syzbot

BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1375
in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 8518, name: syz-executor608
1 lock held by syz-executor608/8518:
 #0: ffffffff8b374160 (rcu_read_lock){....}-{1:2}, at: kernel_migrate_pages+0xed/0x6d0 mm/mempolicy.c:1527
Preemption disabled at:
[<ffffffff81c395b5>] percpu_up_read include/linux/percpu-rwsem.h:101 [inline]
[<ffffffff81c395b5>] __sb_end_write include/linux/fs.h:1587 [inline]
[<ffffffff81c395b5>] sb_end_write include/linux/fs.h:1614 [inline]
[<ffffffff81c395b5>] pipe_write+0xf85/0x1ac0 fs/pipe.c:589
CPU: 0 PID: 8518 Comm: syz-executor608 Not tainted 5.11.0-rc3-next-20210114-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:120
 ___might_sleep.cold+0x1f1/0x237 kernel/sched/core.c:7964
 down_read_killable+0x77/0x480 kernel/locking/rwsem.c:1375
 mm_access+0x48/0x150 kernel/fork.c:1227
 kernel_migrate_pages+0x1f8/0x6d0 mm/mempolicy.c:1546
 __do_sys_migrate_pages mm/mempolicy.c:1599 [inline]
 __se_sys_migrate_pages mm/mempolicy.c:1595 [inline]
 __x64_sys_migrate_pages+0x93/0xf0 mm/mempolicy.c:1595
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4401d9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fff1caf8538 EFLAGS: 00000246 ORIG_RAX: 0000000000000100
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401d9
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000000
RBP: 00000000006ca018 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004019e0
R13: 0000000000401a70 R14: 0000000000000000 R15: 0000000000000000

=============================
[ BUG: Invalid wait context ]
5.11.0-rc3-next-20210114-syzkaller #0 Tainted: G        W        
-----------------------------
syz-executor608/8518 is trying to lock:
ffff88801146c6d8 (&sig->exec_update_lock){++++}-{3:3}, at: mm_access+0x48/0x150 kernel/fork.c:1227
other info that might help us debug this:
context-{4:4}
1 lock held by syz-executor608/8518:
 #0: ffffffff8b374160 (rcu_read_lock){....}-{1:2}, at: kernel_migrate_pages+0xed/0x6d0 mm/mempolicy.c:1527
stack backtrace:
CPU: 0 PID: 8518 Comm: syz-executor608 Tainted: G        W         5.11.0-rc3-next-20210114-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:120
 print_lock_invalid_wait_context kernel/locking/lockdep.c:4484 [inline]
 check_wait_context kernel/locking/lockdep.c:4545 [inline]
 __lock_acquire.cold+0x304/0x39e kernel/locking/lockdep.c:4782
 lock_acquire kernel/locking/lockdep.c:5442 [inline]
 lock_acquire+0x1a8/0x720 kernel/locking/lockdep.c:5407
 down_read_killable+0x98/0x480 kernel/locking/rwsem.c:1376
 mm_access+0x48/0x150 kernel/fork.c:1227
 kernel_migrate_pages+0x1f8/0x6d0 mm/mempolicy.c:1546
 __do_sys_migrate_pages mm/mempolicy.c:1599 [inline]
 __se_sys_migrate_pages mm/mempolicy.c:1595 [inline]
 __x64_sys_migrate_pages+0x93/0xf0 mm/mempolicy.c:1595
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4401d9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fff1caf8538 EFLAGS: 00000246 ORIG_RAX: 0000000000000100
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000