[BKL] add 'might_sleep()' to the outermost lock taker
f01eb364 · Linus Torvalds <[email protected]> · 2009-12-12 14:46:33 -08:00
As shown by the previous patch (6698e3472: "tty: Fix BKL taken under a
spinlock bug introduced in the BKL split") the BKL removal is prone to
some subtle issues, where removing the BKL in one place may in fact make
a previously nested BKL call the new outer call, and then prone to nasty
deadlocks with other spinlocks.
In general, we should never take the BKL while we're holding a spinlock,
so let's just add a "might_sleep()" to it (even though the BKL doesn't
technically sleep - at least not yet), and we'll get nice warnings the
next time this kind of problem happens during BKL removal.
Acked-and-Tested-by: Thomas Gleixner <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
- Commit
- f01eb3640308c005d31b29d0a8bc2b7acb4e3f75
- Parents
- 6698e347
Changes
1 files changed · +3 −1
diff --git a/lib/kernel_lock.c b/lib/kernel_lock.c
index 4ebfa5a..5526b46 100644
--- a/lib/kernel_lock.c
+++ b/lib/kernel_lock.c
@@ -122,8 +122,10 @@ void __lockfunc _lock_kernel(const char *func, const char *file, int line)
trace_lock_kernel(func, file, line);
- if (likely(!depth))
+ if (likely(!depth)) {
+ might_sleep();
__lock_kernel();
+ }
current->lock_depth = depth;
}