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

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Hi all,


Thanks Lianbo, Tao, Alexey and Daisuke for your reviews on this series.

Feels amazing to finally see this merged !

Thank you Tao for collaborating on this for so many months !

Hope this helps many people, I have been pinged my multiple people in dev and support teams that this information can help them classify the issue into which subsystem the issue might be in.


Thanks again,

- Aditya Gupta


On 04/11/24 13:39, lijiang wrote:
Thank you for working on this feature, Aditya, Tao and Alex. Great job! For the [PATCH v7 02/15 -15/15], rearranged them with minor changes: [1] https: //github. com/crash-utility/crash/commit/21e0a345f97324b3472d573ed20ef098f0300fac [2] https: //github. com/crash-utility/crash/commit/c4db469af091edd1ea0897fbce41bc175375314b

Thank you for working on this feature, Aditya, Tao and Alex. Great job!

For the [PATCH v7 02/15 -15/15], rearranged them with minor changes:

[1] https://github.com/crash-utility/crash/commit/21e0a345f97324b3472d573ed20ef098f0300fac [2] https://github.com/crash-utility/crash/commit/c4db469af091edd1ea0897fbce41bc175375314b [3] https://github.com/crash-utility/crash/commit/7c8a7dddda66b3d1043ba99516de57691033154a [4] https://github.com/crash-utility/crash/commit/1fd80c623c205443fdd2a29b14c5230a09984147 [5] https://github.com/crash-utility/crash/commit/6dfda0d2235574cf80530ea92e0ddff270f9c039 [6] https://github.com/crash-utility/crash/commit/89ff1e45734457eb66905ef656775fcfd1b46aec [7] https://github.com/crash-utility/crash/commit/968debd0d5979dd9ddca3af0766bad714dbd51e3

BTW: there are still some known issues about this one, but not critical issues, so which can be fixed later.

Reminder: the current patchset has changed some function interfaces, which may affect crash extensions.

Thanks
Lianbo

On Wed, Sep 11, 2024 at 10:25 AM lijiang <lijiang@xxxxxxxxxx> wrote:

    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@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

        Date: Wed,  4 Sep 2024 19:49:25 +1200
        From: Tao Liu <ltao@xxxxxxxxxx>
        Subject:  [PATCH v7 00/15] gdb stack unwinding
        support
                for crash utility
        To: devel@xxxxxxxxxxxxxxxxxxxxxxxxxxx
        Cc: Tao Liu <ltao@xxxxxxxxxx>
        Message-ID: <20240904074940.21331-1-ltao@xxxxxxxxxx>
        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@xxxxxxxxxxxxxxxxxxxxxxxxxxx/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@xxxxxxxxxxxxxxxxxxxxxxxxxxx/msg00469.html
        [2]:
        https://www.mail-archive.com/devel@xxxxxxxxxxxxxxxxxxxxxxxxxxx/msg00488.html
        [3]:
        https://www.mail-archive.com/devel@xxxxxxxxxxxxxxxxxxxxxxxxxxx/msg00554.html
        [4]:
        https://www.mail-archive.com/devel@xxxxxxxxxxxxxxxxxxxxxxxxxxx/msg00681.html
        [5]:
        https://www.mail-archive.com/devel@xxxxxxxxxxxxxxxxxxxxxxxxxxx/msg00715.html
        [6]:
        https://www.mail-archive.com/devel@xxxxxxxxxxxxxxxxxxxxxxxxxxx/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

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