================================================ WARNING: lock held when returning to user space! syzkaller #0 Not tainted ------------------------------------------------ udevd/2965 is leaving the kernel with locks still held! 1 lock held by udevd/2965: #0: ffffffff896ddaa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff896ddaa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff896ddaa0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x2f/0x300 mm/pgtable-generic.c:290 BUG: sleeping function called from invalid context at ./include/linux/uaccess.h:169 in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 2965, name: udevd preempt_count: 0, expected: 0 RCU nest depth: 1, expected: 0 INFO: lockdep is turned off. CPU: 1 UID: 0 PID: 2965 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) 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 __might_resched.cold+0x1ec/0x232 kernel/sched/core.c:9162 __might_fault+0x8b/0x140 mm/memory.c:7322 _inline_copy_from_user include/linux/uaccess.h:169 [inline] _copy_from_user+0x29/0xd0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:223 [inline] __do_sys_rt_sigprocmask kernel/signal.c:3332 [inline] __se_sys_rt_sigprocmask kernel/signal.c:3319 [inline] __x64_sys_rt_sigprocmask+0x185/0x410 kernel/signal.c:3319 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0x7f0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff1c3e4af07 Code: 00 00 00 53 48 89 fb 48 8d 3d 75 2c 19 00 e8 b0 03 05 00 41 ba 08 00 00 00 31 d2 48 89 de bf 02 00 00 00 b8 0e 00 00 00 0f 05 <5b> c3 0f 1f 80 00 00 00 00 89 f8 f7 d8 0f 48 c7 c3 0f 1f 84 00 00 RSP: 002b:00007ffe95d2e570 EFLAGS: 00000246 ORIG_RAX: 000000000000000e RAX: ffffffffffffffda RBX: 00007ffe95d2e588 RCX: 00007ff1c3e4af07 RDX: 0000000000000000 RSI: 00007ffe95d2e588 RDI: 0000000000000002 RBP: 0000000000000000 R08: 00007ff1c3fddb60 R09: 0000000000000000 R10: 0000000000000008 R11: 0000000000000246 R12: 00007ffe95d2e940 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ------------[ cut here ]------------ Voluntary context switch within RCU read-side critical section! WARNING: kernel/rcu/tree_plugin.h:332 at rcu_note_context_switch+0x859/0x19c0 kernel/rcu/tree_plugin.h:332, CPU#1: udevd/2965 Modules linked in: CPU: 1 UID: 0 PID: 2965 Comm: udevd Tainted: G W syzkaller #0 PREEMPT(full) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:rcu_note_context_switch+0x859/0x19c0 kernel/rcu/tree_plugin.h:332 Code: c1 ea 03 80 3c 02 00 0f 85 9b 0b 00 00 48 8b 53 28 b9 01 00 00 00 4c 89 ef e8 a3 cf fe ff e9 1d f9 ff ff 48 8d 3d 57 fe 59 09 <67> 48 0f b9 3a e9 99 f8 ff ff 48 b8 00 00 00 00 00 fc ff df 48 8d RSP: 0018:ffffc90001597a28 EFLAGS: 00010002 RAX: 0000000000000001 RBX: ffff8881f573a540 RCX: ffffffff8198b8a1 RDX: 0000000000000000 RSI: ffffffff87b03ee0 RDI: ffffffff8af32b20 RBP: ffff88811967bb80 R08: 0000000000000000 R09: fffffbfff15e343a R10: ffffffff8af1a1d7 R11: 0000000000000000 R12: 0000000000000000 R13: ffff88811967bffc R14: ffffffff8cfb0680 R15: ffffffff8af1b164 FS: 00007ff1c3da4880(0000) GS:ffff888268789000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555795e32620 CR3: 0000000123056000 CR4: 00000000003506f0 Call Trace: __schedule+0x25e/0x4840 kernel/sched/core.c:7043 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7282 schedule_hrtimeout_range_clock+0x2d0/0x310 kernel/time/sleep_timeout.c:207 ep_poll fs/eventpoll.c:2032 [inline] do_epoll_wait+0xdc3/0x1020 fs/eventpoll.c:2466 __do_sys_epoll_wait fs/eventpoll.c:2474 [inline] __se_sys_epoll_wait fs/eventpoll.c:2469 [inline] __x64_sys_epoll_wait+0x194/0x290 fs/eventpoll.c:2469 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0x7f0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff1c3e92407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffe95d2e660 EFLAGS: 00000202 ORIG_RAX: 00000000000000e8 RAX: ffffffffffffffda RBX: 00007ff1c3da4880 RCX: 00007ff1c3e92407 RDX: 0000000000000004 RSI: 00007ffe95d2e6f0 RDI: 0000000000000004 RBP: 0000555795c572c0 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000202 R12: 0000555795f0f470 R13: 00007ffe95d2e6f0 R14: 0000000000000000 R15: 0000000000000004 ---------------- Code disassembly (best guess): 0: c1 ea 03 shr $0x3,%edx 3: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) 7: 0f 85 9b 0b 00 00 jne 0xba8 d: 48 8b 53 28 mov 0x28(%rbx),%rdx 11: b9 01 00 00 00 mov $0x1,%ecx 16: 4c 89 ef mov %r13,%rdi 19: e8 a3 cf fe ff call 0xfffecfc1 1e: e9 1d f9 ff ff jmp 0xfffff940 23: 48 8d 3d 57 fe 59 09 lea 0x959fe57(%rip),%rdi # 0x959fe81 * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2f: e9 99 f8 ff ff jmp 0xfffff8cd 34: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 3b: fc ff df 3e: 48 rex.W 3f: 8d .byte 0x8d