Commit a1b2289c authored by Sherry Yang's avatar Sherry Yang Committed by Linus Torvalds
Browse files

android: binder: drop lru lock in isolate callback 

Drop the global lru lock in isolate callback before calling
zap_page_range which calls cond_resched, and re-acquire the global lru
lock before returning.  Also change return code to LRU_REMOVED_RETRY.

Use mmput_async when fail to acquire mmap sem in an atomic context.

Fix "BUG: sleeping function called from invalid context"
errors when CONFIG_DEBUG_ATOMIC_SLEEP is enabled.

Also restore mmput_async, which was initially introduced in commit
ec8d7c14 ("mm, oom_reaper: do not mmput synchronously from the oom
reaper context"), and was removed in commit 21292580 ("mm: oom: let
oom_reap_task and exit_mmap run concurrently").

Link: http://lkml.kernel.org/r/20170914182231.90908-1-sherryy@android.com


Fixes: f2517eb7 ("android: binder: Add global lru shrinker to binder")
Signed-off-by: default avatarSherry Yang <sherryy@android.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reported-by: default avatarKyle Yan <kyan@codeaurora.org>
Acked-by: default avatarArve Hjønnevåg <arve@android.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Martijn Coenen <maco@google.com>
Cc: Todd Kjos <tkjos@google.com>
Cc: Riley Andrews <riandrews@android.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Hoeun Ryu <hoeun.ryu@gmail.com>
Cc: Christopher Lameter <cl@linux.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3f2eb028

drivers/android/binder_alloc.c

+12 −6
Original line number Diff line number Diff line
@@ -913,6 +913,7 @@ enum lru_status binder_alloc_free_page(struct list_head *item, 
	struct binder_alloc *alloc;

	uintptr_t page_addr;

	size_t index;

	struct vm_area_struct *vma;



	alloc = page->alloc;

	if (!mutex_trylock(&alloc->mutex))
@@ -923,16 +924,22 @@ enum lru_status binder_alloc_free_page(struct list_head *item, 


	index = page - alloc->pages;

	page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;

	if (alloc->vma) {

	vma = alloc->vma;

	if (vma) {

		mm = get_task_mm(alloc->tsk);

		if (!mm)

			goto err_get_task_mm_failed;

		if (!down_write_trylock(&mm->mmap_sem))

			goto err_down_write_mmap_sem_failed;

	}



	list_lru_isolate(lru, item);

	spin_unlock(lock);



	if (vma) {

		trace_binder_unmap_user_start(alloc, index);



		zap_page_range(alloc->vma,

		zap_page_range(vma,

			       page_addr + alloc->user_buffer_offset,

			       PAGE_SIZE);
@@ -950,13 +957,12 @@ enum lru_status binder_alloc_free_page(struct list_head *item, 


	trace_binder_unmap_kernel_end(alloc, index);



	list_lru_isolate(lru, item);



	spin_lock(lock);

	mutex_unlock(&alloc->mutex);

	return LRU_REMOVED;

	return LRU_REMOVED_RETRY;



err_down_write_mmap_sem_failed:

	mmput(mm);

	mmput_async(mm);

err_get_task_mm_failed:

err_page_already_freed:

	mutex_unlock(&alloc->mutex);

include/linux/sched/mm.h

+6 −0
Original line number Diff line number Diff line
@@ -84,6 +84,12 @@ static inline bool mmget_not_zero(struct mm_struct *mm) 


/* mmput gets rid of the mappings and all user-space */

extern void mmput(struct mm_struct *);

#ifdef CONFIG_MMU

/* same as above but performs the slow path from the async context. Can

 * be called from the atomic context as well

 */

void mmput_async(struct mm_struct *);

#endif



/* Grab a reference to a task's mm, if it is not already going away */

extern struct mm_struct *get_task_mm(struct task_struct *task);

kernel/fork.c

+18 −0
Original line number Diff line number Diff line
@@ -946,6 +946,24 @@ void mmput(struct mm_struct *mm) 
}

EXPORT_SYMBOL_GPL(mmput);



#ifdef CONFIG_MMU

static void mmput_async_fn(struct work_struct *work)

{

	struct mm_struct *mm = container_of(work, struct mm_struct,

					    async_put_work);



	__mmput(mm);

}



void mmput_async(struct mm_struct *mm)

{

	if (atomic_dec_and_test(&mm->mm_users)) {

		INIT_WORK(&mm->async_put_work, mmput_async_fn);

		schedule_work(&mm->async_put_work);

	}

}

#endif



/**

 * set_mm_exe_file - change a reference to the mm's executable file

 *

CRA Git | Maintained and supported by SUSTech CRA and CCSE