============================= WARNING: suspicious RCU usage syzkaller #0 Tainted: G L ----------------------------- fs/kernfs/dir.c:579 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 2 locks held by kswapd0/78: #0: ffffffff8e9aa8a0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x1db/0x1ca0 mm/vmscan.c:6968 #1: ffff888033c040e0 (&type->s_umount_key#57){.+.+}-{4:4}, at: super_trylock_shared fs/super.c:565 [inline] #1: ffff888033c040e0 (&type->s_umount_key#57){.+.+}-{4:4}, at: super_cache_scan+0x98/0x550 fs/super.c:198 stack backtrace: CPU: 0 UID: 0 PID: 78 Comm: kswapd0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 lockdep_rcu_suspicious.cold+0x4f/0xb1 kernel/locking/lockdep.c:6876 kernfs_put.part.0+0x59c/0x610 fs/kernfs/dir.c:579 kernfs_put+0x53/0x60 fs/kernfs/dir.c:602 evict+0x3c2/0xad0 fs/inode.c:846 iput_final fs/inode.c:1966 [inline] iput.part.0+0x605/0xf50 fs/inode.c:2015 iput+0x35/0x40 fs/inode.c:1981 dentry_unlink_inode+0x2a1/0x490 fs/dcache.c:467 __dentry_kill+0x1d0/0x600 fs/dcache.c:670 shrink_kill fs/dcache.c:1147 [inline] shrink_dentry_list+0x180/0x5e0 fs/dcache.c:1174 prune_dcache_sb+0xea/0x150 fs/dcache.c:1256 super_cache_scan+0x328/0x550 fs/super.c:223 do_shrink_slab+0x416/0x11e0 mm/shrinker.c:437 shrink_slab+0x171/0x12b0 mm/shrinker.c:664 shrink_one+0x398/0x7f0 mm/vmscan.c:4928 shrink_many mm/vmscan.c:4989 [inline] lru_gen_shrink_node mm/vmscan.c:5067 [inline] shrink_node+0x26a2/0x3e20 mm/vmscan.c:6047 kswapd_shrink_node mm/vmscan.c:6894 [inline] balance_pgdat+0xbb7/0x1ca0 mm/vmscan.c:7070 kswapd+0x556/0xba0 mm/vmscan.c:7343 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 ============================= WARNING: suspicious RCU usage syzkaller #0 Tainted: G L ----------------------------- fs/kernfs/dir.c:579 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 2 locks held by kswapd0/78: #0: ffffffff8e9aa8a0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x1db/0x1ca0 mm/vmscan.c:6968 #1: ffff888033c040e0 (&type->s_umount_key#57){.+.+}-{4:4}, at: super_trylock_shared fs/super.c:565 [inline] #1: ffff888033c040e0 (&type->s_umount_key#57){.+.+}-{4:4}, at: super_cache_scan+0x98/0x550 fs/super.c:198 stack backtrace: CPU: 0 UID: 0 PID: 78 Comm: kswapd0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 lockdep_rcu_suspicious.cold+0x4f/0xb1 kernel/locking/lockdep.c:6876 kernfs_put.part.0+0x515/0x610 fs/kernfs/dir.c:579 kernfs_put+0x53/0x60 fs/kernfs/dir.c:602 evict+0x3c2/0xad0 fs/inode.c:846 iput_final fs/inode.c:1966 [inline] iput.part.0+0x605/0xf50 fs/inode.c:2015 iput+0x35/0x40 fs/inode.c:1981 dentry_unlink_inode+0x2a1/0x490 fs/dcache.c:467 __dentry_kill+0x1d0/0x600 fs/dcache.c:670 shrink_kill fs/dcache.c:1147 [inline] shrink_dentry_list+0x180/0x5e0 fs/dcache.c:1174 prune_dcache_sb+0xea/0x150 fs/dcache.c:1256 super_cache_scan+0x328/0x550 fs/super.c:223 do_shrink_slab+0x416/0x11e0 mm/shrinker.c:437 shrink_slab+0x171/0x12b0 mm/shrinker.c:664 shrink_one+0x398/0x7f0 mm/vmscan.c:4928 shrink_many mm/vmscan.c:4989 [inline] lru_gen_shrink_node mm/vmscan.c:5067 [inline] shrink_node+0x26a2/0x3e20 mm/vmscan.c:6047 kswapd_shrink_node mm/vmscan.c:6894 [inline] balance_pgdat+0xbb7/0x1ca0 mm/vmscan.c:7070 kswapd+0x556/0xba0 mm/vmscan.c:7343 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 ------------[ cut here ]------------ kernfs_put: tty/ptyd1: released with incorrect active_ref 0 WARNING: fs/kernfs/dir.c:579 at kernfs_put.part.0+0x478/0x610 fs/kernfs/dir.c:579, CPU#0: kswapd0/78 Modules linked in: CPU: 0 UID: 0 PID: 78 Comm: kswapd0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:kernfs_put.part.0+0x483/0x610 fs/kernfs/dir.c:579 Code: 89 c6 89 44 24 1c e8 5c 2d 51 ff 8b 44 24 1c 85 c0 75 21 e8 9f 32 51 ff 48 8d 3d 88 21 29 0e 48 8b 54 24 10 44 89 f9 4c 89 e6 <67> 48 0f b9 3a e9 3a fc ff ff e8 7e 32 51 ff e8 d9 f0 34 ff 31 ff RSP: 0018:ffffc9000236f2d8 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff888023738000 RCX: 0000000000000000 RDX: ffff888022f9cea0 RSI: ffffffff8c2cde20 RDI: ffffffff90e03230 RBP: ffff88801facbc30 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffffffff8c2cde20 R13: dffffc0000000000 R14: ffff88801c6b5868 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124340000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055923cfd5ee8 CR3: 000000000e598000 CR4: 00000000003526f0 Call Trace: kernfs_put+0x53/0x60 fs/kernfs/dir.c:602 evict+0x3c2/0xad0 fs/inode.c:846 iput_final fs/inode.c:1966 [inline] iput.part.0+0x605/0xf50 fs/inode.c:2015 iput+0x35/0x40 fs/inode.c:1981 dentry_unlink_inode+0x2a1/0x490 fs/dcache.c:467 __dentry_kill+0x1d0/0x600 fs/dcache.c:670 shrink_kill fs/dcache.c:1147 [inline] shrink_dentry_list+0x180/0x5e0 fs/dcache.c:1174 prune_dcache_sb+0xea/0x150 fs/dcache.c:1256 super_cache_scan+0x328/0x550 fs/super.c:223 do_shrink_slab+0x416/0x11e0 mm/shrinker.c:437 shrink_slab+0x171/0x12b0 mm/shrinker.c:664 shrink_one+0x398/0x7f0 mm/vmscan.c:4928 shrink_many mm/vmscan.c:4989 [inline] lru_gen_shrink_node mm/vmscan.c:5067 [inline] shrink_node+0x26a2/0x3e20 mm/vmscan.c:6047 kswapd_shrink_node mm/vmscan.c:6894 [inline] balance_pgdat+0xbb7/0x1ca0 mm/vmscan.c:7070 kswapd+0x556/0xba0 mm/vmscan.c:7343 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 ---------------- Code disassembly (best guess): 0: 89 c6 mov %eax,%esi 2: 89 44 24 1c mov %eax,0x1c(%rsp) 6: e8 5c 2d 51 ff call 0xff512d67 b: 8b 44 24 1c mov 0x1c(%rsp),%eax f: 85 c0 test %eax,%eax 11: 75 21 jne 0x34 13: e8 9f 32 51 ff call 0xff5132b7 18: 48 8d 3d 88 21 29 0e lea 0xe292188(%rip),%rdi # 0xe2921a7 1f: 48 8b 54 24 10 mov 0x10(%rsp),%rdx 24: 44 89 f9 mov %r15d,%ecx 27: 4c 89 e6 mov %r12,%rsi * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2f: e9 3a fc ff ff jmp 0xfffffc6e 34: e8 7e 32 51 ff call 0xff5132b7 39: e8 d9 f0 34 ff call 0xff34f117 3e: 31 ff xor %edi,%edi