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QEMU main repository: Please see https://www.qemu.org/docs/master/devel/submitting-a-patch.html for how to submit changes to QEMU. Pull Requests are ignored. Please only use release tarballs from the QEMU website. http://www.qemu.org

emulation kvm qemu virtualization

History

Andrey Drobyshev 42f3c143c3 scripts/qemugdb: coroutine: Add option for obtaining detailed trace in coredump Commit `772f86839f` ("scripts/qemu-gdb: Support coroutine dumps in coredumps") introduced coroutine traces in coredumps using raw stack unwinding. While this works, this approach does not allow to view the function arguments in the corresponding stack frames. As an alternative, we can obtain saved registers from the coroutine's jmpbuf, patch them into the coredump's struct elf_prstatus in place, and execute another gdb subprocess to get backtrace from the patched temporary coredump. While providing more detailed info, this alternative approach, however, is more invasive as it might potentially corrupt the coredump file. We do take precautions by saving the original registers values into a separate binary blob /path/to/coredump.ptregs, so that it can be restores in the next GDB session. Still, instead of making it a new deault, let's keep raw unwind the default behaviour, but add the '--detailed' option for 'qemu bt' and 'qemu coroutine' command which would enforce the new behaviour. That's how this looks: (gdb) qemu coroutine 0x7fda9335a508 #0 0x5602bdb41c26 in qemu_coroutine_switch<+214> () at ../util/coroutine-ucontext.c:321 #1 0x5602bdb3e8fe in qemu_aio_coroutine_enter<+493> () at ../util/qemu-coroutine.c:293 #2 0x5602bdb3c4eb in co_schedule_bh_cb<+538> () at ../util/async.c:547 #3 0x5602bdb3b518 in aio_bh_call<+119> () at ../util/async.c:172 #4 0x5602bdb3b79a in aio_bh_poll<+457> () at ../util/async.c:219 #5 0x5602bdb10f22 in aio_poll<+1201> () at ../util/aio-posix.c:719 #6 0x5602bd8fb1ac in iothread_run<+123> () at ../iothread.c:63 #7 0x5602bdb18a24 in qemu_thread_start<+355> () at ../util/qemu-thread-posix.c:393 (gdb) qemu coroutine 0x7fda9335a508 --detailed patching core file /tmp/tmpq4hmk2qc found "CORE" at 0x10c48 assume pt_regs at 0x10cbc write r15 at 0x10cbc write r14 at 0x10cc4 write r13 at 0x10ccc write r12 at 0x10cd4 write rbp at 0x10cdc write rbx at 0x10ce4 write rip at 0x10d3c write rsp at 0x10d54 #0 0x00005602bdb41c26 in qemu_coroutine_switch (from_=0x7fda9335a508, to_=0x7fda8400c280, action=COROUTINE_ENTER) at ../util/coroutine-ucontext.c:321 #1 0x00005602bdb3e8fe in qemu_aio_coroutine_enter (ctx=0x5602bf7147c0, co=0x7fda8400c280) at ../util/qemu-coroutine.c:293 #2 0x00005602bdb3c4eb in co_schedule_bh_cb (opaque=0x5602bf7147c0) at ../util/async.c:547 #3 0x00005602bdb3b518 in aio_bh_call (bh=0x5602bf714a40) at ../util/async.c:172 #4 0x00005602bdb3b79a in aio_bh_poll (ctx=0x5602bf7147c0) at ../util/async.c:219 #5 0x00005602bdb10f22 in aio_poll (ctx=0x5602bf7147c0, blocking=true) at ../util/aio-posix.c:719 #6 0x00005602bd8fb1ac in iothread_run (opaque=0x5602bf42b100) at ../iothread.c:63 #7 0x00005602bdb18a24 in qemu_thread_start (args=0x5602bf7164a0) at ../util/qemu-thread-posix.c:393 #8 0x00007fda9e89f7f2 in start_thread (arg=<optimized out>) at pthread_create.c:443 #9 0x00007fda9e83f450 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81 CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> CC: Peter Xu <peterx@redhat.com> Originally-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20251204105019.455060-5-andrey.drobyshev@virtuozzo.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>		4 months ago
..
__init__.py	scripts/qemugdb: Remove shebang header	6 years ago
aio.py	scripts/qemugdb: Remove shebang header	6 years ago
coroutine.py	scripts/qemugdb: coroutine: Add option for obtaining detailed trace in coredump	2 months ago
mtree.py	scripts/qemugdb: mtree: Fix OverflowError in mtree with 128-bit addresses	2 months ago
tcg.py	treewide: remove unnessary "coding" header	6 months ago
timers.py	scripts/qemugdb: timers: Improve 'qemu timers' command readability	2 months ago