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Commit 759d52ee authored by Paul Lawrence's avatar Paul Lawrence
Browse files

ANDROID: Incremental fs: Fix crash polling 0 size read_log 



When read log is 0 sized, we still need to init the wait queue to avoid
kernel panics if someone does decide to poll on the read log.

Test: Added test for this condition, incfs_test crashes
	With fix, incfs_test doesn't crash
Signed-off-by: default avatarPaul Lawrence <paullawrence@google.com>
Bug: 152909243
Change-Id: Ic3250523bb7ddb1839f8e95852c17103e5ffb782
parent 21b6d8c9

fs/incfs/data_mgmt.c

+1 −1
Original line number Diff line number Diff line
@@ -34,13 +34,13 @@ struct mount_info *incfs_alloc_mount_info(struct super_block *sb, 
	mutex_init(&mi->mi_dir_struct_mutex);

	mutex_init(&mi->mi_pending_reads_mutex);

	init_waitqueue_head(&mi->mi_pending_reads_notif_wq);

	init_waitqueue_head(&mi->mi_log.ml_notif_wq);

	INIT_LIST_HEAD(&mi->mi_reads_list_head);



	if (options->read_log_pages != 0) {

		size_t buf_size = PAGE_SIZE * options->read_log_pages;



		spin_lock_init(&mi->mi_log.rl_writer_lock);

		init_waitqueue_head(&mi->mi_log.ml_notif_wq);



		mi->mi_log.rl_size = buf_size / sizeof(*mi->mi_log.rl_ring_buf);

		mi->mi_log.rl_ring_buf = kzalloc(buf_size, GFP_NOFS);

tools/testing/selftests/filesystems/incfs/incfs_test.c

+48 −7
Original line number Diff line number Diff line
@@ -1930,7 +1930,8 @@ static int hash_tree_test(char *mount_dir) 
	return TEST_FAILURE;

}



static int validate_logs(char *mount_dir, int log_fd, struct test_file *file)

static int validate_logs(char *mount_dir, int log_fd, struct test_file *file,

			 bool no_rlog)

{

	uint8_t data[INCFS_DATA_FILE_BLOCK_SIZE];

	struct incfs_pending_read_info prs[100] = {};
@@ -1957,7 +1958,19 @@ static int validate_logs(char *mount_dir, int log_fd, struct test_file *file) 
			goto failure;

	}



	read_count = wait_for_pending_reads(log_fd, 0, prs, prs_size);

	read_count =

		wait_for_pending_reads(log_fd, no_rlog ? 10 : 0, prs, prs_size);

	if (no_rlog) {

		if (read_count == 0)

			goto success;

		if (read_count < 0)

			ksft_print_msg("Error reading logged reads %s.\n",

				       strerror(-read_count));

		else

			ksft_print_msg("Somehow read empty logs.\n");

		goto failure;

	}



	if (read_count < 0) {

		ksft_print_msg("Error reading logged reads %s.\n",

			       strerror(-read_count));
@@ -2001,6 +2014,8 @@ static int validate_logs(char *mount_dir, int log_fd, struct test_file *file) 
			goto failure;

		}

	}



success:

	close(fd);

	return TEST_SUCCESS;
@@ -2029,7 +2044,7 @@ static int read_log_test(char *mount_dir) 
		goto failure;



	log_fd = open_log_file(mount_dir);

	if (cmd_fd < 0)

	if (log_fd < 0)

		ksft_print_msg("Can't open log file.\n");



	/* Write data. */
@@ -2048,7 +2063,7 @@ static int read_log_test(char *mount_dir) 
	for (i = 0; i < file_num; i++) {

		struct test_file *file = &test.files[i];



		if (validate_logs(mount_dir, log_fd, file))

		if (validate_logs(mount_dir, log_fd, file, false))

			goto failure;

	}
@@ -2069,20 +2084,46 @@ static int read_log_test(char *mount_dir) 
		goto failure;



	log_fd = open_log_file(mount_dir);

	if (cmd_fd < 0)

	if (log_fd < 0)

		ksft_print_msg("Can't open log file.\n");



	/* Validate data again */

	for (i = 0; i < file_num; i++) {

		struct test_file *file = &test.files[i];



		if (validate_logs(mount_dir, log_fd, file))

		if (validate_logs(mount_dir, log_fd, file, false))

			goto failure;

	}



	/* Final unmount */

	/*

	 * Unmount and mount again with no read log to make sure poll

	 * doesn't crash

	 */

	close(cmd_fd);

	close(log_fd);

	if (umount(mount_dir) != 0) {

		print_error("Can't unmout FS");

		goto failure;

	}



	if (mount_fs_opt(mount_dir, backing_dir, "readahead=0,rlog_pages=0") !=

	    0)

		goto failure;



	log_fd = open_log_file(mount_dir);

	if (log_fd < 0)

		ksft_print_msg("Can't open log file.\n");



	/* Validate data again - note should fail this time */

	for (i = 0; i < file_num; i++) {

		struct test_file *file = &test.files[i];



		if (validate_logs(mount_dir, log_fd, file, true))

			goto failure;

	}



	/* Final unmount */

	close(log_fd);

	free(backing_dir);

	if (umount(mount_dir) != 0) {

		print_error("Can't unmout FS");