riscv/qemu - qemu - Gitea: Git with a cup of tea

Commit Graph

Author	SHA1	Message	Date
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>	8 months ago
Peter Xu	772f86839f	scripts/qemu-gdb: Support coroutine dumps in coredumps Dumping coroutines don't yet work with coredumps. Let's make it work. We still kept most of the old code because they can be either more flexible, or prettier. Only add the fallbacks when they stop working. Currently the raw unwind is pretty ugly, but it works, like this: (gdb) qemu bt #0 process_incoming_migration_co (opaque=0x0) at ../migration/migration.c:788 #1 0x000055ae6c0dc4d9 in coroutine_trampoline (i0=-1711718576, i1=21934) at ../util/coroutine-ucontext.c:175 #2 0x00007f9f59d72f40 in ??? () at /lib64/libc.so.6 #3 0x00007ffd549214a0 in ??? () #4 0x0000000000000000 in ??? () Coroutine at 0x7f9f4c57c748: #0 0x55ae6c0dc9a8 in qemu_coroutine_switch<+120> () at ../util/coroutine-ucontext.c:321 #1 0x55ae6c0da2f8 in qemu_aio_coroutine_enter<+356> () at ../util/qemu-coroutine.c:293 #2 0x55ae6c0da3f1 in qemu_coroutine_enter<+34> () at ../util/qemu-coroutine.c:316 #3 0x55ae6baf775e in migration_incoming_process<+43> () at ../migration/migration.c:876 #4 0x55ae6baf7ab4 in migration_ioc_process_incoming<+490> () at ../migration/migration.c:1008 #5 0x55ae6bae9ae7 in migration_channel_process_incoming<+145> () at ../migration/channel.c:45 #6 0x55ae6bb18e35 in socket_accept_incoming_migration<+118> () at ../migration/socket.c:132 #7 0x55ae6be939ef in qio_net_listener_channel_func<+131> () at ../io/net-listener.c:54 #8 0x55ae6be8ce1a in qio_channel_fd_source_dispatch<+78> () at ../io/channel-watch.c:84 #9 0x7f9f5b26728c in g_main_context_dispatch_unlocked.lto_priv<+315> () #10 0x7f9f5b267555 in g_main_context_dispatch<+36> () #11 0x55ae6c0d91a7 in glib_pollfds_poll<+90> () at ../util/main-loop.c:287 #12 0x55ae6c0d9235 in os_host_main_loop_wait<+128> () at ../util/main-loop.c:310 #13 0x55ae6c0d9364 in main_loop_wait<+203> () at ../util/main-loop.c:589 #14 0x55ae6bac212a in qemu_main_loop<+41> () at ../system/runstate.c:835 #15 0x55ae6bfdf522 in qemu_default_main<+19> () at ../system/main.c:37 #16 0x55ae6bfdf55f in main<+40> () at ../system/main.c:48 #17 0x7f9f59d42248 in __libc_start_call_main<+119> () #18 0x7f9f59d4230b in __libc_start_main_impl<+138> () Signed-off-by: Peter Xu <peterx@redhat.com> Message-ID: <20241212204801.1420528-4-peterx@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>	2 years ago
Peter Xu	f4e343b655	scripts/qemu-gdb: Simplify fs_base fetching for coroutines There're a bunch of code trying to fetch fs_base in different ways. IIUC the simplest way instead is "$fs_base". It also has the benefit that it'll work for both live gdb session or coredumps. Signed-off-by: Peter Xu <peterx@redhat.com> Message-ID: <20241212204801.1420528-3-peterx@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>	2 years ago
Maxim Levitsky	b9a0de3773	scripts/gdb: implement 'qemu bt' This script first runs the regular gdb's 'bt' command, and then if we are in a coroutine it prints the coroutines backtraces in the order in which they were called. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20201217155436.927320-3-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>	6 years ago
Maxim Levitsky	4cbf8efc5b	scripts/gdb: fix 'qemu coroutine' when users selects a non topmost stack frame The code that dumps the stack frame works like that: * save current registers * overwrite current registers (including rip/rsp) with coroutine snapshot in the jmpbuf * print backtrace * restore the saved registers. If the user has currently selected a non topmost stack frame in gdb, the above code will still restore the selected frame registers, but the gdb will then lose the selected frame index, which makes it impossible to switch back to frame 0, to continue debugging the executable. Therefore switch temporarily to the topmost frame of the stack for the above code. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20201217155436.927320-2-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>	6 years ago
Philippe Mathieu-Daudé	6acc5c0469	scripts/qemugdb: Remove shebang header These scripts are loaded as plugin by GDB (and they don't have any __main__ entry point). Remove the shebang header. Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Acked-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: John Snow <jsnow@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20200512103238.7078-2-philmd@redhat.com> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>	6 years ago
Paolo Bonzini	328eb60dc1	qemugdb: fix licensing qemu-gdb.py was committed after 2012-01-13, so the notice about GPL v2-only contributions does not apply. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>	8 years ago
Vladimir Sementsov-Ogievskiy	6eaa20c836	qemugdb/coroutine: fix arch_prctl has unknown return type qemu coroutine command results in following error output: Python Exception <class 'gdb.error'> 'arch_prctl' has unknown return type; cast the call to its declared return type: Error occurred in Python command: 'arch_prctl' has unknown return type; cast the call to its declared return type Fix it by giving it what it wants: arch_prctl return type. Information on the topic: https://sourceware.org/gdb/onlinedocs/gdb/Calling.html Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20190206151425.105871-1-vsementsov@virtuozzo.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>	8 years ago
Paolo Bonzini	a201b0ff28	qemu-gdb: add $qemu_coroutine_sp and $qemu_coroutine_pc These can be useful to manually get a stack trace of a coroutine inside a core dump. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 1444636974-19950-4-git-send-email-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>	11 years ago
Paolo Bonzini	80ab31b257	qemu-gdb: extract parts of "qemu coroutine" implementation Provide useful Python functions to reach and decipher a jmpbuf. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 1444636974-19950-3-git-send-email-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>	11 years ago
Paolo Bonzini	1138f24645	qemu-gdb: allow using glibc_pointer_guard() on core dumps get_fs_base() cannot be run on a core dump, because it uses the arch_prctl system call. The fs base is the value that is returned by pthread_self(), and it would be nice to just glean it from the "info threads" output: * 1 Thread 0x7f16a3fff700 (LWP 33642) pthread_cond_wait@@GLIBC_2.3.2 () ^^^^^^^^^^^^^^ but unfortunately the gdb API does not provide that. Instead, we can look for the "arg" argument of the start_thread function if glibc debug information are available. If not, fall back to the old mechanism. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 1444636974-19950-2-git-send-email-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>	11 years ago
Peter Maydell	191590f09d	scripts/qemu-gdb: Split CoroutineCommand into its own file Split the implementation of CoroutineCommand into its own file. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 1439574392-4403-3-git-send-email-peter.maydell@linaro.org	11 years ago
Peter Maydell	93b1b365dc	scripts/qemu-gdb: Split MtreeCommand into its own module As we add more commands to our Python gdb debugging support, it's going to get unwieldy to have everything in a single file. Split the implementation of the 'mtree' command from qemu-gdb.py into its own module. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 1439574392-4403-2-git-send-email-peter.maydell@linaro.org	11 years ago
Stefan Hajnoczi	9eddd6a4b3	scripts: add 'qemu coroutine' command to qemu-gdb.py The 'qemu coroutine <coroutine-address>' GDB command prints the backtrace for a CoroutineUContext. This is useful for peeking inside yielded coroutines that are waiting for file descriptor events, timers, etc. For example: $ gdb tests/test-coroutine (gdb) b test_yield (gdb) r (gdb) b qemu_coroutine_enter (gdb) c (gdb) c Continuing. Breakpoint 2, qemu_coroutine_enter (co=0x555555c66520, opaque=0x0) at qemu-coroutine.c:103 103 { (gdb) source scripts/qemu-gdb.py (gdb) qemu coroutine 0x555555c66520 #0 0x000055555557a740 in qemu_coroutine_switch (from_=<optimized out>, to_=0x7ffff7f90a70, action=COROUTINE_YIELD) at coroutine-ucontext.c:177 #1 0x0000555555566af9 in yield_5_times (opaque=0x7fffffffdbb7) at tests/test-coroutine.c:107 #2 0x000055555557a7aa in coroutine_trampoline (i0=<optimized out>, i1=<optimized out>) at coroutine-ucontext.c:80 #3 0x00007ffff08de000 in __start_context () at /lib64/libc.so.6 Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 1427409754-8556-1-git-send-email-stefanha@redhat.com Signed-off-by: Kevin Wolf <kwolf@redhat.com>	12 years ago
Avi Kivity	4daa187d49	scripts: add gdb support script Add a script that enhances gdb to be aware of QEMU data structures. This patch adds a single gdb command, 'qemu mtree'. The command is similar to the monitor's 'info mtree', except that it prints MemoryRegion addresses, and except for working from a core dump as well as a live instance. Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>	15 years ago

12 Commits (42f3c143c3a04a9d193147e503b8f0c64bf0fb78)