[Ltrace-devel] [PATCH] [MIPS] Detect return from rt_sigreturn syscalls

[Faraz Shahbazker]

On 02/18/2015 03:57 PM, Eugene Rudoy wrote:
> hmm, I'm still having the same behavior as without the patch - a lot
> of unexpected breakpoints at exactly the same places. S. attached
> logs.
Might have something to do with difference kernel versions. On my test machine, the signal event is immediate followed by an rt_sigreturn, where as the logs you posted show a sigreturn. rt_sigreturn and sigreturn have different syscall numbers; perhaps we need to check for both.

Just to be clear, this change is not related to tracing PLT-less binaries. The following patch is against master.

2015-02-19
* sysdeps/linux-gnu/mips/trace.c(syscall_p):
- If top of callstack was sigreturn or rt_sigreturn, skip check for preceeding syscall instruction.
- Return the appropriate syscall number in *sysnum

Regards,
Faraz Shahbazker