======================================================
WARNING: possible circular locking dependency detected
4.18.0+ #192 Not tainted
------------------------------------------------------
syz-executor6/18096 is trying to acquire lock:
00000000af10a72f (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2752 [inline]
00000000af10a72f (sb_writers#3){.+.+}, at: vfs_fallocate+0x5be/0x8d0 fs/open.c:318

but task is already holding lock:
00000000087f8d54 (ashmem_mutex){+.+.}, at: ashmem_shrink_scan+0xb4/0x580 drivers/staging/android/ashmem.c:442

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (ashmem_mutex){+.+.}:
       __mutex_lock_common kernel/locking/mutex.c:925 [inline]
       __mutex_lock+0x171/0x1700 kernel/locking/mutex.c:1073
       mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088
       ashmem_mmap+0x53/0x4a0 drivers/staging/android/ashmem.c:361
       call_mmap include/linux/fs.h:1813 [inline]
       mmap_region+0xe39/0x1b50 mm/mmap.c:1762
       do_mmap+0xa06/0x1320 mm/mmap.c:1535
       do_mmap_pgoff include/linux/mm.h:2306 [inline]
       vm_mmap_pgoff+0x213/0x2c0 mm/util.c:357
       ksys_mmap_pgoff+0x4da/0x660 mm/mmap.c:1585
       __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline]
       __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline]
       __x64_sys_mmap+0xe9/0x1b0 arch/x86/kernel/sys_x86_64.c:91
       do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #2 (&mm->mmap_sem){++++}:
       __might_fault+0x155/0x1e0 mm/memory.c:4589
       _copy_to_user+0x30/0x110 lib/usercopy.c:25
       copy_to_user include/linux/uaccess.h:155 [inline]
       filldir+0x1ea/0x3a0 fs/readdir.c:196
       dir_emit_dot include/linux/fs.h:3417 [inline]
       dir_emit_dots include/linux/fs.h:3428 [inline]
       dcache_readdir+0x13a/0x620 fs/libfs.c:192
       iterate_dir+0x4b0/0x5d0 fs/readdir.c:51
       __do_sys_getdents fs/readdir.c:231 [inline]
       __se_sys_getdents fs/readdir.c:212 [inline]
       __x64_sys_getdents+0x29f/0x510 fs/readdir.c:212
       do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #1 (&sb->s_type->i_mutex_key#10){++++}:
       down_write+0x8f/0x130 kernel/locking/rwsem.c:70
       inode_lock include/linux/fs.h:730 [inline]
       generic_file_write_iter+0xed/0x870 mm/filemap.c:3289
       call_write_iter include/linux/fs.h:1808 [inline]
       new_sync_write fs/read_write.c:474 [inline]
       __vfs_write+0x6af/0x9d0 fs/read_write.c:487
       vfs_write+0x1f8/0x560 fs/read_write.c:549
       kernel_write+0xab/0x120 fs/read_write.c:526
       fork_usermode_blob+0x11c/0x1b0 kernel/umh.c:493
       load_umh+0x2b/0xbd net/bpfilter/bpfilter_kern.c:93
       do_one_initcall+0x127/0x913 init/main.c:884
       do_initcall_level init/main.c:952 [inline]
       do_initcalls init/main.c:960 [inline]
       do_basic_setup init/main.c:978 [inline]
       kernel_init_freeable+0x49b/0x58e init/main.c:1142
       kernel_init+0x11/0x1b3 init/main.c:1061
       ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413

-> #0 (sb_writers#3){.+.+}:
       lock_acquire+0x1e4/0x540 kernel/locking/lockdep.c:3924
       percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline]
       percpu_down_read include/linux/percpu-rwsem.h:59 [inline]
       __sb_start_write+0x1e9/0x300 fs/super.c:1403
       file_start_write include/linux/fs.h:2752 [inline]
       vfs_fallocate+0x5be/0x8d0 fs/open.c:318
       ashmem_shrink_scan+0x1f9/0x580 drivers/staging/android/ashmem.c:449
       ashmem_ioctl+0x3dd/0x13c0 drivers/staging/android/ashmem.c:791
       vfs_ioctl fs/ioctl.c:46 [inline]
       file_ioctl fs/ioctl.c:500 [inline]
       do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:684
       ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701
       __do_sys_ioctl fs/ioctl.c:708 [inline]
       __se_sys_ioctl fs/ioctl.c:706 [inline]
       __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706
       do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

other info that might help us debug this:

Chain exists of:
  sb_writers#3 --> &mm->mmap_sem --> ashmem_mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(ashmem_mutex);
                               lock(&mm->mmap_sem);
                               lock(ashmem_mutex);
  lock(sb_writers#3);

 *** DEADLOCK ***

1 lock held by syz-executor6/18096:
 #0: 00000000087f8d54 (ashmem_mutex){+.+.}, at: ashmem_shrink_scan+0xb4/0x580 drivers/staging/android/ashmem.c:442

stack backtrace:
CPU: 0 PID: 18096 Comm: syz-executor6 Not tainted 4.18.0+ #192
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+0x1c9/0x2b4 lib/dump_stack.c:113
 print_circular_bug.isra.37.cold.58+0x1bd/0x27d kernel/locking/lockdep.c:1227
 check_prev_add kernel/locking/lockdep.c:1867 [inline]
 check_prevs_add kernel/locking/lockdep.c:1980 [inline]
 validate_chain kernel/locking/lockdep.c:2421 [inline]
 __lock_acquire+0x3449/0x5020 kernel/locking/lockdep.c:3435
 lock_acquire+0x1e4/0x540 kernel/locking/lockdep.c:3924
 percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline]
 percpu_down_read include/linux/percpu-rwsem.h:59 [inline]
 __sb_start_write+0x1e9/0x300 fs/super.c:1403
 file_start_write include/linux/fs.h:2752 [inline]
 vfs_fallocate+0x5be/0x8d0 fs/open.c:318
 ashmem_shrink_scan+0x1f9/0x580 drivers/staging/android/ashmem.c:449
 ashmem_ioctl+0x3dd/0x13c0 drivers/staging/android/ashmem.c:791
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:684
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701
 __do_sys_ioctl fs/ioctl.c:708 [inline]
 __se_sys_ioctl fs/ioctl.c:706 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457089
Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fed2aba3c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fed2aba46d4 RCX: 0000000000457089
RDX: 0000000000000000 RSI: 000000000000770a RDI: 0000000000000003
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004cd2f0 R14: 00000000004c3dca R15: 0000000000000000
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
QAT: Invalid ioctl
QAT: Invalid ioctl
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
CPU: 0 PID: 19076 Comm: syz-executor4 Not tainted 4.18.0+ #192
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+0x1c9/0x2b4 lib/dump_stack.c:113
 fail_dump lib/fault-inject.c:51 [inline]
 should_fail.cold.4+0xa/0x11 lib/fault-inject.c:149
 __should_failslab+0x124/0x180 mm/failslab.c:32
 should_failslab+0x9/0x14 mm/slab_common.c:1557
 slab_pre_alloc_hook mm/slab.h:423 [inline]
 slab_alloc mm/slab.c:3378 [inline]
 kmem_cache_alloc+0x2af/0x760 mm/slab.c:3552
 kmem_cache_zalloc include/linux/slab.h:697 [inline]
 mmu_topup_memory_cache arch/x86/kvm/mmu.c:865 [inline]
 mmu_topup_memory_caches+0xf7/0x3a0 arch/x86/kvm/mmu.c:911
 kvm_mmu_load+0x21/0x10e0 arch/x86/kvm/mmu.c:4657
 kvm_mmu_reload arch/x86/kvm/mmu.h:85 [inline]
 vcpu_enter_guest+0x3ab7/0x60a0 arch/x86/kvm/x86.c:7420
 vcpu_run arch/x86/kvm/x86.c:7618 [inline]
 kvm_arch_vcpu_ioctl_run+0x373/0x16d0 arch/x86/kvm/x86.c:7795
 kvm_vcpu_ioctl+0x7b8/0x1300 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2580
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:684
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701
 __do_sys_ioctl fs/ioctl.c:708 [inline]
 __se_sys_ioctl fs/ioctl.c:706 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457089
Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fe237356c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fe2373576d4 RCX: 0000000000457089
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000007
R13: 00000000004cedf0 R14: 00000000004c54c9 R15: 0000000000000000
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
CPU: 0 PID: 19110 Comm: syz-executor7 Not tainted 4.18.0+ #192
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+0x1c9/0x2b4 lib/dump_stack.c:113
 fail_dump lib/fault-inject.c:51 [inline]
 should_fail.cold.4+0xa/0x11 lib/fault-inject.c:149
 __should_failslab+0x124/0x180 mm/failslab.c:32
 should_failslab+0x9/0x14 mm/slab_common.c:1557
 slab_pre_alloc_hook mm/slab.h:423 [inline]
 slab_alloc mm/slab.c:3378 [inline]
 kmem_cache_alloc_trace+0x2cb/0x780 mm/slab.c:3618
 kmalloc include/linux/slab.h:513 [inline]
 kzalloc include/linux/slab.h:707 [inline]
 do_shmat+0x6a2/0xef0 ipc/shm.c:1466
 __do_sys_shmat ipc/shm.c:1542 [inline]
 __se_sys_shmat ipc/shm.c:1537 [inline]
 __x64_sys_shmat+0xd7/0x1a0 ipc/shm.c:1537
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457089
Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007faa63eb5c78 EFLAGS: 00000246 ORIG_RAX: 000000000000001e
RAX: ffffffffffffffda RBX: 00007faa63eb66d4 RCX: 0000000000457089
RDX: 0000000000000000 RSI: 0000000020ffc000 RDI: 0000000000000000
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00000000004d5af8 R14: 00000000004c950b R15: 0000000000000000
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
CPU: 0 PID: 19117 Comm: syz-executor4 Not tainted 4.18.0+ #192
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+0x1c9/0x2b4 lib/dump_stack.c:113
IPVS: ip_vs_svc_hash(): request for already hashed, called from do_ip_vs_set_ctl+0x1b3a/0x1d80 net/netfilter/ipvs/ip_vs_ctl.c:2433