============================================ WARNING: possible recursive locking detected 6.11.0-rc4-syzkaller-00280-g8a3f14bb1e94 #0 Not tainted -------------------------------------------- syz.2.438/7378 is trying to acquire lock: ffffffff8eab6458 (kernfs_rename_lock){.-.-}-{2:2}, at: kernfs_path_from_node+0x92/0xb00 fs/kernfs/dir.c:229 but task is already holding lock: ffffffff8eab6458 (kernfs_rename_lock){.-.-}-{2:2}, at: kernfs_path_from_node+0x92/0xb00 fs/kernfs/dir.c:229 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 2 locks held by syz.2.438/7378: #0: ffffffff8eab6458 (kernfs_rename_lock){.-.-}-{2:2}, at: kernfs_path_from_node+0x92/0xb00 fs/kernfs/dir.c:229 #1: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: trace_call_bpf+0xbc/0x8a0 stack backtrace: CPU: 1 UID: 0 PID: 7378 Comm: syz.2.438 Not tainted 6.11.0-rc4-syzkaller-00280-g8a3f14bb1e94 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Call Trace: __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119 check_deadlock kernel/locking/lockdep.c:3061 [inline] validate_chain+0x15d3/0x5900 kernel/locking/lockdep.c:3855 __lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759 __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:160 [inline] _raw_read_lock_irqsave+0xdd/0x130 kernel/locking/spinlock.c:236 kernfs_path_from_node+0x92/0xb00 fs/kernfs/dir.c:229 kernfs_path include/linux/kernfs.h:598 [inline] cgroup_path include/linux/cgroup.h:598 [inline] get_mm_memcg_path+0xb9/0x380 mm/mmap_lock.c:82 __mmap_lock_do_trace_start_locking+0x9c/0x2f0 mm/mmap_lock.c:95 __mmap_lock_trace_start_locking include/linux/mmap_lock.h:29 [inline] mmap_read_trylock include/linux/mmap_lock.h:162 [inline] stack_map_get_build_id_offset+0x98a/0x9d0 kernel/bpf/stackmap.c:141 __bpf_get_stack+0x4ad/0x5a0 kernel/bpf/stackmap.c:449 bpf_prog_e6cf5f9c69743609+0x43/0x47 bpf_dispatcher_nop_func include/linux/bpf.h:1254 [inline] __bpf_prog_run include/linux/filter.h:701 [inline] bpf_prog_run include/linux/filter.h:708 [inline] bpf_prog_run_array include/linux/bpf.h:2120 [inline] trace_call_bpf+0x369/0x8a0 kernel/trace/bpf_trace.c:146 perf_trace_run_bpf_submit+0x82/0x180 kernel/events/core.c:10304 perf_trace_lock+0x388/0x490 include/trace/events/lock.h:50 trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0x9cc/0xa30 kernel/locking/lockdep.c:5770 __raw_read_unlock_irqrestore include/linux/rwlock_api_smp.h:239 [inline] _raw_read_unlock_irqrestore+0x79/0x140 kernel/locking/spinlock.c:268 kernfs_path_from_node+0x235/0xb00 fs/kernfs/dir.c:231 kernfs_path include/linux/kernfs.h:598 [inline] cgroup_path include/linux/cgroup.h:598 [inline] get_mm_memcg_path+0xb9/0x380 mm/mmap_lock.c:82 __mmap_lock_do_trace_start_locking+0x9c/0x2f0 mm/mmap_lock.c:95 __mmap_lock_trace_start_locking include/linux/mmap_lock.h:29 [inline] mmap_read_trylock include/linux/mmap_lock.h:162 [inline] get_mmap_lock_carefully mm/memory.c:5869 [inline] lock_mm_and_find_vma+0x1f1/0x2f0 mm/memory.c:5929 do_user_addr_fault arch/x86/mm/fault.c:1361 [inline] handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x1bf/0x8c0 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0010:do_strncpy_from_user lib/strncpy_from_user.c:41 [inline] RIP: 0010:strncpy_from_user+0x110/0x2e0 lib/strncpy_from_user.c:139 Code: 00 00 00 4c 89 e6 e8 8f c7 a7 fc 49 83 fc 07 0f 86 9a 00 00 00 48 89 6c 24 08 48 c7 44 24 10 f8 ff ff ff 45 31 ed 4c 89 3c 24 <4f> 8b 3c 2f 48 b8 ff fe fe fe fe fe fe fe 49 8d 1c 07 4c 89 fd 48 RSP: 0018:ffffc90009ddfb10 EFLAGS: 00050246 RAX: 0000000000000002 RBX: ffffc90009ddfdb0 RCX: ffff888030e65a00 RDX: ffffc9000c0d9000 RSI: 000000000000007f RDI: 0000000000000007 RBP: 000000000000007f R08: ffffffff84ebca41 R09: ffffffff820a3dd7 R10: 0000000000000003 R11: ffff888030e65a00 R12: 000000000000007f R13: 0000000000000000 R14: ffffc90009ddfc50 R15: 0000000000000000 bpf_prog_load+0xd65/0x20f0 kernel/bpf/syscall.c:2851 __sys_bpf+0x4ee/0x810 kernel/bpf/syscall.c:5712 __do_sys_bpf kernel/bpf/syscall.c:5819 [inline] __se_sys_bpf kernel/bpf/syscall.c:5817 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5817 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff35377cef9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ff354597038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007ff353935f80 RCX: 00007ff35377cef9 RDX: 0000000000000090 RSI: 00000000200000c0 RDI: 0000000000000005 RBP: 00007ff3537ef046 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ff353935f80 R15: 00007ffcdfe11ff8 ---------------- Code disassembly (best guess): 0: 00 00 add %al,(%rax) 2: 00 4c 89 e6 add %cl,-0x1a(%rcx,%rcx,4) 6: e8 8f c7 a7 fc call 0xfca7c79a b: 49 83 fc 07 cmp $0x7,%r12 f: 0f 86 9a 00 00 00 jbe 0xaf 15: 48 89 6c 24 08 mov %rbp,0x8(%rsp) 1a: 48 c7 44 24 10 f8 ff movq $0xfffffffffffffff8,0x10(%rsp) 21: ff ff 23: 45 31 ed xor %r13d,%r13d 26: 4c 89 3c 24 mov %r15,(%rsp) * 2a: 4f 8b 3c 2f mov (%r15,%r13,1),%r15 <-- trapping instruction 2e: 48 b8 ff fe fe fe fe movabs $0xfefefefefefefeff,%rax 35: fe fe fe 38: 49 8d 1c 07 lea (%r15,%rax,1),%rbx 3c: 4c 89 fd mov %r15,%rbp 3f: 48 rex.W