Hi lianbo test case is non-elf-vmcore, so all nt_prstatus_percpu invalid pointer.

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 >> >

Hi lianbo > Thanks for pointing out this. Can you help to try this one? test pass.

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. >> >> > 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 >>>> >>>

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

Hi Guanyou, On Wed, Dec 11, 2024 at 3:20 PM Guanyou Chen <chenguanyou9338(a)gmail.com&gt; wrote: > > 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. Hmm I see... In this case the ELF header is constructed in ramdump_to_elf(), so it is reasonable that the NT_PRSTATUS note is missing. I don't have further questions for this patch, and Ack for the code part. As for the commit log, since it lacks of some useful info, how about we re-draft it as: ---- When the ELF note does not contain CPU registers, attempting to retrieve online CPU registers will cause a crash. This is likely to happen for ramdump cases as follows, where the ELF header is created by crash at runtime. WARNING: cpu 0: 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 ... DDRCS2_2.BIN CPUS: 8 ---- What do you think? @Lianbo Jiang

Thanks, Tao Liu > > 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 >>