5:09 a.m.
Since the panic_on_oops is disabled, when getting a BUG hit in the code,
the system continues and does not panic. However, a short time later, a
hard lockup is hit and the system does panic. Even though the system
panicked at hard lockup, the panic string is still the first BUG hit.
For example:
Without the patch:
crash> sys|grep PANIC
PANIC: "BUG: unable to handle kernel paging request at
ffffab835d7f9d50"
With the patch:
crash> sys|grep PANIC
PANIC: "Kernel panic - not syncing: Hard LOCKUP"
Let's search for the panic string based on the severity of the panic
event, and also refactore the get_panicmsg() a little bit to improve
readability.
Reported-by: John Pittman <jpittman(a)redhat.com>
Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com>
---
task.c | 109 +++++++++++++++++++++++----------------------------------
1 file changed, 44 insertions(+), 65 deletions(-)
diff --git a/task.c b/task.c
index 4018a543b715..6809c27c4b91 100644
--- a/task.c
+++ b/task.c
@@ -6301,6 +6301,31 @@ get_active_task(int cpu)
return NO_TASK;
}
+/*
+ * Arrange the panic strings based on the severity of the panic
+ * events.
+ */
+static const char* panic_msg[] = {
+ "SysRq : Crash",
+ "SysRq : Trigger a crash",
+ "SysRq : Netdump",
+ "Kernel panic: ",
+ "Kernel panic - ",
+ "Kernel BUG at",
+ "kernel BUG at",
+ "Unable to handle kernel paging request",
+ "Unable to handle kernel NULL pointer dereference",
+ "BUG: unable to handle kernel ",
+ "general protection fault: ",
+ "double fault: ",
+ "divide error: ",
+ "stack segment: ",
+ "[Hardware Error]: ",
+ "Bad mode in ",
+ "Oops: ",
+};
+
+#define ARRAY_SIZE(a) (sizeof (a) / sizeof ((a)[0]))
/*
* Read the panic string.
@@ -6308,7 +6333,7 @@ get_active_task(int cpu)
char *
get_panicmsg(char *buf)
{
- int msg_found;
+ int msg_found, i;
BZERO(buf, BUFSIZE);
msg_found = FALSE;
@@ -6332,76 +6357,30 @@ get_panicmsg(char *buf)
* active-task flag appropriately. The message may or
* may not be used as the panic message.
*/
- rewind(pc->tmpfile);
- while (fgets(buf, BUFSIZE, pc->tmpfile)) {
- if (strstr(buf, "SysRq : Crash") ||
- strstr(buf, "SysRq : Trigger a crash")) {
- pc->flags |= SYSRQ;
- break;
- }
- }
- rewind(pc->tmpfile);
- while (!msg_found && fgets(buf, BUFSIZE, pc->tmpfile)) {
- if (strstr(buf, "general protection fault: ") ||
- strstr(buf, "double fault: ") ||
- strstr(buf, "divide error: ") ||
- strstr(buf, "stack segment: ")) {
- msg_found = TRUE;
- break;
- }
- }
- rewind(pc->tmpfile);
- while (!msg_found && fgets(buf, BUFSIZE, pc->tmpfile)) {
- if (strstr(buf, "SysRq : Netdump") ||
- strstr(buf, "SysRq : Crash") ||
- strstr(buf, "SysRq : Trigger a crash")) {
- pc->flags |= SYSRQ;
- msg_found = TRUE;
- break;
+ for (i = 0; i < ARRAY_SIZE(panic_msg); i++) {
+ rewind(pc->tmpfile);
+ while (fgets(buf, BUFSIZE, pc->tmpfile)) {
+ if (strstr(buf, panic_msg[i])) {
+ msg_found = TRUE;
+ if(strstr(buf, "SysRq :"))
+ pc->flags |= SYSRQ;
+ goto FOUND;
+ }
}
- }
- rewind(pc->tmpfile);
- while (!msg_found && fgets(buf, BUFSIZE, pc->tmpfile)) {
- if (strstr(buf, "Oops: ") ||
- strstr(buf, "Kernel BUG at") ||
- strstr(buf, "kernel BUG at") ||
- strstr(buf, "Unable to handle kernel paging request") ||
- strstr(buf, "Unable to handle kernel NULL pointer dereference") ||
- strstr(buf, "BUG: unable to handle kernel "))
- msg_found = TRUE;
+
}
+
rewind(pc->tmpfile);
while (!msg_found && fgets(buf, BUFSIZE, pc->tmpfile)) {
- if (strstr(buf, "sysrq") &&
- symbol_exists("sysrq_pressed")) {
- get_symbol_data("sysrq_pressed", sizeof(int),
- &msg_found);
- break;
- }
+ if (strstr(buf, "sysrq") &&
+ symbol_exists("sysrq_pressed")) {
+ get_symbol_data("sysrq_pressed", sizeof(int),
+ &msg_found);
+ break;
+ }
}
- rewind(pc->tmpfile);
- while (!msg_found && fgets(buf, BUFSIZE, pc->tmpfile)) {
- if (strstr(buf, "Kernel panic: ") ||
- strstr(buf, "Kernel panic - ")) {
- msg_found = TRUE;
- break;
- }
- }
- rewind(pc->tmpfile);
- while (!msg_found && fgets(buf, BUFSIZE, pc->tmpfile)) {
- if (strstr(buf, "[Hardware Error]: ")) {
- msg_found = TRUE;
- break;
- }
- }
- rewind(pc->tmpfile);
- while (!msg_found && fgets(buf, BUFSIZE, pc->tmpfile)) {
- if (strstr(buf, "Bad mode in ")) {
- msg_found = TRUE;
- break;
- }
- }
+FOUND:
close_tmpfile();
if (!msg_found)
--
2.41.0