[LTP] [PATCH 3/3] fanotify24: add mmap() and user page fault to test

[Jan Kara]

On Wed 19-03-25 20:27:42, Amir Goldstein wrote:
> Commit 066e053fe208a ("fsnotify: add pre-content hooks on mmap()")
> in 6.14-rc7 added a pre-content hooh in mmap() before the final release
> of the fsnotify pre-content event feature.
> 
> To test pre-content hook on mmap(), increase the size of the test file
> to 101 pages use mmap() to setup a buffer from the end of the test file.
> 
> Change some of the test cases to allow the write() and use this buffer
> as the input buffer to write(), which tests deadlock avoidance by
> suppresing pre-content hook on user page faults.
> 
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  .../kernel/syscalls/fanotify/fanotify24.c     | 41 ++++++++++++++++---
>  1 file changed, 35 insertions(+), 6 deletions(-)
> 
> diff --git a/testcases/kernel/syscalls/fanotify/fanotify24.c b/testcases/kernel/syscalls/fanotify/fanotify24.c
> index 2d2479b39..3a76f2c1b 100644
> --- a/testcases/kernel/syscalls/fanotify/fanotify24.c
> +++ b/testcases/kernel/syscalls/fanotify/fanotify24.c
> @@ -46,6 +46,7 @@
>  static char fname[BUF_SIZE];
>  static char buf[BUF_SIZE];
>  static volatile int fd_notify;
> +static size_t page_sz;
>  
>  static pid_t child_pid;
>  
> @@ -68,7 +69,8 @@ static struct tcase {
>  		FAN_OPEN_PERM | FAN_PRE_ACCESS,
>  		{
>  			{FAN_OPEN_PERM, FAN_ALLOW},
> -			{FAN_PRE_ACCESS, FAN_DENY},
> +			{FAN_PRE_ACCESS, FAN_ALLOW},
> +			{FAN_PRE_ACCESS, FAN_ALLOW},
>  			{FAN_PRE_ACCESS, FAN_DENY_ERRNO(EIO)},
>  			{FAN_OPEN_PERM, FAN_DENY_ERRNO(EBUSY)}
>  		}
> @@ -78,6 +80,7 @@ static struct tcase {
>  		INIT_FANOTIFY_MARK_TYPE(INODE),
>  		FAN_PRE_ACCESS | FAN_OPEN_EXEC_PERM,
>  		{
> +			{FAN_PRE_ACCESS, FAN_ALLOW},
>  			{FAN_PRE_ACCESS, FAN_DENY},
>  			{FAN_PRE_ACCESS, FAN_DENY_ERRNO(EIO)},
>  			{FAN_OPEN_EXEC_PERM, FAN_DENY_ERRNO(EBUSY)}
> @@ -89,7 +92,8 @@ static struct tcase {
>  		FAN_OPEN_PERM | FAN_PRE_ACCESS,
>  		{
>  			{FAN_OPEN_PERM, FAN_ALLOW},
> -			{FAN_PRE_ACCESS, FAN_DENY},
> +			{FAN_PRE_ACCESS, FAN_ALLOW},
> +			{FAN_PRE_ACCESS, FAN_ALLOW},
>  			{FAN_PRE_ACCESS, FAN_DENY_ERRNO(EIO)},
>  			{FAN_OPEN_PERM, FAN_DENY_ERRNO(EBUSY)}
>  		}
> @@ -99,6 +103,7 @@ static struct tcase {
>  		INIT_FANOTIFY_MARK_TYPE(MOUNT),
>  		FAN_PRE_ACCESS | FAN_OPEN_EXEC_PERM,
>  		{
> +			{FAN_PRE_ACCESS, FAN_ALLOW},
>  			{FAN_PRE_ACCESS, FAN_DENY},
>  			{FAN_PRE_ACCESS, FAN_DENY_ERRNO(EIO)},
>  			{FAN_OPEN_EXEC_PERM, FAN_DENY_ERRNO(EBUSY)}
> @@ -110,7 +115,8 @@ static struct tcase {
>  		FAN_OPEN_PERM | FAN_PRE_ACCESS,
>  		{
>  			{FAN_OPEN_PERM, FAN_ALLOW},
> -			{FAN_PRE_ACCESS, FAN_DENY},
> +			{FAN_PRE_ACCESS, FAN_ALLOW},
> +			{FAN_PRE_ACCESS, FAN_ALLOW},
>  			{FAN_PRE_ACCESS, FAN_DENY_ERRNO(EIO)},
>  			{FAN_OPEN_PERM, FAN_DENY_ERRNO(EBUSY)}
>  		}
> @@ -120,6 +126,7 @@ static struct tcase {
>  		INIT_FANOTIFY_MARK_TYPE(FILESYSTEM),
>  		FAN_PRE_ACCESS | FAN_OPEN_EXEC_PERM,
>  		{
> +			{FAN_PRE_ACCESS, FAN_ALLOW},
>  			{FAN_PRE_ACCESS, FAN_DENY},
>  			{FAN_PRE_ACCESS, FAN_DENY_ERRNO(EIO)},
>  			{FAN_OPEN_EXEC_PERM, FAN_DENY_ERRNO(EBUSY)}
> @@ -130,6 +137,7 @@ static struct tcase {
>  		INIT_FANOTIFY_MARK_TYPE(PARENT),
>  		FAN_PRE_ACCESS | FAN_OPEN_EXEC_PERM | FAN_EVENT_ON_CHILD,
>  		{
> +			{FAN_PRE_ACCESS, FAN_ALLOW},
>  			{FAN_PRE_ACCESS, FAN_DENY},
>  			{FAN_PRE_ACCESS, FAN_DENY},
>  			{FAN_OPEN_EXEC_PERM, FAN_DENY}
> @@ -169,6 +177,7 @@ static int expected_errno(unsigned int response)
>  static void generate_events(struct tcase *tc)
>  {
>  	int fd;
> +	char *addr;
>  	char *const argv[] = {FILE_EXEC_PATH, NULL};
>  	struct event *event = tc->event_set;
>  	int exp_ret, exp_errno = 0;
> @@ -186,8 +195,25 @@ static void generate_events(struct tcase *tc)
>  
>  	exp_ret = exp_errno ? -1 : 1;
>  	errno = 0;
> -	/* FAN_PRE_ACCESS events are reported also on write */
> -	if (write(fd, fname, 1) != exp_ret || errno != exp_errno) {
> +	/*
> +	 * FAN_PRE_ACCESS events are reported on map() and write(), but should
> +	 * not be reported when faulting in the user page at offset page_sz*100
> +	 * that is used as an input buffer to the write() syscall.
> +	 */
> +	addr = SAFE_MMAP(NULL, page_sz, PROT_READ, MAP_PRIVATE, fd, page_sz*100);
> +	if (!addr || errno != exp_errno) {
> +		tst_res(TFAIL, "mmap() got errno %d (expected %d)", errno, exp_errno);
> +		exit(3);
> +	} else if (errno == exp_errno) {
> +		tst_res(TINFO, "mmap() got errno %d as expected", errno);
> +	}
> +
> +	exp_errno = expected_errno(event->response);
> +	event++;
> +
> +	exp_ret = exp_errno ? -1 : 1;
> +	errno = 0;
> +	if (write(fd, addr, 1) != exp_ret || errno != exp_errno) {
>  		tst_res(TFAIL, "write() got errno %d (expected %d)", errno, exp_errno);
>  		exit(3);
>  	} else if (errno == exp_errno) {
> @@ -199,7 +225,7 @@ static void generate_events(struct tcase *tc)
>  	exp_errno = expected_errno(event->response);
>  	event++;
>  
> -	exp_ret = exp_errno ? -1 : 1;
> +	exp_ret = exp_errno ? -1 : BUF_SIZE;
>  	errno = 0;
>  	if (read(fd, buf, BUF_SIZE) != exp_ret || errno != exp_errno) {
>  		tst_res(TFAIL, "read() got errno %d (expected %d)", errno, exp_errno);
> @@ -449,8 +475,11 @@ static void test_fanotify(unsigned int n)
>  
>  static void setup(void)
>  {
> +	page_sz = getpagesize();
> +
>  	sprintf(fname, MOUNT_PATH"/fname_%d", getpid());
>  	SAFE_FILE_PRINTF(fname, "1");
> +	SAFE_TRUNCATE(fname, page_sz*101);
>  
>  	REQUIRE_FANOTIFY_EVENTS_SUPPORTED_ON_FS(FAN_CLASS_PRE_CONTENT, FAN_MARK_FILESYSTEM,
>  						FAN_PRE_ACCESS, fname);
> -- 
> 2.34.1
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR