https://bugzilla.kernel.org/show_bug.cgi?id=218339 Kishen Maloor (kishen.maloor@xxxxxxxxx) changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |kishen.maloor@xxxxxxxxx --- Comment #6 from Kishen Maloor (kishen.maloor@xxxxxxxxx) --- (In reply to Anthony L. Eden from comment #0) > In a debian QEMU/KVM virtual machine, run `gdb` on any executable (e.g. > `/usr/bin/ls`). Run the program by typing `starti`. Proceed to `_dl_start` > (i.e. `break _dl_start`, `continue`). When you get there disassemble the > function (i.e. `disas`). Find an instruction that's going to be executed for > which you can compute the address in memory it will write to. Run the > program to that instruction (i.e. `break *0xINSN`, `continue`). When you're > on that instruction, set a read/write watchpoint on the address it will > write to, then single-step (i.e. `stepi`) and the kernel will go > unresponsive. > > > >(gdb) x/1i $pc > >=> 0x7ffff7fe6510 <_dl_start+48>: mov %rdi,-0x88(%rbp) > >(gdb) x/1wx $rbp-0x88 > >0x7fffffffec28: 0x00000000 > >(gdb) awatch *0x7fffffffec28 > >Hardware access (read/write) watchpoint 2: *0x7fffffffec28 > >(gdb) stepi > I can reproduce the behavior you describe. But it seems that you're not invoking KVM at all, because when I add '-accel kvm' or '-enable-kvm' to your qemu command line the problem goes away. There may be an issue specifically in the handling of hardware watchpoints on the qemu emulation. If I disable hardware watchpoints in gdb using 'set can-use-hw-watchpoints 0' and then use 'watch *<ADDR>', that works. -- You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.
