From: Dominique Martinet <asmadeus@xxxxxxxxxxxxx> commit 0dc54bd4d6e03be1f0b678c4297170b79f1a44ab upstream. fscache_cookie_enabled() could be called on NULL cookies and cause a null pointer dereference when accessing cookie flags: just make sure the cookie is valid first Suggested-by: David Howells <dhowells@xxxxxxxxxx> Acked-by: David Howells <dhowells@xxxxxxxxxx> Signed-off-by: Dominique Martinet <asmadeus@xxxxxxxxxxxxx> Cc: Jeffrey E Altman <jaltman@xxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- include/linux/fscache.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/include/linux/fscache.h +++ b/include/linux/fscache.h @@ -167,7 +167,7 @@ struct fscache_cookie { static inline bool fscache_cookie_enabled(struct fscache_cookie *cookie) { - return test_bit(FSCACHE_COOKIE_ENABLED, &cookie->flags); + return fscache_cookie_valid(cookie) && test_bit(FSCACHE_COOKIE_ENABLED, &cookie->flags); } /*