INFO: task syz-executor.2:6065 blocked for more than 143 seconds. Not tainted 5.8.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28752 6065 7089 0x00004004 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_preempt_disabled+0xf/0x20 kernel/sched/core.c:4312 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x3e2/0x10d0 kernel/locking/mutex.c:1103 lock_fb_info include/linux/fb.h:637 [inline] fb_open+0xd3/0x430 drivers/video/fbdev/core/fbmem.c:1418 chrdev_open+0x266/0x770 fs/char_dev.c:414 do_dentry_open+0x501/0x1290 fs/open.c:828 do_open fs/namei.c:3243 [inline] path_openat+0x1bb9/0x2750 fs/namei.c:3360 do_filp_open+0x17e/0x3c0 fs/namei.c:3387 do_sys_openat2+0x16f/0x3b0 fs/open.c:1179 do_sys_open fs/open.c:1195 [inline] __do_sys_openat fs/open.c:1209 [inline] __se_sys_openat fs/open.c:1204 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1204 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45cba9 Code: Bad RIP value. RSP: 002b:00007ff5a4769c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00000000004f8ba0 RCX: 000000000045cba9 RDX: 0000000000000000 RSI: 0000000020000180 RDI: ffffffffffffff9c RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000007c5 R14: 00000000004cabb1 R15: 00007ff5a476a6d4 Showing all locks held in the system: 1 lock held by khungtaskd/1147: #0: ffffffff89bc11c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779 2 locks held by in:imklog/6522: 2 locks held by agetty/6766: #0: ffff88808dbd8098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900010002e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x223/0x1a30 drivers/tty/n_tty.c:2156 2 locks held by agetty/6767: #0: ffff8880a6d3e098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc90000ff02e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x223/0x1a30 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.0/6064: 1 lock held by syz-executor.2/6065: #0: ffff8880a37fd078 (&fb_info->lock){+.+.}-{3:3}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff8880a37fd078 (&fb_info->lock){+.+.}-{3:3}, at: fb_open+0xd3/0x430 drivers/video/fbdev/core/fbmem.c:1418 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1147 Comm: khungtaskd Not tainted 5.8.0-rc4-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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 6522 Comm: in:imklog Not tainted 5.8.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:163 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x9/0x60 kernel/kcov.c:197 Code: 5d be 03 00 00 00 e9 f6 bf 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 8b 34 24 74 0f f6 c4 01 74 RSP: 0018:ffffc900040d7b58 EFLAGS: 00000246 RAX: 0000000000082331 RBX: ffff888012ba2000 RCX: 0000000000000006 RDX: ffff8880906de0c0 RSI: 0000000000000000 RDI: ffff888012ba2000 RBP: 0000000080000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: ffffc900040d7bb8 R14: 0000000000000000 R15: 0000000000000286 FS: 00007f23f6729700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004440d0 CR3: 00000000a89f5000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __phys_addr+0x14/0x110 arch/x86/mm/physaddr.c:17 virt_to_head_page include/linux/mm.h:841 [inline] qlink_to_cache mm/kasan/quarantine.c:128 [inline] qlist_free_all+0xbb/0x140 mm/kasan/quarantine.c:164 quarantine_reduce+0x17e/0x200 mm/kasan/quarantine.c:260 __kasan_kmalloc.constprop.0+0x9e/0xd0 mm/kasan/common.c:475 kmem_cache_alloc_trace+0x14f/0x2d0 mm/slab.c:3551 kmalloc include/linux/slab.h:555 [inline] syslog_print kernel/printk/printk.c:1384 [inline] do_syslog.part.0+0x252/0x16c0 kernel/printk/printk.c:1557 do_syslog+0x49/0x60 kernel/printk/printk.c:1538 kmsg_read+0x90/0xb0 fs/proc/kmsg.c:40 pde_read fs/proc/inode.c:306 [inline] proc_reg_read+0x119/0x300 fs/proc/inode.c:316 __vfs_read+0x76/0x100 fs/read_write.c:426 vfs_read+0x1f6/0x420 fs/read_write.c:462 ksys_read+0x12d/0x250 fs/read_write.c:588 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f23f8d6c22d Code: Bad RIP value. RSP: 002b:00007f23f6708580 EFLAGS: 00000293 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f23f8d6c22d RDX: 0000000000001fa0 RSI: 00007f23f6708da0 RDI: 0000000000000004 RBP: 000055fe7edb49d0 R08: 0000000000000000 R09: 0000000004000001 R10: 0000000000000001 R11: 0000000000000293 R12: 00007f23f6708da0 R13: 0000000000001fa0 R14: 0000000000001f9f R15: 00007f23f6708dfc