Re: [PATCH] bpf: hide cgroup functions for configs without cgroups
From: Chuyi Zhou
Date: Fri Oct 20 2023 - 23:46:16 EST
Hello,
在 2023/10/21 04:06, Arnd Bergmann 写道:
On Fri, Oct 20, 2023, at 19:26, Alexei Starovoitov wrote:
On Fri, Oct 20, 2023 at 6:27 AM Arnd Bergmann <arnd@xxxxxxxxxx> wrote:
@@ -904,6 +904,7 @@ __diag_push();
__diag_ignore_all("-Wmissing-prototypes",
"Global functions as their definitions will be in vmlinux BTF");
+#ifdef CONFIG_CGROUPS
__bpf_kfunc int bpf_iter_css_task_new(struct bpf_iter_css_task *it,
struct cgroup_subsys_state *css, unsigned int flags)
{
@@ -947,6 +948,7 @@ __bpf_kfunc void bpf_iter_css_task_destroy(struct bpf_iter_css_task *it)
css_task_iter_end(kit->css_it);
bpf_mem_free(&bpf_global_ma, kit->css_it);
}
+#endif
Did you actually test build it without cgroups and with bpf+btf?
I suspect the resolve_btfid step should be failing the build.
It needs
#ifdef CONFIG_CGROUPS
around BTF_ID_FLAGS(func, bpf_iter_css_task*
No, I did test with a few hundred random configurations, but it
looks like CONFIG_DEBUG_INFO_BTF is always disabled
in my builds because I force-disable CONFIG_DEBUG_INFO
to speed up my builds.
I tried reproducing it with CONFIG_DEBUG_INFO_BTF enabled
and it didn't immediately fail but it clearly makes sense that
we'd need another #ifdef.
Arnd
seems the same problem also reported by kernel-robot:
tree:
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head: 2030579113a1b1b5bfd7ff24c0852847836d8fd1
commit: 9c66dc94b62aef23300f05f63404afb8990920b4 [13777/13906] bpf:
Introduce css_task open-coded iterator kfuncs
config: hexagon-randconfig-r003-20230725
(https://download.01.org/0day-ci/archive/20231021/202310211011.pTzXR2o9-lkp@xxxxxxxxx/config)
compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.git
ae42196bc493ffe877a7e3dff8be32035dea4d07)
reproduce (this is a W=1 build):
(https://download.01.org/0day-ci/archive/20231021/202310211011.pTzXR2o9-lkp@xxxxxxxxx/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new
version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes:
https://lore.kernel.org/oe-kbuild-all/202310211011.pTzXR2o9-lkp@xxxxxxxxx/
All errors (new ones prefixed by >>):
In file included from kernel/bpf/task_iter.c:9:
In file included from include/linux/filter.h:9:
In file included from include/linux/bpf.h:31:
In file included from include/linux/memcontrol.h:13:
In file included from include/linux/cgroup.h:26:
In file included from include/linux/kernel_stat.h:9:
In file included from include/linux/interrupt.h:11:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/hexagon/include/asm/io.h:337:
include/asm-generic/io.h:547:31: warning: performing pointer
arithmetic on a null pointer has undefined behavior
[-Wnull-pointer-arithmetic]
val = __raw_readb(PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:560:61: warning: performing pointer
arithmetic on a null pointer has undefined behavior
[-Wnull-pointer-arithmetic]
val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE +
addr));
~~~~~~~~~~ ^
include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded
from macro '__le16_to_cpu'
#define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
^
In file included from kernel/bpf/task_iter.c:9:
In file included from include/linux/filter.h:9:
In file included from include/linux/bpf.h:31:
In file included from include/linux/memcontrol.h:13:
In file included from include/linux/cgroup.h:26:
In file included from include/linux/kernel_stat.h:9:
In file included from include/linux/interrupt.h:11:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/hexagon/include/asm/io.h:337:
include/asm-generic/io.h:573:61: warning: performing pointer
arithmetic on a null pointer has undefined behavior
[-Wnull-pointer-arithmetic]
val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE +
addr));
~~~~~~~~~~ ^
include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded
from macro '__le32_to_cpu'
#define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
^
In file included from kernel/bpf/task_iter.c:9:
In file included from include/linux/filter.h:9:
In file included from include/linux/bpf.h:31:
In file included from include/linux/memcontrol.h:13:
In file included from include/linux/cgroup.h:26:
In file included from include/linux/kernel_stat.h:9:
In file included from include/linux/interrupt.h:11:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/hexagon/include/asm/io.h:337:
include/asm-generic/io.h:584:33: warning: performing pointer
arithmetic on a null pointer has undefined behavior
[-Wnull-pointer-arithmetic]
__raw_writeb(value, PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:594:59: warning: performing pointer
arithmetic on a null pointer has undefined behavior
[-Wnull-pointer-arithmetic]
__raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE +
addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:604:59: warning: performing pointer
arithmetic on a null pointer has undefined behavior
[-Wnull-pointer-arithmetic]
__raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE +
addr);
~~~~~~~~~~ ^
>> kernel/bpf/task_iter.c:919:7: error: use of undeclared identifier
'CSS_TASK_ITER_PROCS'
case CSS_TASK_ITER_PROCS | CSS_TASK_ITER_THREADED:
^
>> kernel/bpf/task_iter.c:919:29: error: use of undeclared identifier
'CSS_TASK_ITER_THREADED'
case CSS_TASK_ITER_PROCS | CSS_TASK_ITER_THREADED:
^
kernel/bpf/task_iter.c:920:7: error: use of undeclared identifier
'CSS_TASK_ITER_PROCS'
case CSS_TASK_ITER_PROCS:
^
>> kernel/bpf/task_iter.c:927:46: error: invalid application of
'sizeof' to an incomplete type 'struct css_task_iter'
kit->css_it = bpf_mem_alloc(&bpf_global_ma, sizeof(struct
css_task_iter));
^
~~~~~~~~~~~~~~~~~~~~~~
kernel/bpf/task_iter.c:902:9: note: forward declaration of 'struct
css_task_iter'
struct css_task_iter *css_it;
^
>> kernel/bpf/task_iter.c:930:2: error: call to undeclared function
'css_task_iter_start'; ISO C99 and later do not support implicit
function declarations [-Wimplicit-function-declaration]
css_task_iter_start(css, flags, kit->css_it);
^
kernel/bpf/task_iter.c:930:2: note: did you mean '__sg_page_iter_start'?
include/linux/scatterlist.h:573:6: note: '__sg_page_iter_start'
declared here
void __sg_page_iter_start(struct sg_page_iter *piter,
^
>> kernel/bpf/task_iter.c:940:9: error: call to undeclared function
'css_task_iter_next'; ISO C99 and later do not support implicit function
declarations [-Wimplicit-function-declaration]
return css_task_iter_next(kit->css_it);
^
>> kernel/bpf/task_iter.c:940:9: error: incompatible integer to pointer
conversion returning 'int' from a function with result type 'struct
task_struct *' [-Wint-conversion]
return css_task_iter_next(kit->css_it);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> kernel/bpf/task_iter.c:949:2: error: call to undeclared function
'css_task_iter_end'; ISO C99 and later do not support implicit function
declarations [-Wimplicit-function-declaration]
css_task_iter_end(kit->css_it);
^
6 warnings and 8 errors generated.
vim +/CSS_TASK_ITER_PROCS +919 kernel/bpf/task_iter.c
904
905 __diag_push();
906 __diag_ignore_all("-Wmissing-prototypes",
907 "Global functions as their definitions will be in vmlinux BTF");
908
909 __bpf_kfunc int bpf_iter_css_task_new(struct bpf_iter_css_task *it,
910 struct cgroup_subsys_state *css, unsigned int flags)
911 {
912 struct bpf_iter_css_task_kern *kit = (void *)it;
913
914 BUILD_BUG_ON(sizeof(struct bpf_iter_css_task_kern) !=
sizeof(struct bpf_iter_css_task));
915 BUILD_BUG_ON(__alignof__(struct bpf_iter_css_task_kern) !=
916 __alignof__(struct bpf_iter_css_task));
917 kit->css_it = NULL;
918 switch (flags) {
> 919 case CSS_TASK_ITER_PROCS | CSS_TASK_ITER_THREADED:
> 920 case CSS_TASK_ITER_PROCS:
921 case 0:
922 break;
923 default:
924 return -EINVAL;
925 }
926
> 927 kit->css_it = bpf_mem_alloc(&bpf_global_ma, sizeof(struct
css_task_iter));
928 if (!kit->css_it)
929 return -ENOMEM;
> 930 css_task_iter_start(css, flags, kit->css_it);
931 return 0;
932 }
933
934 __bpf_kfunc struct task_struct *bpf_iter_css_task_next(struct
bpf_iter_css_task *it)
935 {
936 struct bpf_iter_css_task_kern *kit = (void *)it;
937
938 if (!kit->css_it)
939 return NULL;
> 940 return css_task_iter_next(kit->css_it);
941 }
942
943 __bpf_kfunc void bpf_iter_css_task_destroy(struct
bpf_iter_css_task *it)
944 {
945 struct bpf_iter_css_task_kern *kit = (void *)it;
946
947 if (!kit->css_it)
948 return;
> 949 css_task_iter_end(kit->css_it);
950 bpf_mem_free(&bpf_global_ma, kit->css_it);
951 }
952
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https://github.com/intel/lkp-tests/wiki