[PATCH AUTOSEL 5.10 01/39] virtiofs: Fail dax mount if device does not support it

[PATCH AUTOSEL 5.10 01/39] virtiofs: Fail dax mount if device does not support it

[Sasha Levin]

From: Vivek Goyal <vgoyal@redhat.com>

[ Upstream commit 3f9b9efd82a84f27e95d0414f852caf1fa839e83 ]

Right now "mount -t virtiofs -o dax myfs /mnt/virtiofs" succeeds even
if filesystem deivce does not have a cache window and hence DAX can't
be supported.

This gives a false sense to user that they are using DAX with virtiofs
but fact of the matter is that they are not.

Fix this by returning error if dax can't be supported and user has asked
for it.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/fuse/virtio_fs.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c
index d2c0e58c6416..3d83c9e12848 100644
--- a/fs/fuse/virtio_fs.c
+++ b/fs/fuse/virtio_fs.c
@@ -1324,8 +1324,15 @@ static int virtio_fs_fill_super(struct super_block *sb, struct fs_context *fsc)
 
 	/* virtiofs allocates and installs its own fuse devices */
 	ctx->fudptr = NULL;
-	if (ctx->dax)
+	if (ctx->dax) {
+		if (!fs->dax_dev) {
+			err = -EINVAL;
+			pr_err("virtio-fs: dax can't be enabled as filesystem"
+			       " device does not support it.\n");
+			goto err_free_fuse_devs;
+		}
 		ctx->dax_dev = fs->dax_dev;
+	}
 	err = fuse_fill_super_common(sb, ctx);
 	if (err < 0)
 		goto err_free_fuse_devs;
-- 
2.30.1

[PATCH AUTOSEL 5.10 08/39] iomap: Fix negative assignment to unsigned sis->pages in iomap_swapfile_activate

[Sasha Levin]

From: Ritesh Harjani <riteshh@linux.ibm.com>

[ Upstream commit 5808fecc572391867fcd929662b29c12e6d08d81 ]

In case if isi.nr_pages is 0, we are making sis->pages (which is
unsigned int) a huge value in iomap_swapfile_activate() by assigning -1.
This could cause a kernel crash in kernel v4.18 (with below signature).
Or could lead to unknown issues on latest kernel if the fake big swap gets
used.

Fix this issue by returning -EINVAL in case of nr_pages is 0, since it
is anyway a invalid swapfile. Looks like this issue will be hit when
we have pagesize < blocksize type of configuration.

I was able to hit the issue in case of a tiny swap file with below
test script.
https://raw.githubusercontent.com/riteshharjani/LinuxStudy/master/scripts/swap-issue.sh

kernel crash analysis on v4.18
==============================
On v4.18 kernel, it causes a kernel panic, since sis->pages becomes
a huge value and isi.nr_extents is 0. When 0 is returned it is
considered as a swapfile over NFS and SWP_FILE is set (sis->flags |= SWP_FILE).
Then when swapoff was getting called it was calling a_ops->swap_deactivate()
if (sis->flags & SWP_FILE) is true. Since a_ops->swap_deactivate() is
NULL in case of XFS, it causes below panic.

Panic signature on v4.18 kernel:
=======================================
root@qemu:/home/qemu# [ 8291.723351] XFS (loop2): Unmounting Filesystem
[ 8292.123104] XFS (loop2): Mounting V5 Filesystem
[ 8292.132451] XFS (loop2): Ending clean mount
[ 8292.263362] Adding 4294967232k swap on /mnt1/test/swapfile.  Priority:-2 extents:1 across:274877906880k
[ 8292.277834] Unable to handle kernel paging request for instruction fetch
[ 8292.278677] Faulting instruction address: 0x00000000
cpu 0x19: Vector: 400 (Instruction Access) at [c0000009dd5b7ad0]
    pc: 0000000000000000
    lr: c0000000003eb9dc: destroy_swap_extents+0xfc/0x120
    sp: c0000009dd5b7d50
   msr: 8000000040009033
  current = 0xc0000009b6710080
  paca    = 0xc00000003ffcb280   irqmask: 0x03   irq_happened: 0x01
    pid   = 5604, comm = swapoff
Linux version 4.18.0 (riteshh@xxxxxxx) (gcc version 8.4.0 (Ubuntu 8.4.0-1ubuntu1~18.04)) #57 SMP Wed Mar 3 01:33:04 CST 2021
enter ? for help
[link register   ] c0000000003eb9dc destroy_swap_extents+0xfc/0x120
[c0000009dd5b7d50] c0000000025a7058 proc_poll_event+0x0/0x4 (unreliable)
[c0000009dd5b7da0] c0000000003f0498 sys_swapoff+0x3f8/0x910
[c0000009dd5b7e30] c00000000000bbe4 system_call+0x5c/0x70
Exception: c01 (System Call) at 00007ffff7d208d8

Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
[djwong: rework the comment to provide more details]
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/iomap/swapfile.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/fs/iomap/swapfile.c b/fs/iomap/swapfile.c
index a648dbf6991e..a5e478de1417 100644
--- a/fs/iomap/swapfile.c
+++ b/fs/iomap/swapfile.c
@@ -170,6 +170,16 @@ int iomap_swapfile_activate(struct swap_info_struct *sis,
 			return ret;
 	}
 
+	/*
+	 * If this swapfile doesn't contain even a single page-aligned
+	 * contiguous range of blocks, reject this useless swapfile to
+	 * prevent confusion later on.
+	 */
+	if (isi.nr_pages == 0) {
+		pr_warn("swapon: Cannot find a single usable page in file.\n");
+		return -EINVAL;
+	}
+
 	*pagespan = 1 + isi.highest_ppage - isi.lowest_ppage;
 	sis->max = isi.nr_pages;
 	sis->pages = isi.nr_pages - 1;
-- 
2.30.1

[PATCH AUTOSEL 5.10 23/39] io_uring: fix ->flags races by linked timeouts

[Sasha Levin]

From: Pavel Begunkov <asml.silence@gmail.com>

[ Upstream commit efe814a471e0e58f28f1efaf430c8784a4f36626 ]

It's racy to modify req->flags from a not owning context, e.g. linked
timeout calling req_set_fail_links() for the master request might race
with that request setting/clearing flags while being executed
concurrently. Just remove req_set_fail_links(prev) from
io_link_timeout_fn(), io_async_find_and_cancel() and functions down the
line take care of setting the fail bit.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/io_uring.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 691c99869143..8f57fd328df6 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -6231,7 +6231,6 @@ static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer)
 	spin_unlock_irqrestore(&ctx->completion_lock, flags);
 
 	if (prev) {
-		req_set_fail_links(prev);
 		io_async_find_and_cancel(ctx, req, prev->user_data, -ETIME);
 		io_put_req(prev);
 	} else {
-- 
2.30.1

[PATCH AUTOSEL 5.10 34/39] io_uring: imply MSG_NOSIGNAL for send[msg]()/recv[msg]() calls

[Sasha Levin]

From: Stefan Metzmacher <metze@samba.org>

[ Upstream commit 76cd979f4f38a27df22efb5773a0d567181a9392 ]

We never want to generate any SIGPIPE, -EPIPE only is much better.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Link: https://lore.kernel.org/r/38961085c3ec49fd21550c7788f214d1ff02d2d4.1615908477.git.metze@samba.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/io_uring.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 8f57fd328df6..38a394c6260d 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4410,7 +4410,7 @@ static int io_sendmsg(struct io_kiocb *req, bool force_nonblock,
 		kmsg = &iomsg;
 	}
 
-	flags = req->sr_msg.msg_flags;
+	flags = req->sr_msg.msg_flags | MSG_NOSIGNAL;
 	if (flags & MSG_DONTWAIT)
 		req->flags |= REQ_F_NOWAIT;
 	else if (force_nonblock)
@@ -4454,7 +4454,7 @@ static int io_send(struct io_kiocb *req, bool force_nonblock,
 	msg.msg_controllen = 0;
 	msg.msg_namelen = 0;
 
-	flags = req->sr_msg.msg_flags;
+	flags = req->sr_msg.msg_flags | MSG_NOSIGNAL;
 	if (flags & MSG_DONTWAIT)
 		req->flags |= REQ_F_NOWAIT;
 	else if (force_nonblock)
@@ -4648,7 +4648,7 @@ static int io_recvmsg(struct io_kiocb *req, bool force_nonblock,
 				1, req->sr_msg.len);
 	}
 
-	flags = req->sr_msg.msg_flags;
+	flags = req->sr_msg.msg_flags | MSG_NOSIGNAL;
 	if (flags & MSG_DONTWAIT)
 		req->flags |= REQ_F_NOWAIT;
 	else if (force_nonblock)
@@ -4706,7 +4706,7 @@ static int io_recv(struct io_kiocb *req, bool force_nonblock,
 	msg.msg_iocb = NULL;
 	msg.msg_flags = 0;
 
-	flags = req->sr_msg.msg_flags;
+	flags = req->sr_msg.msg_flags | MSG_NOSIGNAL;
 	if (flags & MSG_DONTWAIT)
 		req->flags |= REQ_F_NOWAIT;
 	else if (force_nonblock)
-- 
2.30.1

[PATCH AUTOSEL 5.10 39/39] io_uring: call req_set_fail_links() on short send[msg]()/recv[msg]() with MSG_WAITALL

[Sasha Levin]

From: Stefan Metzmacher <metze@samba.org>

[ Upstream commit 0031275d119efe16711cd93519b595e6f9b4b330 ]

Without that it's not safe to use them in a linked combination with
others.

Now combinations like IORING_OP_SENDMSG followed by IORING_OP_SPLICE
should be possible.

We already handle short reads and writes for the following opcodes:

- IORING_OP_READV
- IORING_OP_READ_FIXED
- IORING_OP_READ
- IORING_OP_WRITEV
- IORING_OP_WRITE_FIXED
- IORING_OP_WRITE
- IORING_OP_SPLICE
- IORING_OP_TEE

Now we have it for these as well:

- IORING_OP_SENDMSG
- IORING_OP_SEND
- IORING_OP_RECVMSG
- IORING_OP_RECV

For IORING_OP_RECVMSG we also check for the MSG_TRUNC and MSG_CTRUNC
flags in order to call req_set_fail_links().

There might be applications arround depending on the behavior
that even short send[msg]()/recv[msg]() retuns continue an
IOSQE_IO_LINK chain.

It's very unlikely that such applications pass in MSG_WAITALL,
which is only defined in 'man 2 recvmsg', but not in 'man 2 sendmsg'.

It's expected that the low level sock_sendmsg() call just ignores
MSG_WAITALL, as MSG_ZEROCOPY is also ignored without explicitly set
SO_ZEROCOPY.

We also expect the caller to know about the implicit truncation to
MAX_RW_COUNT, which we don't detect.

cc: netdev@vger.kernel.org
Link: https://lore.kernel.org/r/c4e1a4cc0d905314f4d5dc567e65a7b09621aab3.1615908477.git.metze@samba.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/io_uring.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 38a394c6260d..f8a47cebeacd 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4390,6 +4390,7 @@ static int io_sendmsg(struct io_kiocb *req, bool force_nonblock,
 	struct io_async_msghdr iomsg, *kmsg;
 	struct socket *sock;
 	unsigned flags;
+	int min_ret = 0;
 	int ret;
 
 	sock = sock_from_file(req->file, &ret);
@@ -4416,6 +4417,9 @@ static int io_sendmsg(struct io_kiocb *req, bool force_nonblock,
 	else if (force_nonblock)
 		flags |= MSG_DONTWAIT;
 
+	if (flags & MSG_WAITALL)
+		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
+
 	ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
 	if (force_nonblock && ret == -EAGAIN)
 		return io_setup_async_msg(req, kmsg);
@@ -4425,7 +4429,7 @@ static int io_sendmsg(struct io_kiocb *req, bool force_nonblock,
 	if (kmsg->iov != kmsg->fast_iov)
 		kfree(kmsg->iov);
 	req->flags &= ~REQ_F_NEED_CLEANUP;
-	if (ret < 0)
+	if (ret < min_ret)
 		req_set_fail_links(req);
 	__io_req_complete(req, ret, 0, cs);
 	return 0;
@@ -4439,6 +4443,7 @@ static int io_send(struct io_kiocb *req, bool force_nonblock,
 	struct iovec iov;
 	struct socket *sock;
 	unsigned flags;
+	int min_ret = 0;
 	int ret;
 
 	sock = sock_from_file(req->file, &ret);
@@ -4460,6 +4465,9 @@ static int io_send(struct io_kiocb *req, bool force_nonblock,
 	else if (force_nonblock)
 		flags |= MSG_DONTWAIT;
 
+	if (flags & MSG_WAITALL)
+		min_ret = iov_iter_count(&msg.msg_iter);
+
 	msg.msg_flags = flags;
 	ret = sock_sendmsg(sock, &msg);
 	if (force_nonblock && ret == -EAGAIN)
@@ -4467,7 +4475,7 @@ static int io_send(struct io_kiocb *req, bool force_nonblock,
 	if (ret == -ERESTARTSYS)
 		ret = -EINTR;
 
-	if (ret < 0)
+	if (ret < min_ret)
 		req_set_fail_links(req);
 	__io_req_complete(req, ret, 0, cs);
 	return 0;
@@ -4619,6 +4627,7 @@ static int io_recvmsg(struct io_kiocb *req, bool force_nonblock,
 	struct socket *sock;
 	struct io_buffer *kbuf;
 	unsigned flags;
+	int min_ret = 0;
 	int ret, cflags = 0;
 
 	sock = sock_from_file(req->file, &ret);
@@ -4654,6 +4663,9 @@ static int io_recvmsg(struct io_kiocb *req, bool force_nonblock,
 	else if (force_nonblock)
 		flags |= MSG_DONTWAIT;
 
+	if (flags & MSG_WAITALL)
+		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
+
 	ret = __sys_recvmsg_sock(sock, &kmsg->msg, req->sr_msg.umsg,
 					kmsg->uaddr, flags);
 	if (force_nonblock && ret == -EAGAIN)
@@ -4666,7 +4678,7 @@ static int io_recvmsg(struct io_kiocb *req, bool force_nonblock,
 	if (kmsg->iov != kmsg->fast_iov)
 		kfree(kmsg->iov);
 	req->flags &= ~REQ_F_NEED_CLEANUP;
-	if (ret < 0)
+	if (ret < min_ret || ((flags & MSG_WAITALL) && (kmsg->msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))))
 		req_set_fail_links(req);
 	__io_req_complete(req, ret, cflags, cs);
 	return 0;
@@ -4682,6 +4694,7 @@ static int io_recv(struct io_kiocb *req, bool force_nonblock,
 	struct socket *sock;
 	struct iovec iov;
 	unsigned flags;
+	int min_ret = 0;
 	int ret, cflags = 0;
 
 	sock = sock_from_file(req->file, &ret);
@@ -4712,6 +4725,9 @@ static int io_recv(struct io_kiocb *req, bool force_nonblock,
 	else if (force_nonblock)
 		flags |= MSG_DONTWAIT;
 
+	if (flags & MSG_WAITALL)
+		min_ret = iov_iter_count(&msg.msg_iter);
+
 	ret = sock_recvmsg(sock, &msg, flags);
 	if (force_nonblock && ret == -EAGAIN)
 		return -EAGAIN;
@@ -4720,7 +4736,7 @@ static int io_recv(struct io_kiocb *req, bool force_nonblock,
 out_free:
 	if (req->flags & REQ_F_BUFFER_SELECTED)
 		cflags = io_put_recv_kbuf(req);
-	if (ret < 0)
+	if (ret < min_ret || ((flags & MSG_WAITALL) && (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))))
 		req_set_fail_links(req);
 	__io_req_complete(req, ret, cflags, cs);
 	return 0;
-- 
2.30.1