======================================================
WARNING: possible circular locking dependency detected
5.7.0-syzkaller #0 Not tainted
------------------------------------------------------
kswapd0/1670 is trying to acquire lock:
ffff88809340d970 (&sb->s_type->i_mutex_key#16){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:799 [inline]
ffff88809340d970 (&sb->s_type->i_mutex_key#16){+.+.}-{3:3}, at: shmem_fallocate+0x153/0xd40 mm/shmem.c:2708
but task is already holding lock:
ffffffff89a68aa0 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x0/0x30 mm/page_alloc.c:5009
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (fs_reclaim){+.+.}-{0:0}:
__fs_reclaim_acquire mm/page_alloc.c:4183 [inline]
fs_reclaim_acquire.part.0+0x20/0x30 mm/page_alloc.c:4194
fs_reclaim_acquire mm/page_alloc.c:4783 [inline]
prepare_alloc_pages mm/page_alloc.c:4780 [inline]
__alloc_pages_nodemask+0x4da/0x810 mm/page_alloc.c:4832
alloc_pages_vma+0xd9/0x600 mm/mempolicy.c:2255
shmem_alloc_page+0xb0/0x170 mm/shmem.c:1503
shmem_alloc_and_acct_page+0x160/0x980 mm/shmem.c:1528
shmem_getpage_gfp+0x514/0x24f0 mm/shmem.c:1824
shmem_getpage mm/shmem.c:154 [inline]
shmem_write_begin+0x102/0x1e0 mm/shmem.c:2460
generic_perform_write+0x20a/0x4e0 mm/filemap.c:3299
__generic_file_write_iter+0x24c/0x610 mm/filemap.c:3428
generic_file_write_iter+0x3f3/0x630 mm/filemap.c:3460
call_write_iter include/linux/fs.h:1917 [inline]
new_sync_write+0x426/0x650 fs/read_write.c:484
__vfs_write+0xc9/0x100 fs/read_write.c:497
vfs_write+0x268/0x5d0 fs/read_write.c:559
ksys_write+0x12d/0x250 fs/read_write.c:612
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3
-> #0 (&sb->s_type->i_mutex_key#16){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:2496 [inline]
check_prevs_add kernel/locking/lockdep.c:2601 [inline]
validate_chain kernel/locking/lockdep.c:3218 [inline]
__lock_acquire+0x2a9a/0x48a0 kernel/locking/lockdep.c:4380
lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4959
down_write+0x8d/0x150 kernel/locking/rwsem.c:1531
inode_lock include/linux/fs.h:799 [inline]
shmem_fallocate+0x153/0xd40 mm/shmem.c:2708
ashmem_shrink_scan drivers/staging/android/ashmem.c:490 [inline]
ashmem_shrink_scan+0x34d/0x500 drivers/staging/android/ashmem.c:465
do_shrink_slab+0x3fa/0xa30 mm/vmscan.c:518
shrink_slab mm/vmscan.c:679 [inline]
shrink_slab+0x16f/0x5f0 mm/vmscan.c:652
shrink_node_memcgs mm/vmscan.c:2655 [inline]
shrink_node+0x53e/0x1c00 mm/vmscan.c:2767
kswapd_shrink_node mm/vmscan.c:3514 [inline]
balance_pgdat+0x753/0x1110 mm/vmscan.c:3672
kswapd+0x5d0/0xe80 mm/vmscan.c:3929
kthread+0x388/0x470 kernel/kthread.c:268
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(fs_reclaim);
lock(&sb->s_type->i_mutex_key#16);
lock(fs_reclaim);
lock(&sb->s_type->i_mutex_key#16);
*** DEADLOCK ***
2 locks held by kswapd0/1670:
#0: ffffffff89a68aa0 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x0/0x30 mm/page_alloc.c:5009
#1: ffffffff89a43450 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab mm/vmscan.c:669 [inline]
#1: ffffffff89a43450 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0xc7/0x5f0 mm/vmscan.c:652
stack backtrace:
CPU: 1 PID: 1670 Comm: kswapd0 Not tainted 5.7.0-syzkaller #0
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+0x188/0x20d lib/dump_stack.c:118
check_noncircular+0x32e/0x3e0 kernel/locking/lockdep.c:1827
check_prev_add kernel/locking/lockdep.c:2496 [inline]
check_prevs_add kernel/locking/lockdep.c:2601 [inline]
validate_chain kernel/locking/lockdep.c:3218 [inline]
__lock_acquire+0x2a9a/0x48a0 kernel/locking/lockdep.c:4380
lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4959
down_write+0x8d/0x150 kernel/locking/rwsem.c:1531
inode_lock include/linux/fs.h:799 [inline]
shmem_fallocate+0x153/0xd40 mm/shmem.c:2708
ashmem_shrink_scan drivers/staging/android/ashmem.c:490 [inline]
ashmem_shrink_scan+0x34d/0x500 drivers/staging/android/ashmem.c:465
do_shrink_slab+0x3fa/0xa30 mm/vmscan.c:518
shrink_slab mm/vmscan.c:679 [inline]
shrink_slab+0x16f/0x5f0 mm/vmscan.c:652
shrink_node_memcgs mm/vmscan.c:2655 [inline]
shrink_node+0x53e/0x1c00 mm/vmscan.c:2767
kswapd_shrink_node mm/vmscan.c:3514 [inline]
balance_pgdat+0x753/0x1110 mm/vmscan.c:3672
kswapd+0x5d0/0xe80 mm/vmscan.c:3929
kthread+0x388/0x470 kernel/kthread.c:268
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351