The aim of this patch is to either fix the problem or at least describe the circumstances around the crash using a 32 bit x86 linux host with a 32 bit linux guest making use of hw breakpoints.
I had also seen the same problem reported here: https://bugs.launchpad.net/qemu/+bug/501177 ---- running qemu in gdb with a linux kernel as the guest ---- kgdbts:RUN hw breakpoint test [New Thread 0xb7f1d700 (LWP 31553)] Program received signal SIGSEGV, Segmentation fault. raise_interrupt (intno=1, is_int=0, error_code=0, next_eip_addend=0) at /ord-lpggp11/jwessel/git/qemu/target-i386/op_helper.c:1335 1335 env->exception_index = intno; (gdb) info address env Symbol "env" is a variable in register ebp. (gdb) bt #0 raise_interrupt (intno=1, is_int=0, error_code=0, next_eip_addend=0) at /ord-lpggp11/jwessel/git/qemu/target-i386/op_helper.c:1335 #1 0x081380b7 in raise_exception (exception_index=1) at /ord-lpggp11/jwessel/git/qemu/target-i386/op_helper.c:1351 #2 0x0814db6e in breakpoint_handler (env=0x9ed8b50) at /ord-lpggp11/jwessel/git/qemu/target-i386/helper.c:1551 #3 0x080e1643 in cpu_x86_exec (env1=0x9ed8b50) at /ord-lpggp11/jwessel/git/qemu/cpu-exec.c:206 #4 0x08053af9 in main (argc=0, argv=0x0, envp=Cannot access memory at address 0x8 ) at /ord-lpggp11/jwessel/git/qemu/vl.c:3816 (gdb) I concluded that env points to the ebp register and it only has a valid value while executing from the generated code context. I created another function to pass in the valid version of env in order to set ebp in preparation to eventually execute a longjmp() via the raise_exception(). It is not clear that this is the right way to fix the problem, but it does allow the guest hw breakpoint tests to work correctly on a 32 bit and 64 bit x86 linux host. If there is a better way to solve this, please let me know. Thanks, Jason. --- Jason Wessel (1): target-i386: fix crash on x86 32bit linux host with hw breakpoint exceptions target-i386/exec.h | 1 + target-i386/helper.c | 6 +++--- target-i386/op_helper.c | 5 +++++ 3 files changed, 9 insertions(+), 3 deletions(-)