From: Oliver Glitta <[email protected]>
Many stack traces are similar so there are many similar arrays.
Stackdepot saves each unique stack only once.
Replace field addrs in struct track with depot_stack_handle_t handle. Use
stackdepot to save stack trace.
The benefits are smaller memory overhead and possibility to aggregate
per-cache statistics in the following patch using the stackdepot handle
instead of matching stacks manually.
[ [email protected]: rebase to 5.17-rc1 and adjust accordingly ]
This was initially merged as commit 788691464c29 and reverted by commit
ae14c63a9f20 due to several issues, that should now be fixed.
The problem of unconditional memory overhead by stackdepot has been
addressed by commit 2dba5eb1c73b ("lib/stackdepot: allow optional init
and stack_table allocation by kvmalloc()"), so the dependency on
stackdepot will result in extra memory usage only when a slab cache
tracking is actually enabled, and not for all CONFIG_SLUB_DEBUG builds.
The build failures on some architectures were also addressed, and the
reported issue with xfs/433 test did not reproduce on 5.17-rc1 with this
patch.
Signed-off-by: Oliver Glitta <[email protected]>
Signed-off-by: Vlastimil Babka <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: Joonsoo Kim <[email protected]>
---
init/Kconfig | 1 +
mm/slab_common.c | 5 ++++
mm/slub.c | 71 +++++++++++++++++++++++++++---------------------
3 files changed, 46 insertions(+), 31 deletions(-)
diff --git a/init/Kconfig b/init/Kconfig
index e9119bf54b1f..b21dd3a4a106 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1871,6 +1871,7 @@ config SLUB_DEBUG
default y
bool "Enable SLUB debugging support" if EXPERT
depends on SLUB && SYSFS
+ select STACKDEPOT if STACKTRACE_SUPPORT
help
SLUB has extensive debug support features. Disabling these can
result in significant savings in code size. This also disables
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 23f2ab0713b7..e51d50d03000 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -24,6 +24,7 @@
#include <asm/tlbflush.h>
#include <asm/page.h>
#include <linux/memcontrol.h>
+#include <linux/stackdepot.h>
#define CREATE_TRACE_POINTS
#include <trace/events/kmem.h>
@@ -314,9 +315,13 @@ kmem_cache_create_usercopy(const char *name,
* If no slub_debug was enabled globally, the static key is not yet
* enabled by setup_slub_debug(). Enable it if the cache is being
* created with any of the debugging flags passed explicitly.
+ * It's also possible that this is the first cache created with
+ * SLAB_STORE_USER and we should init stack_depot for it.
*/
if (flags & SLAB_DEBUG_FLAGS)
static_branch_enable(&slub_debug_enabled);
+ if (flags & SLAB_STORE_USER && IS_ENABLED(CONFIG_STACKDEPOT))
+ stack_depot_init();
#endif
mutex_lock(&slab_mutex);
diff --git a/mm/slub.c b/mm/slub.c
index 1fc451f4fe62..42cb79af70a0 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -26,6 +26,7 @@
#include <linux/cpuset.h>
#include <linux/mempolicy.h>
#include <linux/ctype.h>
+#include <linux/stackdepot.h>
#include <linux/debugobjects.h>
#include <linux/kallsyms.h>
#include <linux/kfence.h>
@@ -264,8 +265,8 @@ static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
#define TRACK_ADDRS_COUNT 16
struct track {
unsigned long addr; /* Called from address */
-#ifdef CONFIG_STACKTRACE
- unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
+#ifdef CONFIG_STACKDEPOT
+ depot_stack_handle_t handle;
#endif
int cpu; /* Was running on cpu */
int pid; /* Pid context */
@@ -724,22 +725,19 @@ static struct track *get_track(struct kmem_cache *s, void *object,
return kasan_reset_tag(p + alloc);
}
-static void set_track(struct kmem_cache *s, void *object,
+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_STACKTRACE
+#ifdef CONFIG_STACKDEPOT
+ unsigned long entries[TRACK_ADDRS_COUNT];
unsigned int nr_entries;
- metadata_access_enable();
- nr_entries = stack_trace_save(kasan_reset_tag(p->addrs),
- TRACK_ADDRS_COUNT, 3);
- metadata_access_disable();
-
- if (nr_entries < TRACK_ADDRS_COUNT)
- p->addrs[nr_entries] = 0;
+ nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
+ p->handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
#endif
+
p->addr = addr;
p->cpu = smp_processor_id();
p->pid = current->pid;
@@ -759,20 +757,19 @@ static void init_tracking(struct kmem_cache *s, void *object)
static void print_track(const char *s, struct track *t, unsigned long pr_time)
{
+ depot_stack_handle_t handle __maybe_unused;
+
if (!t->addr)
return;
pr_err("%s in %pS age=%lu cpu=%u pid=%d\n",
s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid);
-#ifdef CONFIG_STACKTRACE
- {
- int i;
- for (i = 0; i < TRACK_ADDRS_COUNT; i++)
- if (t->addrs[i])
- pr_err("\t%pS\n", (void *)t->addrs[i]);
- else
- break;
- }
+#ifdef CONFIG_STACKDEPOT
+ handle = READ_ONCE(t->handle);
+ if (handle)
+ stack_depot_print(handle);
+ else
+ pr_err("object allocation/free stack trace missing\n");
#endif
}
@@ -1532,6 +1529,8 @@ static int __init setup_slub_debug(char *str)
global_slub_debug_changed = true;
} else {
slab_list_specified = true;
+ if (flags & SLAB_STORE_USER)
+ stack_depot_want_early_init = true;
}
}
@@ -1549,6 +1548,8 @@ static int __init setup_slub_debug(char *str)
}
out:
slub_debug = global_flags;
+ if (slub_debug & SLAB_STORE_USER)
+ stack_depot_want_early_init = true;
if (slub_debug != 0 || slub_debug_string)
static_branch_enable(&slub_debug_enabled);
else
@@ -4352,18 +4353,26 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
objp = fixup_red_left(s, objp);
trackp = get_track(s, objp, TRACK_ALLOC);
kpp->kp_ret = (void *)trackp->addr;
-#ifdef CONFIG_STACKTRACE
- for (i = 0; i < KS_ADDRS_COUNT && i < TRACK_ADDRS_COUNT; i++) {
- kpp->kp_stack[i] = (void *)trackp->addrs[i];
- if (!kpp->kp_stack[i])
- break;
- }
+#ifdef CONFIG_STACKDEPOT
+ {
+ depot_stack_handle_t handle;
+ unsigned long *entries;
+ unsigned int nr_entries;
+
+ handle = READ_ONCE(trackp->handle);
+ if (handle) {
+ nr_entries = stack_depot_fetch(handle, &entries);
+ for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
+ kpp->kp_stack[i] = (void *)entries[i];
+ }
- trackp = get_track(s, objp, TRACK_FREE);
- for (i = 0; i < KS_ADDRS_COUNT && i < TRACK_ADDRS_COUNT; i++) {
- kpp->kp_free_stack[i] = (void *)trackp->addrs[i];
- if (!kpp->kp_free_stack[i])
- break;
+ trackp = get_track(s, objp, TRACK_FREE);
+ handle = READ_ONCE(trackp->handle);
+ if (handle) {
+ nr_entries = stack_depot_fetch(handle, &entries);
+ for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
+ kpp->kp_free_stack[i] = (void *)entries[i];
+ }
}
#endif
#endif
--
2.35.1
On 3/4/22 12:25, Hyeonggon Yoo wrote:
> On Wed, Mar 02, 2022 at 06:31:19PM +0100, Vlastimil Babka wrote:
>> From: Oliver Glitta <[email protected]>
>>
>> Many stack traces are similar so there are many similar arrays.
>> Stackdepot saves each unique stack only once.
>>
>> Replace field addrs in struct track with depot_stack_handle_t handle. Use
>> stackdepot to save stack trace.
>>
>> The benefits are smaller memory overhead and possibility to aggregate
>> per-cache statistics in the following patch using the stackdepot handle
>> instead of matching stacks manually.
>>
>> [ [email protected]: rebase to 5.17-rc1 and adjust accordingly ]
>>
>> This was initially merged as commit 788691464c29 and reverted by commit
>> ae14c63a9f20 due to several issues, that should now be fixed.
>> The problem of unconditional memory overhead by stackdepot has been
>> addressed by commit 2dba5eb1c73b ("lib/stackdepot: allow optional init
>> and stack_table allocation by kvmalloc()"), so the dependency on
>> stackdepot will result in extra memory usage only when a slab cache
>> tracking is actually enabled, and not for all CONFIG_SLUB_DEBUG builds.
>> The build failures on some architectures were also addressed, and the
>> reported issue with xfs/433 test did not reproduce on 5.17-rc1 with this
>> patch.
>>
>> Signed-off-by: Oliver Glitta <[email protected]>
>> Signed-off-by: Vlastimil Babka <[email protected]>
>> Cc: David Rientjes <[email protected]>
>> Cc: Christoph Lameter <[email protected]>
>> Cc: Pekka Enberg <[email protected]>
>> Cc: Joonsoo Kim <[email protected]>
...
>> @@ -314,9 +315,13 @@ kmem_cache_create_usercopy(const char *name,
>> * If no slub_debug was enabled globally, the static key is not yet
>> * enabled by setup_slub_debug(). Enable it if the cache is being
>> * created with any of the debugging flags passed explicitly.
>> + * It's also possible that this is the first cache created with
>> + * SLAB_STORE_USER and we should init stack_depot for it.
>> */
>> if (flags & SLAB_DEBUG_FLAGS)
>> static_branch_enable(&slub_debug_enabled);
>> + if (flags & SLAB_STORE_USER && IS_ENABLED(CONFIG_STACKDEPOT))
>> + stack_depot_init();
>> #endif
>
> Is this comment and code still valid in v3?
The comment is still valid, as there can be a kmem_cache_create() call with
SLAB_STORE_USER (in fact there's one in kernel/rcu/rcutorture.c) that's not
covered by the slub_debug parsing.
The code in v3 is just without IS_ENABLED(CONFIG_STACKDEPOT).
>> mutex_lock(&slab_mutex);
>> diff --git a/mm/slub.c b/mm/slub.c
>> index 1fc451f4fe62..42cb79af70a0 100644
>> --- a/mm/slub.c
>> +++ b/mm/slub.c
>> @@ -26,6 +26,7 @@
>> #include <linux/cpuset.h>
>> #include <linux/mempolicy.h>
>> #include <linux/ctype.h>
>> +#include <linux/stackdepot.h>
>> #include <linux/debugobjects.h>
>> #include <linux/kallsyms.h>
>> #include <linux/kfence.h>
>> @@ -264,8 +265,8 @@ static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
>> #define TRACK_ADDRS_COUNT 16
>> struct track {
>> unsigned long addr; /* Called from address */
>> -#ifdef CONFIG_STACKTRACE
>> - unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
>> +#ifdef CONFIG_STACKDEPOT
>> + depot_stack_handle_t handle;
>> #endif
>> int cpu; /* Was running on cpu */
>> int pid; /* Pid context */
>> @@ -724,22 +725,19 @@ static struct track *get_track(struct kmem_cache *s, void *object,
>> return kasan_reset_tag(p + alloc);
>> }
>>
>> -static void set_track(struct kmem_cache *s, void *object,
>> +static void noinline set_track(struct kmem_cache *s, void *object,
>> enum track_item alloc, unsigned long addr)
>> {
>
> noinline for debugging purpose?
> I think it's okay. just a question.
These noinlines make sure that the amount of stack entries are stable and
not subject to inline decisions of compiler...
>> struct track *p = get_track(s, object, alloc);
>>
>> -#ifdef CONFIG_STACKTRACE
>> +#ifdef CONFIG_STACKDEPOT
>> + unsigned long entries[TRACK_ADDRS_COUNT];
>> unsigned int nr_entries;
>>
>> - metadata_access_enable();
>> - nr_entries = stack_trace_save(kasan_reset_tag(p->addrs),
>> - TRACK_ADDRS_COUNT, 3);
>> - metadata_access_disable();
>> -
>> - if (nr_entries < TRACK_ADDRS_COUNT)
>> - p->addrs[nr_entries] = 0;
>> + nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
... so that here '3' removes the correct count of 'internal' stack trace
entries that are not interesting for us.
>> + p->handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
>> #endif
>> +
>> p->addr = addr;
>> p->cpu = smp_processor_id();
>> p->pid = current->pid;
>> @@ -759,20 +757,19 @@ static void init_tracking(struct kmem_cache *s, void *object)
>>
>> static void print_track(const char *s, struct track *t, unsigned long pr_time)
>> {
>> + depot_stack_handle_t handle __maybe_unused;
>> +
>> if (!t->addr)
>> return;
>>
>> pr_err("%s in %pS age=%lu cpu=%u pid=%d\n",
>> s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid);
>> -#ifdef CONFIG_STACKTRACE
>> - {
>> - int i;
>> - for (i = 0; i < TRACK_ADDRS_COUNT; i++)
>> - if (t->addrs[i])
>> - pr_err("\t%pS\n", (void *)t->addrs[i]);
>> - else
>> - break;
>> - }
>> +#ifdef CONFIG_STACKDEPOT
>> + handle = READ_ONCE(t->handle);
>> + if (handle)
>> + stack_depot_print(handle);
>> + else
>> + pr_err("object allocation/free stack trace missing\n");
>> #endif
>> }
>>
>> @@ -1532,6 +1529,8 @@ static int __init setup_slub_debug(char *str)
>> global_slub_debug_changed = true;
>> } else {
>> slab_list_specified = true;
>> + if (flags & SLAB_STORE_USER)
>> + stack_depot_want_early_init = true;
>
> This is updated to stack_depot_want_early_init() in v3.
Yes.
>> }
>> }
>>
>> @@ -1549,6 +1548,8 @@ static int __init setup_slub_debug(char *str)
>> }
>> out:
>> slub_debug = global_flags;
>> + if (slub_debug & SLAB_STORE_USER)
>> + stack_depot_want_early_init = true;
>
> This too.
Yes.
>> if (slub_debug != 0 || slub_debug_string)
>> static_branch_enable(&slub_debug_enabled);
>> else
>> @@ -4352,18 +4353,26 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
>> objp = fixup_red_left(s, objp);
>> trackp = get_track(s, objp, TRACK_ALLOC);
>> kpp->kp_ret = (void *)trackp->addr;
>> -#ifdef CONFIG_STACKTRACE
>> - for (i = 0; i < KS_ADDRS_COUNT && i < TRACK_ADDRS_COUNT; i++) {
>> - kpp->kp_stack[i] = (void *)trackp->addrs[i];
>> - if (!kpp->kp_stack[i])
>> - break;
>> - }
>> +#ifdef CONFIG_STACKDEPOT
>> + {
>> + depot_stack_handle_t handle;
>> + unsigned long *entries;
>> + unsigned int nr_entries;
>> +
>> + handle = READ_ONCE(trackp->handle);
>> + if (handle) {
>> + nr_entries = stack_depot_fetch(handle, &entries);
>> + for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
>> + kpp->kp_stack[i] = (void *)entries[i];
>> + }
>>
>> - trackp = get_track(s, objp, TRACK_FREE);
>> - for (i = 0; i < KS_ADDRS_COUNT && i < TRACK_ADDRS_COUNT; i++) {
>> - kpp->kp_free_stack[i] = (void *)trackp->addrs[i];
>> - if (!kpp->kp_free_stack[i])
>> - break;
>> + trackp = get_track(s, objp, TRACK_FREE);
>> + handle = READ_ONCE(trackp->handle);
>> + if (handle) {
>> + nr_entries = stack_depot_fetch(handle, &entries);
>> + for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
>> + kpp->kp_free_stack[i] = (void *)entries[i];
>> + }
>> }
>> #endif
>> #endif
>> --
>> 2.35.1
>
> Otherwise looks good.
> Reviewed-by: Hyeonggon Yoo <[email protected]>
>
> kmem_dump_obj() and slab error report functionality works fine.
> Tested-by: Hyeonggon Yoo <[email protected]>
Thanks!
On Wed, Mar 02, 2022 at 06:31:19PM +0100, Vlastimil Babka wrote:
> From: Oliver Glitta <[email protected]>
>
> Many stack traces are similar so there are many similar arrays.
> Stackdepot saves each unique stack only once.
>
> Replace field addrs in struct track with depot_stack_handle_t handle. Use
> stackdepot to save stack trace.
>
> The benefits are smaller memory overhead and possibility to aggregate
> per-cache statistics in the following patch using the stackdepot handle
> instead of matching stacks manually.
>
> [ [email protected]: rebase to 5.17-rc1 and adjust accordingly ]
>
> This was initially merged as commit 788691464c29 and reverted by commit
> ae14c63a9f20 due to several issues, that should now be fixed.
> The problem of unconditional memory overhead by stackdepot has been
> addressed by commit 2dba5eb1c73b ("lib/stackdepot: allow optional init
> and stack_table allocation by kvmalloc()"), so the dependency on
> stackdepot will result in extra memory usage only when a slab cache
> tracking is actually enabled, and not for all CONFIG_SLUB_DEBUG builds.
> The build failures on some architectures were also addressed, and the
> reported issue with xfs/433 test did not reproduce on 5.17-rc1 with this
> patch.
>
> Signed-off-by: Oliver Glitta <[email protected]>
> Signed-off-by: Vlastimil Babka <[email protected]>
> Cc: David Rientjes <[email protected]>
> Cc: Christoph Lameter <[email protected]>
> Cc: Pekka Enberg <[email protected]>
> Cc: Joonsoo Kim <[email protected]>
> ---
> init/Kconfig | 1 +
> mm/slab_common.c | 5 ++++
> mm/slub.c | 71 +++++++++++++++++++++++++++---------------------
> 3 files changed, 46 insertions(+), 31 deletions(-)
>
> diff --git a/init/Kconfig b/init/Kconfig
> index e9119bf54b1f..b21dd3a4a106 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -1871,6 +1871,7 @@ config SLUB_DEBUG
> default y
> bool "Enable SLUB debugging support" if EXPERT
> depends on SLUB && SYSFS
> + select STACKDEPOT if STACKTRACE_SUPPORT
> help
> SLUB has extensive debug support features. Disabling these can
> result in significant savings in code size. This also disables
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 23f2ab0713b7..e51d50d03000 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -24,6 +24,7 @@
> #include <asm/tlbflush.h>
> #include <asm/page.h>
> #include <linux/memcontrol.h>
> +#include <linux/stackdepot.h>
>
> #define CREATE_TRACE_POINTS
> #include <trace/events/kmem.h>
> @@ -314,9 +315,13 @@ kmem_cache_create_usercopy(const char *name,
> * If no slub_debug was enabled globally, the static key is not yet
> * enabled by setup_slub_debug(). Enable it if the cache is being
> * created with any of the debugging flags passed explicitly.
> + * It's also possible that this is the first cache created with
> + * SLAB_STORE_USER and we should init stack_depot for it.
> */
> if (flags & SLAB_DEBUG_FLAGS)
> static_branch_enable(&slub_debug_enabled);
> + if (flags & SLAB_STORE_USER && IS_ENABLED(CONFIG_STACKDEPOT))
> + stack_depot_init();
> #endif
Is this comment and code still valid in v3?
> mutex_lock(&slab_mutex);
> diff --git a/mm/slub.c b/mm/slub.c
> index 1fc451f4fe62..42cb79af70a0 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -26,6 +26,7 @@
> #include <linux/cpuset.h>
> #include <linux/mempolicy.h>
> #include <linux/ctype.h>
> +#include <linux/stackdepot.h>
> #include <linux/debugobjects.h>
> #include <linux/kallsyms.h>
> #include <linux/kfence.h>
> @@ -264,8 +265,8 @@ static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
> #define TRACK_ADDRS_COUNT 16
> struct track {
> unsigned long addr; /* Called from address */
> -#ifdef CONFIG_STACKTRACE
> - unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
> +#ifdef CONFIG_STACKDEPOT
> + depot_stack_handle_t handle;
> #endif
> int cpu; /* Was running on cpu */
> int pid; /* Pid context */
> @@ -724,22 +725,19 @@ static struct track *get_track(struct kmem_cache *s, void *object,
> return kasan_reset_tag(p + alloc);
> }
>
> -static void set_track(struct kmem_cache *s, void *object,
> +static void noinline set_track(struct kmem_cache *s, void *object,
> enum track_item alloc, unsigned long addr)
> {
noinline for debugging purpose?
I think it's okay. just a question.
> struct track *p = get_track(s, object, alloc);
>
> -#ifdef CONFIG_STACKTRACE
> +#ifdef CONFIG_STACKDEPOT
> + unsigned long entries[TRACK_ADDRS_COUNT];
> unsigned int nr_entries;
>
> - metadata_access_enable();
> - nr_entries = stack_trace_save(kasan_reset_tag(p->addrs),
> - TRACK_ADDRS_COUNT, 3);
> - metadata_access_disable();
> -
> - if (nr_entries < TRACK_ADDRS_COUNT)
> - p->addrs[nr_entries] = 0;
> + nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
> + p->handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
> #endif
> +
> p->addr = addr;
> p->cpu = smp_processor_id();
> p->pid = current->pid;
> @@ -759,20 +757,19 @@ static void init_tracking(struct kmem_cache *s, void *object)
>
> static void print_track(const char *s, struct track *t, unsigned long pr_time)
> {
> + depot_stack_handle_t handle __maybe_unused;
> +
> if (!t->addr)
> return;
>
> pr_err("%s in %pS age=%lu cpu=%u pid=%d\n",
> s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid);
> -#ifdef CONFIG_STACKTRACE
> - {
> - int i;
> - for (i = 0; i < TRACK_ADDRS_COUNT; i++)
> - if (t->addrs[i])
> - pr_err("\t%pS\n", (void *)t->addrs[i]);
> - else
> - break;
> - }
> +#ifdef CONFIG_STACKDEPOT
> + handle = READ_ONCE(t->handle);
> + if (handle)
> + stack_depot_print(handle);
> + else
> + pr_err("object allocation/free stack trace missing\n");
> #endif
> }
>
> @@ -1532,6 +1529,8 @@ static int __init setup_slub_debug(char *str)
> global_slub_debug_changed = true;
> } else {
> slab_list_specified = true;
> + if (flags & SLAB_STORE_USER)
> + stack_depot_want_early_init = true;
This is updated to stack_depot_want_early_init() in v3.
> }
> }
>
> @@ -1549,6 +1548,8 @@ static int __init setup_slub_debug(char *str)
> }
> out:
> slub_debug = global_flags;
> + if (slub_debug & SLAB_STORE_USER)
> + stack_depot_want_early_init = true;
This too.
> if (slub_debug != 0 || slub_debug_string)
> static_branch_enable(&slub_debug_enabled);
> else
> @@ -4352,18 +4353,26 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
> objp = fixup_red_left(s, objp);
> trackp = get_track(s, objp, TRACK_ALLOC);
> kpp->kp_ret = (void *)trackp->addr;
> -#ifdef CONFIG_STACKTRACE
> - for (i = 0; i < KS_ADDRS_COUNT && i < TRACK_ADDRS_COUNT; i++) {
> - kpp->kp_stack[i] = (void *)trackp->addrs[i];
> - if (!kpp->kp_stack[i])
> - break;
> - }
> +#ifdef CONFIG_STACKDEPOT
> + {
> + depot_stack_handle_t handle;
> + unsigned long *entries;
> + unsigned int nr_entries;
> +
> + handle = READ_ONCE(trackp->handle);
> + if (handle) {
> + nr_entries = stack_depot_fetch(handle, &entries);
> + for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
> + kpp->kp_stack[i] = (void *)entries[i];
> + }
>
> - trackp = get_track(s, objp, TRACK_FREE);
> - for (i = 0; i < KS_ADDRS_COUNT && i < TRACK_ADDRS_COUNT; i++) {
> - kpp->kp_free_stack[i] = (void *)trackp->addrs[i];
> - if (!kpp->kp_free_stack[i])
> - break;
> + trackp = get_track(s, objp, TRACK_FREE);
> + handle = READ_ONCE(trackp->handle);
> + if (handle) {
> + nr_entries = stack_depot_fetch(handle, &entries);
> + for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
> + kpp->kp_free_stack[i] = (void *)entries[i];
> + }
> }
> #endif
> #endif
> --
> 2.35.1
Otherwise looks good.
Reviewed-by: Hyeonggon Yoo <[email protected]>
kmem_dump_obj() and slab error report functionality works fine.
Tested-by: Hyeonggon Yoo <[email protected]>
--
Thank you, You are awesome!
Hyeonggon :-)