kernel/lib: add additional debug capabilites for data corruption
Data corruptions in the kernel often end up in system crashes that
are easier to debug closer to the time of detection. Specifically,
if we do not panic immediately after lock or list corruptions have been
detected, the problem context is lost in the ensuing system mayhem.
Add support for allowing system crash immediately after such corruptions
are detected. The CONFIG option controls the enabling/disabling of the
feature.
Change-Id: I9b2eb62da506a13007acff63e85e9515145909ff
Signed-off-by: Syed Rameez Mustafa <rameezmustafa@codeaurora.org>
diff --git a/include/linux/bug.h b/include/linux/bug.h
index 72961c3..cd141a4 100644
--- a/include/linux/bug.h
+++ b/include/linux/bug.h
@@ -96,4 +96,10 @@
}
#endif /* CONFIG_GENERIC_BUG */
+
+#ifdef CONFIG_PANIC_ON_DATA_CORRUPTION
+#define PANIC_CORRUPTION 1
+#else
+#define PANIC_CORRUPTION 0
+#endif /* CONFIG_PANIC_ON_DATA_CORRUPTION */
#endif /* _LINUX_BUG_H */
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index f1a6e9e..90fd57d 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -41,6 +41,7 @@
#include <linux/debug_locks.h>
#include <linux/lockdep.h>
#include <linux/idr.h>
+#include <linux/bug.h>
#include "workqueue_sched.h"
@@ -1878,6 +1879,7 @@
printk(KERN_ERR " last function: ");
print_symbol("%s\n", (unsigned long)f);
debug_show_held_locks(current);
+ BUG_ON(PANIC_CORRUPTION);
dump_stack();
}
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 097d70f..b9060a1 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1290,6 +1290,13 @@
If unsure, say N.
+config PANIC_ON_DATA_CORRUPTION
+ bool "Cause a Kernel Panic When Data Corruption is detected"
+ help
+ Select this option to upgrade warnings for potentially
+ recoverable data corruption scenarios to system-halting panics,
+ for easier detection and debug.
+
source "samples/Kconfig"
source "lib/Kconfig.kgdb"
diff --git a/lib/list_debug.c b/lib/list_debug.c
index 982b850..6a039a6 100644
--- a/lib/list_debug.c
+++ b/lib/list_debug.c
@@ -10,6 +10,7 @@
#include <linux/list.h>
#include <linux/bug.h>
#include <linux/kernel.h>
+#include <linux/bug.h>
/*
* Insert a new entry between two known consecutive entries.
@@ -30,6 +31,10 @@
"list_add corruption. prev->next should be "
"next (%p), but was %p. (prev=%p).\n",
next, prev->next, prev);
+
+ BUG_ON(((prev->next != next) || (next->prev != prev)) &&
+ PANIC_CORRUPTION);
+
next->prev = new;
new->next = next;
new->prev = prev;
@@ -55,8 +60,10 @@
"but was %p\n", entry, prev->next) ||
WARN(next->prev != entry,
"list_del corruption. next->prev should be %p, "
- "but was %p\n", entry, next->prev))
+ "but was %p\n", entry, next->prev)) {
+ BUG_ON(PANIC_CORRUPTION);
return;
+ }
__list_del(prev, next);
}
diff --git a/lib/spinlock_debug.c b/lib/spinlock_debug.c
index f2aa5de..ac516f4 100644
--- a/lib/spinlock_debug.c
+++ b/lib/spinlock_debug.c
@@ -12,6 +12,7 @@
#include <linux/debug_locks.h>
#include <linux/delay.h>
#include <linux/export.h>
+#include <linux/bug.h>
void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
struct lock_class_key *key)
@@ -64,6 +65,7 @@
owner ? owner->comm : "<none>",
owner ? task_pid_nr(owner) : -1,
lock->owner_cpu);
+ BUG_ON(PANIC_CORRUPTION);
dump_stack();
}