ptrace can't work well in kernel 2.6 for mips in qemu?

Question

I want to use ptrace in qemu mips, but I can't wake up the child process when using fork and attach, however, I got success in kernel 3.2. I hope to know why got this ques in kernel 2.6?

I got the kernel from

https://people.debian.org/~aurel32/qemu/mips/

MIPS is an officially supported architecture, you shouldn't need to use anything but the mainline kernel. — Marcus Müller, Oct 11 '16 at 13:42
especially, if you're debugging something, maybe images from 2013 aren't the wisest choice, since everyone else might have moved on — Marcus Müller, Oct 11 '16 at 13:43
thx, I need to monitor something in kernel 2.6, and ptrace in kernel 2.6 is necessary. — jack link, Oct 11 '16 at 13:53
Show us your code. Create a minimal example showing what you tried and what you expected it to do. There is absolutely nothing here we can work with. — Shachar Shemesh, Oct 13 '16 at 01:43
Also, is this just an old kernel, or is the user space also old? Where and how are you building? — Shachar Shemesh, Oct 13 '16 at 01:46

score 0 · Answer 1 · answered Oct 13 '16 at 01:46

0

I cannot really answer your question, because it contains no usable information, so I'll just guess. Some of the ptrace constructs available were introduced into Linux later than the kernel you are using.

If you are using PTRACE_TRACEME or PTRACE_ATTACH, than you should be fine. If you are using PTRACE_SEIZE, then you are using a mechanism that simply did not exist in the kernel version you are using.

answered Oct 13 '16 at 01:46

Shachar Shemesh

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thanks for your help, and I solved this pro. I use kernel 2.6.32, and this kernel had a bug for ptrace mips and I got from here, https://sourceforge.net/p/strace/mailman/message/31856938/, and the patch is here, http://gitlab.pedjaapps.net/pedja/lge-kernel-omap4/commit/55436c91652b45be576b91ec96a8d65f6b7447fa – jack link Oct 17 '16 at 12:47
and I patch it and recompile the kernel and then ptrace work well. – jack link Oct 17 '16 at 12:48
Then write it as an answer, so that anyone else who happens to come across the same problem can find the solution. – Shachar Shemesh Oct 17 '16 at 16:58

score 0 · Accepted Answer · answered Oct 18 '16 at 12:00

I solved this pro. I use kernel 2.6.32, and this kernel had a bug for ptrace mips and I got from here, https://sourceforge.net/p/strace/mailman/message/31856938/,

and the patch is here, http://gitlab.pedjaapps.net/pedja/lge-kernel-omap4/commit/55436c91652b45be576b91ec96a8d65f6b7447fa

and I patch it and recompile the kernel and then ptrace work well.

ptrace can't work well in kernel 2.6 for mips in qemu?

2 Answers2