mm,page_owner: fix recursion
Prior to217b2119b9
("mm,page_owner: implement the tracking of the stacks count") the only place where page_owner could potentially go into recursion due to its need of allocating more memory was in save_stack(), which ends up calling into stackdepot code with the possibility of allocating memory. We made sure to guard against that by signaling that the current task was already in page_owner code, so in case a recursion attempt was made, we could catch that and return dummy_handle. After above commit, a new place in page_owner code was introduced where we could allocate memory, meaning we could go into recursion would we take that path. Make sure to signal that we are in page_owner in that codepath as well. Move the guard code into two helpers {un}set_current_in_page_owner() and use them prior to calling in the two functions that might allocate memory. Link: https://lkml.kernel.org/r/20240315222610.6870-1-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Fixes:217b2119b9
("mm,page_owner: implement the tracking of the stacks count") Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Marco Elver <elver@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
parent
3290032466
commit
7844c01472
|
@ -54,6 +54,22 @@ static depot_stack_handle_t early_handle;
|
||||||
|
|
||||||
static void init_early_allocated_pages(void);
|
static void init_early_allocated_pages(void);
|
||||||
|
|
||||||
|
static inline void set_current_in_page_owner(void)
|
||||||
|
{
|
||||||
|
/*
|
||||||
|
* Avoid recursion.
|
||||||
|
*
|
||||||
|
* We might need to allocate more memory from page_owner code, so make
|
||||||
|
* sure to signal it in order to avoid recursion.
|
||||||
|
*/
|
||||||
|
current->in_page_owner = 1;
|
||||||
|
}
|
||||||
|
|
||||||
|
static inline void unset_current_in_page_owner(void)
|
||||||
|
{
|
||||||
|
current->in_page_owner = 0;
|
||||||
|
}
|
||||||
|
|
||||||
static int __init early_page_owner_param(char *buf)
|
static int __init early_page_owner_param(char *buf)
|
||||||
{
|
{
|
||||||
int ret = kstrtobool(buf, &page_owner_enabled);
|
int ret = kstrtobool(buf, &page_owner_enabled);
|
||||||
|
@ -133,23 +149,16 @@ static noinline depot_stack_handle_t save_stack(gfp_t flags)
|
||||||
depot_stack_handle_t handle;
|
depot_stack_handle_t handle;
|
||||||
unsigned int nr_entries;
|
unsigned int nr_entries;
|
||||||
|
|
||||||
/*
|
|
||||||
* Avoid recursion.
|
|
||||||
*
|
|
||||||
* Sometimes page metadata allocation tracking requires more
|
|
||||||
* memory to be allocated:
|
|
||||||
* - when new stack trace is saved to stack depot
|
|
||||||
*/
|
|
||||||
if (current->in_page_owner)
|
if (current->in_page_owner)
|
||||||
return dummy_handle;
|
return dummy_handle;
|
||||||
current->in_page_owner = 1;
|
|
||||||
|
|
||||||
|
set_current_in_page_owner();
|
||||||
nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 2);
|
nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 2);
|
||||||
handle = stack_depot_save(entries, nr_entries, flags);
|
handle = stack_depot_save(entries, nr_entries, flags);
|
||||||
if (!handle)
|
if (!handle)
|
||||||
handle = failure_handle;
|
handle = failure_handle;
|
||||||
|
unset_current_in_page_owner();
|
||||||
|
|
||||||
current->in_page_owner = 0;
|
|
||||||
return handle;
|
return handle;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -164,9 +173,13 @@ static void add_stack_record_to_list(struct stack_record *stack_record,
|
||||||
gfp_mask &= (GFP_ATOMIC | GFP_KERNEL);
|
gfp_mask &= (GFP_ATOMIC | GFP_KERNEL);
|
||||||
gfp_mask |= __GFP_NOWARN;
|
gfp_mask |= __GFP_NOWARN;
|
||||||
|
|
||||||
|
set_current_in_page_owner();
|
||||||
stack = kmalloc(sizeof(*stack), gfp_mask);
|
stack = kmalloc(sizeof(*stack), gfp_mask);
|
||||||
if (!stack)
|
if (!stack) {
|
||||||
|
unset_current_in_page_owner();
|
||||||
return;
|
return;
|
||||||
|
}
|
||||||
|
unset_current_in_page_owner();
|
||||||
|
|
||||||
stack->stack_record = stack_record;
|
stack->stack_record = stack_record;
|
||||||
stack->next = NULL;
|
stack->next = NULL;
|
||||||
|
|
Loading…
Reference in New Issue