Fix gcc-11 compiler warning on kvmdump.c #2
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Passing '-S' option to 'bt' command was intended to specify the stack pointer manually. But get_stack_frame() handling on ppc64 is ignoring this option altogether. Fix it. Signed-off-by: Hari Bathini <[email protected]>
Only older kernel (v2.4) used h/w interrupt stack to store frames when CPU received IPI. Memory used for this in 'struct machine_specific' is useless for later kernels. For the sake of backward compatibility keep h/w interrupt stack but dynamically allocate memory for it and save some bytes from being wasted. Signed-off-by: Hari Bathini <[email protected]>
ppc64_paca_init() function is specifically used to initialize percpu data_offset for kernels older than v2.6.36. So, the name is slightly misleading. Rename it to ppc64_paca_percpu_offset_init to reflect its purpose. Signed-off-by: Hari Bathini <[email protected]>
A CPU could be in an emergency stack when it is running in real mode
or any special scenario like TM bad thing. Also, there are dedicated
emergency stacks for machine check and system reset interrupt. Right
now, no backtrace is provided if a CPU is in any of these stacks.
This change ensures backtrace is processed appropriately even when
a CPU is in any one of these emergency stacks. Also, if stack info
cannot be found, print that message always instead of only when
verbose logs are enabled.
Related kernel commits:
729b0f715371 ("powerpc/book3s: Introduce exclusive emergency stack for machine check exception.")
b1ee8a3de579 ("powerpc/64s: Dedicated system reset interrupt stack")
Signed-off-by: Hari Bathini <[email protected]>
Print top address of emergency stacks with 'mach' command. Signed-off-by: Hari Bathini <[email protected]>
machdpep->machspec is referred to multiple times. The compiler would likely optimize this but nonetheless, use a variable to optimize in coding and also improve readability. No functional change. Signed-off-by: Hari Bathini <[email protected]>
…TUAL Setting st->_stext_vmlinux to UNINITIALIZED to search for "_stext" from the vmlinux. In the scenario where kaslr is disabled and without vmcoreinfo, crash will get the wrong MODULES/VMALLOC ranges and cause a failure in parsing a raw RAM dumpfile. Signed-off-by: Qianli Zhao <[email protected]>
Without the patch, the following gcc-11 compiler warnings are emitted
for filesys.c:
filesys.c: In function 'mount_point':
filesys.c:718:17: warning: 'pclose' called on pointer returned from a mismatched allocation function [-Wmismatched-dealloc]
718 | pclose(mp);
| ^~~~~~~~~~
filesys.c:709:27: note: returned from 'fopen'
709 | if ((mp = fopen(mntfile, "r")) == NULL)
| ^~~~~~~~~~~~~~~~~~~
filesys.c:738:17: warning: 'pclose' called on pointer returned from a mismatched allocation function [-Wmismatched-dealloc]
738 | pclose(mp);
| ^~~~~~~~~~
filesys.c:723:27: note: returned from 'fopen'
723 | if ((mp = fopen(mntfile, "r")) == NULL)
| ^~~~~~~~~~~~~~~~~~~
Signed-off-by: Kazuhito Hagio <[email protected]>
Without the patch, the following gcc-11 compiler warning is emitted for
symbols.c:
symbols.c: In function 'cmd_p':
symbols.c:7412:38: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
7412 | *(cpuspec-1) = ':';
| ~~~~~~~~~~~~~^~~~~
Signed-off-by: Kazuhito Hagio <[email protected]>
Without the patch, the following gcc-11 compiler warning is emitted for
makedumpfile.c:
In function 'flattened_format_get_osrelease',
inlined from 'check_flattened_format' at makedumpfile.c:236:3:
makedumpfile.c:392:9: warning: 'fclose' called on pointer returned from a mismatched allocation function [-Wmismatched-dealloc]
392 | fclose(pipe);
| ^~~~~~~~~~~~
makedumpfile.c: In function 'check_flattened_format':
makedumpfile.c:380:21: note: returned from 'popen'
380 | if ((pipe = popen(buf, "r")) == NULL)
| ^~~~~~~~~~~~~~~
Signed-off-by: Kazuhito Hagio <[email protected]>
Without the patch, the following gcc-11 compiler warning is emitted for
kvmdump.c:
In function 'write_mapfile_registers',
inlined from 'write_mapfile_trailer' at kvmdump.c:947:3,
inlined from 'kvmdump_init' at kvmdump.c:145:4:
kvmdump.c:972:13: warning: 'write' reading 8 bytes from a region of size 4 [-Wstringop-overread]
972 | if (write(kvm->mapfd, &kvm->cpu_devices, sizeof(uint64_t)) != sizeof(uint64_t))
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from kvmdump.c:19:
kvmdump.c: In function 'kvmdump_init':
kvmdump.h:67:18: note: source object 'cpu_devices' of size 4
67 | uint32_t cpu_devices;
| ^~~~~~~~~~~
In file included from defs.h:26,
from kvmdump.c:18:
/usr/include/unistd.h:378:16: note: in a call to function 'write' declared with attribute 'access (read_only, 2, 3)'
378 | extern ssize_t write (int __fd, const void *__buf, size_t __n) __wur
| ^~~~~
Signed-off-by: Kazuhito Hagio <[email protected]>
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The previous implementation to locate the call instruction is
to strstr "call", then check whether the previous char is ' '
or '\t'. The implementation is problematic. For example it
cannot resolve the following disassembly string:
"0xffffffffc0995378 <nfs41_callback_svc+344>:\tcall 0xffffffff8ecfa4c0 <schedule>\n"
strstr will locate the "_call" and char check fails,
as a result, extract_hex fails to get the calling address.
NOTE: the issue is more likely to be reproduced when patch[1] applied.
Because without patch[1], the disassembly string will be as follows,
so the issue is no longer reproducible.
"0xffffffffc0995378:\tcall 0xffffffff8ecfa4c0 <schedule>\n"
Before the patch:
crash> bt 1472
PID: 1472 TASK: ffff8c121fa72f70 CPU: 18 COMMAND: "nfsv4.1-svc"
#0 [ffff8c16231a3db8] __schedule at ffffffff8ecf9ef3
#1 [ffff8c16231a3e40] schedule at ffffffff8ecfa4e9
After the patch:
crash> bt 1472
PID: 1472 TASK: ffff8c121fa72f70 CPU: 18 COMMAND: "nfsv4.1-svc"
#0 [ffff8c16231a3db8] __schedule at ffffffff8ecf9ef3
#1 [ffff8c16231a3e40] schedule at ffffffff8ecfa4e9
#2 [ffff8c16231a3e50] nfs41_callback_svc at ffffffffc099537d [nfsv4]
#3 [ffff8c16231a3ec8] kthread at ffffffff8e6b966f
#4 [ffff8c16231a3f50] ret_from_fork at ffffffff8ed07898
This patch fix the issue by strstr "\tcall" and " call", to
locate the correct call instruction.
[1]: https://listman.redhat.com/archives/crash-utility/2022-August/010085.html
Signed-off-by: Tao Liu <[email protected]>
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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]>
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Currently, the "bt" command may print a bogus exception frame and the remaining frame will be truncated on x86_64 when using the "virsh send-key <kvm guest> KEY_LEFTALT KEY_SYSRQ KEY_C" command to trigger a panic from the KVM host. For example: crash> bt PID: 0 TASK: ffff9e7a47e32f00 CPU: 3 COMMAND: "swapper/3" #0 [ffffba7900118bb8] machine_kexec at ffffffff87e5c2c7 #1 [ffffba7900118c08] __crash_kexec at ffffffff87f9500d #2 [ffffba7900118cd0] panic at ffffffff87edfff9 #3 [ffffba7900118d50] sysrq_handle_crash at ffffffff883ce2c1 ... #16 [ffffba7900118fd8] handle_edge_irq at ffffffff87f559f2 #17 [ffffba7900118ff0] asm_call_on_stack at ffffffff88800fa2 --- <IRQ stack> --- #18 [ffffba790008bda0] asm_call_on_stack at ffffffff88800fa2 RIP: ffffffffffffffff RSP: 0000000000000124 RFLAGS: 00000003 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000 RDX: ffffffff88800c1e RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000001 R8: 0000000000000000 R9: 0000000000000000 R10: 0000000000000000 R11: ffffffff88760555 R12: ffffba790008be08 R13: ffffffff87f18002 R14: ffff9e7a47e32f00 R15: ffff9e7bb6198e00 ORIG_RAX: 0000000000000000 CS: 0003 SS: 0000 bt: WARNING: possibly bogus exception frame crash> The following related kernel commits cause the current issue, crash needs to adjust the value of irq_eframe_link. Related kernel commits: [1] v5.8: 931b94145981 ("x86/entry: Provide helpers for executing on the irqstack") [2] v5.8: fa5e5c409213 ("x86/entry: Use idtentry for interrupts") [3] v5.12: 52d743f3b712 ("x86/softirq: Remove indirection in do_softirq_own_stack()") Signed-off-by: Lianbo Jiang <[email protected]> Signed-off-by: Kazuhito Hagio <[email protected]>
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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]>
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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]>
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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]>
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Without the patch, do_mt_entry() can call dump_struct_members_for_tree()
with a NULL entry, and parse_for_member_extended() will cause a
segmentation fault during strncpy().
This is caused by "tree -t maple -s struct.member.member" style multiple
level member access:
crash> tree -t maple -s irq_desc.irq_data.irq sparse_irqs
ffff936980188400
irq_data.irq = 0,
ffff93698018be00
irq_data.irq = 1,
...
ffff936980f38e00
irq_data.irq = 19,
Segmentation fault (core dumped)
(gdb) bt
#0 0x00007faaf8e51635 in __strncpy_avx2 () from /lib64/libc.so.6
#1 0x00000000005e5927 in parse_for_member_extended (dm=dm@entry=0x7ffcb9e6d860, ...
#2 0x0000000000603c45 in dump_struct_member (s=s@entry=0x128cde0 <shared_bufs+1024> ...
#3 0x0000000000513cf5 in dump_struct_members_for_tree (td=td@entry=0x7ffcb9e6eeb0, ...
#4 0x0000000000651f15 in do_mt_entry (entry=0, min=min@entry=20, max=max@entry=119, ...
...
Signed-off-by: Kazuhito Hagio <[email protected]>
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…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]>
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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]>
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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]>
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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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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]>
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…ss range Previously, to find a module symbol and its offset by an arbitrary address, all symbols within the module will be iterated by address ascending order until the last symbol with a smaller address been noticed. However if the address is not within the module address range, e.g. the address is higher than the module's last symbol's address, then the module can be surely skipped, because its symbol iteration is unnecessary. This can speed up the kernel module symbols finding and improve the overall performance. Without the patch: $ time echo "bt 8993" | ~/crash-dev/crash vmcore vmlinux crash> bt 8993 PID: 8993 TASK: ffff927569cc2100 CPU: 2 COMMAND: "WriterPool0" #0 [ffff927569cd76f0] __schedule at ffffffffb3db78d8 #1 [ffff927569cd7758] schedule_preempt_disabled at ffffffffb3db8bf9 #2 [ffff927569cd7768] __mutex_lock_slowpath at ffffffffb3db6ca7 #3 [ffff927569cd77c0] mutex_lock at ffffffffb3db602f #4 [ffff927569cd77d8] ucache_retrieve at ffffffffc0cf4409 [secfs2] ...snip the stacktrace of the same module... #11 [ffff927569cd7ba0] cskal_path_vfs_getattr_nosec at ffffffffc05cae76 [falcon_kal] ...snip... #13 [ffff927569cd7c40] _ZdlPv at ffffffffc086e751 [falcon_lsm_serviceable] ...snip... crash-utility#20 [ffff927569cd7ef8] unload_network_ops_symbols at ffffffffc06f11c0 [falcon_lsm_pinned_14713] crash-utility#21 [ffff927569cd7f50] system_call_fastpath at ffffffffb3dc539a RIP: 00007f2b28ed4023 RSP: 00007f2a45fe7f80 RFLAGS: 00000206 RAX: 0000000000000012 RBX: 00007f2a68302e00 RCX: 00007f2a682546d8 RDX: 0000000000000826 RSI: 00007eb57ea6a000 RDI: 00000000000000e3 RBP: 00007eb57ea6a000 R8: 0000000000000826 R9: 00000002670bdfd2 R10: 00000002670bdfd2 R11: 0000000000000293 R12: 00000002670bdfd2 R13: 00007f29d501a480 R14: 0000000000000826 R15: 00000002670bdfd2 ORIG_RAX: 0000000000000012 CS: 0033 SS: 002b crash> real 7m14.826s user 7m12.502s sys 0m1.091s With the patch: $ time echo "bt 8993" | ~/crash-dev/crash vmcore vmlinux crash> bt 8993 PID: 8993 TASK: ffff927569cc2100 CPU: 2 COMMAND: "WriterPool0" #0 [ffff927569cd76f0] __schedule at ffffffffb3db78d8 #1 [ffff927569cd7758] schedule_preempt_disabled at ffffffffb3db8bf9 ...snip the same output... crash> real 0m8.827s user 0m7.896s sys 0m0.938s Signed-off-by: Tao Liu <[email protected]>
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- 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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