[Crash-utility] Re: [PATCH] bugfix command "help -r" segv fault

Hi Tao Thanks for your explanation. Test env: WARNING: cpu 0: cannot find NT_PRSTATUS note WARNING: cpu 1: cannot find NT_PRSTATUS note WARNING: cpu 2: cannot find NT_PRSTATUS note WARNING: cpu 3: cannot find NT_PRSTATUS note WARNING: cpu 4: cannot find NT_PRSTATUS note WARNING: cpu 5: cannot find NT_PRSTATUS note WARNING: cpu 6: cannot find NT_PRSTATUS note WARNING: cpu 7: cannot find NT_PRSTATUS note KERNEL: vmlinux [TAINTED] DUMPFILES: /var/tmp/ramdump_elf_RabECD [temporary ELF header] DDRCS0_0.BIN DDRCS1_0.BIN DDRCS1_1.BIN DDRCS2_0.BIN DDRCS2_1.BIN DDRCS2_2.BIN CPUS: 8 The non-elf-vmcore is composed of multiple DDR memory files.

Thanks Guanyou Tao Liu <ltao(a)redhat.com&gt; 于2024年12月11日周三 07:12写道： > > Hi Guanyou, > > On Tue, Dec 10, 2024 at 7:35 PM lijiang <lijiang(a)redhat.com&gt; wrote: > > > > On Wed, Nov 27, 2024 at 11:09 AM Guanyou Chen <chenguanyou9338(a)gmail.com&gt; wrote: > >> > >> Hi lianbo > >> > >> > Thanks for pointing out this. Can you help to try this one? > >> > >> test pass. > >> > > > > Thank you for the confirmation, Guanyou. > > > > Lets pick up this one. so: Ack(with this correction) > > > > Thanks > > Lianbo > > > >> > >> Thanks > >> Guanyou > >> > >> lijiang <lijiang(a)redhat.com&gt; 于2024年11月27日周三 10:16写道： > >>> > >>> On Tue, Nov 26, 2024 at 11:46 AM Guanyou Chen <chenguanyou9338(a)gmail.com&gt; wrote: > >>>> > >>>> Hi lianbo > >>>> > >>>> test case is non-elf-vmcore, so all nt_prstatus_percpu invalid pointer. > > I have a question, if your test case is non-elf-vmcore, then why did > the code execution reach the function "display_regs_from_elf_notes()" > here? It shouldn't pass the is_netdump() check for ELF header in the > first place, am I right? > > How did you generate the non-elf-vmcore? If you generate it by some > special method(those not generated by makedumpfile), please also point > it out in your commit message at first, so we can know it is a special > case. > > In addition, we are lack of none-standard vmcores(none makedumpfile > generated) for testing, and I know in the arm world there are > different methods for getting the kernel memory dumping, which by the > way, are not our expertise. So please try to provide as much info as > possible to help us understand your test case/environment in your > commit message next time. > > Thanks, > Tao Liu > > > >>>> > >>> > >>> Thanks for pointing out this. Can you help to try this one? > >>> > >>> diff --git a/netdump.c b/netdump.c > >>> index b4e2a5cb2037..b67bdad3c511 100644 > >>> --- a/netdump.c > >>> +++ b/netdump.c > >>> @@ -2768,7 +2768,8 @@ display_regs_from_elf_notes(int cpu, FILE *ofp) > >>> } > >>> } > >>> > >>> - if ((cpu - skipped_count) >= nd->num_prstatus_notes && > >>> + if (((cpu < 0 ) || (!nd->nt_prstatus_percpu[cpu]) || > >>> + (cpu - skipped_count) >= nd->num_prstatus_notes) && > >>> !machine_type("MIPS")) { > >>> error(INFO, "registers not collected for cpu %d\n", cpu); > >>> return; > >>> > >>> Lianbo > >>> > >>>> > >>>> Thanks > >>>> Guanyou. > >>>> > >>>> lijiang <lijiang(a)redhat.com&gt; 于2024年11月26日周二 11:27写道： > >>>>> > >>>>> Hi, Guanyou > >>>>> Thank you for the fix. > >>>>> On Mon, Nov 4, 2024 at 4:13 PM <devel-request(a)lists.crash-utility.osci.io&gt; wrote: > >>>>>> > >>>>>> Date: Fri, 1 Nov 2024 18:01:27 +0800 > >>>>>> From: Guanyou Chen <chenguanyou9338(a)gmail.com&gt; > >>>>>> Subject: [Crash-utility] [PATCH] bugfix command "help -r" segv fault > >>>>>> To: Lianbo <lijiang(a)redhat.com&gt;, Tao Liu <ltao(a)redhat.com&gt;, > >>>>>> devel(a)lists.crash-utility.osci.io > >>>>>> Message-ID: > >>>>>> <CAHS3RMU3nuiqW4z=Qo9RoufADrUxcaLhyjnxwMCuGODB_+37yQ(a)mail.gmail.com&gt; > >>>>>> Content-Type: multipart/mixed; boundary="00000000000065fc530625d705b8" > >>>>>> > >>>>>> --00000000000065fc530625d705b8 > >>>>>> Content-Type: multipart/alternative; boundary="00000000000065fc530625d705b6" > >>>>>> > >>>>>> --00000000000065fc530625d705b6 > >>>>>> Content-Type: text/plain; charset="UTF-8" > >>>>>> > >>>>>> Hi Lianbo, Tao > >>>>>> > >>>>>> When the ELF Note does not contain CPU registers, > >>>>>> attempting to retrieve online CPU registers will cause a crash. > >>>>>> > >>>>>> After: > >>>>>> CPU 6: > >>>>>> help: registers not collected for cpu 6 > >>>>>> ... > >>>>>> > >>>>>> Signed-off-by: Guanyou.Chen <chenguanyou(a)xiaomi.com&gt; > >>>>>> --- > >>>>>> netdump.c | 16 ++++++++++++++++ > >>>>>> 1 file changed, 16 insertions(+) > >>>>>> > >>>>>> diff --git a/netdump.c b/netdump.c > >>>>>> index 8ea5159..435793b 100644 > >>>>>> --- a/netdump.c > >>>>>> +++ b/netdump.c > >>>>>> @@ -2780,6 +2780,10 @@ display_regs_from_elf_notes(int cpu, FILE *ofp) > >>>>> > >>>>> > >>>>> I copied the code block here: > >>>>> display_regs_from_elf_notes(int cpu, FILE *ofp) > >>>>> { > >>>>> Elf32_Nhdr *note32; > >>>>> Elf64_Nhdr *note64; > >>>>> size_t len; > >>>>> char *user_regs; > >>>>> int c, skipped_count; > >>>>> > >>>>> /* > >>>>> * Kdump NT_PRSTATUS notes are only related to online cpus, > >>>>> * so offline cpus should be skipped. > >>>>> */ > >>>>> if (pc->flags2 & QEMU_MEM_DUMP_ELF) > >>>>> skipped_count = 0; > >>>>> else { > >>>>> for (c = skipped_count = 0; c < cpu; c++) { > >>>>> if (check_offline_cpu(c)) > >>>>> skipped_count++; > >>>>> } > >>>>> } > >>>>> > >>>>> if ((cpu - skipped_count) >= nd->num_prstatus_notes && > >>>>> !machine_type("MIPS")) { > >>>>> error(INFO, "registers not collected for cpu %d\n", cpu); > >>>>> return; > >>>>> } > >>>>> ... > >>>>> Could you please point out why the above check does not work? > >>>>> > >>>>> BTW: I'm not sure if it can work for you, can you help to try this? Just a guess. > >>>>> > >>>>> if (((cpu < 0 ) || (!dd->nt_prstatus_percpu[cpu]) > >>>>> || (cpu - skipped_count) >= nd->num_prstatus_notes) && > >>>>> !machine_type("MIPS")) { > >>>>> error(INFO, "registers not collected for cpu %d\n", cpu); > >>>>> return; > >>>>> } > >>>>> > >>>>> Thanks > >>>>> Lianbo > >>>>> > >>>>> > >>>>>> nd->nt_prstatus_percpu[cpu]; > >>>>>> else > >>>>>> note64 = (Elf64_Nhdr *)nd->nt_prstatus; > >>>>>> + if (!note64) { > >>>>>> + error(INFO, "registers not collected for cpu %d\n", cpu); > >>>>>> + return; > >>>>>> + } > >>>>>> len = sizeof(Elf64_Nhdr); > >>>>>> len = roundup(len + note64->n_namesz, 4); > >>>>>> len = roundup(len + note64->n_descsz, 4); > >>>>>> @@ -2820,6 +2824,10 @@ display_regs_from_elf_notes(int cpu, FILE *ofp) > >>>>>> nd->nt_prstatus_percpu[cpu]; > >>>>>> else > >>>>>> note32 = (Elf32_Nhdr *)nd->nt_prstatus; > >>>>>> + if (!note32) { > >>>>>> + error(INFO, "registers not collected for cpu %d\n", cpu); > >>>>>> + return; > >>>>>> + } > >>>>>> len = sizeof(Elf32_Nhdr); > >>>>>> len = roundup(len + note32->n_namesz, 4); > >>>>>> len = roundup(len + note32->n_descsz, 4); > >>>>>> @@ -2857,6 +2865,10 @@ display_regs_from_elf_notes(int cpu, FILE *ofp) > >>>>>> else > >>>>>> note64 = (Elf64_Nhdr *)nd->nt_prstatus; > >>>>>> > >>>>>> + if (!note64) { > >>>>>> + error(INFO, "registers not collected for cpu %d\n", cpu); > >>>>>> + return; > >>>>>> + } > >>>>>> prs = (struct ppc64_elf_prstatus *) > >>>>>> ((char *)note64 + sizeof(Elf64_Nhdr) + note64->n_namesz); > >>>>>> prs = (struct ppc64_elf_prstatus *)roundup((ulong)prs, 4); > >>>>>> @@ -2903,6 +2915,10 @@ display_regs_from_elf_notes(int cpu, FILE *ofp) > >>>>>> nd->nt_prstatus_percpu[cpu]; > >>>>>> else > >>>>>> note64 = (Elf64_Nhdr *)nd->nt_prstatus; > >>>>>> + if (!note64) { > >>>>>> + error(INFO, "registers not collected for cpu %d\n", cpu); > >>>>>> + return; > >>>>>> + } > >>>>>> len = sizeof(Elf64_Nhdr); > >>>>>> len = roundup(len + note64->n_namesz, 4); > >>>>>> len = roundup(len + note64->n_descsz, 4); > >>>>>> -- > >>>>>> 2.34.1 > >>>>>> > >>>>>> Guanyou. > >>>>>> Thanks >