Hello, have you meet the problem that of SEGV on unknown address 0x000000000008
I met this problem when I am initializing the fuzzer(vbox-coverage), the error info is
UndefinedBehaviorSanitizer:DEADLYSIGNAL
==9078==ERROR: UndefinedBehaviorSanitizer: SEGV on unknown address 0x000000000008 (pc 0x0000004ba955 bp 0x7ffd9fa84560 sp 0x7ffd9fa84240 T9078)
==9078==The signal is caused by a READ memory access.
==9078==Hint: address points to the zero page.
#0 0x4ba955 in LLVMFuzzerInitialize /root/videzzo/videzzo_vbox/vbox/src/VBox/Frontends/VBoxManage/VBoxViDeZZo.cpp:1121:17
#1 0x451427 in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char*, unsigned long)) /home/kiki/vdtest/videzzo-llvm-project/compiler-rt/lib/fuzzer/FuzzerDriver.cpp:664:29
#2 0x4433c6 in main /home/kiki/vdtest/videzzo-llvm-project/compiler-rt/lib/fuzzer/FuzzerMain.cpp:20:30
#3 0x7e0dfac00d8f in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
#4 0x7e0dfac00e3f in __libc_start_main csu/../csu/libc-start.c:392:3
#5 0x443944 in _start (/root/videzzo/videzzo_vbox/out-cov/vbox-videzzo-i386-target-videzzo-fuzz-e1000+0x443944)
And I find that when the code executing pVM = pUVM->pVM in LLVMFuzzerInitialize, the machine code will do
0x4ba932 <LLVMFuzzerInitialize+10e2> mov rax, QWORD PTR [rbp-0x120]
0x4ba939 <LLVMFuzzerInitialize+10e9> mov QWORD PTR [rbp-0x130], rax
0x4ba940 <LLVMFuzzerInitialize+10f0> mov rax, QWORD PTR [rbp-0x128]
0x4ba947 <LLVMFuzzerInitialize+10f7> mov QWORD PTR [rbp-0x138], rax
0x4ba94e <LLVMFuzzerInitialize+10fe> mov rax, QWORD PTR [rbp-0x130]
0x4ba955 <LLVMFuzzerInitialize+1105> mov rax, QWORD PTR [rax+0x8]
while the [rbp-0x120]is 0, so after the 0x4ba932, when it is executing 0x4ba955, it will try to accecc 0x8, it is an invalid addr.
Hello, have you meet the problem that of SEGV on unknown address 0x000000000008
I met this problem when I am initializing the fuzzer(vbox-coverage), the error info is
And I find that when the code executing
pVM = pUVM->pVMin LLVMFuzzerInitialize, the machine code will dowhile the
[rbp-0x120]is 0, so after the 0x4ba932, when it is executing 0x4ba955, it will try to accecc 0x8, it is an invalid addr.