Re: [linux-next:master 11808/13503] kernel/bpf/syscall.c:154: undefined reference to `vmalloc_user_node_flags'

[Rong Chen <rong.a.chen@intel.com>]

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On 11/24/19 1:37 AM, Andrii Nakryiko wrote:
> On 11/23/19 3:44 AM, kbuild test robot wrote:
>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
>> head:   b9d3d01405061bb42358fe53f824e894a1922ced
>> commit: fc9702273e2edb90400a34b3be76f7b08fa3344b [11808/13503] bpf: Add mmap() support for BPF_MAP_TYPE_ARRAY
>> config: arm-randconfig-a001-20191123 (attached as .config)
>> compiler: arm-linux-gnueabi-gcc (GCC) 7.4.0
>> reproduce:
>>           wget https://urldefense.proofpoint.com/v2/url?u=https-3A__raw.githubusercontent.com_intel_lkp-2Dtests_master_sbin_make.cross&d=DwIBAg&c=5VD0RTtNlTh3ycd41b3MUw&r=vxqvl81C2rT6GOGdPyz8iQ&m=OyqPkKr2ayhE9rsjQ3V9TjPHNWGAzMj67odoKch8_YM&s=JuUtGb4L_bH6ANKEMAgVL3zSBnFkOW4jhVP9W3WBHBM&e=  -O ~/bin/make.cross
>>           chmod +x ~/bin/make.cross
>>           git checkout fc9702273e2edb90400a34b3be76f7b08fa3344b
>>           # save the attached .config to linux build tree
>>           GCC_VERSION=7.4.0 make.cross ARCH=arm
>>
>> If you fix the issue, kindly add following tag
>> Reported-by: kbuild test robot <lkp@intel.com>
>>
>> All errors (new ones prefixed by >>):
>>
>>      arm-linux-gnueabi-ld: section .data VMA [0000000000808000,00000000008829bf] overlaps section .ARM.unwind_idx VMA [00000000007d7000,000000000080b8ef]
>>      arm-linux-gnueabi-ld: section .ARM.unwind_tab VMA [000000000080b8f0,000000000080febb] overlaps section .data VMA [0000000000808000,00000000008829bf]
>>      kernel/bpf/syscall.o: In function `__bpf_map_area_alloc':
>>>> kernel/bpf/syscall.c:154: undefined reference to `vmalloc_user_node_flags'
> Can't repro this with given config on x86_64. Trying to make make.cross
> work for me still. Any ideas why this is happening?

Hi Andrii,

We can reproduce it with make.cross command.

xsang(a)xsang-OptiPlex-9020:~/OLT-10114/linux-next$ GCC_VERSION=7.4.0 make.cross ARCH=arm
make CONFIG_OF_ALL_DTBS=y CONFIG_DTC=y CROSS_COMPILE=/home/xsang/0day/gcc-7.4.0-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- --jobs=16 ARCH=arm
...
   CC      include/uapi/linux/netfilter/ipset/ip_set_hash.h.s
   GEN     .version
   CHK     include/generated/compile.h
   LD      vmlinux.o
   MODPOST vmlinux.o
WARNING:"return_address"  [vmlinux] is astatic  EXPORT_SYMBOL_GPL
   MODINFO modules.builtin.modinfo
   LD      .tmp_vmlinux1
/home/xsang/0day/gcc-7.4.0-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi-ld: section .data VMA [0000000000808000,00000000008829bf] overlaps section .init.text VMA [00000000007f4db0,0000000000814207]
/home/xsang/0day/gcc-7.4.0-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi-ld: section .exit.text VMA [0000000000814208,0000000000817593] overlaps section .data VMA [0000000000808000,00000000008829bf]
kernel/bpf/syscall.o: In function `__bpf_map_area_alloc':
/home/xsang/OLT-10114/linux-next/kernel/bpf/syscall.c:154: undefined reference to `vmalloc_user_node_flags'
Makefile:1074: recipefor  target'vmlinux'  failed
make: *** [vmlinux] Error 1


Best Regards,
Rong Chen

> I see that
> __vmalloc_node_flags_caller that we also use if #ifdef'ed as static
> inline in include/linux/vmalloc.h if no CONFIG_MMU is defined. Are we
> missing some config dependency or should I do the same trick as
> __vmalloc_node_flags_caller does?
>
> Also. Daniel, when I tried to build latest bpf-next with this config, I
> got another compilation error, related to your recent patch, you might
> want to take a look as well:
>
>     CC      kernel/tracepoint.o
>     CC      kernel/elfcore.o
> /data/users/andriin/linux/kernel/bpf/verifier.c: In function
> ‘fixup_bpf_calls’:
> /data/users/andriin/linux/kernel/bpf/verifier.c:9132:25: error: implicit
> declaration of function ‘bpf_jit_blinding_enabled’; did you mean
> ‘bpf_jit_kallsyms_enabled’? [-Werror=implicit-function-declaration]
>     bool expect_blinding = bpf_jit_blinding_enabled(prog);
>                            ^~~~~~~~~~~~~~~~~~~~~~~~
>                            bpf_jit_kallsyms_enabled
>     CC      kernel/irq_work.o
>     CC      kernel/crash_dump.o
>
>> vim +154 kernel/bpf/syscall.c
>>
>>      129	
>>      130	static void *__bpf_map_area_alloc(size_t size, int numa_node, bool mmapable)
>>      131	{
>>      132		/* We really just want to fail instead of triggering OOM killer
>>      133		 * under memory pressure, therefore we set __GFP_NORETRY to kmalloc,
>>      134		 * which is used for lower order allocation requests.
>>      135		 *
>>      136		 * It has been observed that higher order allocation requests done by
>>      137		 * vmalloc with __GFP_NORETRY being set might fail due to not trying
>>      138		 * to reclaim memory from the page cache, thus we set
>>      139		 * __GFP_RETRY_MAYFAIL to avoid such situations.
>>      140		 */
>>      141	
>>      142		const gfp_t flags = __GFP_NOWARN | __GFP_ZERO;
>>      143		void *area;
>>      144	
>>      145		/* kmalloc()'ed memory can't be mmap()'ed */
>>      146		if (!mmapable && size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
>>      147			area = kmalloc_node(size, GFP_USER | __GFP_NORETRY | flags,
>>      148					    numa_node);
>>      149			if (area != NULL)
>>      150				return area;
>>      151		}
>>      152		if (mmapable) {
>>      153			BUG_ON(!PAGE_ALIGNED(size));
>>    > 154			return vmalloc_user_node_flags(size, numa_node, GFP_KERNEL |
>>      155						       __GFP_RETRY_MAYFAIL | flags);
>>      156		}
>>      157		return __vmalloc_node_flags_caller(size, numa_node,
>>      158						   GFP_KERNEL | __GFP_RETRY_MAYFAIL |
>>      159						   flags, __builtin_return_address(0));
>>      160	}
>>      161	
>>
>> ---
>> 0-DAY kernel test infrastructure                 Open Source Technology Center
>> https://urldefense.proofpoint.com/v2/url?u=https-3A__lists.01.org_hyperkitty_list_kbuild-2Dall-40lists.01.org&d=DwIBAg&c=5VD0RTtNlTh3ycd41b3MUw&r=vxqvl81C2rT6GOGdPyz8iQ&m=OyqPkKr2ayhE9rsjQ3V9TjPHNWGAzMj67odoKch8_YM&s=zQax2z98Tn-V1wcH0rtwmJ0iA9DpFhqbVNzexx7wOWw&e=  Intel Corporation
>>
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