refcount_t: Introduce a special purpose refcount type
Provide refcount_t, an atomic_t like primitive built just for
refcounting.
It provides saturation semantics such that overflow becomes impossible
and thereby 'spurious' use-after-free is avoided.
Change-Id: Id360e29bb9c19af8672726539d0d16c0f6d2be3f
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Git-commit: f405df5de3170c00e5c54f8b7cf4766044a032ba
Git-repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Srinivasa Rao Kuppala <srkupp@codeaurora.org>
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 079d91a..37641d1 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -707,6 +707,19 @@
source "lib/Kconfig.kasan"
+config DEBUG_REFCOUNT
+ bool "Verbose refcount checks"
+ help
+ Say Y here if you want reference counters (refcount_t and kref) to
+ generate WARNs on dubious usage. Without this refcount_t will still
+ be a saturating counter and avoid Use-After-Free by turning it into
+ a resource leak Denial-Of-Service.
+
+ Use of this option will increase kernel text size but will alert the
+ admin of potential abuse.
+
+ If in doubt, say "N".
+
endmenu # "Memory Debugging"
config ARCH_HAS_KCOV