syzbot

random: sshd: uninitialized urandom read (32 bytes read)
random: crng init done
syz-executor632 (2068) used greatest stack depth: 23784 bytes left
BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:51
in_atomic(): 1, irqs_disabled(): 0, pid: 0, name: swapper/0
no locks held by swapper/0/0.
Preemption disabled at:[   36.849289] [<ffffffff828094ad>] schedule_preempt_disabled+0x1d/0x20 kernel/sched/core.c:3587
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.9.141+ #1
 ffff8801db607a20 ffffffff81b42e79 ffffffff828094ad 0000000000000000
 0000000000000101 ffffffff83029180 ffffffff83029180 ffff8801db607a58
 ffffffff813f9ecf ffffffff83029180 ffffffff82a4fa80 0000000000000033
Call Trace:
 <IRQ> [   36.890926]  [<ffffffff81b42e79>] __dump_stack lib/dump_stack.c:15 [inline]
 <IRQ> [   36.890926]  [<ffffffff81b42e79>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff813f9ecf>] ___might_sleep.cold.31+0x18a/0x1fc kernel/sched/core.c:7988
 [<ffffffff81167c85>] __might_sleep+0x95/0x1a0 kernel/sched/core.c:7945
 [<ffffffff828116d1>] down_write+0x21/0xa0 kernel/locking/rwsem.c:51
 [<ffffffff8158b831>] inode_lock include/linux/fs.h:766 [inline]
 [<ffffffff8158b831>] __generic_file_fsync+0xc1/0x1a0 fs/libfs.c:978
 [<ffffffff816b5209>] ext4_sync_file+0x659/0x10a0 fs/ext4/fsync.c:116
 [<ffffffff815b195c>] vfs_fsync_range+0x10c/0x260 fs/sync.c:195
 [<ffffffff815cd622>] generic_write_sync include/linux/fs.h:2607 [inline]
 [<ffffffff815cd622>] dio_complete+0x512/0x6c0 fs/direct-io.c:282
 [<ffffffff815cd8ec>] dio_bio_end_aio+0x11c/0x370 fs/direct-io.c:323
 [<ffffffff81ab5f75>] bio_endio+0x1a5/0x1f0 block/bio.c:1781
 [<ffffffff81ad65d8>] req_bio_endio block/blk-core.c:157 [inline]
 [<ffffffff81ad65d8>] blk_update_request+0x248/0x9b0 block/blk-core.c:2628
 [<ffffffff81e1c7ed>] scsi_end_request+0x9d/0x5c0 drivers/scsi/scsi_lib.c:606
 [<ffffffff81e257f3>] scsi_io_completion+0x273/0x17a0 drivers/scsi/scsi_lib.c:829
 [<ffffffff81e0871a>] scsi_finish_command+0x3ba/0x530 drivers/scsi/scsi.c:607
 [<ffffffff81e23d20>] scsi_softirq_done+0x250/0x360 drivers/scsi/scsi_lib.c:1567
 [<ffffffff81af449d>] blk_done_softirq+0x27d/0x3e0 block/blk-softirq.c:35
 [<ffffffff8281cb9e>] __do_softirq+0x20e/0x964 kernel/softirq.c:288
 [<ffffffff810efdbc>] invoke_softirq kernel/softirq.c:368 [inline]
 [<ffffffff810efdbc>] irq_exit+0x11c/0x150 kernel/softirq.c:409
 [<ffffffff82819b9d>] exiting_irq arch/x86/include/asm/apic.h:669 [inline]
 [<ffffffff82819b9d>] do_IRQ+0x10d/0x1c0 arch/x86/kernel/irq.c:252
 [<ffffffff8281819d>] common_interrupt+0x9d/0x9d arch/x86/entry/entry_64.S:461
 <EOI> [   37.098554]  [<ffffffff82816496>] ? native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:56
 [<ffffffff828159f5>] arch_safe_halt arch/x86/include/asm/paravirt.h:104 [inline]
 [<ffffffff828159f5>] default_idle+0x55/0x360 arch/x86/kernel/process.c:437
 [<ffffffff81068a40>] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:428
 [<ffffffff828168f5>] default_idle_call+0x45/0x60 kernel/sched/idle.c:97
 [<ffffffff811f0a85>] cpuidle_idle_call kernel/sched/idle.c:155 [inline]
 [<ffffffff811f0a85>] cpu_idle_loop kernel/sched/idle.c:248 [inline]
 [<ffffffff811f0a85>] cpu_startup_entry+0x2b5/0x380 kernel/sched/idle.c:303
 [<ffffffff82804eac>] rest_init+0x183/0x189 init/main.c:409
 [<ffffffff8341a91b>] start_kernel+0x5fb/0x62f init/main.c:664
 [<ffffffff8341929a>] x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:196
 [<ffffffff834193d6>] x86_64_start_kernel+0x13a/0x15d arch/x86/kernel/head64.c:177

=================================
[ INFO: inconsistent lock state ]
4.9.141+ #1 Tainted: G        W      
---------------------------------
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
swapper/0/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
 (&sb->s_type->i_mutex_key#9){+.?.+.}, at: [<ffffffff8158b831>] inode_lock include/linux/fs.h:766 [inline]
 (&sb->s_type->i_mutex_key#9){+.?.+.}, at: [<ffffffff8158b831>] __generic_file_fsync+0xc1/0x1a0 fs/libfs.c:978
  mark_irqflags kernel/locking/lockdep.c:2941 [inline]
  __lock_acquire+0xbdd/0x4a10 kernel/locking/lockdep.c:3302
  lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756
  down_write+0x41/0xa0 kernel/locking/rwsem.c:52
  inode_lock include/linux/fs.h:766 [inline]
  bprm_fill_uid fs/exec.c:1506 [inline]
  prepare_binprm+0x2b7/0x750 fs/exec.c:1540
  do_execveat_common.isra.14+0xe9f/0x1ed0 fs/exec.c:1766
  do_execve fs/exec.c:1829 [inline]
  SYSC_execve fs/exec.c:1910 [inline]
  SyS_execve+0x42/0x50 fs/exec.c:1905
  do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285
  entry_SYSCALL_64_after_swapgs+0x5d/0xdb
irq event stamp: 283986
hardirqs last  enabled at (283986): [<ffffffff82818226>] restore_regs_and_iret+0x0/0x1d
hardirqs last disabled at (283985): [<ffffffff82819028>] apic_timer_interrupt+0x98/0xb0 arch/x86/entry/entry_64.S:648
softirqs last  enabled at (283948): [<ffffffff810ef61c>] _local_bh_enable+0x1c/0x50 kernel/softirq.c:159
softirqs last disabled at (283949): [<ffffffff810efdbc>] invoke_softirq kernel/softirq.c:368 [inline]
softirqs last disabled at (283949): [<ffffffff810efdbc>] irq_exit+0x11c/0x150 kernel/softirq.c:409

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&sb->s_type->i_mutex_key#9);
  <Interrupt>
    lock(&sb->s_type->i_mutex_key#9);

 *** DEADLOCK ***

no locks held by swapper/0/0.

stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Tainted: G        W       4.9.141+ #1
 ffff8801db607790 ffffffff81b42e79 ffffffff83029180 ffffffff83cab370
 ffffffff83029a30 ffffffff83029a50 ffffffff84244d40 ffff8801db607808
 ffffffff81400780 0000000000000001 ffffffff00000001 0000000000000000
Call Trace:
 <IRQ> [   37.376862]  [<ffffffff81b42e79>] __dump_stack lib/dump_stack.c:15 [inline]
 <IRQ> [   37.376862]  [<ffffffff81b42e79>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81400780>] print_usage_bug.cold.40+0x44e/0x57e kernel/locking/lockdep.c:2387
 [<ffffffff81205d42>] valid_state kernel/locking/lockdep.c:2400 [inline]
 [<ffffffff81205d42>] mark_lock_irq kernel/locking/lockdep.c:2602 [inline]
 [<ffffffff81205d42>] mark_lock+0x2f2/0x1290 kernel/locking/lockdep.c:3065
 [<ffffffff81208434>] mark_irqflags kernel/locking/lockdep.c:2923 [inline]
 [<ffffffff81208434>] __lock_acquire+0x1084/0x4a10 kernel/locking/lockdep.c:3302
 [<ffffffff8120c8d0>] lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756
 [<ffffffff828116f1>] down_write+0x41/0xa0 kernel/locking/rwsem.c:52
 [<ffffffff8158b831>] inode_lock include/linux/fs.h:766 [inline]
 [<ffffffff8158b831>] __generic_file_fsync+0xc1/0x1a0 fs/libfs.c:978
 [<ffffffff816b5209>] ext4_sync_file+0x659/0x10a0 fs/ext4/fsync.c:116
 [<ffffffff815b195c>] vfs_fsync_range+0x10c/0x260 fs/sync.c:195
 [<ffffffff815cd622>] generic_write_sync include/linux/fs.h:2607 [inline]
 [<ffffffff815cd622>] dio_complete+0x512/0x6c0 fs/direct-io.c:282
 [<ffffffff815cd8ec>] dio_bio_end_aio+0x11c/0x370 fs/direct-io.c:323
 [<ffffffff81ab5f75>] bio_endio+0x1a5/0x1f0 block/bio.c:1781
 [<ffffffff81ad65d8>] req_bio_endio block/blk-core.c:157 [inline]
 [<ffffffff81ad65d8>] blk_update_request+0x248/0x9b0 block/blk-core.c:2628
 [<ffffffff81e1c7ed>] scsi_end_request+0x9d/0x5c0 drivers/scsi/scsi_lib.c:606
 [<ffffffff81e257f3>] scsi_io_completion+0x273/0x17a0 drivers/scsi/scsi_lib.c:829
 [<ffffffff81e0871a>] scsi_finish_command+0x3ba/0x530 drivers/scsi/scsi.c:607
 [<ffffffff81e23d20>] scsi_softirq_done+0x250/0x360 drivers/scsi/scsi_lib.c:1567
 [<ffffffff81af449d>] blk_done_softirq+0x27d/0x3e0 block/blk-softirq.c:35
 [<ffffffff8281cb9e>] __do_softirq+0x20e/0x964 kernel/softirq.c:288
 [<ffffffff810efdbc>] invoke_softirq kernel/softirq.c:368 [inline]
 [<ffffffff810efdbc>] irq_exit+0x11c/0x150 kernel/softirq.c:409
 [<ffffffff82819b9d>] exiting_irq arch/x86/include/asm/apic.h:669 [inline]
 [<ffffffff82819b9d>] do_IRQ+0x10d/0x1c0 arch/x86/kernel/irq.c:252
 [<ffffffff8281819d>] common_interrupt+0x9d/0x9d arch/x86/entry/entry_64.S:461
 <EOI> [   37.657761]  [<ffffffff82816496>] ? native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:56
 [<ffffffff828159f5>] arch_safe_halt arch/x86/include/asm/paravirt.h:104 [inline]
 [<ffffffff828159f5>] default_idle+0x55/0x360 arch/x86/kernel/process.c:437
 [<ffffffff81068a40>] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:428
 [<ffffffff828168f5>] default_idle_call+0x45/0x60 kernel/sched/idle.c:97
 [<ffffffff811f0a85>] cpuidle_idle_call kernel/sched/idle.c:155 [inline]
 [<ffffffff811f0a85>] cpu_idle_loop kernel/sched/idle.c:248 [inline]
 [<ffffffff811f0a85>] cpu_startup_entry+0x2b5/0x380 kernel/sched/idle.c:303
 [<ffffffff82804eac>] rest_init+0x183/0x189 init/main.c:409
 [<ffffffff8341a91b>] start_kernel+0x5fb/0x62f init/main.c:664
 [<ffffffff8341929a>] x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:196
 [<ffffffff834193d6>] x86_64_start_kernel+0x13a/0x15d arch/x86/kernel/head64.c:177
BUG: scheduling while atomic: swapper/0/0/0x00000102
INFO: lockdep is turned off.
Modules linked in:
Preemption disabled at:[   37.754120] [<ffffffff828094ad>] schedule_preempt_disabled+0x1d/0x20 kernel/sched/core.c:3587