loop0: rw=0, want=18442984958116442982, limit=264192
attempt to access beyond end of device
loop0: rw=0, want=18442984958116442984, limit=264192
attempt to access beyond end of device
loop0: rw=0, want=18442984958116442986, limit=264192
INFO: task syz-executor6:10886 blocked for more than 140 seconds.
Not tainted 4.9.124-g09eb2ba #31
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor6 D28504 10886 3866 0x00000004
ffff8801982ec800 0000000000000000 ffff8801d73ec540 ffff8801d9a38000
ffff8801db221c18 ffff8801cd4c7b58 ffffffff839f0afd 0000000000000002
0000000041b58ab3 ffffffff843bbc94 00ffffff81223870 ffff8801db2224e8
Call Trace:
[<ffffffff839f20ff>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
[<ffffffff816073d9>] wb_wait_for_completion+0x149/0x1b0 fs/fs-writeback.c:221
[<ffffffff8160cb69>] sync_inodes_sb+0x1a9/0x8d0 fs/fs-writeback.c:2412
[<ffffffff8161ec93>] sync_inodes_one_sb+0x43/0x60 fs/sync.c:73
[<ffffffff81581590>] iterate_supers+0x130/0x260 fs/super.c:593
[<ffffffff8161f5a2>] sys_sync+0xa2/0x170 fs/sync.c:112
[<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
[<ffffffff83a019d3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Showing all locks held in the system:
2 locks held by khungtaskd/519:
#0: (rcu_read_lock){......}, at: [<ffffffff813689dc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
#0: (rcu_read_lock){......}, at: [<ffffffff813689dc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
#1: (tasklist_lock){.+.+..}, at: [<ffffffff81428248>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/3762:
#0: (&tty->ldisc_sem){++++++}, at: [<ffffffff839ffba2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
#1: (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff82125402>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor6/10886:
#0: (&type->s_umount_key#38){++++..}, at: [<ffffffff81581541>] iterate_supers+0xe1/0x260 fs/super.c:591
1 lock held by syz-executor6/10923:
#0: (&type->s_umount_key#38){++++..}, at: [<ffffffff81581541>] iterate_supers+0xe1/0x260 fs/super.c:591
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.124-g09eb2ba #31
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
ffff8801d979fd08 ffffffff81eb95e9 0000000000000000 0000000000000000
0000000000000000 0000000000000001 ffffffff810b9fa0 ffff8801d979fd40
ffffffff81ec4927 0000000000000000 0000000000000000 0000000000000003
Call Trace:
[<ffffffff81eb95e9>] __dump_stack lib/dump_stack.c:15 [inline]
[<ffffffff81eb95e9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
[<ffffffff81ec4927>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
[<ffffffff81ec48ba>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
[<ffffffff810ba0a4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
[<ffffffff81368f74>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
[<ffffffff81368f74>] check_hung_task kernel/hung_task.c:125 [inline]
[<ffffffff81368f74>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
[<ffffffff81368f74>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
[<ffffffff8119f3cd>] kthread+0x26d/0x300 kernel/kthread.c:211
[<ffffffff83a01b9c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 6 Comm: kworker/u4:0 Not tainted 4.9.124-g09eb2ba #31
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: writeback wb_workfnc (flush-7:0)c
task: ffff8801d9a38000 task.stack: ffff8801d9a40000
RIP: 0010:[<ffffffff81360cf1>] c [<ffffffff81360cf1>] __sanitizer_cov_trace_pc+0x1/0x50 kernel/kcov.c:93
RSP: 0018:ffff8801d9a47690 EFLAGS: 00000202
RAX: ffff8801d9a38000 RBX: 0000000000000001 RCX: 0000000000000009
RDX: 0000000000000000 RSI: ffffffff81629df9 RDI: ffff8801c54749e0
RBP: ffff8801d9a47730 R08: ffff8801d9a38988 R09: 0000000000000001
R10: 0000000000000000 R11: 1ffff1003b34712c R12: 0000000000000200
R13: ffffea0006adefc0 R14: 0000000000000200 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f21e33d4000 CR3: 00000001cb77d000 CR4: 00000000001606f0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Stack:
ffff8801d9a47730c ffffffff81629e0ac ffff8801b9a20148c ffff8801cbfb2848c
ffffffff839f7176c ffffed00397f6509c 00000000000004b2c ffff8801cbfb2a00c
ffffea0006adefe0c 0000000000000000c ffff8801cbfb29d0c 00000008d9a38940c
Call Trace:
[<ffffffff8162d48d>] __bread_gfp+0x2d/0x270 fs/buffer.c:1420
[<ffffffff818db771>] sb_bread include/linux/buffer_head.h:300 [inline]
[<ffffffff818db771>] fat_clusters_flush+0x111/0x380 fs/fat/misc.c:69
[<ffffffff818d56d2>] fat_write_inode+0xf2/0x170 fs/fat/inode.c:898
[<ffffffff81606add>] write_inode fs/fs-writeback.c:1180 [inline]
[<ffffffff81606add>] __writeback_single_inode+0x86d/0x1020 fs/fs-writeback.c:1379
[<ffffffff81607ddc>] writeback_sb_inodes+0x4ac/0xe70 fs/fs-writeback.c:1584
[<ffffffff8160889b>] __writeback_inodes_wb+0xfb/0x1e0 fs/fs-writeback.c:1653
[<ffffffff81609022>] wb_writeback+0x512/0xbd0 fs/fs-writeback.c:1762
[<ffffffff8161230e>] wb_do_writeback fs/fs-writeback.c:1894 [inline]
[<ffffffff8161230e>] wb_workfn+0x20e/0xdb0 fs/fs-writeback.c:1930
[<ffffffff8118f461>] process_one_work+0x7e1/0x1500 kernel/workqueue.c:2092
[<ffffffff81190256>] worker_thread+0xd6/0x10a0 kernel/workqueue.c:2226
[<ffffffff8119f3cd>] kthread+0x26d/0x300 kernel/kthread.c:211
[<ffffffff83a01b9c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Code: c00 ceb c81 c4c c89 cff ce8 caf cee c1d c00 ce9 c5f cff cff cff c48 c89 cdf ce8 c02 cee c1d c00 ce9 cf9 cfe cff cff c66 c2e c0f c1f c84 c00 c00 c00 c00 c00 c0f c1f c00 c55 c<48> c89 ce5 c65 c48 c8b c04 c25 cc0 c7d c01 c00 c65 c8b c15 c4c c70 ccb c7e c81 ce2 c