Unverified Commit 4e576094 authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
Browse files

!11007 mm: avoid overflows in dirty throttling logic 

Merge Pull Request from: @ci-robot 
 
PR sync from: Wupeng Ma <mawupeng1@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/BHYXIOPCDTSF3WZATGDEN3EMPEPDPLTW/ 
 
https://gitee.com/src-openeuler/kernel/issues/IAGZUU 
 
Link:https://gitee.com/openeuler/kernel/pulls/11007

 

Reviewed-by: default avatarYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: default avatarYang Yingliang <yangyingliang@huawei.com>
parents c654da7d 46a3b01e

mm/page-writeback.c

+26 −4
Original line number Diff line number Diff line
@@ -427,13 +427,20 @@ static void domain_dirty_limits(struct dirty_throttle_control *dtc) 
	else

		bg_thresh = (bg_ratio * available_memory) / PAGE_SIZE;



	if (bg_thresh >= thresh)

		bg_thresh = thresh / 2;

	tsk = current;

	if (rt_task(tsk)) {

		bg_thresh += bg_thresh / 4 + global_wb_domain.dirty_limit / 32;

		thresh += thresh / 4 + global_wb_domain.dirty_limit / 32;

	}

	/*

	 * Dirty throttling logic assumes the limits in page units fit into

	 * 32-bits. This gives 16TB dirty limits max which is hopefully enough.

	 */

	if (thresh > UINT_MAX)

		thresh = UINT_MAX;

	/* This makes sure bg_thresh is within 32-bits as well */

	if (bg_thresh >= thresh)

		bg_thresh = thresh / 2;

	dtc->thresh = thresh;

	dtc->bg_thresh = bg_thresh;
@@ -483,7 +490,11 @@ static unsigned long node_dirty_limit(struct pglist_data *pgdat) 
	if (rt_task(tsk))

		dirty += dirty / 4;



	return dirty;

	/*

	 * Dirty throttling logic assumes the limits in page units fit into

	 * 32-bits. This gives 16TB dirty limits max which is hopefully enough.

	 */

	return min_t(unsigned long, dirty, UINT_MAX);

}



/**
@@ -519,10 +530,17 @@ int dirty_background_bytes_handler(struct ctl_table *table, int write, 
		void *buffer, size_t *lenp, loff_t *ppos)

{

	int ret;

	unsigned long old_bytes = dirty_background_bytes;



	ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);

	if (ret == 0 && write)

	if (ret == 0 && write) {

		if (DIV_ROUND_UP(dirty_background_bytes, PAGE_SIZE) >

								UINT_MAX) {

			dirty_background_bytes = old_bytes;

			return -ERANGE;

		}

		dirty_background_ratio = 0;

	}

	return ret;

}
@@ -548,6 +566,10 @@ int dirty_bytes_handler(struct ctl_table *table, int write, 


	ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);

	if (ret == 0 && write && vm_dirty_bytes != old_bytes) {

		if (DIV_ROUND_UP(vm_dirty_bytes, PAGE_SIZE) > UINT_MAX) {

			vm_dirty_bytes = old_bytes;

			return -ERANGE;

		}

		writeback_set_ratelimit();

		vm_dirty_ratio = 0;

	}