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Commit cf9c1e45 authored by Syed Rameez Mustafa's avatar Syed Rameez Mustafa Committed by Patrick Daly
Browse files

kernel/lib: add additional debug capabilities 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: default avatarSyed Rameez Mustafa <rameezmustafa@codeaurora.org>
Signed-off-by: default avatarPatrick Daly <pdaly@codeaurora.org>
parent a24e0237

include/linux/bug.h

+6 −0
Original line number Diff line number Diff line
@@ -121,4 +121,10 @@ static inline enum bug_trap_type report_bug(unsigned long bug_addr, 
}



#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 */

kernel/workqueue.c

+1 −0
Original line number Diff line number Diff line
@@ -2116,6 +2116,7 @@ __acquires(&pool->lock) 
		       current->comm, preempt_count(), task_pid_nr(current),

		       worker->current_func);

		debug_show_held_locks(current);

		BUG_ON(PANIC_CORRUPTION);

		dump_stack();

	}

lib/Kconfig.debug

+7 −0
Original line number Diff line number Diff line
@@ -2038,6 +2038,13 @@ config TEST_STATIC_KEYS 


	  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"

lib/list_debug.c

+9 −2
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/bug.h>

#include <linux/kernel.h>

#include <linux/rculist.h>

#include <linux/bug.h>



/*

 * Insert a new entry between two known consecutive entries.
@@ -34,6 +35,10 @@ void __list_add(struct list_head *new, 
	WARN(new == prev || new == next,

	     "list_add double add: new=%p, prev=%p, next=%p.\n",

	     new, prev, next);



	BUG_ON((prev->next != next || next->prev != prev ||

		 new == prev || new == next) && PANIC_CORRUPTION);



	next->prev = new;

	new->next = next;

	new->prev = prev;
@@ -58,9 +63,11 @@ void __list_del_entry(struct list_head *entry) 
		"list_del corruption. prev->next should be %p, "

		"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))

		"list_del corruption. next->prev should be %p, but was %p\n",

		entry, next->prev)) {

		BUG_ON(PANIC_CORRUPTION);

		return;

	}



	__list_del(prev, next);

}