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

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)

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