============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- syz-execprog/4267 is trying to acquire lock: ffffffff8cc81038 (kernfs_rename_lock){..-.}-{2:2}, at: kernfs_path_from_node+0x87/0xd10 fs/kernfs/dir.c:232 but task is already holding lock: ffffffff8cc81038 (kernfs_rename_lock){..-.}-{2:2}, at: kernfs_path_from_node+0x87/0xd10 fs/kernfs/dir.c:232 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(kernfs_rename_lock); lock(kernfs_rename_lock); *** DEADLOCK *** May be due to missing lock nesting notation 4 locks held by syz-execprog/4267: #0: ffff88801db2f958 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline] #0: ffff88801db2f958 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5322 [inline] #0: ffff88801db2f958 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5384 #1: ffffffff8cc81038 (kernfs_rename_lock){..-.}-{2:2}, at: kernfs_path_from_node+0x87/0xd10 fs/kernfs/dir.c:232 #2: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #2: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #2: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline] #2: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xda/0x3b0 kernel/trace/bpf_trace.c:2324 #3: ffff88801db2f958 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline] #3: ffff88801db2f958 (&mm->mmap_lock){++++}-{3:3}, at: stack_map_get_build_id_offset+0x1fd/0x9c0 kernel/bpf/stackmap.c:144 stack backtrace: CPU: 1 PID: 4267 Comm: syz-execprog Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 __lock_acquire+0x122f/0x7c50 kernel/locking/lockdep.c:-1 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162 kernfs_path_from_node+0x87/0xd10 fs/kernfs/dir.c:232 kernfs_path include/linux/kernfs.h:595 [inline] cgroup_path include/linux/cgroup.h:674 [inline] get_mm_memcg_path+0xb9/0x360 mm/mmap_lock.c:82 __mmap_lock_do_trace_acquire_returned+0x9b/0x330 mm/mmap_lock.c:102 __mmap_lock_trace_acquire_returned include/linux/mmap_lock.h:36 [inline] mmap_read_trylock include/linux/mmap_lock.h:137 [inline] stack_map_get_build_id_offset+0x68d/0x9c0 kernel/bpf/stackmap.c:144 __bpf_get_stack+0x44d/0x4f0 kernel/bpf/stackmap.c:452 ____bpf_get_stack_raw_tp kernel/trace/bpf_trace.c:1880 [inline] bpf_get_stack_raw_tp+0x189/0x1c0 kernel/trace/bpf_trace.c:1870 bpf_prog_ec3b2eefa702d8d3+0x3a/0x3e bpf_dispatcher_nop_func include/linux/bpf.h:1011 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline] bpf_trace_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324 trace_contention_end+0x13f/0x190 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x7e8/0x9c0 kernel/locking/qspinlock.c:560 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:591 [inline] queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x217/0x280 kernel/locking/spinlock_debug.c:115 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xb0/0xf0 kernel/locking/spinlock.c:162 kernfs_path_from_node+0x87/0xd10 fs/kernfs/dir.c:232 kernfs_path include/linux/kernfs.h:595 [inline] cgroup_path include/linux/cgroup.h:674 [inline] get_mm_memcg_path+0xb9/0x360 mm/mmap_lock.c:82 __mmap_lock_do_trace_acquire_returned+0x9b/0x330 mm/mmap_lock.c:102 __mmap_lock_trace_acquire_returned include/linux/mmap_lock.h:36 [inline] mmap_read_trylock include/linux/mmap_lock.h:137 [inline] get_mmap_lock_carefully mm/memory.c:5322 [inline] lock_mm_and_find_vma+0x21f/0x2f0 mm/memory.c:5384 do_user_addr_fault+0x2db/0xb10 arch/x86/mm/fault.c:1312 handle_page_fault arch/x86/mm/fault.c:1431 [inline] exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1487 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608 RIP: 0033:0x47efab Code: 1f f8 c3 f3 44 0f 7f 3f f3 44 0f 7f 7c 1f f0 c3 f3 44 0f 7f 3f f3 44 0f 7f 7f 10 f3 44 0f 7f 7c 1f e0 f3 44 0f 7f 7c 1f f0 c3 44 0f 7f 3f f3 44 0f 7f 7f 10 f3 44 0f 7f 7f 20 f3 44 0f 7f 7f RSP: 002b:000000c004055248 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000080 RCX: 0000000000000010 RDX: 000000c0085a1f80 RSI: 0000000000000000 RDI: 000000c0085a1f80 RBP: 000000c004055260 R08: 0000000000000001 R09: 000000c0085a0000 R10: 0000000000000001 R11: 00007f2c9ac7d000 R12: 000000000002bf00 R13: 0000000000000016 R14: 000000c004030e00 R15: 0000000000000000