[Crash-utility] [PATCH] arm64: Fix segfault by "bt" command with offline cpus
Currently on arm64, NT_PRSTATUS notes in dumpfile are not mapped to
online cpus and machine_specific->panic_task_regs correctly. As a
result, the "bt" command can cause a segmentation fault.
crash> bt -c 0
PID: 0 TASK: ffff8000117fa240 CPU: 0 COMMAND: "swapper/0"
Segmentation fault (core dumped)
To fix this,
1) make map_cpus_to_prstatus_kdump_cmprs() map the notes to
dd->nt_prstatus_percpu also on arm64, and
2) move arm64_get_crash_notes() to machdep_init(POST_INIT) in order
to apply the mapping to machine_specific->panic_task_regs.
Resolves: https://github.com/crash-utility/crash/issues/105
Reported-by: xuchunmei000 <xuchunmei(a)linux.alibaba.com>
Signed-off-by: Kazuhito Hagio <k-hagio-ab(a)nec.com>
---
Note: I suspect that the machine_type("ARM64") in commit 9b41d403b16c might
be placed for debugging and contained in the commit by accident. Because
that segfault could be caused by the uninitialized machdep->process_elf_notes.
arm64.c | 2 +-
diskdump.c | 3 +--
2 files changed, 2 insertions(+), 3 deletions(-)
diff --git a/arm64.c b/arm64.c
index 23c3d75d85aa..4f2c2b5104a1 100644
--- a/arm64.c
+++ b/arm64.c
@@ -472,7 +472,7 @@ arm64_init(int when)
arm64_stackframe_init();
break;
- case POST_VM:
+ case POST_INIT:
/*
* crash_notes contains machine specific information about the
* crash. In particular, it contains CPU registers at the time
diff --git a/diskdump.c b/diskdump.c
index 3e1cfd548c96..d5674276e1fd 100644
--- a/diskdump.c
+++ b/diskdump.c
@@ -111,8 +111,7 @@ map_cpus_to_prstatus_kdump_cmprs(void)
if (pc->flags2 & QEMU_MEM_DUMP_COMPRESSED) /* notes exist for all cpus */
goto resize_note_pointers;
- if (!(online = get_cpus_online()) || (online == kt->cpus) ||
- machine_type("ARM64"))
+ if (!(online = get_cpus_online()) || (online == kt->cpus))
goto resize_note_pointers;
if (CRASHDEBUG(1))
--
2.27.0