On Fri, Nov 22, 2024 at 11:08 PM Guanyou Chen <chenguanyou9338@gmail.com> wrote:
>
> Hi tao
>
> > The reason is, kt->kernel_NR_CPUS might be large(5120 in this case),
> > without the filter of in_cpu_map(), it will exhaust the memory buffer.
>
> I hadn't thought about this before, why don't we choose kt->cpus but kt->kernel_NR_CPUS ?
There are differences of the 2. nt_prstatus_percpu[i] should be
iterated by kt->kernel_NR_CPUS rather than kt->cpus right? Because
kt->cpus deals only with online cpu, kt->kernel_NR_CPUS is for all
possible CPUs. If you have a better solution, please post the patch so
we can discuss it against the code itself.
>
> Thanks,
> Gunayou
>
> Tao Liu <ltao@redhat.com> 于2024年11月22日周五 17:15写道：
>>
>> Hi Guanyou,
>>
>> On Sat, Nov 2, 2024 at 1:35 AM Guanyou Chen <chenguanyou9338@gmail.com> wrote:
>> >
>> > Hi Lianbo, Tao
>> >
>> > Remove offline status check, We can query the registers of
>> > each CPU at any time and obtain their stack.
>> >
>> > CPU 0: [OFFLINE]
>> > X0: 0000000000000000 X1: 0000000000000000 X2: 0000000000000000
>> > X3: 000000000003fcbc X4: 0000000000000001 X5: 0000000000000000
>> > X6: 0000000000000000 X7: 0000000000000000 X8: 00000000ffffffff
>> > X9: ffffffc009e6ae48 X10: ffffffc009e6ae20 X11: 0000000000000000
>> > X12: 0000000000000002 X13: 0000000000000004 X14: 0000000000000000
>> > X15: 0000000000004000 X16: 00000000f90f05f6 X17: 00000000f90f05f6
>> > X18: 0000000000000000 X19: 0000000000000002 X20: ffffffc009e3b008
>> > X21: ffffffc00a01d020 X22: ffffffc009f798f0 X23: 0000000060001000
>> > X24: 0000000000000000 X25: 0000000000000000 X26: 0000000000000000
>> > X27: 0000000000000000 X28: ffffff8111eecb00 X29: ffffffc008003f50
>> > LR: ffffffc00802df88 SP: ffffffc008003f40 PC: ffffffc00802df94
>> > PSTATE: 024003c5 FPVALID: 00000000
>> >
>> > crash> bt -c 0
>> > PID: 1842 TASK: ffffff8111eecb00 CPU: 0 COMMAND: "android.bg"
>> > 00 [ffffffc008003f50] ipi_handler at ffffffc00802df90
>> > 01 [ffffffc008003f90] handle_percpu_devid_irq at ffffffc008146f50
>> > 02 [ffffffc008003fd0] generic_handle_domain_irq at ffffffc00813f484
>> > 03 [ffffffc008003fe0] gic_handle_irq at ffffffc008010140
>> > --- <IRQ stack> ---
>> > 04 [ffffffc019c3be20] call_on_irq_stack at ffffffc008016ed4
>> > 05 [ffffffc019c3be40] do_interrupt_handler at ffffffc008019cb4
>> > 06 [ffffffc019c3be60] el0_interrupt at ffffffc008f7b848
>> > 07 [ffffffc019c3be90] __el0_irq_handler_common at ffffffc008f7b368
>> > 08 [ffffffc019c3bea0] el0t_64_irq_handler at ffffffc008f7b344
>> > 09 [ffffffc019c3bfe0] el0t_64_irq at ffffffc008011720
>> > PC: 0000000072415108 LR: 00000000724150d0 SP: 0000007691d2bfa0
>> > X29: 00000000734f60e0 X28: 000000001a2fa678 X27: 0000000000000063
>> > X26: 000000001a2fa678 X25: 000000001a2fa678 X24: 000000001a7bb718
>> > X23: 000000001a7ba198 X22: 000000001a7ba190 X21: b4000076f9a828c8
>> > X20: 0000000000000000 X19: b4000076f9a82800 X18: 000000768d68a000
>> > X17: 00000000708f89f8 X16: 00000000000000f0 X15: 0000000000000000
>> > X14: 0000007691d2bca0 X13: 0000000080100000 X12: 0000000000000000
>> > X11: 0000000000000000 X10: 0000000000000000 X9: 9636716211228cd4
>> > X8: 9636716211228cd4 X7: 0000000000000010 X6: 000000001a7bb728
>> > X5: 0000000070845200 X4: 0000000018a40d38 X3: 00000000707e8f98
>> > X2: 000000001a2fa678 X1: 000000001a7ba198 X0: 0000000070847aa8
>> > ORIG_X0: 00000000ffffff9c SYSCALLNO: ffffffff PSTATE: 60001000
>> >
>> > Signed-off-by: Guanyou.Chen <chenguanyou@xiaomi.com>
>> > ---
>> > netdump.c | 15 +++++----------
>> > 1 file changed, 5 insertions(+), 10 deletions(-)
>> >
>> > diff --git a/netdump.c b/netdump.c
>> > index 435793b..455f90e 100644
>> > --- a/netdump.c
>> > +++ b/netdump.c
>> > @@ -101,7 +101,7 @@ map_cpus_to_prstatus(void)
>> > nrcpus = (kt->kernel_NR_CPUS ? kt->kernel_NR_CPUS : NR_CPUS);
>> >
>> > for (i = 0; i < nrcpus; i++) {
>> > - if (in_cpu_map(ONLINE_MAP, i) && machdep->is_cpu_prstatus_valid(i)) {
>> > + if (machdep->is_cpu_prstatus_valid(i)) {
>> > nd->nt_prstatus_percpu[i] = nt_ptr[i];
>>
>> This patch has dependency on your previous "bugfix map cpus register"
>> patch. I'm not sure about the relations of the 2 patches, but they
>> don't seem to be independent. So please send them within one patchset
>> is preferred.
>>
>> However, for this patch, it will cause regressions after removing
>> in_cpu_map(ONLINE_MAP, i) check before
>> machdep->is_cpu_prstatus_valid(i), see the following stacktrace:
>>
>> ...
>> WARNING: cpu 2027: invalid NT_PRSTATUS note (n_type != NT_PRSTATUS)
>> WARNING: cpu 2028: invalid NT_PRSTATUS note (n_type != NT_PRSTATUS)
>> malloc_bp[1999]: 585a3c0
>> smallest: 32
>> largest: 65536
>> embedded: 2032
>> max_embedded: 2032
>> mallocs: 2000
>> frees: 0
>> reqs/total: 2063/837500
>> average size: 406
>>
>> crash: cannot allocate any more memory!
>> ...
>> (gdb) bt
>> #0 getbuf (reqsize=368) at tools.c:6130
>> #1 0x000000000065be0b in have_crash_notes (cpu=2029) at diskdump.c:123
>> #2 0x000000000065bf57 in diskdump_is_cpu_prstatus_valid (cpu=2029) at
>> diskdump.c:155
>> #3 0x000000000064b055 in map_cpus_to_prstatus () at netdump.c:104
>> ...
>>
>> The reason is, kt->kernel_NR_CPUS might be large(5120 in this case),
>> without the filter of in_cpu_map(), it will exhaust the memory
>> buffer.
>>
>> Thanks,
>> Tao Liu
>>
>> > nd->num_prstatus_notes =
>> > MAX(nd->num_prstatus_notes, i+1);
>> > @@ -2998,15 +2998,10 @@ dump_registers_for_elf_dumpfiles(void)
>> > return;
>> > }
>> >
>> > - for (c = 0; c < kt->cpus; c++) {
>> > - if (check_offline_cpu(c)) {
>> > - fprintf(fp, "%sCPU %d: [OFFLINE]\n", c ? "\n" : "", c);
>> > - continue;
>> > - }
>> > -
>> > - fprintf(fp, "%sCPU %d:\n", c ? "\n" : "", c);
>> > - display_regs_from_elf_notes(c, fp);
>> > - }
>> > + for (c = 0; c < kt->cpus; c++) {
>> > + fprintf(fp, "%sCPU %d: %s\n", c ? "\n" : "", c, check_offline_cpu(c) ? "[OFFLINE]" : "[ONLINE]");
>> > + display_regs_from_elf_notes(c, fp);
>> > + }
>> > }
>> >
>> > struct x86_64_user_regs_struct {
>> > --
>> > 2.34.1
>> >
>> > Guanyou.
>> > Thanks.
>>