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Commit 489506a2 authored by Hongchen Zhang's avatar Hongchen Zhang Committed by Greg Kroah-Hartman
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PM: hibernate: Enforce ordering during image compression/decompression 



commit 71cd7e80cfde548959952eac7063aeaea1f2e1c6 upstream.

An S4 (suspend to disk) test on the LoongArch 3A6000 platform sometimes
fails with the following error messaged in the dmesg log:

	Invalid LZO compressed length

That happens because when compressing/decompressing the image, the
synchronization between the control thread and the compress/decompress/crc
thread is based on a relaxed ordering interface, which is unreliable, and the
following situation may occur:

CPU 0					CPU 1
save_image_lzo				lzo_compress_threadfn
					  atomic_set(&d->stop, 1);
  atomic_read(&data[thr].stop)
  data[thr].cmp = data[thr].cmp_len;
	  				  WRITE data[thr].cmp_len

Then CPU0 gets a stale cmp_len and writes it to disk. During resume from S4,
wrong cmp_len is loaded.

To maintain data consistency between the two threads, use the acquire/release
variants of atomic set and read operations.

Fixes: 081a9d04 ("PM / Hibernate: Improve performance of LZO/plain hibernation, checksum image")
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: default avatarHongchen Zhang <zhanghongchen@loongson.cn>
Co-developed-by: default avatarWeihao Li <liweihao@loongson.cn>
Signed-off-by: default avatarWeihao Li <liweihao@loongson.cn>
[ rjw: Subject rewrite and changelog edits ]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 15a67115

kernel/power/swap.c

+19 −19
Original line number Diff line number Diff line
@@ -596,11 +596,11 @@ static int crc32_threadfn(void *data) 
	unsigned i;



	while (1) {

		wait_event(d->go, atomic_read(&d->ready) ||

		wait_event(d->go, atomic_read_acquire(&d->ready) ||

		                  kthread_should_stop());

		if (kthread_should_stop()) {

			d->thr = NULL;

			atomic_set(&d->stop, 1);

			atomic_set_release(&d->stop, 1);

			wake_up(&d->done);

			break;

		}
@@ -609,7 +609,7 @@ static int crc32_threadfn(void *data) 
		for (i = 0; i < d->run_threads; i++)

			*d->crc32 = crc32_le(*d->crc32,

			                     d->unc[i], *d->unc_len[i]);

		atomic_set(&d->stop, 1);

		atomic_set_release(&d->stop, 1);

		wake_up(&d->done);

	}

	return 0;
@@ -639,12 +639,12 @@ static int lzo_compress_threadfn(void *data) 
	struct cmp_data *d = data;



	while (1) {

		wait_event(d->go, atomic_read(&d->ready) ||

		wait_event(d->go, atomic_read_acquire(&d->ready) ||

		                  kthread_should_stop());

		if (kthread_should_stop()) {

			d->thr = NULL;

			d->ret = -1;

			atomic_set(&d->stop, 1);

			atomic_set_release(&d->stop, 1);

			wake_up(&d->done);

			break;

		}
@@ -653,7 +653,7 @@ static int lzo_compress_threadfn(void *data) 
		d->ret = lzo1x_1_compress(d->unc, d->unc_len,

		                          d->cmp + LZO_HEADER, &d->cmp_len,

		                          d->wrk);

		atomic_set(&d->stop, 1);

		atomic_set_release(&d->stop, 1);

		wake_up(&d->done);

	}

	return 0;
@@ -791,7 +791,7 @@ static int save_image_lzo(struct swap_map_handle *handle, 


			data[thr].unc_len = off;



			atomic_set(&data[thr].ready, 1);

			atomic_set_release(&data[thr].ready, 1);

			wake_up(&data[thr].go);

		}
@@ -799,12 +799,12 @@ static int save_image_lzo(struct swap_map_handle *handle, 
			break;



		crc->run_threads = thr;

		atomic_set(&crc->ready, 1);

		atomic_set_release(&crc->ready, 1);

		wake_up(&crc->go);



		for (run_threads = thr, thr = 0; thr < run_threads; thr++) {

			wait_event(data[thr].done,

			           atomic_read(&data[thr].stop));

				atomic_read_acquire(&data[thr].stop));

			atomic_set(&data[thr].stop, 0);



			ret = data[thr].ret;
@@ -843,7 +843,7 @@ static int save_image_lzo(struct swap_map_handle *handle, 
			}

		}



		wait_event(crc->done, atomic_read(&crc->stop));

		wait_event(crc->done, atomic_read_acquire(&crc->stop));

		atomic_set(&crc->stop, 0);

	}
@@ -1124,12 +1124,12 @@ static int lzo_decompress_threadfn(void *data) 
	struct dec_data *d = data;



	while (1) {

		wait_event(d->go, atomic_read(&d->ready) ||

		wait_event(d->go, atomic_read_acquire(&d->ready) ||

		                  kthread_should_stop());

		if (kthread_should_stop()) {

			d->thr = NULL;

			d->ret = -1;

			atomic_set(&d->stop, 1);

			atomic_set_release(&d->stop, 1);

			wake_up(&d->done);

			break;

		}
@@ -1142,7 +1142,7 @@ static int lzo_decompress_threadfn(void *data) 
			flush_icache_range((unsigned long)d->unc,

					   (unsigned long)d->unc + d->unc_len);



		atomic_set(&d->stop, 1);

		atomic_set_release(&d->stop, 1);

		wake_up(&d->done);

	}

	return 0;
@@ -1330,7 +1330,7 @@ static int load_image_lzo(struct swap_map_handle *handle, 
		}



		if (crc->run_threads) {

			wait_event(crc->done, atomic_read(&crc->stop));

			wait_event(crc->done, atomic_read_acquire(&crc->stop));

			atomic_set(&crc->stop, 0);

			crc->run_threads = 0;

		}
@@ -1366,7 +1366,7 @@ static int load_image_lzo(struct swap_map_handle *handle, 
					pg = 0;

			}



			atomic_set(&data[thr].ready, 1);

			atomic_set_release(&data[thr].ready, 1);

			wake_up(&data[thr].go);

		}
@@ -1385,7 +1385,7 @@ static int load_image_lzo(struct swap_map_handle *handle, 


		for (run_threads = thr, thr = 0; thr < run_threads; thr++) {

			wait_event(data[thr].done,

			           atomic_read(&data[thr].stop));

				atomic_read_acquire(&data[thr].stop));

			atomic_set(&data[thr].stop, 0);



			ret = data[thr].ret;
@@ -1416,7 +1416,7 @@ static int load_image_lzo(struct swap_map_handle *handle, 
				ret = snapshot_write_next(snapshot);

				if (ret <= 0) {

					crc->run_threads = thr + 1;

					atomic_set(&crc->ready, 1);

					atomic_set_release(&crc->ready, 1);

					wake_up(&crc->go);

					goto out_finish;

				}
@@ -1424,13 +1424,13 @@ static int load_image_lzo(struct swap_map_handle *handle, 
		}



		crc->run_threads = thr;

		atomic_set(&crc->ready, 1);

		atomic_set_release(&crc->ready, 1);

		wake_up(&crc->go);

	}



out_finish:

	if (crc->run_threads) {

		wait_event(crc->done, atomic_read(&crc->stop));

		wait_event(crc->done, atomic_read_acquire(&crc->stop));

		atomic_set(&crc->stop, 0);

	}

	stop = ktime_get();