Re: sparse problem with Linux kernel v5.5

[Luc Van Oostenryck <luc.vanoostenryck@gmail.com>]

On Thu, Feb 06, 2020 at 07:18:45AM +0000, Linus Torvalds wrote:
> On Thu, Feb 6, 2020 at 4:49 AM Randy Dunlap <rdunlap@infradead.org> wrote:
> >
> > Also, what is errno 137? (0x89)
> 
> I think that's just "killed by signal 9" (the high bit is "killed by
> signal", the low bits are the signal number).
> 
> SIGKILL - oom? What does 'dmesg' say? Maybe there's some exponential
> memory use triggered by something in that bpf_sk_storage file..
> 

Hi Randy,
What config are you using?

Here, on next-20200205 (commit 14b549456391a8b8f812529896b2690c16349734)
the file bpf_sk_storage.c is not compiled with the default config
(I suppose because of CONFIG_BPF_SYSCALL).
With allyesconfig, I see nothing particular ('-fmem-report' added):
  $ time sparse -fmem-report -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ -Wbitwise -Wno-return-void -Wno-unknown-attribute  -D__x86_64__ --arch=x86 -mlittle-endian -m64 -Wp,-MD,net/core/.bpf_sk_storage.o.d  -nostdinc -isystem /usr/lib/gcc/x86_64-linux-gnu/8/include -I./arch/x86/include -I./arch/x86/include/generated  -I./include -I./arch/x86/include/uapi -I./arch/x86/include/generated/uapi -I./include/uapi -I./include/generated/uapi -include ./include/linux/kconfig.h -include ./include/linux/compiler_types.h -D__KERNEL__ -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -fshort-wchar -fno-PIE -Werror=implicit-function-declaration -Werror=implicit-int -Wno-format-security -std=gnu89 -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx -m64 -falign-jumps=1 -falign-loops=1 -mno-80387 -mno-fp-ret-in-387 -mpreferred-stack-boundary=3 -mskip-rax-setup -mtune=generic -mno-red-zone -mcmodel=kernel -DCONFIG_X86_X32_ABI -DCONFIG_AS_CFI=1 -DCONFIG_AS_CFI_SIGNAL_FRAME=1 -DCONFIG_AS_CFI_SECTIONS=1 -DCONFIG_AS_SSSE3=1 -DCONFIG_AS_AVX=1 -DCONFIG_AS_AVX2=1 -DCONFIG_AS_AVX512=1 -DCONFIG_AS_SHA1_NI=1 -DCONFIG_AS_SHA256_NI=1 -Wno-sign-compare -fno-asynchronous-unwind-tables -mindirect-branch=thunk-extern -mindirect-branch-register -fno-jump-tables -fno-delete-null-pointer-checks -Wno-frame-address -Wno-format-truncation -Wno-format-overflow -O2 --param=allow-store-data-races=0 -fno-reorder-blocks -fno-ipa-cp-clone -fno-partial-inlining -Wframe-larger-than=2048 -fstack-protector-strong -Wno-unused-but-set-variable -Wimplicit-fallthrough -Wno-unused-const-variable -fno-var-tracking-assignments -pg -mrecord-mcount -mfentry -DCC_USING_FENTRY -fno-inline-functions-called-once -Wdeclaration-after-statement -Wvla -Wno-pointer-sign -Wno-stringop-truncation -fno-strict-overflow -fno-merge-all-constants -fmerge-constants -fno-stack-check -fconserve-stack -Werror=date-time -Werror=incompatible-pointer-types -Werror=designated-init -fmacro-prefix-map=./= -fcf-protection=none -Wno-packed-not-aligned    -fsanitize=kernel-address -fasan-shadow-offset=0xdffffc0000000000   --param asan-globals=1   --param asan-instrumentation-with-call-threshold=0   --param asan-stack=1   --param asan-instrument-allocas=1   -fsanitize-coverage=trace-pc -fsanitize-coverage=trace-cmp    -DKBUILD_MODFILE='"net/core/bpf_sk_storage"' -DKBUILD_BASENAME='"bpf_sk_storage"' -DKBUILD_MODNAME='"bpf_sk_storage"' net/core/bpf_sk_storage.c; echo $?
       allocator:   allocs,      bytes,      total,  %usage,  average
          tokens:        0,          0,          0,   0.00%,     0.00
     identifiers:    56223,    2262233,    2490368,  90.84%,    40.24
         symbols:   799200,  172627200,  173441024,  99.53%,   216.00
     expressions: 39852179, 2550539456, 2555543552,  99.80%,    64.00
      statements:   663762,   53100960,   53182464,  99.85%,    80.00
          scopes:    18206,     291296,     294912,  98.77%,    16.00
     basic_block:     1736,     180544,     196608,  91.83%,   104.00
     instruction:     7289,     583120,     589824,  98.86%,    80.00
          pseudo:     5181,     207240,     229376,  90.35%,    40.00
     pseudo_user:     6967,     111472,     131072,  85.05%,    16.00
        ptr list:   961807,  123111296,  123600896,  99.60%,   128.00
        multijmp:      275,       6600,      32768,  20.14%,    24.00
       asm rules:      241,       5784,      32768,  17.65%,    24.00
 asm constraints:      218,       6976,      32768,  21.29%,    32.00
        contexts:       42,        672,      32768,   2.05%,    16.00
         strings:    11288,     329766,     360448,  91.49%,    29.21
           bytes:    31957,     125216,     131072,  95.53%,     3.92
           total: 42416571, 2903489831, 2910322688,  99.77%,    68.45

real	0m5.391s
user	0m3.594s
sys	0m1.797s
0

In short, using 3G of RAM in 5secs without errors.


-- Luc