There is a question mark in front of the function name in the call trace log.What does the question mark imply?

[孙世龙]

Hi,

I have never seen such a call trace log before: there is a question
mark(i.e. symbol of "?")  in front of the function name. What does the
question mark imply?

Here is the related log:

[22041.387697] Call Trace:

[22041.387711] dump_stack+0x9e/0xc8

[22041.387718] warn_alloc+0x100/0x190

[22041.387725] __alloc_pages_slowpath+0xb93/0xbd0

[22041.387732] __alloc_pages_nodemask+0x26d/0x2b0

[22041.387739] alloc_pages_current+0x6a/0xe0

[22041.387744] kmalloc_order+0x18/0x40

[22041.387748] kmalloc_order_trace+0x24/0xb0

[22041.387754] __kmalloc+0x20e/0x230

[22041.387759] ? __vmalloc_node_range+0x171/0x250

[22041.387765] xnheap_init+0x87/0x200

[22041.387770] ? remove_process+0xc0/0xc0

[22041.387775] cobalt_umm_init+0x61/0xb0

[22041.387779] cobalt_process_attach+0x64/0x4c0

[22041.387784] ? snprintf+0x45/0x70

[22041.387790] ? security_capable+0x46/0x60

[22041.387794] bind_personality+0x5a/0x120

[22041.387798] cobalt_bind_core+0x27/0x60

[22041.387803] CoBaLt_bind+0x18a/0x1d0

[22041.387812] ? handle_head_syscall+0x3f0/0x3f0

[22041.387816] ipipe_syscall_hook+0x119/0x340

[22041.387822] __ipipe_notify_syscall+0xd3/0x190

[22041.387827] ? __x64_sys_rt_sigaction+0x7b/0xd0

[22041.387832] ipipe_handle_syscall+0x3e/0xc0

[22041.387837] do_syscall_64+0x3b/0x250

[22041.387842] entry_SYSCALL_64_after_hwframe+0x44/0xa9
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