INFO: task hung in con_set

INFO: task hung in con_set_cmap
Status: closed as dup on 2020/07/26 05:18
Reported-by: syzbot+382942b1a0524b2f916f@syzkaller.appspotmail.com
First crash: 33d, last: 33d
Duplicate of (1):
Title	Repro	Bisected	Count	Last	Reported
KASAN: vmalloc-out-of-bounds Write in bitfill_aligned	C		475	11d	245d
Sample crash report:
INFO: task syz-executor.2:31005 blocked for more than 143 seconds.
      Not tainted 5.8.0-rc3-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D28760 31005  30593 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:3453 [inline]
 __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4178
 schedule+0xd0/0x2a0 kernel/sched/core.c:4253
 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1873
 __down_common kernel/locking/semaphore.c:220 [inline]
 __down+0x183/0x2a0 kernel/locking/semaphore.c:237
 down+0x57/0x80 kernel/locking/semaphore.c:61
 console_lock+0x25/0x80 kernel/printk/printk.c:2309
 con_set_cmap+0xa8/0x510 drivers/tty/vt/vt.c:4396
 vt_ioctl+0x1682/0x2670 drivers/tty/vt/vt_ioctl.c:936
 tty_ioctl+0x1019/0x15f0 drivers/tty/tty_io.c:2656
 vfs_ioctl fs/ioctl.c:48 [inline]
 ksys_ioctl+0x11a/0x180 fs/ioctl.c:753
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl fs/ioctl.c:760 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cb29
Code: Bad RIP value.
RSP: 002b:00007f9e4bf41c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004ea220 RCX: 000000000045cb29
RDX: 0000000020000000 RSI: 0000000000004b71 RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000042e R14: 00000000004c7022 R15: 00007f9e4bf426d4

Showing all locks held in the system:
1 lock held by khungtaskd/1146:
 #0: ffffffff89bc1180 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779
1 lock held by in:imklog/6563:
 #0: ffff8880a8141670 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826
4 locks held by syz-executor.3/30468:
 #0: ffff888092c5d098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267
 #1: ffff888092c5d130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_write_lock drivers/tty/tty_io.c:888 [inline]
 #1: ffff888092c5d130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: do_tty_write drivers/tty/tty_io.c:911 [inline]
 #1: ffff888092c5d130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_write+0x280/0x870 drivers/tty/tty_io.c:1046
 #2: ffff888092c5d2e8 (&tty->termios_rwsem){++++}-{3:3}, at: n_tty_write+0x1bf/0xf80 drivers/tty/n_tty.c:2316
 #3: ffffc90004961378 (&ldata->output_lock){+.+.}-{3:3}, at: process_output_block drivers/tty/n_tty.c:550 [inline]
 #3: ffffc90004961378 (&ldata->output_lock){+.+.}-{3:3}, at: n_tty_write+0x4fa/0xf80 drivers/tty/n_tty.c:2333
2 locks held by syz-executor.1/31001:

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 1146 Comm: khungtaskd Not tainted 5.8.0-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+0x18f/0x20d lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline]
 watchdog+0xd7d/0x1000 kernel/hung_task.c:295
 kthread+0x3b5/0x4a0 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 31001 Comm: syz-executor.1 Not tainted 5.8.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:196
Code: 48 89 ef 5d e9 01 07 3f 00 5d be 03 00 00 00 e9 26 b3 23 02 66 0f 1f 44 00 00 48 8b be b0 01 00 00 e8 b4 ff ff ff 31 c0 c3 90 <65> 48 8b 14 25 00 ff 01 00 65 8b 05 50 47 8e 7e a9 00 01 ff 00 48
RSP: 0018:ffffc900038ef5a8 EFLAGS: 00000202
RAX: 0000000000000002 RBX: 0000000000000001 RCX: ffffffff83c64684
RDX: 0000000000000001 RSI: ffff888049fee0c0 RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000000000001 R09: ffff888218ff165f
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880000a0000
R13: ffff8880000a0000 R14: 0000000000000000 R15: 00000000688abb28
FS:  00007fef1ab8c700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff49f020000 CR3: 0000000090fc1000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 writeb arch/x86/include/asm/io.h:65 [inline]
 vga16fb_fillrect+0x9c0/0x193b drivers/video/fbdev/vga16fb.c:923
 bit_clear_margins+0x2d5/0x4a0 drivers/video/fbdev/core/bitblit.c:232
 fbcon_clear_margins+0x1d5/0x230 drivers/video/fbdev/core/fbcon.c:1381
 fbcon_switch+0xb6e/0x16c0 drivers/video/fbdev/core/fbcon.c:2363
 redraw_screen+0x2ae/0x770 drivers/tty/vt/vt.c:1015
 fbcon_modechanged+0x575/0x710 drivers/video/fbdev/core/fbcon.c:3001
 fbcon_update_vcs+0x3a/0x50 drivers/video/fbdev/core/fbcon.c:3048
 fb_set_var+0xae8/0xd60 drivers/video/fbdev/core/fbmem.c:1056
 do_fb_ioctl+0x33f/0x6c0 drivers/video/fbdev/core/fbmem.c:1109
 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1185
 vfs_ioctl fs/ioctl.c:48 [inline]
 ksys_ioctl+0x11a/0x180 fs/ioctl.c:753
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl fs/ioctl.c:760 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cb29
Code: Bad RIP value.
RSP: 002b:00007fef1ab8bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e55e0 RCX: 000000000045cb29
RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000002fd R14: 00000000004c58a5 R15: 00007fef1ab8c6d4
Crashes (1):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	Maintainers
ci-upstream-kasan-gce-root	2020/07/04 19:49	upstream	7cc2a8ea	51095195	.config	log	report			ebiggers@google.com, gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org, nico@fluxnic.net, sam@ravnborg.org