[Crash-utility] Re: [PATCH v7 00/15] gdb stack unwinding support for crash utility

Hi, Tao Thank you for the update. The following patch is a regression issue, so I tend to discuss it as a separate patch. [PATCH v7 01/15] Fix the regression of cpumask_t for xen hyper In addition, I found another issue in my tests(on ppc64le), the gdb bt can display the back trace for the panic task, but when I switch to another task, the gdb bt can not display the back trace: crash> gdb bt #0 0xc0000000002bde04 in crash_setup_regs (newregs=0xc00000003264b858, oldregs=0x0) at ./arch/powerpc/include/asm/kexec.h:133 #1 0xc0000000002be4f8 in __crash_kexec (regs=0x0) at kernel/crash_core.c:122 #2 0xc00000000016c254 in panic (fmt=0xc0000000015eef20 "sysrq triggered crash\n") at kernel/panic.c:373 #3 0xc000000000a708b8 in sysrq_handle_crash (key=<optimized out>) at drivers/tty/sysrq.c:154 #4 0xc000000000a713d4 in __handle_sysrq (key=key@entry=99 'c', check_mask=check_mask@entry=false) at drivers/tty/sysrq.c:612 #5 0xc000000000a71e94 in write_sysrq_trigger (file=<optimized out>, buf=<optimized out>, count=2, ppos=<optimized out>) at drivers/tty/sysrq.c:1181 #6 0xc00000000073260c in pde_write (pde=0xc00000000af9cc00, file=<optimized out>, buf=<optimized out>, count=<optimized out>, ppos=<optimized out>) at fs/proc/inode.c:334 #7 proc_reg_write (file=<optimized out>, buf=<optimized out>, count=<optimized out>, ppos=<optimized out>) at fs/proc/inode.c:346 #8 0xc00000000063c0e0 in vfs_write (file=0xc0000000092d2900, buf=0x10012536f60 <error: Cannot access memory at address 0x10012536f60>, count=2, pos=0xc00000003264bd30) at fs/read_write.c:588 #9 vfs_write (file=0xc0000000092d2900, buf=0x10012536f60 <error: Cannot access memory at address 0x10012536f60>, count=<optimized out>, pos=0xc00000003264bd30) at fs/read_write.c:570 #10 0xc00000000063c690 in ksys_write (fd=<optimized out>, buf=0x10012536f60 <error: Cannot access memory at address 0x10012536f60>, count=2) at fs/read_write.c:643 #11 0xc000000000031a28 in system_call_exception (regs=0xc00000003264be80, r0=<optimized out>) at arch/powerpc/kernel/syscall.c:153 #12 0xc00000000000d05c in system_call_vectored_common () at arch/powerpc/kernel/interrupt_64.S:198 crash> ps PID PPID CPU TASK ST %MEM VSZ RSS COMM 0 0 0 c000000002bda980 RU 0.0 0 0 [swapper/0] > 0 0 1 c000000003864c80 RU 0.0 0 0 [swapper/1] ... 8017 923 0 c000000043a20000 IN 0.2 22528 16256 sshd-session 8025 8017 6 c000000032271880 IN 0.1 22784 11840 sshd-session > 8026 8025 0 c000000043a26600 RU 0.1 9664 6208 bash ... 11645 2 3 c000000032264c80 ID 0.0 0 0 [kworker/u32:2] 11738 6188 2 c00000003811b180 IN 0.1 43520 9408 pickup 12326 2 0 c00000003226b280 ID 0.0 0 0 [kworker/0:1] 13112 6089 2 c00000000c809900 IN 0.0 7232 3456 sleep Let's take the "pickup" task as an example: crash> set 11738 PID: 11738 COMMAND: "pickup" TASK: c00000003811b180 [THREAD_INFO: c00000003811b180] CPU: 2 STATE: TASK_INTERRUPTIBLE crash> gdb bt #0 0xc0000000a7f876a0 in ?? () gdb: gdb request failed: bt crash> set gdb on gdb: on gdb> bt #0 0xc0000000a7f876a0 in ?? () gdb> Anyway, I did the same test on x86 64 and aarch64, it can work well as expected. Can you help to double check on ppc64 architecture? X86 64: crash> set 14599 PID: 14599 COMMAND: "pickup" TASK: ffff8f57a0d7c180 [THREAD_INFO: ffff8f57a0d7c180] CPU: 41 STATE: TASK_INTERRUPTIBLE crash> gdb bt #0 0xffffffff8b3efe29 in context_switch (rq=0xffff8f6f1f835900, prev=0xffff8f57a0d7c180, next=0xffff8f5786720000, rf=0xffff9df22fea7b80) at kernel/sched/core.c:5208 #1 __schedule (sched_mode=sched_mode@entry=0) at kernel/sched/core.c:6549 #2 0xffffffff8b3f0217 in __schedule_loop (sched_mode=<optimized out>) at kernel/sched/core.c:6626 #3 schedule () at kernel/sched/core.c:6641 #4 0xffffffff8b3f6eef in schedule_hrtimeout_range_clock (expires=expires@entry=0xffff9df22fea7cb0, delta=<optimized out>, delta@entry=99999999, mode=mode@entry=HRTIMER_MODE_ABS, clock_id=clock_id@entry=1) at kernel/time/hrtimer.c:2293 #5 0xffffffff8b3f7003 in schedule_hrtimeout_range (expires=expires@entry=0xffff9df22fea7cb0, delta=delta@entry=99999999, mode=mode@entry=HRTIMER_MODE_ABS) at kernel/time/hrtimer.c:2340 #6 0xffffffff8aae301c in ep_poll (ep=0xffff8f5790d15d40, events=events@entry=0x7ffea91b6b90, maxevents=maxevents@entry=100, timeout=timeout@entry=0xffff9df22fea7d58) at fs/eventpoll.c:2062 #7 0xffffffff8aae3138 in do_epoll_wait (epfd=epfd@entry=8, events=events@entry=0x7ffea91b6b90, maxevents=maxevents@entry=100, to=0xffff9df22fea7d58) at fs/eventpoll.c:2464 #8 0xffffffff8aae44a1 in __do_sys_epoll_wait (epfd=<optimized out>, events=0x7ffea91b6b90, maxevents=<optimized out>, timeout=<optimized out>) at fs/eventpoll.c:2476 #9 __se_sys_epoll_wait (epfd=<optimized out>, events=<optimized out>, maxevents=<optimized out>, timeout=<optimized out>) at fs/eventpoll.c:2471 #10 __x64_sys_epoll_wait (regs=<optimized out>) at fs/eventpoll.c:2471 #11 0xffffffff8b3e293d in do_syscall_x64 (regs=0xffff9df22fea7f48, nr=232) at arch/x86/entry/common.c:52 #12 do_syscall_64 (regs=0xffff9df22fea7f48, nr=232) at arch/x86/entry/common.c:83 #13 0xffffffff8b40012f in entry_SYSCALL_64 () at arch/x86/entry/entry_64.S:121 crash> aarch64: crash> set 9338 PID: 9338 COMMAND: "pickup" TASK: ffff0000c7b05400 [THREAD_INFO: ffff0000c7b05400] CPU: 3 STATE: TASK_INTERRUPTIBLE crash> gdb bt #0 __switch_to (prev=<unavailable>, prev@entry=0xffff0000c7b05400, next=next@entry=<unavailable>) at arch/arm64/kernel/process.c:555 #1 0xffffafc5b5ebd744 in context_switch (rq=0xffff00077bbd0ec0, prev=0xffff0000c7b05400, next=<unavailable>, rf=0xffff80008ac63a60) at kernel/sched/core.c:5208 #2 __schedule (sched_mode=sched_mode@entry=0) at kernel/sched/core.c:6549 #3 0xffffafc5b5ebdc2c in __schedule_loop (sched_mode=<optimized out>) at kernel/sched/core.c:6626 #4 schedule () at kernel/sched/core.c:6641 #5 0xffffafc5b5ec6030 in schedule_hrtimeout_range_clock (expires=expires@entry=0xffff80008ac63be8, delta=delta@entry=99999999, mode=mode@entry=HRTIMER_MODE_ABS, clock_id=clock_id@entry=1) at kernel/time/hrtimer.c:2293 #6 0xffffafc5b5ec618c in schedule_hrtimeout_range (expires=expires@entry=0xffff80008ac63be8, delta=delta@entry=99999999, mode=mode@entry=HRTIMER_MODE_ABS) at kernel/time/hrtimer.c:2340 #7 0xffffafc5b545d33c in ep_poll (ep=<unavailable>, events=events@entry=0xffffde5c3f68, maxevents=maxevents@entry=100, timeout=timeout@entry=0xffff80008ac63ce0) at fs/eventpoll.c:2062 #8 0xffffafc5b545d4e4 in do_epoll_wait (epfd=epfd@entry=8, events=events@entry=0xffffde5c3f68, maxevents=maxevents@entry=100, to=to@entry=0xffff80008ac63ce0) at fs/eventpoll.c:2464 #9 0xffffafc5b545d534 in do_epoll_pwait (epfd=epfd@entry=8, events=events@entry=0xffffde5c3f68, maxevents=maxevents@entry=100, to=to@entry=0xffff80008ac63ce0, sigsetsize=<optimized out>, sigmask=<optimized out>) at fs/eventpoll.c:2498 #10 0xffffafc5b545e7c8 in do_epoll_pwait (epfd=8, events=0xffffde5c3f68, maxevents=100, to=0xffff80008ac63ce0, sigmask=<optimized out>, sigsetsize=<optimized out>) at fs/eventpoll.c:2495 #11 __do_sys_epoll_pwait (epfd=8, events=0xffffde5c3f68, maxevents=100, timeout=<optimized out>, sigmask=<optimized out>, sigsetsize=<optimized out>) at fs/eventpoll.c:2511 #12 __se_sys_epoll_pwait (epfd=8, events=281474412330856, maxevents=100, timeout=<optimized out>, sigmask=<optimized out>, sigsetsize=<optimized out>) at fs/eventpoll.c:2505 #13 __arm64_sys_epoll_pwait (regs=<optimized out>) at fs/eventpoll.c:2505 #14 0xffffafc5b4fa99bc in __invoke_syscall (regs=0xffff80008ac63eb0, syscall_fn=<optimized out>) at arch/arm64/kernel/syscall.c:35 #15 invoke_syscall (regs=regs@entry=0xffff80008ac63eb0, scno=<optimized out>, sc_nr=sc_nr@entry=463, syscall_table=<optimized out>) at arch/arm64/kernel/syscall.c:49 #16 0xffffafc5b4fa9ac8 in el0_svc_common (sc_nr=463, syscall_table=<optimized out>, regs=0xffff80008ac63eb0, scno=<optimized out>) at arch/arm64/kernel/syscall.c:132 #17 do_el0_svc (regs=regs@entry=0xffff80008ac63eb0) at arch/arm64/kernel/syscall.c:151 #18 0xffffafc5b5eb6fa4 in el0_svc (regs=0xffff80008ac63eb0) at arch/arm64/kernel/entry-common.c:712 #19 0xffffafc5b5eb74c0 in el0t_64_sync_handler (regs=<optimized out>) at arch/arm64/kernel/entry-common.c:730 #20 0xffffafc5b4f91634 in el0t_64_sync () at arch/arm64/kernel/entry.S:598 crash> BTW: other changes are fine to me. Thanks Lianbo On Wed, Sep 4, 2024 at 3:54 PM <devel-request(a)lists.crash-utility.osci.io&gt; wrote: > Date: Wed, 4 Sep 2024 19:49:25 +1200 > From: Tao Liu <ltao(a)redhat.com&gt; > Subject: [Crash-utility] [PATCH v7 00/15] gdb stack unwinding support > for crash utility > To: devel(a)lists.crash-utility.osci.io > Cc: Tao Liu <ltao(a)redhat.com&gt; > Message-ID: <20240904074940.21331-1-ltao(a)redhat.com&gt; > Content-Type: text/plain; charset=UTF-8 > > This patchset is a rebase/merged version of the following 3 patchsets: > > 1): [PATCH v10 0/5] Improve stack unwind on ppc64 [1] > 2): [PATCH 0/5] x86_64 gdb stack unwinding support [2] > 3): Clean up on top of one-thread-v2 [3] > > A complete description of gdb stack unwinding support for crash can be > found in [1]. > > This patchset can be divided into the following 3 parts: > > 1) part1: preparations before stack unwinding support, some > bugs/regressions found when drafting this patchset. > 2) part2: common part for all CPU archs, mainly dealing with > crash_target.c/gdb_interface.c files, in order to > support different archs. > 3) part3: arch specific, for each ppc64/x86_64/arm64/vmware > stack unwinding support. > > === part 3 > arm64: Add gdb stack unwinding support > vmware_guestdump: Various format versions support > x86_64: Add gdb stack unwinding support > ppc64: correct gdb passthroughs by implementing > machdep->get_current_task_reg > > === part 2 > Conditionally output gdb stack unwinding stop reasons > Stop stack unwinding at non-kernel address > Print task pid/command instead of CPU index > Rename get_cpu_reg to get_current_task_reg > Let crash change gdb context > Leave only one gdb thread for crash > Remove 'frame' from prohibited commands list > > === part 1 > Fix gdb_interface: restore gdb's output streams at end of gdb_interface > x86_64: Fix invalid input "=>" for bt command > Fix cpumask_t recursive dependence issue > Fix the regression of cpumask_t for xen hyper > === > > v7 -> v6: > 1) Reorganise the patchset, re-divided them into 3 part against the > previous 2 parts. > 2) Re-dealed with the cpumask_t part, which solved the comment No.4 > pointed out by lianbo in [4]. > 3) Add conditional output for the failing message of gdb stack unwinding. > see [PATCH 11/15] Conditionally output gdb stack unwinding stop reasons > 4) Redraft the commit messages, updated some outdated info. > 5) Merged "Let crash change gdb context" and "set_context(): check if > context is already current" into one. > > [4]: > https://www.mail-archive.com/devel@lists.crash-utility.osci.io/msg01067.html > > v6 -> v5: > 1) Refactor patch 4 & 9, which changed the function signature of struct > get_cpu_reg/get_current_task_reg, and let each patch compile with no > error when added on. > 2) Rebased the patchset on top of latest upstream: > ("79b93ecb2e72ec Fix a "Bus error" issue caused by 'crash --osrelease' > or > crash loading") > > v5 -> v4: > 1) Plenty of code refactoring based on Lianbo's comments on v4. > 2) Removed the magic number when dealing with regs bitmap, see [6]. > 3) Rebased the patchset on top of latest upstream: > ("1c6da3eaff8207 arm64: Fix bt command show wrong stacktrace on > ramdump source") > > v4 -> v3: > Fixed the author issue in [PATCH v3 06/16] Fix gdb_interface: restore > gdb's > output streams at end of gdb_interface. > > v3 -> v2: > 1) Updated CC list as pointed out in [4] > 2) Compiling issues as in [5] > > v2 -> v1: > 1) Added the patch: x86_64: Fix invalid input "=>" for bt command, > thanks for Kazu's testing. > 2) Modify the patch: x86_64: Add gdb stack unwinding support, added the > pcp_save, spp_save and sp, for restoring the value in match of the > original > code logic. > > [1]: > https://www.mail-archive.com/devel@lists.crash-utility.osci.io/msg00469.html > [2]: > https://www.mail-archive.com/devel@lists.crash-utility.osci.io/msg00488.html > [3]: > https://www.mail-archive.com/devel@lists.crash-utility.osci.io/msg00554.html > [4]: > https://www.mail-archive.com/devel@lists.crash-utility.osci.io/msg00681.html > [5]: > https://www.mail-archive.com/devel@lists.crash-utility.osci.io/msg00715.html > [6]: > https://www.mail-archive.com/devel@lists.crash-utility.osci.io/msg00819.html > > Aditya Gupta (3): > Fix gdb_interface: restore gdb's output streams at end of > gdb_interface > Remove 'frame' from prohibited commands list > ppc64: correct gdb passthroughs by implementing > machdep->get_current_task_reg > > Alexey Makhalov (1): > vmware_guestdump: Various format versions support > > Tao Liu (11): > Fix the regression of cpumask_t for xen hyper > Fix cpumask_t recursive dependence issue > x86_64: Fix invalid input "=>" for bt command > Leave only one gdb thread for crash > Let crash change gdb context > Rename get_cpu_reg to get_current_task_reg > Print task pid/command instead of CPU index > Stop stack unwinding at non-kernel address > Conditionally output gdb stack unwinding stop reasons > x86_64: Add gdb stack unwinding support > arm64: Add gdb stack unwinding support > > arm64.c | 120 +++++++++++++++-- > crash_target.c | 71 ++++++---- > defs.h | 194 ++++++++++++++++++++++++++- > gdb-10.2.patch | 96 ++++++++++++++ > gdb_interface.c | 39 ++---- > kernel.c | 63 +++++++-- > ppc64.c | 174 +++++++++++++++++++++++- > symbols.c | 15 +++ > task.c | 34 +++-- > tools.c | 16 ++- > unwind_x86_64.h | 4 - > vmware_guestdump.c | 321 +++++++++++++++++++++++++++++++------------- > x86_64.c | 323 ++++++++++++++++++++++++++++++++++++++++----- > 13 files changed, 1247 insertions(+), 223 deletions(-) > > -- > 2.40.1 >