Commit 022012dc authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Andrew Morton
Browse files

lib/stackdepot, kasan: add flags to __stack_depot_save and rename 

Change the bool can_alloc argument of __stack_depot_save to a u32
  argument that accepts a set of flags.

The following patch will add another flag to stack_depot_save_flags
  besides the existing STACK_DEPOT_FLAG_CAN_ALLOC.

Also rename the function to stack_depot_save_flags, as
  __stack_depot_save is a cryptic name,

Link: https://lkml.kernel.org/r/645fa15239621eebbd3a10331e5864b718839512.1700502145.git.andreyknvl@google.com


Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Reviewed-by: default avatarAlexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 3bddc310

include/linux/stackdepot.h

+25 −11
Original line number Diff line number Diff line
@@ -32,6 +32,17 @@ typedef u32 depot_stack_handle_t; 
 */

#define STACK_DEPOT_EXTRA_BITS 5



typedef u32 depot_flags_t;



/*

 * Flags that can be passed to stack_depot_save_flags(); see the comment next

 * to its declaration for more details.

 */

#define STACK_DEPOT_FLAG_CAN_ALLOC	((depot_flags_t)0x0001)



#define STACK_DEPOT_FLAGS_NUM	1

#define STACK_DEPOT_FLAGS_MASK	((depot_flags_t)((1 << STACK_DEPOT_FLAGS_NUM) - 1))



/*

 * Using stack depot requires its initialization, which can be done in 3 ways:

 *
@@ -69,31 +80,34 @@ static inline int stack_depot_early_init(void) { return 0; } 
#endif



/**

 * __stack_depot_save - Save a stack trace to stack depot

 * stack_depot_save_flags - Save a stack trace to stack depot

 *

 * @entries:		Pointer to the stack trace

 * @nr_entries:		Number of frames in the stack

 * @alloc_flags:	Allocation GFP flags

 * @can_alloc:		Allocate stack pools (increased chance of failure if false)

 * @depot_flags:	Stack depot flags

 *

 * Saves a stack trace from @entries array of size @nr_entries.

 *

 * Saves a stack trace from @entries array of size @nr_entries. If @can_alloc is

 * %true, stack depot can replenish the stack pools in case no space is left

 * (allocates using GFP flags of @alloc_flags). If @can_alloc is %false, avoids

 * any allocations and fails if no space is left to store the stack trace.

 * If STACK_DEPOT_FLAG_CAN_ALLOC is set in @depot_flags, stack depot can

 * replenish the stack pools in case no space is left (allocates using GFP

 * flags of @alloc_flags). Otherwise, stack depot avoids any allocations and

 * fails if no space is left to store the stack trace.

 *

 * If the provided stack trace comes from the interrupt context, only the part

 * up to the interrupt entry is saved.

 *

 * Context: Any context, but setting @can_alloc to %false is required if

 * Context: Any context, but setting STACK_DEPOT_FLAG_CAN_ALLOC is required if

 *          alloc_pages() cannot be used from the current context. Currently

 *          this is the case for contexts where neither %GFP_ATOMIC nor

 *          %GFP_NOWAIT can be used (NMI, raw_spin_lock).

 *

 * Return: Handle of the stack struct stored in depot, 0 on failure

 */

depot_stack_handle_t __stack_depot_save(unsigned long *entries,

depot_stack_handle_t stack_depot_save_flags(unsigned long *entries,

					    unsigned int nr_entries,

					gfp_t gfp_flags, bool can_alloc);

					    gfp_t gfp_flags,

					    depot_flags_t depot_flags);



/**

 * stack_depot_save - Save a stack trace to stack depot
@@ -103,7 +117,7 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, 
 * @alloc_flags:	Allocation GFP flags

 *

 * Context: Contexts where allocations via alloc_pages() are allowed.

 *          See __stack_depot_save() for more details.

 *          See stack_depot_save_flags() for more details.

 *

 * Return: Handle of the stack trace stored in depot, 0 on failure

 */

lib/stackdepot.c

+11 −5
Original line number Diff line number Diff line
@@ -450,19 +450,24 @@ static inline struct stack_record *find_stack(struct list_head *bucket, 
	return NULL;

}



depot_stack_handle_t __stack_depot_save(unsigned long *entries,

depot_stack_handle_t stack_depot_save_flags(unsigned long *entries,

					    unsigned int nr_entries,

					gfp_t alloc_flags, bool can_alloc)

					    gfp_t alloc_flags,

					    depot_flags_t depot_flags)

{

	struct list_head *bucket;

	struct stack_record *found = NULL;

	depot_stack_handle_t handle = 0;

	struct page *page = NULL;

	void *prealloc = NULL;

	bool can_alloc = depot_flags & STACK_DEPOT_FLAG_CAN_ALLOC;

	bool need_alloc = false;

	unsigned long flags;

	u32 hash;



	if (WARN_ON(depot_flags & ~STACK_DEPOT_FLAGS_MASK))

		return 0;



	/*

	 * If this stack trace is from an interrupt, including anything before

	 * interrupt entry usually leads to unbounded stack depot growth.
@@ -541,13 +546,14 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, 
		handle = found->handle.handle;

	return handle;

}

EXPORT_SYMBOL_GPL(__stack_depot_save);

EXPORT_SYMBOL_GPL(stack_depot_save_flags);



depot_stack_handle_t stack_depot_save(unsigned long *entries,

				      unsigned int nr_entries,

				      gfp_t alloc_flags)

{

	return __stack_depot_save(entries, nr_entries, alloc_flags, true);

	return stack_depot_save_flags(entries, nr_entries, alloc_flags,

				      STACK_DEPOT_FLAG_CAN_ALLOC);

}

EXPORT_SYMBOL_GPL(stack_depot_save);

mm/kasan/common.c

+4 −3
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 
#include <linux/sched.h>

#include <linux/sched/task_stack.h>

#include <linux/slab.h>

#include <linux/stackdepot.h>

#include <linux/stacktrace.h>

#include <linux/string.h>

#include <linux/types.h>
@@ -37,19 +38,19 @@ struct slab *kasan_addr_to_slab(const void *addr) 
	return NULL;

}



depot_stack_handle_t kasan_save_stack(gfp_t flags, bool can_alloc)

depot_stack_handle_t kasan_save_stack(gfp_t flags, depot_flags_t depot_flags)

{

	unsigned long entries[KASAN_STACK_DEPTH];

	unsigned int nr_entries;



	nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);

	return __stack_depot_save(entries, nr_entries, flags, can_alloc);

	return stack_depot_save_flags(entries, nr_entries, flags, depot_flags);

}



void kasan_set_track(struct kasan_track *track, gfp_t flags)

{

	track->pid = current->pid;

	track->stack = kasan_save_stack(flags, true);

	track->stack = kasan_save_stack(flags, STACK_DEPOT_FLAG_CAN_ALLOC);

}



#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)

mm/kasan/generic.c

+5 −4
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <linux/sched.h>

#include <linux/sched/task_stack.h>

#include <linux/slab.h>

#include <linux/stackdepot.h>

#include <linux/stacktrace.h>

#include <linux/string.h>

#include <linux/types.h>
@@ -472,7 +473,7 @@ size_t kasan_metadata_size(struct kmem_cache *cache, bool in_object) 
			sizeof(struct kasan_free_meta) : 0);

}



static void __kasan_record_aux_stack(void *addr, bool can_alloc)

static void __kasan_record_aux_stack(void *addr, depot_flags_t depot_flags)

{

	struct slab *slab = kasan_addr_to_slab(addr);

	struct kmem_cache *cache;
@@ -489,17 +490,17 @@ static void __kasan_record_aux_stack(void *addr, bool can_alloc) 
		return;



	alloc_meta->aux_stack[1] = alloc_meta->aux_stack[0];

	alloc_meta->aux_stack[0] = kasan_save_stack(0, can_alloc);

	alloc_meta->aux_stack[0] = kasan_save_stack(0, depot_flags);

}



void kasan_record_aux_stack(void *addr)

{

	return __kasan_record_aux_stack(addr, true);

	return __kasan_record_aux_stack(addr, STACK_DEPOT_FLAG_CAN_ALLOC);

}



void kasan_record_aux_stack_noalloc(void *addr)

{

	return __kasan_record_aux_stack(addr, false);

	return __kasan_record_aux_stack(addr, 0);

}



void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags)

mm/kasan/kasan.h

+1 −1
Original line number Diff line number Diff line
@@ -368,7 +368,7 @@ static inline void kasan_init_cache_meta(struct kmem_cache *cache, unsigned int 
static inline void kasan_init_object_meta(struct kmem_cache *cache, const void *object) { }

#endif



depot_stack_handle_t kasan_save_stack(gfp_t flags, bool can_alloc);

depot_stack_handle_t kasan_save_stack(gfp_t flags, depot_flags_t depot_flags);

void kasan_set_track(struct kasan_track *track, gfp_t flags);

void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags);

void kasan_save_free_info(struct kmem_cache *cache, void *object);