Messages in this thread | | | Subject | Re: A issue about ptrace/SINGLESTEP on arm64 | From | "chengjian (D)" <> | Date | Tue, 17 Oct 2017 10:04:00 +0800 |
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On 2017/10/16 23:30, Will Deacon wrote: > Can you jump the PC once the child appears to be "stuck"? > > IIRC, GDB has special heuristics to step through LDXR/STXR critical > sections. The function can be returned, But the number of instructions looks too much We use objdump to count the assembly code length of the program
#======= #trace #======= ptrace/2-arm64-loop # objdump -d ./nop | wc -l 115885
ptrace/2-arm64-loop # ./ptrace_singlestep ./nop
./nop : nop Please wait Number of machine instructions : 186688022
/ptrace/2-arm64-loop # ./ptrace_singlestep ./nop
./nop : nop Please wait Number of machine instructions : 103670668
The number of instructions executed twice is not the same
#======= #trace ls #=======
ptrace/2-arm64-loop # objdump -d /bin/ls | wc -l 18095
ptrace/2-arm64-loop # ./ptrace_singlestep /bin/ls /bin/ls : ls Please wait Number of machine instructions : 7718122167
It seems that the child has also been tracked by the parent process when it goes into the kernel space.
Is this what your 'stuck' mean? Does all the instructions been tracked in kernel space, or only the LDXR/STXR?
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