Valgrind無法找到未初始化數據的堆棧分配

當我通過valgrind運行我的程序時，出現一個錯誤。問題是，它不會告訴我哪裏有未初始化的字節被分配：Valgrind無法找到未初始化數據的堆棧分配

==22141== Syscall param write(buf) points to uninitialised byte(s) 
==22141== at 0x5B68900: __write_nocancel (syscall-template.S:82) 
==22141== by 0x5AFB882: [email protected]@GLIBC_2.2.5 (fileops.c:1289) 
==22141== by 0x5AFB749: new_do_write (fileops.c:543) 
==22141== by 0x5AFCEB4: [email protected]@GLIBC_2.2.5 (fileops.c:516) 
==22141== by 0x5AFDD3E: _IO_switch_to_get_mode (genops.c:189) 
==22141== by 0x5AFBA96: [email protected]@GLIBC_2.2.5 (fileops.c:999) 
==22141== by 0x5AF4F25: rewind (rewind.c:37) 
==22141== by 0x567D149: CBFileAppend (CBFileEC.c:69) 
==22141== by 0x5473AFA: CBDatabaseCreateDeletionIndex (CBDatabase.c:270) 
==22141== by 0x5473195: CBInitDatabase (CBDatabase.c:112) 
==22141== by 0x54721A1: CBNewAddressStorage (CBAddressStorage.c:37) 
==22141== by 0x401F67: main (testCBAddressManager.c:226) 
==22141== Address 0x402a009 is not stack'd, malloc'd or (recently) free'd 
==22141== Uninitialised value was created by a stack allocation 
==22141== at 0x546F750: ??? (in /media/sf_BitEagle_Projects/cbitcoin/bin/libcbitcoin-storage.2.0.so)

我將是假設這意味着一些無效的指針的堆棧是否正確？這發生在rewind（）中，我不明白爲什麼倒帶會是這樣的。我嘗試將valgrind進程附加到gdb，並試圖在文件指針上打印ftell（）的結果。這導致valgrind與此退出：

valgrind: m_syswrap/syswrap-main.c:1296 (vgPlain_client_syscall): Assertion 'sci->status.what == SsIdle' failed. 
==22938== at 0x3804CA36: ??? (in /usr/lib/valgrind/memcheck-amd64-linux) 
==22938== by 0x3804CBDC: ??? (in /usr/lib/valgrind/memcheck-amd64-linux) 
==22938== by 0x38091F55: ??? (in /usr/lib/valgrind/memcheck-amd64-linux) 
==22938== by 0x3808E5DF: ??? (in /usr/lib/valgrind/memcheck-amd64-linux) 
==22938== by 0x3808F739: ??? (in /usr/lib/valgrind/memcheck-amd64-linux) 
==22938== by 0x3809F7D5: ??? (in /usr/lib/valgrind/memcheck-amd64-linux) 

sched status: 
    running_tid=1 

Thread 1: status = VgTs_Runnable 
==22938== at 0x5B68900: __write_nocancel (syscall-template.S:82) 
==22938== by 0x5AFB882: [email protected]@GLIBC_2.2.5 (fileops.c:1289) 
==22938== by 0x5AFB749: new_do_write (fileops.c:543) 
==22938== by 0x5AFCEB4: [email protected]@GLIBC_2.2.5 (fileops.c:516) 
==22938== by 0x5AFDD3E: _IO_switch_to_get_mode (genops.c:189) 
==22938== by 0x5AFBA96: [email protected]@GLIBC_2.2.5 (fileops.c:999) 
==22938== by 0x5AF1AA5: ftell (ioftell.c:41) 
==22938== by 0x40133F: ??? (in /media/sf_BitEagle_Projects/cbitcoin/bin/testCBAddressManager) 
==22938== by 0xF75E467: ??? 
==22938== by 0x7FEFFF3BF: ??? 
==22938== by 0xF75E467: ??? 
==22938== by 0x546DE87: ??? (in /media/sf_BitEagle_Projects/cbitcoin/bin/libcbitcoin-storage.2.0.so) 
==22938== by 0x7FEFFF3DF: ???

我將如何去確定此錯誤的原因？

編輯：我解決了我遇到的其他問題，但這仍然存在。

這是從這裏代碼：https://github.com/MatthewLM/cbitcoin/blob/master/test/testCBAddressManager.c

文件IO代碼是在這裏：https://github.com/MatthewLM/cbitcoin/tree/master/dependencies/storage

謝謝。

來源

2013-02-03 Matthew Mitchell

您使用哪個過程來安裝valgrind？ – Sebivor

我很確定這是包含在Linux Mint中，我不需要自己安裝它。 –

請給我們展示一個最小的可編譯測試用例。 – Sebivor

系統調用PARAM寫（BUF）指向未初始化的字節

不一定有什麼不對的。試想一下：

int main() { 
    struct Foo { int a; int b; int c; } x; 
    x.a = 1; x.c = 3; 
    write(1, &x, sizeof(x)); // part of x is not initialized 
    return 0; 
}

如果以後你回讀取數據，並且只使用.a和.c成員，那麼你的程序是明確界定。

我認爲這是否意味着某種指向堆棧的無效指針？

號

如果你真的想找出數據的部分未初始化，使用Valgrind'd built-in gdbserver，併發出monitor check_memory definedcommand。

來源

2013-02-04 04:21:54

好的，謝謝。我明白這意味着什麼。這只是'''我想出去。 –

這個建議很糟糕，容易出錯。始終初始化數據結構。 – alecco

@alecco我*沒有*建議使用未初始化的數據;我只解釋了Vaglrind錯誤的含義，這並不一定表示程序中存在錯誤。「始終初始化數據結構。」 - 你有一個非常簡單的世界觀。初始化所有數據確實是謹慎的，除非這樣做會損害性能，並且知道自己在做什麼。 –

Valgrind無法找到未初始化數據的堆棧分配

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