======================================================
[ INFO: possible circular locking dependency detected ]
4.9.202+ #0 Not tainted
-------------------------------------------------------
syz-executor.1/27538 is trying to acquire lock:
(&mm->mmap_sem){++++++}, at: [<00000000493dff7d>] __do_page_fault+0x7bd/0xa60 arch/x86/mm/fault.c:1337
but task is already holding lock:
(&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<0000000014c8c723>] inode_lock include/linux/fs.h:771 [inline]
(&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<0000000014c8c723>] generic_file_write_iter+0x9a/0x630 mm/filemap.c:3090
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3759
down_write+0x41/0xa0 kernel/locking/rwsem.c:52
inode_lock include/linux/fs.h:771 [inline]
shmem_fallocate+0x143/0xab0 mm/shmem.c:2683
ashmem_shrink_scan drivers/staging/android/ashmem.c:462 [inline]
ashmem_shrink_scan+0x1c3/0x4c0 drivers/staging/android/ashmem.c:446
ashmem_ioctl+0x29b/0xdd0 drivers/staging/android/ashmem.c:804
vfs_ioctl fs/ioctl.c:43 [inline]
file_ioctl fs/ioctl.c:493 [inline]
do_vfs_ioctl+0xb87/0x11d0 fs/ioctl.c:677
SYSC_ioctl fs/ioctl.c:694 [inline]
SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288
entry_SYSCALL_64_after_swapgs+0x5d/0xdb
lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3759
__mutex_lock_common kernel/locking/mutex.c:521 [inline]
mutex_lock_nested+0xc7/0x920 kernel/locking/mutex.c:621
ashmem_mmap+0x53/0x470 drivers/staging/android/ashmem.c:378
mmap_region+0x7e7/0xfa0 mm/mmap.c:1726
do_mmap+0x539/0xbc0 mm/mmap.c:1505
do_mmap_pgoff include/linux/mm.h:2066 [inline]
vm_mmap_pgoff+0x179/0x1c0 mm/util.c:329
SYSC_mmap_pgoff mm/mmap.c:1555 [inline]
SyS_mmap_pgoff+0xfa/0x1b0 mm/mmap.c:1513
SYSC_mmap arch/x86/kernel/sys_x86_64.c:96 [inline]
SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:87
do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288
entry_SYSCALL_64_after_swapgs+0x5d/0xdb
check_prev_add kernel/locking/lockdep.c:1828 [inline]
check_prevs_add kernel/locking/lockdep.c:1938 [inline]
validate_chain kernel/locking/lockdep.c:2265 [inline]
__lock_acquire+0x2d22/0x4390 kernel/locking/lockdep.c:3345
lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3759
down_read+0x44/0xb0 kernel/locking/rwsem.c:22
__do_page_fault+0x7bd/0xa60 arch/x86/mm/fault.c:1337
do_page_fault+0x28/0x30 arch/x86/mm/fault.c:1464
page_fault+0x25/0x30 arch/x86/entry/entry_64.S:956
generic_perform_write+0x1b6/0x500 mm/filemap.c:2930
__generic_file_write_iter+0x340/0x530 mm/filemap.c:3065
generic_file_write_iter+0x38a/0x630 mm/filemap.c:3093
new_sync_write fs/read_write.c:498 [inline]
__vfs_write+0x3c1/0x560 fs/read_write.c:511
vfs_write+0x185/0x520 fs/read_write.c:559
SYSC_write fs/read_write.c:607 [inline]
SyS_write+0x121/0x270 fs/read_write.c:599
do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288
entry_SYSCALL_64_after_swapgs+0x5d/0xdb
other info that might help us debug this:
Chain exists of:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&sb->s_type->i_mutex_key#10);
lock(ashmem_mutex);
lock(&sb->s_type->i_mutex_key#10);
lock(&mm->mmap_sem);
*** DEADLOCK ***
2 locks held by syz-executor.1/27538:
#0: (sb_writers#6){.+.+.+}, at: [<00000000a049d4b8>] file_start_write include/linux/fs.h:2645 [inline]
#0: (sb_writers#6){.+.+.+}, at: [<00000000a049d4b8>] vfs_write+0x3e9/0x520 fs/read_write.c:558
#1: (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<0000000014c8c723>] inode_lock include/linux/fs.h:771 [inline]
#1: (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<0000000014c8c723>] generic_file_write_iter+0x9a/0x630 mm/filemap.c:3090
stack backtrace:
CPU: 1 PID: 27538 Comm: syz-executor.1 Not tainted 4.9.202+ #0
ffff8801c8a575d8 ffffffff81b55d2b ffffffff83caeb80 ffffffff83cb8000
ffffffff83ce3590 ffffffff8424ff40 ffff8801d03d5f00 ffff8801c8a57630
ffffffff81406d6a dffffc0000000000 ffffffff840965c0 ffff8801d03d6800
Call Trace:
[<00000000787db5b6>] __dump_stack lib/dump_stack.c:15 [inline]
[<00000000787db5b6>] dump_stack+0xcb/0x130 lib/dump_stack.c:56
[<000000008315a25e>] print_circular_bug.cold+0x2f6/0x454 kernel/locking/lockdep.c:1202
[<00000000b304627e>] check_prev_add kernel/locking/lockdep.c:1828 [inline]
[<00000000b304627e>] check_prevs_add kernel/locking/lockdep.c:1938 [inline]
[<00000000b304627e>] validate_chain kernel/locking/lockdep.c:2265 [inline]
[<00000000b304627e>] __lock_acquire+0x2d22/0x4390 kernel/locking/lockdep.c:3345
[<000000007d8aa01b>] lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3759
[<000000007ea8672a>] down_read+0x44/0xb0 kernel/locking/rwsem.c:22
[<00000000493dff7d>] __do_page_fault+0x7bd/0xa60 arch/x86/mm/fault.c:1337
[<00000000c9d1789b>] do_page_fault+0x28/0x30 arch/x86/mm/fault.c:1464
[<00000000c4f4d87c>] page_fault+0x25/0x30 arch/x86/entry/entry_64.S:956
[<000000005c792ed3>] generic_perform_write+0x1b6/0x500 mm/filemap.c:2930
[<000000003d49a087>] __generic_file_write_iter+0x340/0x530 mm/filemap.c:3065
[<00000000f29f47b5>] generic_file_write_iter+0x38a/0x630 mm/filemap.c:3093
[<0000000044d33f06>] new_sync_write fs/read_write.c:498 [inline]
[<0000000044d33f06>] __vfs_write+0x3c1/0x560 fs/read_write.c:511
[<00000000ac707d72>] vfs_write+0x185/0x520 fs/read_write.c:559
[<00000000d8a3c0a7>] SYSC_write fs/read_write.c:607 [inline]
[<00000000d8a3c0a7>] SyS_write+0x121/0x270 fs/read_write.c:599
[<000000005b35e43d>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288
[<000000005bd677ca>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
audit_printk_skb: 39 callbacks suppressed
audit: type=1400 audit(2126.003:5590): avc: denied { create } for pid=27587 comm="syz-executor.5" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
audit: type=1400 audit(2126.033:5591): avc: denied { write } for pid=27587 comm="syz-executor.5" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
audit: type=1400 audit(2126.072:5592): avc: denied { read } for pid=27587 comm="syz-executor.5" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
FAT-fs (loop3): bogus logical sector size 57856
FAT-fs (loop3): Can't find a valid FAT filesystem
FAT-fs (loop3): bogus logical sector size 57856
FAT-fs (loop3): Can't find a valid FAT filesystem
FAT-fs (loop3): bogus logical sector size 57856
FAT-fs (loop3): Can't find a valid FAT filesystem
FAT-fs (loop3): bogus logical sector size 57856
FAT-fs (loop3): Can't find a valid FAT filesystem
FAT-fs (loop3): bogus logical sector size 57856
FAT-fs (loop3): Can't find a valid FAT filesystem