====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ kswapd0/79 is trying to acquire lock: ffff88801fd02698 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_reclaim_inode fs/xfs/xfs_icache.c:1035 [inline] ffff88801fd02698 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1727 [inline] ffff88801fd02698 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_icwalk_ag+0x1229/0x1a90 fs/xfs/xfs_icache.c:1809 but task is already holding lock: ffffffff8e051900 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6975 [inline] ffffffff8e051900 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0x92a/0x2820 mm/vmscan.c:7354 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:4301 [inline] fs_reclaim_acquire+0x72/0x100 mm/page_alloc.c:4315 might_alloc include/linux/sched/mm.h:317 [inline] slab_pre_alloc_hook mm/slub.c:4904 [inline] slab_alloc_node mm/slub.c:5239 [inline] __kmalloc_cache_noprof+0x40/0x700 mm/slub.c:5771 kmalloc_noprof include/linux/slab.h:957 [inline] iomap_fill_dirty_folios+0xf4/0x260 fs/iomap/buffered-io.c:1557 xfs_buffered_write_iomap_begin+0xa23/0x1a70 fs/xfs/xfs_iomap.c:1857 iomap_iter+0x5ef/0xeb0 fs/iomap/iter.c:110 iomap_zero_range+0x917/0xa30 fs/iomap/buffered-io.c:1590 xfs_zero_range+0x9a/0x100 fs/xfs/xfs_iomap.c:2289 xfs_free_file_space+0x8ad/0xcc0 fs/xfs/xfs_bmap_util.c:900 xfs_falloc_zero_range fs/xfs/xfs_file.c:1306 [inline] __xfs_file_fallocate+0xe1d/0x15d0 fs/xfs/xfs_file.c:1421 xfs_file_fallocate+0x26e/0x320 fs/xfs/xfs_file.c:1500 vfs_fallocate+0x669/0x7e0 fs/open.c:339 ksys_fallocate fs/open.c:363 [inline] __do_sys_fallocate fs/open.c:368 [inline] __se_sys_fallocate fs/open.c:366 [inline] __x64_sys_fallocate+0xc0/0x110 fs/open.c:366 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&xfs_nondir_ilock_class){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 down_write_nested+0x9d/0x200 kernel/locking/rwsem.c:1706 xfs_reclaim_inode fs/xfs/xfs_icache.c:1035 [inline] xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1727 [inline] xfs_icwalk_ag+0x1229/0x1a90 fs/xfs/xfs_icache.c:1809 xfs_icwalk fs/xfs/xfs_icache.c:1857 [inline] xfs_reclaim_inodes_nr+0x1e3/0x260 fs/xfs/xfs_icache.c:1101 super_cache_scan+0x41b/0x4b0 fs/super.c:228 do_shrink_slab+0x6df/0x10d0 mm/shrinker.c:437 shrink_slab+0xd74/0x10d0 mm/shrinker.c:664 shrink_one+0x2d9/0x720 mm/vmscan.c:4921 shrink_many mm/vmscan.c:4982 [inline] lru_gen_shrink_node mm/vmscan.c:5060 [inline] shrink_node+0x2f7d/0x35b0 mm/vmscan.c:6047 kswapd_shrink_node mm/vmscan.c:6901 [inline] balance_pgdat mm/vmscan.c:7084 [inline] kswapd+0x145a/0x2820 mm/vmscan.c:7354 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(&xfs_nondir_ilock_class); lock(fs_reclaim); lock(&xfs_nondir_ilock_class); *** DEADLOCK *** 2 locks held by kswapd0/79: #0: ffffffff8e051900 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6975 [inline] #0: ffffffff8e051900 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0x92a/0x2820 mm/vmscan.c:7354 #1: ffff8880422980e0 (&type->s_umount_key#51){.+.+}-{4:4}, at: super_trylock_shared fs/super.c:563 [inline] #1: ffff8880422980e0 (&type->s_umount_key#51){.+.+}-{4:4}, at: super_cache_scan+0x91/0x4b0 fs/super.c:197 stack backtrace: CPU: 0 UID: 0 PID: 79 Comm: kswapd0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2043 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 down_write_nested+0x9d/0x200 kernel/locking/rwsem.c:1706 xfs_reclaim_inode fs/xfs/xfs_icache.c:1035 [inline] xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1727 [inline] xfs_icwalk_ag+0x1229/0x1a90 fs/xfs/xfs_icache.c:1809 xfs_icwalk fs/xfs/xfs_icache.c:1857 [inline] xfs_reclaim_inodes_nr+0x1e3/0x260 fs/xfs/xfs_icache.c:1101 super_cache_scan+0x41b/0x4b0 fs/super.c:228 do_shrink_slab+0x6df/0x10d0 mm/shrinker.c:437 shrink_slab+0xd74/0x10d0 mm/shrinker.c:664 shrink_one+0x2d9/0x720 mm/vmscan.c:4921 shrink_many mm/vmscan.c:4982 [inline] lru_gen_shrink_node mm/vmscan.c:5060 [inline] shrink_node+0x2f7d/0x35b0 mm/vmscan.c:6047 kswapd_shrink_node mm/vmscan.c:6901 [inline] balance_pgdat mm/vmscan.c:7084 [inline] kswapd+0x145a/0x2820 mm/vmscan.c:7354 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246