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Merge tag 'core-debugobjects-2023-05-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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Pull debugobjects fixes from Thomas Gleixner:
 "Two fixes for debugobjects:

   - Prevent the allocation path from waking up kswapd.

     That's a long standing issue due to the GFP_ATOMIC allocation flag.
     As debug objects can be invoked from pretty much any context waking
     kswapd can end up in arbitrary lock chains versus the waitqueue
     lock

   - Correct the explicit lockdep wait-type violation in
     debug_object_fill_pool()"

* tag 'core-debugobjects-2023-05-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  debugobjects: Don't wake up kswapd from fill_pool()
  debugobjects,locking: Annotate debug_object_fill_pool() wait type violation
This commit is contained in:
Linus Torvalds
2023-05-28 07:15:33 -04:00
parent 9bd5386c65 eb799279fb
commit d8f14b84fe
4 changed files with 50 additions and 10 deletions
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17
lib/debugobjects.c
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@@ -126,7 +126,7 @@ static const char *obj_states[ODEBUG_STATE_MAX] = {
static void fill_pool(void)
{
gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
gfp_t gfp = __GFP_HIGH | __GFP_NOWARN;
struct debug_obj *obj;
unsigned long flags;
@@ -591,10 +591,21 @@ static void debug_objects_fill_pool(void)
{
/*
* On RT enabled kernels the pool refill must happen in preemptible
* context:
* context -- for !RT kernels we rely on the fact that spinlock_t and
* raw_spinlock_t are basically the same type and this lock-type
* inversion works just fine.
*/
if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible())
if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible()) {
/*
* Annotate away the spinlock_t inside raw_spinlock_t warning
* by temporarily raising the wait-type to WAIT_SLEEP, matching
* the preemptible() condition above.
*/
static DEFINE_WAIT_OVERRIDE_MAP(fill_pool_map, LD_WAIT_SLEEP);
lock_map_acquire_try(&fill_pool_map);
fill_pool();
lock_map_release(&fill_pool_map);
}
}
static void