 e8 93 99 c0 fd 49 8b 06 48 31 c3 48 23 5d d0 48 31 c3 <49> 89 1e e8 7e 99 c0 fd 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f 5d RSP: 0018:ffffc90001567388 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc9000daef000 RDX: 0000000000040000 RSI: ffffffff83b491fd RDI: 0000000000000007 RBP: ffffc900015673c8 R08: ffff88808cdf4100 R09: 0000000000000040 R10: ffffed10147ab25b R11: ffff8880a3d592df R12: 0000000000000040 R13: 0000000000000040 R14: ffff8880000a0000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880ae900000(0063) knlGS:00000000f5d3db40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 00007f793125b140 CR3: 00000000a520a000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: cfb_fillrect+0x423/0x7c0 drivers/video/fbdev/core/cfbfillrect.c:327 vga16fb_fillrect+0x6ce/0x19b0 drivers/video/fbdev/vga16fb.c:951 bit_clear_margins+0x30b/0x530 drivers/video/fbdev/core/bitblit.c:232 fbcon_clear_margins+0x1e9/0x250 drivers/video/fbdev/core/fbcon.c:1372 fbcon_switch+0xd7f/0x17f0 drivers/video/fbdev/core/fbcon.c:2354 redraw_screen+0x2b6/0x7d0 drivers/tty/vt/vt.c:997 fbcon_modechanged+0x5c3/0x790 drivers/video/fbdev/core/fbcon.c:2991 fbcon_update_vcs+0x42/0x50 drivers/video/fbdev/core/fbcon.c:3038 fb_set_var+0xb32/0xdd0 drivers/video/fbdev/core/fbmem.c:1051 do_fb_ioctl+0x390/0x7d0 drivers/video/fbdev/core/fbmem.c:1104 fb_compat_ioctl+0x305/0xc50 drivers/video/fbdev/core/fbmem.c:1310 __do_compat_sys_ioctl fs/compat_ioctl.c:214 [inline] __se_compat_sys_ioctl fs/compat_ioctl.c:142 [inline] __ia32_compat_sys_ioctl+0x233/0x610 fs/compat_ioctl.c:142 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: 0023:0xf7f41a39 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:00000000f5d3d0cc EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000004601 RDX: 0000000020000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 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. 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=-5.4 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 8B6BFC43603 for ; Fri, 13 Dec 2019 08:22:33 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6819C214D8 for ; Fri, 13 Dec 2019 08:22:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6819C214D8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 181A06E28E; Fri, 13 Dec 2019 08:22:25 +0000 (UTC) Received: from mail-io1-f69.google.com (mail-io1-f69.google.com [209.85.166.69]) by gabe.freedesktop.org (Postfix) with ESMTPS id 848406ED13 for ; Thu, 12 Dec 2019 10:37:10 +0000 (UTC) Received: by mail-io1-f69.google.com with SMTP id p206so1234381iod.13 for ; Thu, 12 Dec 2019 02:37:10 -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=Bms5KEZuCxqFIWyEcowNRHJS4NglBx1UsLruzo2i8fY=; b=P2rIZvOSUYIIAJ8gyM9hmilcAkY2ishBC1bCeH094GNRmGVG+lEzzzofTzCrLnsaLL H+7GT8/mB2HYbNFxZg05OdjaPQyUPEVgM5JL6NcGjmvdPsMiR6lCVkajndcfmCmaKjM+ RMAy547epaiO857K/94jB6Bwgw26nU3Tthz047tt2u11CQA5WipJjNXvb3SVt4rGladC TGBMlY7y+CFwgyaIRc6kIPM/U5NCw3wI9vsLXPb9os/9o+DV/8CCcNT3DBbTwp757lz5 DiWo5UwB4XXWD6JDccZHXqW07h5/5Kpwym7SNyVbd872FtBWY08zQG7MI3gEII/GcuL1 6myg== X-Gm-Message-State: APjAAAW1KizD+BbvB0TnXhKJNKVLPiPVsSa0x/aUQqbCGgU6zXpST9/q 4NKDa6wUGMUES97xHv8WhvmlIVu6DQoPDhLL9m/PZk9VFjmv X-Google-Smtp-Source: APXvYqy3V5/Z6YXCyYGjeN1zP/bkuqwl/DOITmE9tCkoh2BwBIXnlE7K8Ykcmtcza36DFiVfMchVS6dRIlh/GPU7lyaARABcpFy1 MIME-Version: 1.0 X-Received: by 2002:a5e:8345:: with SMTP id y5mr2267186iom.122.1576147029859; Thu, 12 Dec 2019 02:37:09 -0800 (PST) Date: Thu, 12 Dec 2019 02:37:09 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000d424a205997f53bd@google.com> Subject: INFO: task hung in fb_compat_ioctl From: syzbot To: b.zolnierkie@samsung.com, daniel.vetter@ffwll.ch, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, maarten.lankhorst@linux.intel.com, peda@axentia.se, sam@ravnborg.org, syzkaller-bugs@googlegroups.com X-Mailman-Approved-At: Fri, 13 Dec 2019 08:22:24 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed"; DelSp="yes" Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hello, syzbot found the following crash on: HEAD commit: 687dec9b Merge tag 'erofs-for-5.5-rc2-fixes' of git://git... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16979cfae00000 kernel config: https://syzkaller.appspot.com/x/.config?x=79f79de2a27d3e3d dashboard link: https://syzkaller.appspot.com/bug?extid=061df5e46ec99b40552c 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+061df5e46ec99b40552c@syzkaller.appspotmail.com INFO: task syz-executor.2:25386 blocked for more than 143 seconds. Not tainted 5.5.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D29712 25386 9095 0x20020004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1036 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1106 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1121 lock_fb_info include/linux/fb.h:637 [inline] fb_get_fscreeninfo drivers/video/fbdev/core/fbmem.c:1283 [inline] fb_compat_ioctl+0x6ed/0xc50 drivers/video/fbdev/core/fbmem.c:1314 __do_compat_sys_ioctl fs/compat_ioctl.c:214 [inline] __se_compat_sys_ioctl fs/compat_ioctl.c:142 [inline] __ia32_compat_sys_ioctl+0x233/0x610 fs/compat_ioctl.c:142 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: 0023:0xf7f41a39 Code: Bad RIP value. RSP: 002b:00000000f5d1c0cc EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000004602 RDX: 0000000020000080 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 INFO: task syz-executor.2:25392 blocked for more than 143 seconds. Not tainted 5.5.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28520 25392 9095 0x20020004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1036 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1106 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1121 lock_fb_info include/linux/fb.h:637 [inline] fb_open+0xd7/0x450 drivers/video/fbdev/core/fbmem.c:1406 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3420 [inline] path_openat+0x10df/0x4500 fs/namei.c:3537 do_filp_open+0x1a1/0x280 fs/namei.c:3567 do_sys_open+0x3fe/0x5d0 fs/open.c:1097 __do_compat_sys_openat fs/open.c:1143 [inline] __se_compat_sys_openat fs/open.c:1141 [inline] __ia32_compat_sys_openat+0x98/0xf0 fs/open.c:1141 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: 0023:0xf7f41a39 Code: Bad RIP value. RSP: 002b:00000000f5cda0cc EFLAGS: 00000296 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00000000ffffff9c RCX: 0000000020000180 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/1113: #0: ffffffff899a56c0 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5334 1 lock held by rsyslogd/8960: #0: ffff88808c2640e0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/9050: #0: ffff88809b3bf090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900017cb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9051: #0: ffff888095020090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000184b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9052: #0: ffff8880a322a090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000182b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9053: #0: ffff88809a312090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000183b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9054: #0: ffff8880935fc090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900017eb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9055: #0: ffff88809edd6090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000181b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9056: #0: ffff8880959b2090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000178b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.2/25382: 1 lock held by syz-executor.2/25386: #0: ffff888218cbf070 (&fb_info->lock){+.+.}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff888218cbf070 (&fb_info->lock){+.+.}, at: fb_get_fscreeninfo drivers/video/fbdev/core/fbmem.c:1283 [inline] #0: ffff888218cbf070 (&fb_info->lock){+.+.}, at: fb_compat_ioctl+0x6ed/0xc50 drivers/video/fbdev/core/fbmem.c:1314 1 lock held by syz-executor.2/25392: #0: ffff888218cbf070 (&fb_info->lock){+.+.}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff888218cbf070 (&fb_info->lock){+.+.}, at: fb_open+0xd7/0x450 drivers/video/fbdev/core/fbmem.c:1406 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1113 Comm: khungtaskd Not tainted 5.5.0-rc1-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 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xb11/0x10c0 kernel/hung_task.c:289 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 25382 Comm: syz-executor.2 Not tainted 5.5.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__writeq arch/x86/include/asm/io.h:98 [inline] RIP: 0010:bitfill_aligned drivers/video/fbdev/core/cfbfillrect.c:50 [inline] RIP: 0010:bitfill_aligned+0xaa/0x210 drivers/video/fbdev/core/cfbfillrect.c:35 Code: 31 ff 4c 89 fe e8 46 9b c0 fd 4d 85 ff 74 09 e8 9c 99 c0 fd 4c 21 7d d0 e8 93 99 c0 fd 49 8b 06 48 31 c3 48 23 5d d0 48 31 c3 <49> 89 1e e8 7e 99 c0 fd 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f 5d RSP: 0018:ffffc90001567388 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc9000daef000 RDX: 0000000000040000 RSI: ffffffff83b491fd RDI: 0000000000000007 RBP: ffffc900015673c8 R08: ffff88808cdf4100 R09: 0000000000000040 R10: ffffed10147ab25b R11: ffff8880a3d592df R12: 0000000000000040 R13: 0000000000000040 R14: ffff8880000a0000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880ae900000(0063) knlGS:00000000f5d3db40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 00007f793125b140 CR3: 00000000a520a000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: cfb_fillrect+0x423/0x7c0 drivers/video/fbdev/core/cfbfillrect.c:327 vga16fb_fillrect+0x6ce/0x19b0 drivers/video/fbdev/vga16fb.c:951 bit_clear_margins+0x30b/0x530 drivers/video/fbdev/core/bitblit.c:232 fbcon_clear_margins+0x1e9/0x250 drivers/video/fbdev/core/fbcon.c:1372 fbcon_switch+0xd7f/0x17f0 drivers/video/fbdev/core/fbcon.c:2354 redraw_screen+0x2b6/0x7d0 drivers/tty/vt/vt.c:997 fbcon_modechanged+0x5c3/0x790 drivers/video/fbdev/core/fbcon.c:2991 fbcon_update_vcs+0x42/0x50 drivers/video/fbdev/core/fbcon.c:3038 fb_set_var+0xb32/0xdd0 drivers/video/fbdev/core/fbmem.c:1051 do_fb_ioctl+0x390/0x7d0 drivers/video/fbdev/core/fbmem.c:1104 fb_compat_ioctl+0x305/0xc50 drivers/video/fbdev/core/fbmem.c:1310 __do_compat_sys_ioctl fs/compat_ioctl.c:214 [inline] __se_compat_sys_ioctl fs/compat_ioctl.c:142 [inline] __ia32_compat_sys_ioctl+0x233/0x610 fs/compat_ioctl.c:142 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: 0023:0xf7f41a39 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:00000000f5d3d0cc EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000004601 RDX: 0000000020000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 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. _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel 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=-5.4 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS 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 5BC41C43603 for ; Thu, 12 Dec 2019 10:37:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2712220663 for ; Thu, 12 Dec 2019 10:37:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728761AbfLLKhM (ORCPT ); Thu, 12 Dec 2019 05:37:12 -0500 Received: from mail-io1-f72.google.com ([209.85.166.72]:51654 "EHLO mail-io1-f72.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728713AbfLLKhK (ORCPT ); Thu, 12 Dec 2019 05:37:10 -0500 Received: by mail-io1-f72.google.com with SMTP id t18so1208900iob.18 for ; Thu, 12 Dec 2019 02:37:10 -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=Bms5KEZuCxqFIWyEcowNRHJS4NglBx1UsLruzo2i8fY=; b=l8HUx7N41o/NP57wT/Ptb7BjEmsqUXO5nQTKuiAAqFoKzkIFNMXIJ6yKoNDlv1/Ad8 nNMbyrvxRxqcR4VsMdWWchVbiUDoDCK+QPm3+vaq/9QdPxLXhHf4YT3m9L369RxB/7UY uITzcI+rjOvdxBB4FyGbzhnvomoInBzud542W0n84wcEv84GRCaZTbGKCQqpMJtwGSXe BcZs5W++9g0vjSPDlOW/9jr33Xo0RyKsaKMrWtIX+xk+q92gCuMBrfidP2o1TGKMtj3g MJuwyKIgT+iA1ff5TiZnJ5lOKCSKLuAtIPVdv55oebRbjQft3QGH5v4Tj+OCVO4HEkxI q9VA== X-Gm-Message-State: APjAAAU7wv8sMYjTHsMi4basbBXa0kM9Wl0V9W/nMclaafKD70OX/s5n 0s2fn39lvXBOqqvx3X3KSQ4jid4GimGHlUS/wBXGcr+E629M X-Google-Smtp-Source: APXvYqy3V5/Z6YXCyYGjeN1zP/bkuqwl/DOITmE9tCkoh2BwBIXnlE7K8Ykcmtcza36DFiVfMchVS6dRIlh/GPU7lyaARABcpFy1 MIME-Version: 1.0 X-Received: by 2002:a5e:8345:: with SMTP id y5mr2267186iom.122.1576147029859; Thu, 12 Dec 2019 02:37:09 -0800 (PST) Date: Thu, 12 Dec 2019 02:37:09 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000d424a205997f53bd@google.com> Subject: INFO: task hung in fb_compat_ioctl From: syzbot To: b.zolnierkie@samsung.com, daniel.vetter@ffwll.ch, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, maarten.lankhorst@linux.intel.com, peda@axentia.se, sam@ravnborg.org, syzkaller-bugs@googlegroups.com 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: 687dec9b Merge tag 'erofs-for-5.5-rc2-fixes' of git://git... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16979cfae00000 kernel config: https://syzkaller.appspot.com/x/.config?x=79f79de2a27d3e3d dashboard link: https://syzkaller.appspot.com/bug?extid=061df5e46ec99b40552c 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+061df5e46ec99b40552c@syzkaller.appspotmail.com INFO: task syz-executor.2:25386 blocked for more than 143 seconds. Not tainted 5.5.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D29712 25386 9095 0x20020004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1036 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1106 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1121 lock_fb_info include/linux/fb.h:637 [inline] fb_get_fscreeninfo drivers/video/fbdev/core/fbmem.c:1283 [inline] fb_compat_ioctl+0x6ed/0xc50 drivers/video/fbdev/core/fbmem.c:1314 __do_compat_sys_ioctl fs/compat_ioctl.c:214 [inline] __se_compat_sys_ioctl fs/compat_ioctl.c:142 [inline] __ia32_compat_sys_ioctl+0x233/0x610 fs/compat_ioctl.c:142 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: 0023:0xf7f41a39 Code: Bad RIP value. RSP: 002b:00000000f5d1c0cc EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000004602 RDX: 0000000020000080 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 INFO: task syz-executor.2:25392 blocked for more than 143 seconds. Not tainted 5.5.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28520 25392 9095 0x20020004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1036 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1106 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1121 lock_fb_info include/linux/fb.h:637 [inline] fb_open+0xd7/0x450 drivers/video/fbdev/core/fbmem.c:1406 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3420 [inline] path_openat+0x10df/0x4500 fs/namei.c:3537 do_filp_open+0x1a1/0x280 fs/namei.c:3567 do_sys_open+0x3fe/0x5d0 fs/open.c:1097 __do_compat_sys_openat fs/open.c:1143 [inline] __se_compat_sys_openat fs/open.c:1141 [inline] __ia32_compat_sys_openat+0x98/0xf0 fs/open.c:1141 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: 0023:0xf7f41a39 Code: Bad RIP value. RSP: 002b:00000000f5cda0cc EFLAGS: 00000296 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00000000ffffff9c RCX: 0000000020000180 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/1113: #0: ffffffff899a56c0 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5334 1 lock held by rsyslogd/8960: #0: ffff88808c2640e0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/9050: #0: ffff88809b3bf090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900017cb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9051: #0: ffff888095020090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000184b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9052: #0: ffff8880a322a090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000182b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9053: #0: ffff88809a312090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000183b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9054: #0: ffff8880935fc090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900017eb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9055: #0: ffff88809edd6090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000181b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9056: #0: ffff8880959b2090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000178b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.2/25382: 1 lock held by syz-executor.2/25386: #0: ffff888218cbf070 (&fb_info->lock){+.+.}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff888218cbf070 (&fb_info->lock){+.+.}, at: fb_get_fscreeninfo drivers/video/fbdev/core/fbmem.c:1283 [inline] #0: ffff888218cbf070 (&fb_info->lock){+.+.}, at: fb_compat_ioctl+0x6ed/0xc50 drivers/video/fbdev/core/fbmem.c:1314 1 lock held by syz-executor.2/25392: #0: ffff888218cbf070 (&fb_info->lock){+.+.}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff888218cbf070 (&fb_info->lock){+.+.}, at: fb_open+0xd7/0x450 drivers/video/fbdev/core/fbmem.c:1406 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1113 Comm: khungtaskd Not tainted 5.5.0-rc1-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 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xb11/0x10c0 kernel/hung_task.c:289 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 25382 Comm: syz-executor.2 Not tainted 5.5.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__writeq arch/x86/include/asm/io.h:98 [inline] RIP: 0010:bitfill_aligned drivers/video/fbdev/core/cfbfillrect.c:50 [inline] RIP: 0010:bitfill_aligned+0xaa/0x210 drivers/video/fbdev/core/cfbfillrect.c:35 Code: 31 ff 4c 89 fe e8 46 9b c0 fd 4d 85 ff 74 09 e8 9c 99 c0 fd 4c 21 7d d0 e8 93 99 c0 fd 49 8b 06 48 31 c3 48 23 5d d0 48 31 c3 <49> 89 1e e8 7e 99 c0 fd 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f 5d RSP: 0018:ffffc90001567388 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc9000daef000 RDX: 0000000000040000 RSI: ffffffff83b491fd RDI: 0000000000000007 RBP: ffffc900015673c8 R08: ffff88808cdf4100 R09: 0000000000000040 R10: ffffed10147ab25b R11: ffff8880a3d592df R12: 0000000000000040 R13: 0000000000000040 R14: ffff8880000a0000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880ae900000(0063) knlGS:00000000f5d3db40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 00007f793125b140 CR3: 00000000a520a000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: cfb_fillrect+0x423/0x7c0 drivers/video/fbdev/core/cfbfillrect.c:327 vga16fb_fillrect+0x6ce/0x19b0 drivers/video/fbdev/vga16fb.c:951 bit_clear_margins+0x30b/0x530 drivers/video/fbdev/core/bitblit.c:232 fbcon_clear_margins+0x1e9/0x250 drivers/video/fbdev/core/fbcon.c:1372 fbcon_switch+0xd7f/0x17f0 drivers/video/fbdev/core/fbcon.c:2354 redraw_screen+0x2b6/0x7d0 drivers/tty/vt/vt.c:997 fbcon_modechanged+0x5c3/0x790 drivers/video/fbdev/core/fbcon.c:2991 fbcon_update_vcs+0x42/0x50 drivers/video/fbdev/core/fbcon.c:3038 fb_set_var+0xb32/0xdd0 drivers/video/fbdev/core/fbmem.c:1051 do_fb_ioctl+0x390/0x7d0 drivers/video/fbdev/core/fbmem.c:1104 fb_compat_ioctl+0x305/0xc50 drivers/video/fbdev/core/fbmem.c:1310 __do_compat_sys_ioctl fs/compat_ioctl.c:214 [inline] __se_compat_sys_ioctl fs/compat_ioctl.c:142 [inline] __ia32_compat_sys_ioctl+0x233/0x610 fs/compat_ioctl.c:142 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: 0023:0xf7f41a39 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:00000000f5d3d0cc EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000004601 RDX: 0000000020000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 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.