[Crash-utility] Re: [PATCH] remove offline status check for CPU register map

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.

Hi Guanyou, On Sat, Nov 2, 2024 at 1:35 AM Guanyou Chen <chenguanyou9338(a)gmail.com&gt; 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(a)xiaomi.com&gt; > --- > 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.