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Fix for the invalid linux_banner pointer issue #6

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merged 1 commit into from
Sep 20, 2022

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Currently, crash may fail with the following error:

./crash -s vmlinux vmcore

WARNING: invalid linux_banner pointer: 65762078756e694c
crash: vmlinux and vmcore do not match!

The reason is that the type of the symbol in the data segment may be defined as 'D' or 'd'. The crash only handled the type 'D', but it didn't deal with the type 'd'. For example:

nm vmlinux | grep linux_banner

ffffffff827cfa80 d linux_banner

It has been observed that a vmlinux compiled by clang has this type. Let's add the type 'd' recognition to solve such issue.

Signed-off-by: Lianbo Jiang [email protected]

Currently, crash may fail with the following error:

  # ./crash -s vmlinux vmcore
  WARNING: invalid linux_banner pointer: 65762078756e694c
  crash: vmlinux and vmcore do not match!

The reason is that the type of the symbol in the data segment may be
defined as 'D' or 'd'. The crash only handled the type 'D', but it
didn't deal with the type 'd'. For example:

  # nm vmlinux | grep linux_banner
  ffffffff827cfa80 d linux_banner

It has been observed that a vmlinux compiled by clang has this type.
Let's add the type 'd' recognition to solve such issue.

Signed-off-by: Lianbo Jiang <[email protected]>
@fengjixuchui fengjixuchui merged commit a8f416c into fengjixuchui:master Sep 20, 2022
fengjixuchui pushed a commit that referenced this pull request Jan 12, 2023
1, Add the implementation to get stack frame from active & inactive
   task's stack.
2, Add 'bt -l' command support get a line number associated with a
   current pc address.
3, Add 'bt -f' command support to display all stack data contained
   in a frame

With the patch, we can get the backtrace,
crash> bt
PID: 113      TASK: ff6000000226c200  CPU: 0    COMMAND: "sh"
 #0 [ff20000010333b90] riscv_crash_save_regs at ffffffff800078f8
 #1 [ff20000010333cf0] panic at ffffffff806578c6
 #2 [ff20000010333d50] sysrq_reset_seq_param_set at ffffffff8038c03c
 #3 [ff20000010333da0] __handle_sysrq at ffffffff8038c604
 #4 [ff20000010333e00] write_sysrq_trigger at ffffffff8038cae4
 #5 [ff20000010333e20] proc_reg_write at ffffffff801b7ee8
 #6 [ff20000010333e40] vfs_write at ffffffff80152bb2
 #7 [ff20000010333e80] ksys_write at ffffffff80152eda
 #8 [ff20000010333ed0] sys_write at ffffffff80152f52

crash> bt -l
PID: 113      TASK: ff6000000226c200  CPU: 0    COMMAND: "sh"
 #0 [ff20000010333b90] riscv_crash_save_regs at ffffffff800078f8
    /buildroot/qemu_riscv64_virt_defconfig/build/linux-custom/arch/riscv/kernel/crash_save_regs.S: 47
 #1 [ff20000010333cf0] panic at ffffffff806578c6
    /buildroot/qemu_riscv64_virt_defconfig/build/linux-custom/kernel/panic.c: 276
 ... ...

crash> bt -f
PID: 113      TASK: ff6000000226c200  CPU: 0    COMMAND: "sh"
 #0 [ff20000010333b90] riscv_crash_save_regs at ffffffff800078f8
    [PC: ffffffff800078f8 RA: ffffffff806578c6 SP: ff20000010333b90 SIZE: 352]
    ff20000010333b90: ff20000010333bb0 ffffffff800078f8
    ff20000010333ba0: ffffffff8008862c ff20000010333b90
    ff20000010333bb0: ffffffff810dde38 ff6000000226c200
    ff20000010333bc0: ffffffff8032be68 0720072007200720
 ... ...

Signed-off-by: Xianting Tian <[email protected]>
fengjixuchui pushed a commit that referenced this pull request Feb 27, 2023
Kernel commit 7d65f4a65532 ("irq: Consolidate do_softirq() arch overriden
implementations") renamed the call_softirq to do_softirq_own_stack, and
there is no exception frame also when coming from do_softirq_own_stack.
Without the patch, crash may unnecessarily output an exception frame with
a warning as below:

  crash> foreach bt
  ...
  PID: 0        TASK: ffff914f820a8000  CPU: 25   COMMAND: "swapper/25"
   #0 [fffffe0000504e48] crash_nmi_callback at ffffffffa665d763
   #1 [fffffe0000504e50] nmi_handle at ffffffffa662a423
   #2 [fffffe0000504ea8] default_do_nmi at ffffffffa6fe7dc9
   #3 [fffffe0000504ec8] do_nmi at ffffffffa662a97f
   #4 [fffffe0000504ef0] end_repeat_nmi at ffffffffa70015e8
      [exception RIP: clone_endio+172]
      RIP: ffffffffc005c1ec  RSP: ffffa1d403d08e98  RFLAGS: 00000246
      RAX: 0000000000000000  RBX: ffff915326fba230  RCX: 0000000000000018
      RDX: ffffffffc0075400  RSI: 0000000000000000  RDI: ffff915326fba230
      RBP: ffff915326fba1c0   R8: 0000000000001000   R9: ffff915308d6d2a0
      R10: 000000a97dfe5e10  R11: ffffa1d40038fe98  R12: ffff915302babc40
      R13: ffff914f94360000  R14: 0000000000000000  R15: 0000000000000000
      ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
  --- <NMI exception stack> ---
   #5 [ffffa1d403d08e98] clone_endio at ffffffffc005c1ec [dm_mod]
   #6 [ffffa1d403d08ed0] blk_update_request at ffffffffa6a96954
   #7 [ffffa1d403d08f10] scsi_end_request at ffffffffa6c9b968
   #8 [ffffa1d403d08f48] scsi_io_completion at ffffffffa6c9bb3e
   #9 [ffffa1d403d08f90] blk_complete_reqs at ffffffffa6aa0e95
   #10 [ffffa1d403d08fa0] __softirqentry_text_start at ffffffffa72000dc
   #11 [ffffa1d403d08ff0] do_softirq_own_stack at ffffffffa7000f9a
  --- <IRQ stack> ---
   #12 [ffffa1d40038fe70] do_softirq_own_stack at ffffffffa7000f9a
      [exception RIP: unknown or invalid address]
      RIP: 0000000000000000  RSP: 0000000000000000  RFLAGS: 00000000
      RAX: ffffffffa672eae5  RBX: ffffffffa83b34e0  RCX: ffffffffa672eb12
      RDX: 0000000000000010  RSI: 8b7d6c8869010c00  RDI: 0000000000000085
      RBP: 0000000000000286   R8: ffff914f820a8000   R9: ffffffffa67a94e0
      R10: 0000000000000286  R11: ffffffffa66fb4c5  R12: ffffffffa67a898b
      R13: 0000000000000000  R14: fffffffffffffff8  R15: ffffffffa67a1e68
      ORIG_RAX: 0000000000000000  CS: 0000  SS: ffffffffa672edff
   bt: WARNING: possibly bogus exception frame
   #13 [ffffa1d40038ff30] start_secondary at ffffffffa665fa2c
   #14 [ffffa1d40038ff50] secondary_startup_64_no_verify at ffffffffa6600116
   ...

Reported-by: Marco Patalano <[email protected]>
Signed-off-by: Lianbo Jiang <[email protected]>
fengjixuchui pushed a commit that referenced this pull request Feb 27, 2023
On kernels configured with CONFIG_RANDOMIZE_KSTACK_OFFSET=y and
random_kstack_offset=on, a random offset is added to task stacks with
__kstack_alloca() at the beginning of do_syscall_64() and other syscall
entry functions.  This eventually does the following instruction.

  <do_syscall_64+32>:  sub    %rax,%rsp

On the other hand, crash uses only a part of data for ORC unwinder to
unwind stacks and if an ip value doesn't have a usable ORC data, it
caluculates the frame size with parsing the assembly of the function.

However, crash cannot calculate the frame size correctly with the
instruction above, and prints stale return addresses like this:

  crash> bt 1
  PID: 1        TASK: ffff9c250023b880  CPU: 0    COMMAND: "systemd"
    #0 [ffffb7e5c001fc80] __schedule at ffffffff91ae2b16
    #1 [ffffb7e5c001fd00] schedule at ffffffff91ae2ed3
    #2 [ffffb7e5c001fd18] schedule_hrtimeout_range_clock at ffffffff91ae7ed8
    #3 [ffffb7e5c001fda8] ep_poll at ffffffff913ef828
    #4 [ffffb7e5c001fe48] do_epoll_wait at ffffffff913ef943
    #5 [ffffb7e5c001fe80] __x64_sys_epoll_wait at ffffffff913f0130
    #6 [ffffb7e5c001fed0] do_syscall_64 at ffffffff91ad7169
    #7 [ffffb7e5c001fef0] do_syscall_64 at ffffffff91ad7179             <<
    #8 [ffffb7e5c001ff10] syscall_exit_to_user_mode at ffffffff91adaab2 << stale entries
    #9 [ffffb7e5c001ff20] do_syscall_64 at ffffffff91ad7179             <<
   #10 [ffffb7e5c001ff50] entry_SYSCALL_64_after_hwframe at ffffffff91c0009b
       RIP: 00007f258d9427ae  RSP: 00007fffda631d60  RFLAGS: 00000293
       ...

To fix this, enhance the use of ORC data.  The ORC unwinder often uses
%rbp value, so keep it from exception frames and inactive task stacks.

Signed-off-by: Kazuhito Hagio <[email protected]>
fengjixuchui pushed a commit that referenced this pull request Sep 5, 2023
Kernel commit fb799447ae29 ("x86,objtool: Split UNWIND_HINT_EMPTY in
two"), which is contained in Linux 6.4 and later kernels, changed
ORC_TYPE_CALL macro from 0 to 2.  As a result, the "bt" command cannot
use ORC entries, and can display stale entries in a call trace.

  crash> bt 1
  PID: 1        TASK: ffff93cd06294180  CPU: 51   COMMAND: "systemd"
   #0 [ffffb72bc00cbc98] __schedule at ffffffff86e52aae
   #1 [ffffb72bc00cbd00] schedule at ffffffff86e52f6a
   #2 [ffffb72bc00cbd18] schedule_hrtimeout_range_clock at ffffffff86e58ef5
   #3 [ffffb72bc00cbd88] ep_poll at ffffffff8669624d
   #4 [ffffb72bc00cbe28] do_epoll_wait at ffffffff86696371
   #5 [ffffb72bc00cbe30] do_timerfd_settime at ffffffff8669902b        <<
   #6 [ffffb72bc00cbe60] __x64_sys_epoll_wait at ffffffff86696bf0
   #7 [ffffb72bc00cbeb0] do_syscall_64 at ffffffff86e3feb9
   #8 [ffffb72bc00cbee0] __task_pid_nr_ns at ffffffff863330d7          <<
   #9 [ffffb72bc00cbf08] syscall_exit_to_user_mode at ffffffff86e466b2 << stale entries
  #10 [ffffb72bc00cbf18] do_syscall_64 at ffffffff86e3fec9             <<
  #11 [ffffb72bc00cbf50] entry_SYSCALL_64_after_hwframe at ffffffff870000aa

Also, kernel commit ffb1b4a41016 added a member to struct orc_entry.
Although this does not affect the crash's unwinder, its debugging
information can be displayed incorrectly.

To fix these,
(1) introduce "kernel_orc_entry_6_4" structure corresponding to 6.4 and
    abstruction layer "orc_entry" structure in crash,
(2) switch ORC_TYPE_CALL to 2 or 0 with kernel's orc_entry structure.

Related orc_entry history:
 v4.14 39358a033b2e introduced struct orc_entry
 v4.19 d31a580266ee added orc_entry.end member
 v6.3  ffb1b4a41016 added orc_entry.signal member
 v6.4  fb799447ae29 removed end member and changed type member to 3 bits

Signed-off-by: Kazuhito Hagio <[email protected]>
fengjixuchui pushed a commit that referenced this pull request Mar 5, 2024
…usly

There is an issue that, for kernel modules, "dis -rl" fails to display
modules code line number data after execute "bt" command in crash.

Without the patch:
  crsah> mod -S
  crash> bt
  PID: 1500     TASK: ff2bd8b093524000  CPU: 16   COMMAND: "lpfc_worker_0"
   #0 [ff2c9f725c39f9e0] machine_kexec at ffffffff8e0686d3
   ...snip...
   #8 [ff2c9f725c39fcc0] __lpfc_sli_release_iocbq_s4 at ffffffffc0f2f425 [lpfc]
   ...snip...
  crash> dis -rl ffffffffc0f60f82
  0xffffffffc0f60eb0 <lpfc_nlp_get>:      nopl   0x0(%rax,%rax,1) [FTRACE NOP]
  0xffffffffc0f60eb5 <lpfc_nlp_get+5>:    push   %rbp
  0xffffffffc0f60eb6 <lpfc_nlp_get+6>:    push   %rbx
  0xffffffffc0f60eb7 <lpfc_nlp_get+7>:    test   %rdi,%rdi

With the patch:
  crash> mod -S
  crash> bt
  PID: 1500     TASK: ff2bd8b093524000  CPU: 16   COMMAND: "lpfc_worker_0"
   #0 [ff2c9f725c39f9e0] machine_kexec at ffffffff8e0686d3
   ...snip...
   #8 [ff2c9f725c39fcc0] __lpfc_sli_release_iocbq_s4 at ffffffffc0f2f425 [lpfc]
   ...snip...
  crash> dis -rl ffffffffc0f60f82
  /usr/src/debug/kernel-4.18.0-425.13.1.el8_7/linux-4.18.0-425.13.1.el8_7.x86_64/drivers/scsi/lpfc/lpfc_hbadisc.c: 6756
  0xffffffffc0f60eb0 <lpfc_nlp_get>:      nopl   0x0(%rax,%rax,1) [FTRACE NOP]
  /usr/src/debug/kernel-4.18.0-425.13.1.el8_7/linux-4.18.0-425.13.1.el8_7.x86_64/drivers/scsi/lpfc/lpfc_hbadisc.c: 6759
  0xffffffffc0f60eb5 <lpfc_nlp_get+5>:    push   %rbp

The root cause is, after kernel module been loaded by mod command, the symtable
is not expanded in gdb side. crash bt or dis command will trigger such an
expansion. However the symtable expansion is different for the 2 commands:

The stack trace of "dis -rl" for symtable expanding:

  #0  0x00000000008d8d9f in add_compunit_symtab_to_objfile ...
  #1  0x00000000006d3293 in buildsym_compunit::end_symtab_with_blockvector ...
  #2  0x00000000006d336a in buildsym_compunit::end_symtab_from_static_block ...
  #3  0x000000000077e8e9 in process_full_comp_unit ...
  #4  process_queue ...
  #5  dw2_do_instantiate_symtab ...
  #6  0x000000000077ed67 in dw2_instantiate_symtab ...
  #7  0x000000000077f75e in dw2_expand_all_symtabs ...
  #8  0x00000000008f254d in gdb_get_line_number ...
  #9  0x00000000008f22af in gdb_command_funnel_1 ...
  #10 0x00000000008f2003 in gdb_command_funnel ...
  #11 0x00000000005b7f02 in gdb_interface ...
  #12 0x00000000005f5bd8 in get_line_number ...
  #13 0x000000000059e574 in cmd_dis ...

The stack trace of "bt" for symtable expanding:

  #0  0x00000000008d8d9f in add_compunit_symtab_to_objfile ...
  #1  0x00000000006d3293 in buildsym_compunit::end_symtab_with_blockvector ...
  #2  0x00000000006d336a in buildsym_compunit::end_symtab_from_static_block ...
  #3  0x000000000077e8e9 in process_full_comp_unit ...
  #4  process_queue ...
  #5  dw2_do_instantiate_symtab ...
  #6  0x000000000077ed67 in dw2_instantiate_symtab ...
  #7  0x000000000077f8ed in dw2_lookup_symbol ...
  #8  0x00000000008e6d03 in lookup_symbol_via_quick_fns ...
  #9  0x00000000008e7153 in lookup_symbol_in_objfile ...
  #10 0x00000000008e73c6 in lookup_symbol_global_or_static_iterator_cb ...
  #11 0x00000000008b99c4 in svr4_iterate_over_objfiles_in_search_order ...
  #12 0x00000000008e754e in lookup_global_or_static_symbol ...
  #13 0x00000000008e75da in lookup_static_symbol ...
  #14 0x00000000008e632c in lookup_symbol_aux ...
  #15 0x00000000008e5a7a in lookup_symbol_in_language ...
  #16 0x00000000008e5b30 in lookup_symbol ...
  #17 0x00000000008f2a4a in gdb_get_datatype ...
  #18 0x00000000008f22c0 in gdb_command_funnel_1 ...
  crash-utility#19 0x00000000008f2003 in gdb_command_funnel ...
  crash-utility#20 0x00000000005b7f02 in gdb_interface ...
  crash-utility#21 0x00000000005f8a9f in datatype_info ...
  crash-utility#22 0x0000000000599947 in cpu_map_size ...
  crash-utility#23 0x00000000005a975d in get_cpus_online ...
  crash-utility#24 0x0000000000637a8b in diskdump_get_prstatus_percpu ...
  crash-utility#25 0x000000000062f0e4 in get_netdump_regs_x86_64 ...
  crash-utility#26 0x000000000059fe68 in back_trace ...
  crash-utility#27 0x00000000005ab1cb in cmd_bt ...

For the stacktrace of "dis -rl", it calls dw2_expand_all_symtabs() to expand
all symtable of the objfile, or "*.ko.debug" in our case. However for
the stacktrace of "bt", it doesn't expand all, but only a subset of symtable
which is enough to find a symbol by dw2_lookup_symbol(). As a result, the
objfile->compunit_symtabs, which is the head of a single linked list of
struct compunit_symtab, is not NULL but didn't contain all symtables. It
will not be reinitialized in gdb_get_line_number() by "dis -rl" because
!objfile_has_full_symbols(objfile) check will fail, so it cannot display
the proper code line number data.

Since objfile_has_full_symbols(objfile) check cannot ensure all symbols
been expanded, this patch add a new member as a flag for struct objfile
to record if all symbols have been expanded. The flag will be set only ofter
expand_all_symtabs been called.

Signed-off-by: Tao Liu <[email protected]>
fengjixuchui pushed a commit that referenced this pull request Mar 5, 2024
Same as the Linux commit f766f77a74f5 ("riscv/stacktrace: Fix
stack output without ra on the stack top").

When a function doesn't have a callee, then it will not
push ra into the stack, such as lkdtm functions, so
correct the FP of the second frame and use pt_regs to get
the right PC of the second frame.

Before this patch, the `bt -f` outputs only the first frame with
the wrong PC and FP of next frame:
```
crash> bt -f
PID: 1        TASK: ff600000000e0000  CPU: 1    COMMAND: "sh"
 #0 [ff20000000013cf0] lkdtm_EXCEPTION at ffffffff805303c0
    [PC: ffffffff805303c0 RA: ff20000000013d10 SP: ff20000000013cf0 SIZE: 16] <- wrong next PC
    ff20000000013cf0: 0000000000000001 ff20000000013d10 <- next FP
    ff20000000013d00: ff20000000013d40
crash>
```
After this patch, the `bt` outputs the full frames:
```
crash> bt
PID: 1        TASK: ff600000000e0000  CPU: 1    COMMAND: "sh"
 #0 [ff20000000013cf0] lkdtm_EXCEPTION at ffffffff805303c0
 #1 [ff20000000013d00] lkdtm_do_action at ffffffff8052fe36
 #2 [ff20000000013d10] direct_entry at ffffffff80530018
 #3 [ff20000000013d40] full_proxy_write at ffffffff80305044
 #4 [ff20000000013d80] vfs_write at ffffffff801b68b4
 #5 [ff20000000013e30] ksys_write at ffffffff801b6c4a
 #6 [ff20000000013e80] __riscv_sys_write at ffffffff801b6cc4
 #7 [ff20000000013e90] do_trap_ecall_u at ffffffff80836798
crash>
```

Acked-by: Kazuhito Hagio <[email protected]>
Signed-off-by: Song Shuai <[email protected]>
fengjixuchui pushed a commit that referenced this pull request Mar 5, 2024
This patch introduces per-cpu IRQ stacks for RISCV64 to let
"bt" do backtrace on it and 'bt -E' search eframes on it,
and the 'help -m' command displays the addresses of each
per-cpu IRQ stack.

TEST: a vmcore dumped via hacking the handle_irq_event_percpu()
( Why not using lkdtm INT_HW_IRQ_EN EXCEPTION ?
  There is a deadlock[1] in crash_kexec path if use that)

  crash> bt
  PID: 0        TASK: ffffffff8140db00  CPU: 0    COMMAND: "swapper/0"
   #0 [ff20000000003e60] __handle_irq_event_percpu at ffffffff8006462e
   #1 [ff20000000003ed0] handle_irq_event_percpu at ffffffff80064702
   #2 [ff20000000003ef0] handle_irq_event at ffffffff8006477c
   #3 [ff20000000003f20] handle_fasteoi_irq at ffffffff80068664
   #4 [ff20000000003f50] generic_handle_domain_irq at ffffffff80063988
   #5 [ff20000000003f60] plic_handle_irq at ffffffff8046633e
   #6 [ff20000000003fb0] generic_handle_domain_irq at ffffffff80063988
   #7 [ff20000000003fc0] riscv_intc_irq at ffffffff80465f8e
   #8 [ff20000000003fd0] handle_riscv_irq at ffffffff808361e8
       PC: ffffffff80837314  [default_idle_call+50]
       RA: ffffffff80837310  [default_idle_call+46]
       SP: ffffffff81403da0  CAUSE: 8000000000000009
  epc : ffffffff80837314 ra : ffffffff80837310 sp : ffffffff81403da0
   gp : ffffffff814ef848 tp : ffffffff8140db00 t0 : ff2000000004bb18
   t1 : 0000000000032c73 t2 : ffffffff81200a48 s0 : ffffffff81403db0
   s1 : 0000000000000000 a0 : 0000000000000004 a1 : 0000000000000000
   a2 : ff6000009f1e7000 a3 : 0000000000002304 a4 : ffffffff80c1c2d8
   a5 : 0000000000000000 a6 : ff6000001fe01958 a7 : 00002496ea89dbf1
   s2 : ffffffff814f0220 s3 : 0000000000000001 s4 : 000000000000003f
   s5 : ffffffff814f03d8 s6 : 0000000000000000 s7 : ffffffff814f00d0
   s8 : ffffffff81526f10 s9 : ffffffff80c1d880 s10: 0000000000000000
   s11: 0000000000000001 t3 : 0000000000003392 t4 : 0000000000000000
   t5 : 0000000000000000 t6 : 0000000000000040
   status: 0000000200000120 badaddr: 0000000000000000
    cause: 8000000000000009 orig_a0: ffffffff80837310
  --- <IRQ stack> ---
   #9 [ffffffff81403da0] default_idle_call at ffffffff80837314
   #10 [ffffffff81403db0] do_idle at ffffffff8004d0a0
   #11 [ffffffff81403e40] cpu_startup_entry at ffffffff8004d21e
   #12 [ffffffff81403e60] kernel_init at ffffffff8083746a
   #13 [ffffffff81403e70] arch_post_acpi_subsys_init at ffffffff80a006d8
   #14 [ffffffff81403e80] console_on_rootfs at ffffffff80a00c92
  crash>

  crash> bt -E
  CPU 0 IRQ STACK:
  KERNEL-MODE EXCEPTION FRAME AT: ff20000000003a48
       PC: ffffffff8006462e  [__handle_irq_event_percpu+30]
       RA: ffffffff80064702  [handle_irq_event_percpu+18]
       SP: ff20000000003e60  CAUSE: 000000000000000d
  epc : ffffffff8006462e ra : ffffffff80064702 sp : ff20000000003e60
   gp : ffffffff814ef848 tp : ffffffff8140db00 t0 : 0000000000046600
   t1 : ffffffff80836464 t2 : ffffffff81200a48 s0 : ff20000000003ed0
   s1 : 0000000000000000 a0 : 0000000000000000 a1 : 0000000000000118
   a2 : 0000000000000052 a3 : 0000000000000000 a4 : 0000000000000000
   a5 : 0000000000010001 a6 : ff6000001fe01958 a7 : 00002496ea89dbf1
   s2 : ff60000000941ab0 s3 : ffffffff814a0658 s4 : ff60000000089230
   s5 : ffffffff814a0518 s6 : ffffffff814a0620 s7 : ffffffff80e5f0f8
   s8 : ffffffff80fc50b0 s9 : ffffffff80c1d880 s10: 0000000000000000
   s11: 0000000000000001 t3 : 0000000000003392 t4 : 0000000000000000
   t5 : 0000000000000000 t6 : 0000000000000040
   status: 0000000200000100 badaddr: 0000000000000078
    cause: 000000000000000d orig_a0: ff20000000003ea0

  CPU 1 IRQ STACK: (none found)

  crash>

  crash> help -m
  <snip>
             machspec: ced1e0
          irq_stack_size: 16384
           irq_stacks[0]: ff20000000000000
           irq_stacks[1]: ff20000000008000
  crash>

[1]: https://lore.kernel.org/linux-riscv/[email protected]/

Signed-off-by: Song Shuai <[email protected]>
fengjixuchui pushed a commit that referenced this pull request Mar 5, 2024
On recent x86_64 kernels, the check of caller function (BT_CHECK_CALLER)
does not work correctly due to inappropriate direct_call_targets.  As a
result, the correct frame is ignored and the remaining frames will be
truncated.

Skip the caller check if ORC unwinder is available, as the check is not
necessary with it.

Without the patch:
  crash> bt 493113
  PID: 493113   TASK: ff2e34ecbd3ca2c0  CPU: 27   COMMAND: "sriov_fec_daemo"
   #0 [ff77abc4e81cfb08] __schedule at ffffffff81b239cb
   #1 [ff77abc4e81cfb70] schedule at ffffffff81b23e2d
   #2 [ff77abc4e81cfb88] schedule_timeout at ffffffff81b2c9e8
      RIP: 000000000047cdbb  RSP: 000000c0000975a8  RFLAGS: 00000216
      ...

With the patch:
  crash> bt 493113
  PID: 493113   TASK: ff2e34ecbd3ca2c0  CPU: 27   COMMAND: "sriov_fec_daemo"
   #0 [ff77abc4e81cfb08] __schedule at ffffffff81b239cb
   #1 [ff77abc4e81cfb70] schedule at ffffffff81b23e2d
   #2 [ff77abc4e81cfb88] schedule_timeout at ffffffff81b2c9e8
   #3 [ff77abc4e81cfbf0] __wait_for_common at ffffffff81b24abb
   #4 [ff77abc4e81cfc68] vfio_unregister_group_dev at ffffffffc10e76ae [vfio]
   #5 [ff77abc4e81cfca8] vfio_pci_core_unregister_device at ffffffffc11bb599 [vfio_pci_core]
   #6 [ff77abc4e81cfcc0] vfio_pci_remove at ffffffffc103e045 [vfio_pci]
   #7 [ff77abc4e81cfcd0] pci_device_remove at ffffffff815d7513
   ...

Reported-by: Crystal Wood <[email protected]>
Signed-off-by: Kazuhito Hagio <[email protected]>
fengjixuchui pushed a commit that referenced this pull request Mar 5, 2024
- Add basic support for the 'bt' command.
- LooongArch64: Add 'bt -f' command support
- LoongArch64: Add 'bt -l' command support

E.g. With this patch:
crash> bt
PID: 1832     TASK: 900000009a552100  CPU: 11   COMMAND: "bash"
 #0 [900000009beffb60] __cpu_possible_mask at 90000000014168f0
 #1 [900000009beffb60] __crash_kexec at 90000000002e7660
 #2 [900000009beffcd0] panic at 9000000000f0ec28
 #3 [900000009beffd60] sysrq_handle_crash at 9000000000a2c188
 #4 [900000009beffd70] __handle_sysrq at 9000000000a2c85c
 #5 [900000009beffdc0] write_sysrq_trigger at 9000000000a2ce10
 #6 [900000009beffde0] proc_reg_write at 90000000004ce454
 #7 [900000009beffe00] vfs_write at 900000000043e838
 #8 [900000009beffe40] ksys_write at 900000000043eb58
 #9 [900000009beffe80] do_syscall at 9000000000f2da54
 #10 [900000009beffea0] handle_syscall at 9000000000221440
crash>
...

Co-developed-by: Youling Tang <[email protected]>
Signed-off-by: Youling Tang <[email protected]>
Signed-off-by: Ming Wang <[email protected]>
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2 participants