Pavel Dovgalyuk <dovga...@ispras.ru> writes:
>> From: Alex Bennée [mailto:alex.ben...@linaro.org] >> Pavel Dovgalyuk <pavel.dovga...@ispras.ru> writes: >> >> > Ping? >> >> I started having a look but I ran into this straight away. First I >> recorded a boot of the kernel: >> >> ./aarch64-softmmu/qemu-system-aarch64 -machine virt,graphics=on,gic- >> version=3,virtualization=on -cpu cortex-a53 --serial mon:stdio -display none >> -kernel >> ../images/aarch64-current-linux-initrd-guest.img -icount >> shift=7,rr=record,rrfile=replay.bin >> >> Then played back: >> >> ./aarch64-softmmu/qemu-system-aarch64 -machine virt,graphics=on,gic- >> version=3,virtualization=on -cpu cortex-a53 --serial mon:stdio -display none >> -kernel >> ../images/aarch64-current-linux-initrd-guest.img -icount >> shift=7,rr=replay,rrfile=replay.bin - >> s -S > > This looks ok, but... > >> And did the following on gdb: >> >> (gdb) i >> 0x0000000040000004 in ?? () >> => 0x40000004: mov x1, xzr >> 0x40000008: mov x2, xzr >> 0x4000000c: mov x3, xzr >> (gdb) >> 0x0000000040000008 in ?? () >> => 0x40000008: mov x2, xzr >> 0x4000000c: mov x3, xzr >> 0x40000010: ldr x4, 0x40000020 >> (gdb) >> 0x000000004000000c in ?? () >> => 0x4000000c: mov x3, xzr >> 0x40000010: ldr x4, 0x40000020 >> 0x40000014: br x4 >> (gdb) >> 0x0000000040000010 in ?? () >> => 0x40000010: ldr x4, 0x40000020 >> 0x40000014: br x4 >> 0x40000018: .inst 0x44000000 ; undefined >> (gdb) >> 0x0000000040000014 in ?? () >> => 0x40000014: br x4 >> 0x40000018: .inst 0x44000000 ; undefined >> 0x4000001c: .inst 0x00000000 ; undefined >> (gdb) p/x $x4 >> $1 = 0x40080000 >> (gdb) reverse-stepi >> warning: Remote failure reply: E14 >> >> Surely this is the simple case and doesn't require any snapshots for >> block devices as there are none. Am I missing something? > > Reverse debugging requires the snapshotting. QEMU can't revert the VM state > without the snapshots. > You can try adding an empty qcow2 image to allow snapshotting there. I suspect a recent patch has broken locking again: Starting program: /home/alex/lsrc/qemu/qemu.git/aarch64-softmmu/qemu-system-aarch64 -machine virt,graphics=on,gic-version=3,virtualization=on -cpu cortex-a53 --serial mon:stdio -display none -kernel ../images/aarch64-current-linux-initrd-guest.img -icount shift=7,rr=replay,rrfile=replay.bin,rrsnapshot=debug -drive file=rr.qcow2,if=none,snapshot,id=rr -s -S [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". [New Thread 0x7fffd8536700 (LWP 32452)] [New Thread 0x7fffd5bb3700 (LWP 32453)] [New Thread 0x7fffd4eab700 (LWP 32454)] ** ERROR:replay/replay-time.c:49:replay_read_clock: assertion failed: (replay_file && replay_mutex_locked()) Once I have the linux-user TCG tests merged I'm planning on focusing on the system emulation tests and we should be able to add some record/replay tests to defend the behaviour. -- Alex Bennée
