The patch titled
Subject: kernel/panic/kexec: fix "crash_kexec_post_notifiers" option issue in oops path
has been added to the -mm tree. Its filename is
kernel-panic-kexec-fix-crash_kexec_post_notifiers-option-issue-in-oops-path.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kernel-panic-kexec-fix-crash_kexec_post_notifiers-option-issue-in-oops-path.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kernel-panic-kexec-fix-crash_kexec_post_notifiers-option-issue-in-oops-path.patch
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------------------------------------------------------
From: HATAYAMA Daisuke <d.hatayama@xxxxxxxxxxxxxx>
Subject: kernel/panic/kexec: fix "crash_kexec_post_notifiers" option issue in oops path
Commit f06e5153f4ae2e ("kernel/panic.c: add "crash_kexec_post_notifiers"
option for kdump after panic_notifers") introduced
"crash_kexec_post_notifiers" kernel boot option, which toggles wheather
panic() calls crash_kexec() before panic_notifiers and dump kmsg or after.
The problem is that the commit overlooks panic_on_oops kernel boot option.
If it is enabled, crash_kexec() is called directly without going through
panic() in oops path.
To fix this issue, this patch adds a check to "crash_kexec_post_notifiers"
in the condition of kexec_should_crash().
Also, put a comment in kexec_should_crash() to explain not obvious things
on this patch.
Signed-off-by: HATAYAMA Daisuke <d.hatayama@xxxxxxxxxxxxxx>
Acked-by: Baoquan He <bhe@xxxxxxxxxx>
Tested-by: Hidehiro Kawai <hidehiro.kawai.ez@xxxxxxxxxxx>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@xxxxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/kernel.h | 3 +++
kernel/kexec.c | 11 +++++++++++
kernel/panic.c | 2 +-
3 files changed, 15 insertions(+), 1 deletion(-)
diff -puN include/linux/kernel.h~kernel-panic-kexec-fix-crash_kexec_post_notifiers-option-issue-in-oops-path include/linux/kernel.h
--- a/include/linux/kernel.h~kernel-panic-kexec-fix-crash_kexec_post_notifiers-option-issue-in-oops-path
+++ a/include/linux/kernel.h
@@ -438,6 +438,9 @@ extern int panic_on_unrecovered_nmi;
extern int panic_on_io_nmi;
extern int panic_on_warn;
extern int sysctl_panic_on_stackoverflow;
+
+extern bool crash_kexec_post_notifiers;
+
/*
* Only to be used by arch init code. If the user over-wrote the default
* CONFIG_PANIC_TIMEOUT, honor it.
diff -puN kernel/kexec.c~kernel-panic-kexec-fix-crash_kexec_post_notifiers-option-issue-in-oops-path kernel/kexec.c
--- a/kernel/kexec.c~kernel-panic-kexec-fix-crash_kexec_post_notifiers-option-issue-in-oops-path
+++ a/kernel/kexec.c
@@ -84,6 +84,17 @@ struct resource crashk_low_res = {
int kexec_should_crash(struct task_struct *p)
{
+ /*
+ * If crash_kexec_post_notifiers is enabled, don't run
+ * crash_kexec() here yet, which must be run after panic
+ * notifiers in panic().
+ */
+ if (crash_kexec_post_notifiers)
+ return 0;
+ /*
+ * There are 4 panic() calls in do_exit() path, each of which
+ * corresponds to each of these 4 conditions.
+ */
if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops)
return 1;
return 0;
diff -puN kernel/panic.c~kernel-panic-kexec-fix-crash_kexec_post_notifiers-option-issue-in-oops-path kernel/panic.c
--- a/kernel/panic.c~kernel-panic-kexec-fix-crash_kexec_post_notifiers-option-issue-in-oops-path
+++ a/kernel/panic.c
@@ -32,7 +32,7 @@ static unsigned long tainted_mask;
static int pause_on_oops;
static int pause_on_oops_flag;
static DEFINE_SPINLOCK(pause_on_oops_lock);
-static bool crash_kexec_post_notifiers;
+bool crash_kexec_post_notifiers;
int panic_on_warn __read_mostly;
int panic_timeout = CONFIG_PANIC_TIMEOUT;
_
Patches currently in -mm which might be from d.hatayama@xxxxxxxxxxxxxx are
kernel-panic-call-the-2nd-crash_kexec-only-if-crash_kexec_post_notifiers-is-enabled.patch
kernel-panic-kexec-fix-crash_kexec_post_notifiers-option-issue-in-oops-path.patch
kdump-vmcoreinfo-report-actual-value-of-phys_base.patch
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