Commit Graph

62912 Commits

Author SHA1 Message Date
Trond Myklebust
3cab1854b0 nfs: Fix up documentation in nfs_follow_referral() and nfs_do_submount()
Fallout from the mount patches.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-17 18:40:57 -04:00
Gustavo A. R. Silva
5601cda82b nfs: Replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 10:16:26 -04:00
Murphy Zhou
f5fdf1243f NFSv4.2: error out when relink swapfile
This fixes xfstests generic/356 failure on NFSv4.2.

Signed-off-by: Murphy Zhou <jencce.kernel@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 10:14:30 -04:00
Zhouyi Zhou
eb095c1403 NFS:remove redundant call to nfs_do_access
In function nfs_permission:
1. the rcu_read_lock and rcu_read_unlock around nfs_do_access
is unnecessary because the rcu critical data structure is already
protected in subsidiary function nfs_access_get_cached_rcu. No other
data structure needs rcu_read_lock in nfs_do_access.

2. call nfs_do_access once is enough, because:
2-1. when mask has MAY_NOT_BLOCK bit
The second call to nfs_do_access will not happen.

2-2. when mask has no MAY_NOT_BLOCK bit
The second call to nfs_do_access will happen if res == -ECHILD, which
means the first nfs_do_access goes out after statement if (!may_block).
The second call to nfs_do_access will go through this procedure once
again except continue the work after if (!may_block).
But above work can be performed by only one call to nfs_do_access
without mangling the mask flag.

Tested in x86_64
Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 10:11:59 -04:00
Trond Myklebust
b5fdf8418c NFSv4: Add support for CB_RECALL_ANY for flexfiles layouts
When we receive a CB_RECALL_ANY that asks us to return flexfiles
layouts, we iterate through all the layouts and look at whether or
not there are active open file descriptors that might need them
for I/O. If there are no such descriptors, we return the layouts.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:30 -04:00
Trond Myklebust
7f156ef0bf NFSv4: Clean up nfs_delegation_reap_expired()
Convert to use nfs_client_for_each_server() for efficiency.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:30 -04:00
Trond Myklebust
1bba38b283 NFSv4: Clean up nfs_delegation_reap_unclaimed()
Convert nfs_delegation_reap_unclaimed() to use nfs_client_for_each_server()
for efficiency.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:30 -04:00
Trond Myklebust
af3b61bf61 NFSv4: Clean up nfs_client_return_marked_delegations()
Convert it to use the nfs_client_for_each_server() helper, and
make it more efficient by skipping delegations for inodes we
know are in the process of being freed. Also improve the efficiency
of the cursor by skipping delegations that are being freed.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:30 -04:00
Trond Myklebust
3c9e502b59 NFS: Add a helper nfs_client_for_each_server()
Add a helper nfs_client_for_each_server() to iterate through all the
filesystems that are attached to a struct nfs_client, and apply
a function to all the active ones.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:30 -04:00
Trond Myklebust
58ac3e5923 NFSv4/pnfs: Clean up nfs_layout_find_inode()
Now that we can rely on just the rcu_read_lock(), remove the
clp->cl_lock and clean up.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:29 -04:00
Trond Myklebust
cf6605d194 NFSv4: Ensure layout headers are RCU safe
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:29 -04:00
Trond Myklebust
d911c57a19 NFSv4/pnfs: Return valid stateids in nfs_layout_find_inode_by_stateid()
Make sure to test the stateid for validity so that we catch instances
where the server may have been reusing stateids in
nfs_layout_find_inode_by_stateid().

Fixes: 7b410d9ce4 ("pNFS: Delay getting the layout header in CB_LAYOUTRECALL handlers")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:29 -04:00
Trond Myklebust
194a0dc8e2 pNFS/flexfiles: Report DELAY and GRACE errors from the DS to the server
Ensure that if the DS is returning too many DELAY and GRACE errors, we
also report that to the MDS through the layouterror mechanism.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:29 -04:00
Trond Myklebust
a8b373eefc NFS: Limit the size of the access cache by default
Currently, we have no real limit on the access cache size (we set it
to ULONG_MAX). That can lead to credentials getting pinned for a
very long time on lots of files if you have a system with a lot of
memory.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:29 -04:00
Trond Myklebust
49cd32543f NFS: Avoid referencing the cred twice in async rename/unlink
In both async rename and rename, we take a reference to the
cred in the call arguments.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:29 -04:00
Trond Myklebust
63ec2b69e9 NFSv4: Avoid unnecessary credential references in layoutget
Layoutget is just using the credential attached to the open context.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:29 -04:00
Trond Myklebust
6129650720 NFSv4: Avoid referencing the cred unnecessarily during NFSv4 I/O
Avoid unnecessary references to the cred when we have already referenced
it through the open context or the open owner.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:29 -04:00
Trond Myklebust
542b994bdb NFS: Assume cred is pinned by open context in I/O requests
In read/write/commit, we should be able to assume that the cred is
pinned by the open context.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:29 -04:00
Trond Myklebust
1d179d6bd6 NFS: alloc_nfs_open_context() must use the file cred when available
If we're creating a nfs_open_context() for a specific file pointer,
we must use the cred assigned to that file.

Fixes: a52458b48a ("NFS/NFSD/SUNRPC: replace generic creds with 'struct cred'.")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:28 -04:00
Trond Myklebust
244fcd2f9a NFS: Ensure we time out if a delegreturn does not complete
We can't allow delegreturn to hold up nfs4_evict_inode() forever,
since that can cause the memory shrinkers to block. This patch
therefore ensures that we eventually time out, and complete the
reclaim of the inode.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:28 -04:00
Trond Myklebust
59b5639490 NFSv4/pnfs: pnfs_set_layout_stateid() should update the layout cred
If the cred assigned to the layout that we're updating differs from
the one used to retrieve the new layout segment, then we need to
update the layout plh_lc_cred field.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:28 -04:00
Trond Myklebust
57f188e047 NFSv4: nfs_update_inplace_delegation() should update delegation cred
If the cred assigned to the delegation that we're updating differs
from the one we're updating too, then we need to update that field
too.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:28 -04:00
Trond Myklebust
59e356a967 NFS: Use the 64-bit server readdir cookies when possible
When we're running as a 64-bit architecture and are not running in
32-bit compatibility mode, it is better to use the 64-bit readdir
cookies that supplied by the server. Doing so improves the accuracy
of telldir()/seekdir(), particularly when the directory is changing,
for instance, when doing 'rm -rf'.

We still fall back to using the 32-bit offsets on 32-bit architectures
and when in compatibility mode.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:28 -04:00
Linus Torvalds
34d5a4b336 Fix for yet another subtle futex issue. The futex code used ihold() to
prevent inodes from vanishing, but ihold() does not guarantee inode
 persistence. Replace the inode pointer with a per boot, machine wide,
 unique inode identifier. The second commit fixes the breakage of the hash
 mechanism whihc causes a 100% performance regression.
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Merge tag 'locking-urgent-2020-03-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull futex fix from Thomas Gleixner:
 "Fix for yet another subtle futex issue.

  The futex code used ihold() to prevent inodes from vanishing, but
  ihold() does not guarantee inode persistence. Replace the inode
  pointer with a per boot, machine wide, unique inode identifier.

  The second commit fixes the breakage of the hash mechanism which
  causes a 100% performance regression"

* tag 'locking-urgent-2020-03-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Unbreak futex hashing
  futex: Fix inode life-time issue
2020-03-15 12:55:52 -07:00
Linus Torvalds
b0ea262a23 NFS Client Bugfixes for Linux 5.6-rc5
Fixes:
 - Ensure the fs_context has the correct fs_type when mounting and submounting
 - Fix leaking of ctx->nfs_server.hostname
 - Add minor version to fscache key to prevent collisions
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Merge tag 'nfs-for-5.6-3' of git://git.linux-nfs.org/projects/anna/linux-nfs

Pull NFS client bugfixes from Anna Schumaker:
 "These are mostly fscontext fixes, but there is also one that fixes
  collisions seen in fscache:

   - Ensure the fs_context has the correct fs_type when mounting and
     submounting

   - Fix leaking of ctx->nfs_server.hostname

   - Add minor version to fscache key to prevent collisions"

* tag 'nfs-for-5.6-3' of git://git.linux-nfs.org/projects/anna/linux-nfs:
  nfs: add minor version to nfs_server_key for fscache
  NFS: Fix leak of ctx->nfs_server.hostname
  NFS: Don't hard-code the fs_type when submounting
  NFS: Ensure the fs_context has the correct fs_type before mounting
2020-03-13 15:21:32 -07:00
Linus Torvalds
7e6d869f5f fuse fixes for 5.6-rc6
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Merge tag 'fuse-fixes-5.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

Pull fuse fix from Miklos Szeredi:
 "Fix an Oops introduced in v5.4"

* tag 'fuse-fixes-5.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: fix stack use after return
2020-03-13 15:19:38 -07:00
Linus Torvalds
2af82177af overlayfs fixes for 5.6-rc6
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Merge tag 'ovl-fixes-5.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull overlayfs fixes from Miklos Szeredi:
 "Fix three bugs introduced in this cycle"

* tag 'ovl-fixes-5.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: fix lockdep warning for async write
  ovl: fix some xino configurations
  ovl: fix lock in ovl_llseek()
2020-03-13 15:17:21 -07:00
Linus Torvalds
5007928eae io_uring-5.6-2020-03-13
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Merge tag 'io_uring-5.6-2020-03-13' of git://git.kernel.dk/linux-block

Pull io_uring fix from Jens Axboe:
 "Just a single fix here, improving the RCU callback ordering from last
  week. After a bit more perusing by Paul, he poked a hole in the
  original"

* tag 'io_uring-5.6-2020-03-13' of git://git.kernel.dk/linux-block:
  io_uring: ensure RCU callback ordering with rcu_barrier()
2020-03-13 13:00:08 -07:00
Jann Horn
ddd2b85ff7 afs: Use kfree_rcu() instead of casting kfree() to rcu_callback_t
afs_put_addrlist() casts kfree() to rcu_callback_t. Apart from being wrong
in theory, this might also blow up when people start enforcing function
types via compiler instrumentation, and it means the rcu_head has to be
first in struct afs_addr_list.

Use kfree_rcu() instead, it's simpler and more correct.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-03-13 10:47:33 -07:00
Miklos Szeredi
c853680453 ovl: fix lockdep warning for async write
Lockdep reports "WARNING: lock held when returning to user space!" due to
async write holding freeze lock over the write.  Apparently aio.c already
deals with this by lying to lockdep about the state of the lock.

Do the same here.  No need to check for S_IFREG() here since these file ops
are regular-only.

Reported-by: syzbot+9331a354f4f624a52a55@syzkaller.appspotmail.com
Fixes: 2406a307ac ("ovl: implement async IO routines")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-03-13 15:53:06 +01:00
Amir Goldstein
53afcd310e ovl: fix some xino configurations
Fix up two bugs in the coversion to xino_mode:
1. xino=off does not always end up in disabled mode
2. xino=auto on 32bit arch should end up in disabled mode

Take a proactive approach to disabling xino on 32bit kernel:
1. Disable XINO_AUTO config during build time
2. Disable xino with a warning on mount time

As a by product, xino=on on 32bit arch also ends up in disabled mode.
We never intended to enable xino on 32bit arch and this will make the
rest of the logic simpler.

Fixes: 0f831ec85e ("ovl: simplify ovl_same_sb() helper")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-03-13 15:53:06 +01:00
Linus Torvalds
807f030b44 Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs fixes from Al Viro:
 "A couple of fixes for old crap in ->atomic_open() instances"

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  cifs_atomic_open(): fix double-put on late allocation failure
  gfs2_atomic_open(): fix O_EXCL|O_CREAT handling on cold dcache
2020-03-12 15:51:26 -07:00
Al Viro
d9a9f4849f cifs_atomic_open(): fix double-put on late allocation failure
several iterations of ->atomic_open() calling conventions ago, we
used to need fput() if ->atomic_open() failed at some point after
successful finish_open().  Now (since 2016) it's not needed -
struct file carries enough state to make fput() work regardless
of the point in struct file lifecycle and discarding it on
failure exits in open() got unified.  Unfortunately, I'd missed
the fact that we had an instance of ->atomic_open() (cifs one)
that used to need that fput(), as well as the stale comment in
finish_open() demanding such late failure handling.  Trivially
fixed...

Fixes: fe9ec8291f "do_last(): take fput() on error after opening to out:"
Cc: stable@kernel.org # v4.7+
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-03-12 18:25:20 -04:00
Al Viro
2103913265 gfs2_atomic_open(): fix O_EXCL|O_CREAT handling on cold dcache
with the way fs/namei.c:do_last() had been done, ->atomic_open()
instances needed to recognize the case when existing file got
found with O_EXCL|O_CREAT, either by falling back to finish_no_open()
or failing themselves.  gfs2 one didn't.

Fixes: 6d4ade986f (GFS2: Add atomic_open support)
Cc: stable@kernel.org # v3.11
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-03-12 18:21:24 -04:00
Amir Goldstein
531d3040bc ovl: fix lock in ovl_llseek()
ovl_inode_lock() is interruptible. When inode_lock() in ovl_llseek()
was replaced with ovl_inode_lock(), we did not add a check for error.

Fix this by making ovl_inode_lock() uninterruptible and change the
existing call sites to use an _interruptible variant.

Reported-by: syzbot+66a9752fa927f745385e@syzkaller.appspotmail.com
Fixes: b1f9d3858f ("ovl: use ovl_inode_lock in ovl_llseek()")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-03-12 16:38:10 +01:00
Linus Torvalds
e6e6ec48dd fscrypt fix for v5.6-rc6
Fix a bug where if userspace is writing to encrypted files while the
 FS_IOC_REMOVE_ENCRYPTION_KEY ioctl (introduced in v5.4) is running,
 dirty inodes could be evicted, causing writes could be lost or the
 filesystem to hang due to a use-after-free.  This was encountered during
 real-world use, not just theoretical.
 
 Tested with the existing fscrypt xfstests, and with a new xfstest I
 wrote to reproduce this bug.  This fix does expose an existing bug with
 '-o lazytime' that Ted is working on fixing, but this fix is more
 critical and needed anyway regardless of the lazytime fix.
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Merge tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt

Pull fscrypt fix from Eric Biggers:
 "Fix a bug where if userspace is writing to encrypted files while the
  FS_IOC_REMOVE_ENCRYPTION_KEY ioctl (introduced in v5.4) is running,
  dirty inodes could be evicted, causing writes could be lost or the
  filesystem to hang due to a use-after-free. This was encountered
  during real-world use, not just theoretical.

  Tested with the existing fscrypt xfstests, and with a new xfstest I
  wrote to reproduce this bug. This fix does expose an existing bug with
  '-o lazytime' that Ted is working on fixing, but this fix is more
  critical and needed anyway regardless of the lazytime fix"

* tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt:
  fscrypt: don't evict dirty inodes after removing key
2020-03-11 13:35:34 -07:00
Jens Axboe
805b13adde io_uring: ensure RCU callback ordering with rcu_barrier()
After more careful studying, Paul informs me that we cannot rely on
ordering of RCU callbacks in the way that the the tagged commit did.
The current construct looks like this:

	void C(struct rcu_head *rhp)
	{
		do_something(rhp);
		call_rcu(&p->rh, B);
	}

	call_rcu(&p->rh, A);
	call_rcu(&p->rh, C);

and we're relying on ordering between A and B, which isn't guaranteed.
Make this explicit instead, and have a work item issue the rcu_barrier()
to ensure that A has run before we manually execute B.

While thorough testing never showed this issue, it's dependent on the
per-cpu load in terms of RCU callbacks. The updated method simplifies
the code as well, and eliminates the need to maintain an rcu_head in
the fileset data.

Fixes: c1e2148f8e ("io_uring: free fixed_file_data after RCU grace period")
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-08 20:07:28 -06:00
Linus Torvalds
b34e5c1332 Driver core / debugfs fixes for 5.6-rc5
Here are 4 small driver core / debugfs patches for 5.6-rc3
 
 They are:
 	- debugfs api cleanup now that all callers for
 	  debugfs_create_regset32() have been fixed up.  This was
 	  waiting until after the -rc1 merge as these fixes came in
 	  through different trees
 	- driver core sync state fixes based on reports of minor issues
 	  found in the feature
 
 All of these have been in linux-next with no reported issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-5.6-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core and debugfs fixes from Greg KH:
 "Here are four small driver core / debugfs patches for 5.6-rc3:

   - debugfs api cleanup now that all debugfs_create_regset32() callers
     have been fixed up. This was waiting until after the -rc1 merge as
     these fixes came in through different trees

   - driver core sync state fixes based on reports of minor issues found
     in the feature

  All of these have been in linux-next with no reported issues"

* tag 'driver-core-5.6-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  driver core: Skip unnecessary work when device doesn't have sync_state()
  driver core: Add dev_has_sync_state()
  driver core: Call sync_state() even if supplier has no consumers
  debugfs: remove return value of debugfs_create_regset32()
2020-03-08 10:39:40 -05:00
Eric Biggers
2b4eae95c7 fscrypt: don't evict dirty inodes after removing key
After FS_IOC_REMOVE_ENCRYPTION_KEY removes a key, it syncs the
filesystem and tries to get and put all inodes that were unlocked by the
key so that unused inodes get evicted via fscrypt_drop_inode().
Normally, the inodes are all clean due to the sync.

However, after the filesystem is sync'ed, userspace can modify and close
one of the files.  (Userspace is *supposed* to close the files before
removing the key.  But it doesn't always happen, and the kernel can't
assume it.)  This causes the inode to be dirtied and have i_count == 0.
Then, fscrypt_drop_inode() failed to consider this case and indicated
that the inode can be dropped, causing the write to be lost.

On f2fs, other problems such as a filesystem freeze could occur due to
the inode being freed while still on f2fs's dirty inode list.

Fix this bug by making fscrypt_drop_inode() only drop clean inodes.

I've written an xfstest which detects this bug on ext4, f2fs, and ubifs.

Fixes: b1c0ec3599 ("fscrypt: add FS_IOC_REMOVE_ENCRYPTION_KEY ioctl")
Cc: <stable@vger.kernel.org> # v5.4+
Link: https://lore.kernel.org/r/20200305084138.653498-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-03-07 18:43:07 -08:00
Linus Torvalds
c200376527 io_uring-5.6-2020-03-07
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Merge tag 'io_uring-5.6-2020-03-07' of git://git.kernel.dk/linux-block

Pull io_uring fixes from Jens Axboe:
 "Here are a few io_uring fixes that should go into this release. This
  contains:

   - Removal of (now) unused io_wq_flush() and associated flag (Pavel)

   - Fix cancelation lockup with linked timeouts (Pavel)

   - Fix for potential use-after-free when freeing percpu ref for fixed
     file sets

   - io-wq cancelation fixups (Pavel)"

* tag 'io_uring-5.6-2020-03-07' of git://git.kernel.dk/linux-block:
  io_uring: fix lockup with timeouts
  io_uring: free fixed_file_data after RCU grace period
  io-wq: remove io_wq_flush and IO_WQ_WORK_INTERNAL
  io-wq: fix IO_WQ_WORK_NO_CANCEL cancellation
2020-03-07 14:20:29 -06:00
Pavel Begunkov
f0e20b8943 io_uring: fix lockup with timeouts
There is a recipe to deadlock the kernel: submit a timeout sqe with a
linked_timeout (e.g.  test_single_link_timeout_ception() from liburing),
and SIGKILL the process.

Then, io_kill_timeouts() takes @ctx->completion_lock, but the timeout
isn't flagged with REQ_F_COMP_LOCKED, and will try to double grab it
during io_put_free() to cancel the linked timeout. Probably, the same
can happen with another io_kill_timeout() call site, that is
io_commit_cqring().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-07 08:35:56 -07:00
Linus Torvalds
30fe0d07fd for-5.6-rc4-tag
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Merge tag 'for-5.6-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fix from David Sterba:
 "One fixup for DIO when in use with the new checksums, a missed case
  where the checksum size was still assuming u32"

* tag 'for-5.6-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix RAID direct I/O reads with alternate csums
2020-03-06 14:56:46 -06:00
Linus Torvalds
0b25d45803 File locking fixes for v5.6
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Merge tag 'filelock-v5.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux

Pull file locking fixes from Jeff Layton:
 "Just a couple of late-breaking patches for the file locking code. The
  second patch (from yangerkun) fixes a rather nasty looking potential
  use-after-free that should go to stable.

  The other patch could technically wait for 5.7, but it's fairly
  innocuous so I figured we might as well take it"

* tag 'filelock-v5.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux:
  locks: fix a potential use-after-free problem when wakeup a waiter
  fcntl: Distribute switch variables for initialization
2020-03-06 14:55:27 -06:00
Jens Axboe
c1e2148f8e io_uring: free fixed_file_data after RCU grace period
The percpu refcount protects this structure, and we can have an atomic
switch in progress when exiting. This makes it unsafe to just free the
struct normally, and can trigger the following KASAN warning:

BUG: KASAN: use-after-free in percpu_ref_switch_to_atomic_rcu+0xfa/0x1b0
Read of size 1 at addr ffff888181a19a30 by task swapper/0/0

CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0-rc4+ #5747
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
Call Trace:
 <IRQ>
 dump_stack+0x76/0xa0
 print_address_description.constprop.0+0x3b/0x60
 ? percpu_ref_switch_to_atomic_rcu+0xfa/0x1b0
 ? percpu_ref_switch_to_atomic_rcu+0xfa/0x1b0
 __kasan_report.cold+0x1a/0x3d
 ? percpu_ref_switch_to_atomic_rcu+0xfa/0x1b0
 percpu_ref_switch_to_atomic_rcu+0xfa/0x1b0
 rcu_core+0x370/0x830
 ? percpu_ref_exit+0x50/0x50
 ? rcu_note_context_switch+0x7b0/0x7b0
 ? run_rebalance_domains+0x11d/0x140
 __do_softirq+0x10a/0x3e9
 irq_exit+0xd5/0xe0
 smp_apic_timer_interrupt+0x86/0x200
 apic_timer_interrupt+0xf/0x20
 </IRQ>
RIP: 0010:default_idle+0x26/0x1f0

Fix this by punting the final exit and free of the struct to RCU, then
we know that it's safe to do so. Jann suggested the approach of using a
double rcu callback to achieve this. It's important that we do a nested
call_rcu() callback, as otherwise the free could be ordered before the
atomic switch, even if the latter was already queued.

Reported-by: syzbot+e017e49c39ab484ac87a@syzkaller.appspotmail.com
Suggested-by: Jann Horn <jannh@google.com>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-06 10:15:21 -07:00
yangerkun
6d390e4b5d locks: fix a potential use-after-free problem when wakeup a waiter
'16306a61d3b7 ("fs/locks: always delete_block after waiting.")' add the
logic to check waiter->fl_blocker without blocked_lock_lock. And it will
trigger a UAF when we try to wakeup some waiter:

Thread 1 has create a write flock a on file, and now thread 2 try to
unlock and delete flock a, thread 3 try to add flock b on the same file.

Thread2                         Thread3
                                flock syscall(create flock b)
	                        ...flock_lock_inode_wait
				    flock_lock_inode(will insert
				    our fl_blocked_member list
				    to flock a's fl_blocked_requests)
				   sleep
flock syscall(unlock)
...flock_lock_inode_wait
    locks_delete_lock_ctx
    ...__locks_wake_up_blocks
        __locks_delete_blocks(
	b->fl_blocker = NULL)
	...
                                   break by a signal
				   locks_delete_block
				    b->fl_blocker == NULL &&
				    list_empty(&b->fl_blocked_requests)
	                            success, return directly
				 locks_free_lock b
	wake_up(&b->fl_waiter)
	trigger UAF

Fix it by remove this logic, and this patch may also fix CVE-2019-19769.

Cc: stable@vger.kernel.org
Fixes: 16306a61d3 ("fs/locks: always delete_block after waiting.")
Signed-off-by: yangerkun <yangerkun@huawei.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
2020-03-06 11:54:13 -05:00
OGAWA Hirofumi
bc87302a09 fat: fix uninit-memory access for partial initialized inode
When get an error in the middle of reading an inode, some fields in the
inode might be still not initialized.  And then the evict_inode path may
access those fields via iput().

To fix, this makes sure that inode fields are initialized.

Reported-by: syzbot+9d82b8de2992579da5d0@syzkaller.appspotmail.com
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/871rqnreqx.fsf@mail.parknet.co.jp
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-03-06 07:06:09 -06:00
Peter Zijlstra
8019ad13ef futex: Fix inode life-time issue
As reported by Jann, ihold() does not in fact guarantee inode
persistence. And instead of making it so, replace the usage of inode
pointers with a per boot, machine wide, unique inode identifier.

This sequence number is global, but shared (file backed) futexes are
rare enough that this should not become a performance issue.

Reported-by: Jann Horn <jannh@google.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2020-03-06 11:06:15 +01:00
Linus Torvalds
8b614cb8f1 five small cifs/smb3 fixes, two for stable
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Merge tag '5.6-rc4-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs fixes from Steve French:
 "Five small cifs/smb3 fixes, two for stable (one for a reconnect
  problem and the other fixes a use case when renaming an open file)"

* tag '5.6-rc4-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: Use #define in cifs_dbg
  cifs: fix rename() by ensuring source handle opened with DELETE bit
  cifs: add missing mount option to /proc/mounts
  cifs: fix potential mismatch of UNC paths
  cifs: don't leak -EAGAIN for stat() during reconnect
2020-03-03 17:31:19 -06:00
Kees Cook
0a68ff5e2e fcntl: Distribute switch variables for initialization
Variables declared in a switch statement before any case statements
cannot be automatically initialized with compiler instrumentation (as
they are not part of any execution flow). With GCC's proposed automatic
stack variable initialization feature, this triggers a warning (and they
don't get initialized). Clang's automatic stack variable initialization
(via CONFIG_INIT_STACK_ALL=y) doesn't throw a warning, but it also
doesn't initialize such variables[1]. Note that these warnings (or silent
skipping) happen before the dead-store elimination optimization phase,
so even when the automatic initializations are later elided in favor of
direct initializations, the warnings remain.

To avoid these problems, move such variables into the "case" where
they're used or lift them up into the main function body.

fs/fcntl.c: In function ‘send_sigio_to_task’:
fs/fcntl.c:738:20: warning: statement will never be executed [-Wswitch-unreachable]
  738 |   kernel_siginfo_t si;
      |                    ^~

[1] https://bugs.llvm.org/show_bug.cgi?id=44916

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
2020-03-03 10:55:06 -05:00
Omar Sandoval
e7a04894c7 btrfs: fix RAID direct I/O reads with alternate csums
btrfs_lookup_and_bind_dio_csum() does pointer arithmetic which assumes
32-bit checksums. If using a larger checksum, this leads to spurious
failures when a direct I/O read crosses a stripe. This is easy
to reproduce:

  # mkfs.btrfs -f --checksum blake2 -d raid0 /dev/vdc /dev/vdd
  ...
  # mount /dev/vdc /mnt
  # cd /mnt
  # dd if=/dev/urandom of=foo bs=1M count=1 status=none
  # dd if=foo of=/dev/null bs=1M iflag=direct status=none
  dd: error reading 'foo': Input/output error
  # dmesg | tail -1
  [  135.821568] BTRFS warning (device vdc): csum failed root 5 ino 257 off 421888 ...

Fix it by using the actual checksum size.

Fixes: 1e25a2e3ca ("btrfs: don't assume ordered sums to be 4 bytes")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-03-03 15:26:08 +01:00