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mm/slub: Move the stackdepot related allocation out of IRQ-off section. 

The set_track() invocation in free_debug_processing() is invoked with
acquired slab_lock(). The lock disables interrupts on PREEMPT_RT and
this forbids to allocate memory which is done in stack_depot_save().

Split set_track() into two parts: set_track_prepare() which allocate
memory and set_track_update() which only performs the assignment of the
trace data structure. Use set_track_prepare() before disabling
interrupts.

[ vbabka@suse.cz: make set_track() call set_track_update() instead of
  open-coded assignments ]

Fixes: 5cf909c553 ("mm/slub: use stackdepot to save stack trace in objects")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Link: https://lore.kernel.org/r/Yp9sqoUi4fVa5ExF@linutronix.de
This commit is contained in:
Sebastian Andrzej Siewior 2022-06-07 17:20:10 +02:00 committed by Vlastimil Babka
parent b13baccc38
commit c4cf678559
1 changed files with 34 additions and 7 deletions
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41
mm/slub.c
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@ -726,25 +726,48 @@ static struct track *get_track(struct kmem_cache *s, void *object,
return kasan_reset_tag(p + alloc);
}
static void noinline set_track(struct kmem_cache *s, void *object,
enum track_item alloc, unsigned long addr)
{
struct track *p = get_track(s, object, alloc);
#ifdef CONFIG_STACKDEPOT
static noinline depot_stack_handle_t set_track_prepare(void)
{
depot_stack_handle_t handle;
unsigned long entries[TRACK_ADDRS_COUNT];
unsigned int nr_entries;
nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
p->handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
return handle;
}
#else
static inline depot_stack_handle_t set_track_prepare(void)
{
return 0;
}
#endif
static void set_track_update(struct kmem_cache *s, void *object,
enum track_item alloc, unsigned long addr,
depot_stack_handle_t handle)
{
struct track *p = get_track(s, object, alloc);
#ifdef CONFIG_STACKDEPOT
p->handle = handle;
#endif
p->addr = addr;
p->cpu = smp_processor_id();
p->pid = current->pid;
p->when = jiffies;
}
static __always_inline void set_track(struct kmem_cache *s, void *object,
enum track_item alloc, unsigned long addr)
{
depot_stack_handle_t handle = set_track_prepare();
set_track_update(s, object, alloc, addr, handle);
}
static void init_tracking(struct kmem_cache *s, void *object)
{
struct track *p;
@ -1373,6 +1396,10 @@ static noinline int free_debug_processing(
int cnt = 0;
unsigned long flags, flags2;
int ret = 0;
depot_stack_handle_t handle = 0;
if (s->flags & SLAB_STORE_USER)
handle = set_track_prepare();
spin_lock_irqsave(&n->list_lock, flags);
slab_lock(slab, &flags2);
@ -1391,7 +1418,7 @@ next_object:
}
if (s->flags & SLAB_STORE_USER)
set_track(s, object, TRACK_FREE, addr);
set_track_update(s, object, TRACK_FREE, addr, handle);
trace(s, slab, object, 0);
/* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
init_object(s, object, SLUB_RED_INACTIVE);