FAILED: patch "[PATCH] io_uring: statx must grab the file table for valid fd" failed to apply to 5.6-stable tree

PATCH [email protected] 2 participants 4 messages May 4, 2020

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[email protected]

author maintainer

2020-05-04 09:56 UTC #0 lore raw

The patch below does not apply to the 5.6-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 5b0bbee4732cbd58aa98213d4c11a366356bba3d Mon Sep 17 00:00:00 2001
From: Jens Axboe <[email protected]>
Date: Mon, 27 Apr 2020 10:41:22 -0600
Subject: [PATCH] io_uring: statx must grab the file table for valid fd

Clay reports that OP_STATX fails for a test case with a valid fd and empty path:

-- Test 0: statx:fd 3: SUCCEED, file mode 100755
-- Test 1: statx:path ./uring_statx: SUCCEED, file mode 100755 -- Test 2: io_uring_statx:fd 3: FAIL, errno 9: Bad file descriptor -- Test 3: io_uring_statx:path ./uring_statx: SUCCEED, file mode 100755

This is due to statx not grabbing the process file table, hence we can't lookup the fd in async context. If the fd is valid, ensure that we grab the file table so we can grab the file from async context.

Cc [email protected] # v5.6

Reported-by Clay Harris <[email protected]>

Signed-off-by Jens Axboe <[email protected]>

fs/io_uring.c +10 -2

index c687f57fb651..084dfade5cda 100644
@@ -524,6 +524,7 @@ enum {
 	REQ_F_OVERFLOW_BIT,
 	REQ_F_POLLED_BIT,
 	REQ_F_BUFFER_SELECTED_BIT,
+	REQ_F_NO_FILE_TABLE_BIT,
 
 	/* not a real bit, just to check we're not overflowing the space */
 	__REQ_F_LAST_BIT,

@@ -577,6 +578,8 @@ enum {
 	REQ_F_POLLED		= BIT(REQ_F_POLLED_BIT),
 	/* buffer already selected */
 	REQ_F_BUFFER_SELECTED	= BIT(REQ_F_BUFFER_SELECTED_BIT),
+	/* doesn't need file table for this request */
+	REQ_F_NO_FILE_TABLE	= BIT(REQ_F_NO_FILE_TABLE_BIT),
 };
 
 struct async_poll {

@@ -799,6 +802,7 @@ static const struct io_op_def io_op_defs[] = {
 		.needs_file		= 1,
 		.fd_non_neg		= 1,
 		.needs_fs		= 1,
+		.file_table		= 1,
 	},
 	[IORING_OP_READ] = {
 		.needs_mm		= 1,

@@ -3355,8 +3359,12 @@ static int io_statx(struct io_kiocb *req, bool force_nonblock)
 	struct kstat stat;
 	int ret;
 
-	if (force_nonblock)
+	if (force_nonblock) {
+		/* only need file table for an actual valid fd */
+		if (ctx->dfd == -1 || ctx->dfd == AT_FDCWD)
+			req->flags |= REQ_F_NO_FILE_TABLE;
 		return -EAGAIN;
+	}
 
 	if (vfs_stat_set_lookup_flags(&lookup_flags, ctx->how.flags))
 		return -EINVAL;

@@ -5429,7 +5437,7 @@ static int io_grab_files(struct io_kiocb *req)
 	int ret = -EBADF;
 	struct io_ring_ctx *ctx = req->ctx;
 
-	if (req->work.files)
+	if (req->work.files || (req->flags & REQ_F_NO_FILE_TABLE))
 		return 0;
 	if (!ctx->ring_file)
 		return -EBADF;

Jens Axboe

2020-05-04 13:47 UTC #1 lore raw

Quoted 5 lines · On 5/4/20 3:56 AM, [email protected] wrote:

The patch below does not apply to the 5.6-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Here's a 5.6 backport.

Clay reports that OP_STATX fails for a test case with a valid fd and empty path:

Cc [email protected] # v5.6

Reported-by Clay Harris <[email protected]>

Signed-off-by Jens Axboe <[email protected]>

---

fs/io_uring.c +10 -2

index a46de2cfc28e..38b25f599896 100644
@@ -479,6 +479,7 @@ enum {
 	REQ_F_COMP_LOCKED_BIT,
 	REQ_F_NEED_CLEANUP_BIT,
 	REQ_F_OVERFLOW_BIT,
+	REQ_F_NO_FILE_TABLE_BIT,
 };
 
 enum {

@@ -521,6 +522,8 @@ enum {
 	REQ_F_NEED_CLEANUP	= BIT(REQ_F_NEED_CLEANUP_BIT),
 	/* in overflow list */
 	REQ_F_OVERFLOW		= BIT(REQ_F_OVERFLOW_BIT),
+	/* doesn't need file table for this request */
+	REQ_F_NO_FILE_TABLE	= BIT(REQ_F_NO_FILE_TABLE_BIT),
 };
 
 /*

@@ -711,6 +714,7 @@ static const struct io_op_def io_op_defs[] = {
 		.needs_file		= 1,
 		.fd_non_neg		= 1,
 		.needs_fs		= 1,
+		.file_table		= 1,
 	},
 	[IORING_OP_READ] = {
 		.needs_mm		= 1,

@@ -2843,8 +2847,12 @@ static int io_statx(struct io_kiocb *req, struct io_kiocb **nxt,
 	struct kstat stat;
 	int ret;
 
-	if (force_nonblock)
+	if (force_nonblock) {
+		/* only need file table for an actual valid fd */
+		if (ctx->dfd == -1 || ctx->dfd == AT_FDCWD)
+			req->flags |= REQ_F_NO_FILE_TABLE;
 		return -EAGAIN;
+	}
 
 	if (vfs_stat_set_lookup_flags(&lookup_flags, ctx->how.flags))
 		return -EINVAL;

@@ -4632,7 +4640,7 @@ static int io_grab_files(struct io_kiocb *req)
 	int ret = -EBADF;
 	struct io_ring_ctx *ctx = req->ctx;
 
-	if (req->work.files)
+	if (req->work.files || (req->flags & REQ_F_NO_FILE_TABLE))
 		return 0;
 	if (!ctx->ring_file)
 		return -EBADF;

Signature · 1 line

Jens Axboe

Greg KH

author maintainer

2020-05-04 16:36 UTC #2 lore raw

Quoted 8 lines · Jens Axboe

Quoted 5 lines · On 5/4/20 3:56 AM, [email protected] wrote:
The patch below does not apply to the 5.6-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
Here's a 5.6 backport.

Thanks, now queued up.

greg k-h

Jens Axboe

2020-05-04 16:38 UTC #3 lore raw

Quoted 11 lines · Greg KH

Quoted 8 lines · Jens Axboe
Quoted 5 lines · On 5/4/20 3:56 AM, [email protected] wrote:
The patch below does not apply to the 5.6-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
Here's a 5.6 backport.
Thanks, now queued up.

Thanks Greg!

Signature · 1 line

Jens Axboe