Commit fabe874a authored Jan 24, 2008 by Arjan van de Ven Committed by Linus Torvalds Jan 24, 2008

lockdep: fix kernel crash on module unload

Michael Wu noticed in his lkml post at

    http://marc.info/?l=linux-kernel&m=119396182726091&w=2



that certain wireless drivers ended up having their name in module
memory, which would then crash the kernel on module unload.

The patch he proposed was a bit clumsy in that it increased the size of
a lockdep entry significantly; the patch below tries another approach,
it checks, on module teardown, if the name of a class is in module space
and then zaps the class.  This is very similar to what we already do
with keys that are in module space.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 4784b11c

kernel/lockdep.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -2932,7 +2932,7 @@ static void zap_class(struct lock_class *class)

		}

		static inline int within(void addr, void start, unsigned long size)
		static inline int within(const void addr, void start, unsigned long size)
		{
		return addr >= start && addr < start + size;
		}
		@@ -2955,9 +2955,12 @@ void lockdep_free_key_range(void *start, unsigned long size)
		head = classhash_table + i;
		if (list_empty(head))
		continue;
		list_for_each_entry_safe(class, next, head, hash_entry)
		list_for_each_entry_safe(class, next, head, hash_entry) {
		if (within(class->key, start, size))
		zap_class(class);
		else if (within(class->name, start, size))
		zap_class(class);
		}
		}

		if (locked)

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