On 18 August 2014 09:41, Akos Kiss <ak...@inf.u-szeged.hu> wrote: > I've "stock" Ubuntu 14.04.1 running under an aarch64-qemu (built from > mainline git) in full-system emulation [1]. Everything worked fine until > I tried to find a bug in an application built for aarch64 (that bug most > likely being not the fault of qemu but the app itself). When I started > debugging, strange things happened: breakpoints in gdb did not behave as > they should. First, together with gdb developers, we speculated that > it's a bug in gdb (which still may hold, at least partially) [2], but > then I traced back the problem to a point where it has led out of gdb. > It seems that PTRACE_SINGLESTEP is not working as it should, it does not > stop the execution of the child after a step but lets it run > indefinitely.
Yes, this feature wasn't implemented yet in QEMU 2.1. I posted a set of patches to the list last week for this: https://lists.nongnu.org/archive/html/qemu-devel/2014-08/msg01291.html You might like to try testing them. There's also a bug where we don't report the correct PC value to the kernel when we hit a BRK instruction. I've just sent the one-liner fix to the list (cc'ing you). That ought to make gdb work without having to hack it to call set_gdbarch_decr_pc_after_break. thanks -- PMM
