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Fix C99 compatibility issues in embedded copy of GDB #16

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merged 3 commits into from
Mar 9, 2023

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liutgnu and others added 3 commits March 8, 2023 09:41
Kernel with maple tree enabled doesn't have mmap as a member of mm_struct[1],
so OFFSET(mm_struct_mmap) case needed to be handled differently for
maple tree kernel.

Before:
crash> search -u a

search: invalid structure member offset: mm_struct_mmap
        FILE: memory.c  LINE: 14255  FUNCTION: address_space_start()

[crash] error trace: 549500 => 548fff => 5f1c91 => 5f1c13

  5f1c13: OFFSET_verify.part.36+51
  5f1c91: OFFSET_verify+49
  548fff: address_space_start+106
  549500: cmd_search+855

search: invalid structure member offset: mm_struct_mmap
        FILE: memory.c  LINE: 14255  FUNCTION: address_space_start()

After:
crash> search -u a
7ffea63e6440: a

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=763ecb035029f500d7e6dc99acd1ad299b7726a1

Signed-off-by: Tao Liu <[email protected]>
Currently, the "net" command displays only the IPv4 address of a network
interface.  Support outputting IPv6 addresses.  For example:

Without the patch:
  crash> net
     NET_DEVICE     NAME   IP ADDRESS(ES)
  ffff8d01b1205000  lo     127.0.0.1
  ffff8d0087e40000  eno1   192.168.122.2

With the patch:
  crash> net
     NET_DEVICE     NAME       IP ADDRESS(ES)
  ffff8d01b1205000  lo         127.0.0.1, ::1
  ffff8d0087e40000  eno1       192.168.122.2, xxxx:xx:x:xxxx:xxxx:xxx:xxxx:xxxx, yyyy::yyyy:yyy:yyyy:yyyy

Also align with longer device names.

Related kernel commit:
502a2ffd7376 ("ipv6: convert idev_list to list macros")

Reported-by: Buland Kumar Singh <[email protected]>
Signed-off-by: Lianbo Jiang <[email protected]>
Signed-off-by: Kazuhito Hagio <[email protected]>
These issues have been fixed in upstream GDB already:

In the file bfd/elf-bfd.h, startswith is now used in stead of
strncmp.  libiberty was fixed via an import from GCC.  Readline
8.1 has been imported and has these issues fixed upstream.

While at it, also update the bundled copy of <sys/cdefs.h> in
gnulib.  This header file unfortunately shadows the glibc version,
causing build failures on ppc64le if it is too old.

Related GDB commits:
0075c53724f7 Impport libiberty commit: 885b6660c17f from gcc mainline.
b4f26d541aa7 Import GNU Readline 8.1
9c9d63b15ad5 gnulib: update to 776af40e0
3f3328b816ee Use startswith more for strncmp function calls.

Related glibc commit:
2337e04e21ba cdefs: Limit definition of fortification macros

Related gnulib commit:
afeeb21058d1 libc-config: fix include problem on older Debian

Signed-off-by: Florian Weimer <[email protected]>
Signed-off-by: Kazuhito Hagio <[email protected]>
@fengjixuchui fengjixuchui merged commit 90f4a71 into fengjixuchui:master Mar 9, 2023
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
The patch introduces per-cpu overflow stacks for RISCV64 to let
"bt" do backtrace on it and the 'help -m' command dispalys the
addresss of each per-cpu overflow stack.

TEST: a lkdtm DIRECT EXHAUST_STACK vmcore

  crash> bt
  PID: 1        TASK: ff600000000d8000  CPU: 1    COMMAND: "sh"
   #0 [ff6000001fc501c0] riscv_crash_save_regs at ffffffff8000a1dc
   #1 [ff6000001fc50320] panic at ffffffff808773ec
   #2 [ff6000001fc50380] walk_stackframe at ffffffff800056da
       PC: ffffffff80876a34  [memset+96]
       RA: ffffffff80563dc0  [recursive_loop+68]
       SP: ff2000000000fd50  CAUSE: 000000000000000f
  epc : ffffffff80876a34 ra : ffffffff80563dc0 sp : ff2000000000fd50
   gp : ffffffff81515d38 tp : 0000000000000000 t0 : ff2000000000fd58
   t1 : ff600000000d88c8 t2 : 6143203a6d74646b s0 : ff20000000010190
   s1 : 0000000000000012 a0 : ff2000000000fd58 a1 : 1212121212121212
   a2 : 0000000000000400 a3 : ff20000000010158 a4 : 0000000000000000
   a5 : 725bedba92260900 a6 : 000000000130e0f0 a7 : 0000000000000000
   s2 : ff2000000000fd58 s3 : ffffffff815170d8 s4 : ff20000000013e60
   s5 : 000000000000000e s6 : ff20000000013e60 s7 : 0000000000000000
   s8 : ff60000000861000 s9 : 00007fffc3641694 s10: 00007fffc3641690
   s11: 00005555796ed240 t3 : 0000000000010297 t4 : ffffffff80c17810
   t5 : ffffffff8195e7b8 t6 : ff20000000013b18
   status: 0000000200000120 badaddr: ff2000000000fd58
    cause: 000000000000000f orig_a0: 0000000000000000
  --- <OVERFLOW stack> ---
   #3 [ff2000000000fd50] memset at ffffffff80876a34
   #4 [ff20000000010190] recursive_loop at ffffffff80563e16
   #5 [ff200000000105d0] recursive_loop at ffffffff80563e16
   < recursive_loop ...>
   #16 [ff20000000013490] recursive_loop at ffffffff80563e16
   #17 [ff200000000138d0] recursive_loop at ffffffff80563e16
   #18 [ff20000000013d10] lkdtm_EXHAUST_STACK at ffffffff8088005e
   crash-utility#19 [ff20000000013d30] lkdtm_do_action at ffffffff80563292
   crash-utility#20 [ff20000000013d40] direct_entry at ffffffff80563474
   crash-utility#21 [ff20000000013d70] full_proxy_write at ffffffff8032fb3a
   crash-utility#22 [ff20000000013db0] vfs_write at ffffffff801d6414
   crash-utility#23 [ff20000000013e60] ksys_write at ffffffff801d67b8
   crash-utility#24 [ff20000000013eb0] __riscv_sys_write at ffffffff801d6832
   crash-utility#25 [ff20000000013ec0] do_trap_ecall_u at ffffffff80884a20
  crash>

  crash> help -m
  <snip>
          irq_stack_size: 16384
           irq_stacks[0]: ff20000000000000
           irq_stacks[1]: ff20000000008000
          overflow_stack_size: 4096
           overflow_stacks[0]: ff6000001fa7a510
           overflow_stacks[1]: ff6000001fc4f510
  crash>

Signed-off-by: Song Shuai <[email protected]>
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4 participants