From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.1) Gecko/20021003 Description of problem: In the kernel BUG() gets compiled into the opcode ud2a. When objdump sees this it gets the offsets used in the disassembly all confused for a few instructions. c024f699: 0f 0b ud2a c024f69b: 99 cltd c024f69c: 01 80 70 2b c0 be add %eax,0xbec02b70(%eax) c024f6a2: 01 00 add %eax,(%eax) c024f6a4: 00 00 add %al,(%eax) c024f6a6: f0 0f c1 32 lock xadd %esi,(%edx) I'm not sure what the 99 01 80 70 2b c0 is but I know that the instruction be 01 00 00 00 should load 1 into %edx. So it seems like the compiler is generating some additional code after the ud2a opcode that objdump doesn't expect. Version-Release number of selected component (if applicable): How reproducible: Always Steps to Reproduce: 1. build a kernel 2. disassemble it. 3. Actual Results: objdump gets confused around the ud2f instructions Expected Results: it should expect whatever is after ud2f and deal with it. Additional info:
objdump --version GNU objdump 2.11.93.0.2 20020207 devi@ben:rpm -q binutils binutils-2.11.93.0.2-11
Can you please attach a sample .s file which shows this?
Why do you need a .s file from me? All that you have to do is objdump a vmlinux (not vmlinuz) and you will see the problem.
Ok, I see it myself: #define BUG() \ __asm__ __volatile__( "ud2\n" \ "\t.word %c0\n" \ "\t.long %c1\n" \ : : "i" (__LINE__), "i" (__FILE__)) There is nothing objdump can do about this thoughit has no way how to guess kernel has 8 bytes of data in the instruction stream followed again by instructions. If there was a jump around it, ie. ud2; jmp 1f; .word something; .long somethingelse; 1: then objdump would dump it correctly. But it would make kernel larger.