Commit Graph

57964 Commits

Author SHA1 Message Date
David Howells
79ddbfa500 afs: Implement sillyrename for unlink and rename
Implement sillyrename for AFS unlink and rename, using the NFS variant
implementation as a basis.

Note that the asynchronous file locking extender/releaser has to be
notified with a state change to stop it complaining if there's a race
between that and the actual file deletion.

A tracepoint, afs_silly_rename, is also added to note the silly rename and
the cleanup.  The afs_edit_dir tracepoint is given some extra reason
indicators and the afs_flock_ev tracepoint is given a silly-delete file
lock cancellation indicator.

Signed-off-by: David Howells <dhowells@redhat.com>
2019-04-25 14:26:51 +01:00
David Howells
99987c5600 afs: Add directory reload tracepoint
Add a tracepoint (afs_reload_dir) to indicate when a directory is being
reloaded.

Signed-off-by: David Howells <dhowells@redhat.com>
2019-04-25 14:26:51 +01:00
David Howells
cdfb26b40d afs: Handle lock rpc ops failing on a file that got deleted
Holding a file lock on an AFS file does not prevent it from being deleted
on the server, so we need to handle an error resulting from that when we
try setting, extending or releasing a lock.

Fix this by adding a "deleted" lock state and cancelling the lock extension
process for that file and aborting all waiters for the lock.

Fixes: 0fafdc9f88 ("afs: Fix file locking")
Reported-by: Jonathan Billings <jsbillin@umich.edu>
Signed-off-by: David Howells <dhowells@redhat.com>
2019-04-25 14:26:51 +01:00
David Howells
445b10289f afs: Improve dir check failure reports
Improve the content of directory check failure reports from:

	kAFS: afs_dir_check_page(6d57): bad magic 1/2 is 0000

to dump more information about the individual blocks in a directory page.

Signed-off-by: David Howells <dhowells@redhat.com>
2019-04-25 14:26:51 +01:00
David Howells
d46966013b afs: Add file locking tracepoints
Add two tracepoints for monitoring AFS file locking.  Firstly, add one that
follows the operational part:

    echo 1 >/sys/kernel/debug/tracing/events/afs/afs_flock_op/enable

And add a second that more follows the event-driven part:

    echo 1 >/sys/kernel/debug/tracing/events/afs/afs_flock_ev/enable

Individual file_lock structs seen by afs are tagged with debugging IDs that
are displayed in the trace log to make it easier to see what's going on,
especially as setting the first lock always seems to involve copying the
file_lock twice.

Signed-off-by: David Howells <dhowells@redhat.com>
2019-04-25 14:26:50 +01:00
David Howells
4be5975aea afs: Further fix file locking
Further fix the file locking in the afs filesystem client in a number of
ways, including:

 (1) Don't submit the operation to obtain a lock from the server in a work
     queue context, but rather do it in the process context of whoever
     issued the requesting system call.

 (2) The owner of the file_lock struct at the front of the pending_locks
     queue now owns right to talk to the server.

 (3) Write locks can be instantly granted if they don't overlap with any
     other locks *and* we have a write lock on the server.

 (4) In the event of an authentication/permission error, all other matching
     pending locks requests are also immediately aborted.

 (5) Properly use VFS core locks_lock_file_wait() to distribute the server
     lock amongst local client locks, including waiting for the lock to
     become available.

Test with:

	sqlite3 /afs/.../scratch/billings.sqlite <<EOF
	CREATE TABLE hosts (
	    hostname varchar(80),
	    shorthost varchar(80),
	    room varchar(30),
	    building varchar(30),
	    PRIMARY KEY(shorthost)
	    );
	EOF

With the version of sqlite3 that I have, this should fail consistently with
EAGAIN, whether or not the program is straced (which introduces some delays
between lock syscalls).

Fixes: 0fafdc9f88 ("afs: Fix file locking")
Reported-by: Jonathan Billings <jsbillin@umich.edu>
Signed-off-by: David Howells <dhowells@redhat.com>
2019-04-25 14:26:50 +01:00
David Howells
68ce801ffd afs: Fix AFS file locking to allow fine grained locks
Fix AFS file locking to allow fine grained locks as some applications, such
as firefox, won't work if they can't take such locks on certain state files
- thereby preventing the use of kAFS to distribute a home directory.

Note that this cannot be made completely functional as the protocol only
has provision for whole-file locks, so there exists the possibility of a
process deadlocking itself by getting a partial read-lock on a file first
and then trying to get a non-overlapping write-lock - but we got the
server's read lock with the first lock, so we're now stuck.

OpenAFS solves this by just granting any partial-range lock directly
without consulting the server - and hoping there's no remote collision.  I
want to implement that in a separate patch and it requires a bit more
thought.

Fixes: 8d6c554126b8 ("AFS: implement file locking")
Reported-by: Jonathan Billings <jsbillings@jsbillings.org>
Signed-off-by: David Howells <dhowells@redhat.com>
2019-04-25 14:26:50 +01:00
David Howells
a690f60a2b afs: Calculate lock extend timer from set/extend reply reception
Record the timestamp on the first reply DATA packet received in response to
a set- or extend-lock operation, then use this to calculate the time
remaining till the lock expires rather than using whatever time the
requesting process wakes up and finishes processing the operation as a
base.

Signed-off-by: David Howells <dhowells@redhat.com>
2019-04-25 14:26:50 +01:00
David Howells
0b9bf3812a afs: Split wait from afs_make_call()
Split the call to afs_wait_for_call_to_complete() from afs_make_call() to
make it easier to handle asynchronous calls and to make it easier to
convert a synchronous call to an asynchronous one in future, for instance
when someone tries to interrupt an operation by pressing Ctrl-C.

Signed-off-by: David Howells <dhowells@redhat.com>
2019-04-25 14:26:50 +01:00
Linus Torvalds
12a54b150f Fix miscellaneous nfsd bugs, in NFSv4.1 callbacks, NFSv4.1
lock-notification callbacks, NFSv3 readdir encoding, and the
 cache/upcall code.
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Merge tag 'nfsd-5.1-1' of git://linux-nfs.org/~bfields/linux

Pull nfsd bugfixes from Bruce Fields:
 "Fix miscellaneous nfsd bugs, in NFSv4.1 callbacks, NFSv4.1
  lock-notification callbacks, NFSv3 readdir encoding, and the
  cache/upcall code"

* tag 'nfsd-5.1-1' of git://linux-nfs.org/~bfields/linux:
  nfsd: wake blocked file lock waiters before sending callback
  nfsd: wake waiters blocked on file_lock before deleting it
  nfsd: Don't release the callback slot unless it was actually held
  nfsd/nfsd3_proc_readdir: fix buffer count and page pointers
  sunrpc: don't mark uninitialised items as VALID.
2019-04-23 13:40:55 -07:00
Jeff Layton
f456458e4d nfsd: wake blocked file lock waiters before sending callback
When a blocked NFS lock is "awoken" we send a callback to the server and
then wake any hosts waiting on it. If a client attempts to get a lock
and then drops off the net, we could end up waiting for a long time
until we end up waking locks blocked on that request.

So, wake any other waiting lock requests before sending the callback.
Do this by calling locks_delete_block in a new "prepare" phase for
CB_NOTIFY_LOCK callbacks.

URL: https://bugzilla.kernel.org/show_bug.cgi?id=203363
Fixes: 16306a61d3 ("fs/locks: always delete_block after waiting.")
Reported-by: Slawomir Pryczek <slawek1211@gmail.com>
Cc: Neil Brown <neilb@suse.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2019-04-22 15:38:41 -04:00
Jeff Layton
6aaafc43a4 nfsd: wake waiters blocked on file_lock before deleting it
After a blocked nfsd file_lock request is deleted, knfsd will send a
callback to the client and then free the request. Commit 16306a61d3
("fs/locks: always delete_block after waiting.") changed it such that
locks_delete_block is always called on a request after it is awoken,
but that patch missed fixing up blocked nfsd request handling.

Call locks_delete_block on the block to wake up any locks still blocked
on the nfsd lock request before freeing it. Some of its callers already
do this however, so just remove those calls.

URL: https://bugzilla.kernel.org/show_bug.cgi?id=203363
Fixes: 16306a61d3 ("fs/locks: always delete_block after waiting.")
Reported-by: Slawomir Pryczek <slawek1211@gmail.com>
Cc: Neil Brown <neilb@suse.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2019-04-22 15:31:54 -04:00
Linus Torvalds
38a2ca2cac for-linus-20190420
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Merge tag 'for-linus-20190420' of git://git.kernel.dk/linux-block

Pull block fixes from Jens Axboe:
 "A set of small fixes that should go into this series. This contains:

   - Removal of unused queue member (Hou)

   - Overflow bvec fix (Ming)

   - Various little io_uring tweaks (me)
       - kthread parking
       - Only call cpu_possible() for verified CPU
       - Drop unused 'file' argument to io_file_put()
       - io_uring_enter vs io_uring_register deadlock fix
       - CQ overflow fix

   - BFQ internal depth update fix (me)"

* tag 'for-linus-20190420' of git://git.kernel.dk/linux-block:
  block: make sure that bvec length can't be overflow
  block: kill all_q_node in request_queue
  io_uring: fix CQ overflow condition
  io_uring: fix possible deadlock between io_uring_{enter,register}
  io_uring: drop io_file_put() 'file' argument
  bfq: update internal depth state when queue depth changes
  io_uring: only test SQPOLL cpu after we've verified it
  io_uring: park SQPOLL thread if it's percpu
2019-04-20 12:20:58 -07:00
Andrea Arcangeli
04f5866e41 coredump: fix race condition between mmget_not_zero()/get_task_mm() and core dumping
The core dumping code has always run without holding the mmap_sem for
writing, despite that is the only way to ensure that the entire vma
layout will not change from under it.  Only using some signal
serialization on the processes belonging to the mm is not nearly enough.
This was pointed out earlier.  For example in Hugh's post from Jul 2017:

  https://lkml.kernel.org/r/alpine.LSU.2.11.1707191716030.2055@eggly.anvils

  "Not strictly relevant here, but a related note: I was very surprised
   to discover, only quite recently, how handle_mm_fault() may be called
   without down_read(mmap_sem) - when core dumping. That seems a
   misguided optimization to me, which would also be nice to correct"

In particular because the growsdown and growsup can move the
vm_start/vm_end the various loops the core dump does around the vma will
not be consistent if page faults can happen concurrently.

Pretty much all users calling mmget_not_zero()/get_task_mm() and then
taking the mmap_sem had the potential to introduce unexpected side
effects in the core dumping code.

Adding mmap_sem for writing around the ->core_dump invocation is a
viable long term fix, but it requires removing all copy user and page
faults and to replace them with get_dump_page() for all binary formats
which is not suitable as a short term fix.

For the time being this solution manually covers the places that can
confuse the core dump either by altering the vma layout or the vma flags
while it runs.  Once ->core_dump runs under mmap_sem for writing the
function mmget_still_valid() can be dropped.

Allowing mmap_sem protected sections to run in parallel with the
coredump provides some minor parallelism advantage to the swapoff code
(which seems to be safe enough by never mangling any vma field and can
keep doing swapins in parallel to the core dumping) and to some other
corner case.

In order to facilitate the backporting I added "Fixes: 86039bd3b4e6"
however the side effect of this same race condition in /proc/pid/mem
should be reproducible since before 2.6.12-rc2 so I couldn't add any
other "Fixes:" because there's no hash beyond the git genesis commit.

Because find_extend_vma() is the only location outside of the process
context that could modify the "mm" structures under mmap_sem for
reading, by adding the mmget_still_valid() check to it, all other cases
that take the mmap_sem for reading don't need the new check after
mmget_not_zero()/get_task_mm().  The expand_stack() in page fault
context also doesn't need the new check, because all tasks under core
dumping are frozen.

Link: http://lkml.kernel.org/r/20190325224949.11068-1-aarcange@redhat.com
Fixes: 86039bd3b4 ("userfaultfd: add new syscall to provide memory externalization")
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Jann Horn <jannh@google.com>
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Jann Horn <jannh@google.com>
Acked-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-04-19 09:46:05 -07:00
Linus Torvalds
2a852fd1ac AFS fixes
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Merge tag 'afs-fixes-20190413' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull AFS fixes from David Howells:

 - Stop using the deprecated get_seconds().

 - Don't make tracepoint strings const as the section they go in isn't
   read-only.

 - Differentiate failure due to unmarshalling from other failure cases.
   We shouldn't abort with RXGEN_CC/SS_UNMARSHAL if it's not due to
   unmarshalling.

 - Add a missing unlock_page().

 - Fix the interaction between receiving a notification from a server
   that it has invalidated all outstanding callback promises and a
   client call that we're in the middle of making that will get a new
   promise.

* tag 'afs-fixes-20190413' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: Fix in-progess ops to ignore server-level callback invalidation
  afs: Unlock pages for __pagevec_release()
  afs: Differentiate abort due to unmarshalling from other errors
  afs: Avoid section confusion in CM_NAME
  afs: avoid deprecated get_seconds()
2019-04-18 08:10:22 -07:00
Linus Torvalds
e53f31bffe five small SMB3 fixes, all also for stable - an important fix for an oplock (lease) bug, a handle leak, and 3 bugs spotted by KASAN
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Merge tag '5.1-rc5-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6

Pull smb3 fixes from Steve French:
 "Five small SMB3 fixes, all also for stable - an important fix for an
  oplock (lease) bug, a handle leak, and three bugs spotted by KASAN"

* tag '5.1-rc5-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  CIFS: keep FileInfo handle live during oplock break
  cifs: fix handle leak in smb2_query_symlink()
  cifs: Fix lease buffer length error
  cifs: Fix use-after-free in SMB2_read
  cifs: Fix use-after-free in SMB2_write
2019-04-17 13:36:45 -07:00
Jens Axboe
74f464e970 io_uring: fix CQ overflow condition
This is a leftover from when the rings initially were not free flowing,
and hence a test for tail + 1 == head would indicate full. Since we now
let them wrap instead of mask them with the size, we need to check if
they drift more than the ring size from each other.

This fixes a case where we'd overwrite CQ ring entries, if the user
failed to reap completions. Both cases would ultimately result in lost
completions as the application violated the depth it asked for. The only
difference is that before this fix we'd return invalid entries for the
overflowed completions, instead of properly flagging it in the
cq_ring->overflow variable.

Reported-by: Stefan Bühler <source@stbuehler.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-17 11:41:49 -06:00
Linus Torvalds
2a3a028fc6 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking fixes from David Miller:

 1) Handle init flow failures properly in iwlwifi driver, from Shahar S
    Matityahu.

 2) mac80211 TXQs need to be unscheduled on powersave start, from Felix
    Fietkau.

 3) SKB memory accounting fix in A-MDSU aggregation, from Felix Fietkau.

 4) Increase RCU lock hold time in mlx5 FPGA code, from Saeed Mahameed.

 5) Avoid checksum complete with XDP in mlx5, also from Saeed.

 6) Fix netdev feature clobbering in ibmvnic driver, from Thomas Falcon.

 7) Partial sent TLS record leak fix from Jakub Kicinski.

 8) Reject zero size iova range in vhost, from Jason Wang.

 9) Allow pending work to complete before clcsock release from Karsten
    Graul.

10) Fix XDP handling max MTU in thunderx, from Matteo Croce.

11) A lot of protocols look at the sa_family field of a sockaddr before
    validating it's length is large enough, from Tetsuo Handa.

12) Don't write to free'd pointer in qede ptp error path, from Colin Ian
    King.

13) Have to recompile IP options in ipv4_link_failure because it can be
    invoked from ARP, from Stephen Suryaputra.

14) Doorbell handling fixes in qed from Denis Bolotin.

15) Revert net-sysfs kobject register leak fix, it causes new problems.
    From Wang Hai.

16) Spectre v1 fix in ATM code, from Gustavo A. R. Silva.

17) Fix put of BROPT_VLAN_STATS_PER_PORT in bridging code, from Nikolay
    Aleksandrov.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (111 commits)
  socket: fix compat SO_RCVTIMEO_NEW/SO_SNDTIMEO_NEW
  tcp: tcp_grow_window() needs to respect tcp_space()
  ocelot: Clean up stats update deferred work
  ocelot: Don't sleep in atomic context (irqs_disabled())
  net: bridge: fix netlink export of vlan_stats_per_port option
  qed: fix spelling mistake "faspath" -> "fastpath"
  tipc: set sysctl_tipc_rmem and named_timeout right range
  tipc: fix link established but not in session
  net: Fix missing meta data in skb with vlan packet
  net: atm: Fix potential Spectre v1 vulnerabilities
  net/core: work around section mismatch warning for ptp_classifier
  net: bridge: fix per-port af_packet sockets
  bnx2x: fix spelling mistake "dicline" -> "decline"
  route: Avoid crash from dereferencing NULL rt->from
  MAINTAINERS: normalize Woojung Huh's email address
  bonding: fix event handling for stacked bonds
  Revert "net-sysfs: Fix memory leak in netdev_register_kobject"
  rtnetlink: fix rtnl_valid_stats_req() nlmsg_len check
  qed: Fix the DORQ's attentions handling
  qed: Fix missing DORQ attentions
  ...
2019-04-17 09:57:45 -07:00
Aurelien Aptel
b98749cac4 CIFS: keep FileInfo handle live during oplock break
In the oplock break handler, writing pending changes from pages puts
the FileInfo handle. If the refcount reaches zero it closes the handle
and waits for any oplock break handler to return, thus causing a deadlock.

To prevent this situation:

* We add a wait flag to cifsFileInfo_put() to decide whether we should
  wait for running/pending oplock break handlers

* We keep an additionnal reference of the SMB FileInfo handle so that
  for the rest of the handler putting the handle won't close it.
  - The ref is bumped everytime we queue the handler via the
    cifs_queue_oplock_break() helper.
  - The ref is decremented at the end of the handler

This bug was triggered by xfstest 464.

Also important fix to address the various reports of
oops in smb2_push_mandatory_locks

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
CC: Stable <stable@vger.kernel.org>
2019-04-16 09:38:38 -05:00
Ronnie Sahlberg
e6d0fb7b34 cifs: fix handle leak in smb2_query_symlink()
If we enter smb2_query_symlink() for something that is not a symlink
and where the SMB2_open() would succeed we would never end up
closing this handle and would thus leak a handle on the server.

Fix this by immediately calling SMB2_close() on successfull open.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2019-04-16 09:38:26 -05:00
ZhangXiaoxu
b57a55e220 cifs: Fix lease buffer length error
There is a KASAN slab-out-of-bounds:
BUG: KASAN: slab-out-of-bounds in _copy_from_iter_full+0x783/0xaa0
Read of size 80 at addr ffff88810c35e180 by task mount.cifs/539

CPU: 1 PID: 539 Comm: mount.cifs Not tainted 4.19 #10
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
            rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
Call Trace:
 dump_stack+0xdd/0x12a
 print_address_description+0xa7/0x540
 kasan_report+0x1ff/0x550
 check_memory_region+0x2f1/0x310
 memcpy+0x2f/0x80
 _copy_from_iter_full+0x783/0xaa0
 tcp_sendmsg_locked+0x1840/0x4140
 tcp_sendmsg+0x37/0x60
 inet_sendmsg+0x18c/0x490
 sock_sendmsg+0xae/0x130
 smb_send_kvec+0x29c/0x520
 __smb_send_rqst+0x3ef/0xc60
 smb_send_rqst+0x25a/0x2e0
 compound_send_recv+0x9e8/0x2af0
 cifs_send_recv+0x24/0x30
 SMB2_open+0x35e/0x1620
 open_shroot+0x27b/0x490
 smb2_open_op_close+0x4e1/0x590
 smb2_query_path_info+0x2ac/0x650
 cifs_get_inode_info+0x1058/0x28f0
 cifs_root_iget+0x3bb/0xf80
 cifs_smb3_do_mount+0xe00/0x14c0
 cifs_do_mount+0x15/0x20
 mount_fs+0x5e/0x290
 vfs_kern_mount+0x88/0x460
 do_mount+0x398/0x31e0
 ksys_mount+0xc6/0x150
 __x64_sys_mount+0xea/0x190
 do_syscall_64+0x122/0x590
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

It can be reproduced by the following step:
  1. samba configured with: server max protocol = SMB2_10
  2. mount -o vers=default

When parse the mount version parameter, the 'ops' and 'vals'
was setted to smb30,  if negotiate result is smb21, just
update the 'ops' to smb21, but the 'vals' is still smb30.
When add lease context, the iov_base is allocated with smb21
ops, but the iov_len is initiallited with the smb30. Because
the iov_len is longer than iov_base, when send the message,
copy array out of bounds.

we need to keep the 'ops' and 'vals' consistent.

Fixes: 9764c02fcb ("SMB3: Add support for multidialect negotiate (SMB2.1 and later)")
Fixes: d5c7076b77 ("smb3: add smb3.1.1 to default dialect list")

Signed-off-by: ZhangXiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2019-04-16 09:38:23 -05:00
ZhangXiaoxu
088aaf17aa cifs: Fix use-after-free in SMB2_read
There is a KASAN use-after-free:
BUG: KASAN: use-after-free in SMB2_read+0x1136/0x1190
Read of size 8 at addr ffff8880b4e45e50 by task ln/1009

Should not release the 'req' because it will use in the trace.

Fixes: eccb4422cf ("smb3: Add ftrace tracepoints for improved SMB3 debugging")

Signed-off-by: ZhangXiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org> 4.18+
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2019-04-16 09:38:21 -05:00
ZhangXiaoxu
6a3eb33606 cifs: Fix use-after-free in SMB2_write
There is a KASAN use-after-free:
BUG: KASAN: use-after-free in SMB2_write+0x1342/0x1580
Read of size 8 at addr ffff8880b6a8e450 by task ln/4196

Should not release the 'req' because it will use in the trace.

Fixes: eccb4422cf ("smb3: Add ftrace tracepoints for improved SMB3 debugging")

Signed-off-by: ZhangXiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org> 4.18+
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2019-04-16 09:38:18 -05:00
Linus Torvalds
5512320c9f fsdax fix 5.1-rc6
- Avoid a crash scenario with architectures like powerpc that require
   'pgtable_deposit' for the zero page.
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Merge tag 'fsdax-fix-5.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull fsdax fix from Dan Williams:
 "A single filesystem-dax fix. It has been lingering in -next for a long
  while and there are no other fsdax fixes on the horizon:

   - Avoid a crash scenario with architectures like powerpc that require
     'pgtable_deposit' for the zero page"

* tag 'fsdax-fix-5.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  fs/dax: Deposit pagetable even when installing zero page
2019-04-15 15:10:20 -07:00
Jens Axboe
b19062a567 io_uring: fix possible deadlock between io_uring_{enter,register}
If we have multiple threads, one doing io_uring_enter() while the other
is doing io_uring_register(), we can run into a deadlock between the
two. io_uring_register() must wait for existing users of the io_uring
instance to exit. But it does so while holding the io_uring mutex.
Callers of io_uring_enter() may need this mutex to make progress (and
eventually exit). If we wait for users to exit in io_uring_register(),
we can't do so with the io_uring mutex held without potentially risking
a deadlock.

Drop the io_uring mutex while waiting for existing callers to exit. This
is safe and guaranteed to make forward progress, since we already killed
the percpu ref before doing so. Hence later callers of io_uring_enter()
will be rejected.

Reported-by: syzbot+16dc03452dee970a0c3e@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-15 10:49:38 -06:00
Linus Torvalds
6b3a707736 Merge branch 'page-refs' (page ref overflow)
Merge page ref overflow branch.

Jann Horn reported that he can overflow the page ref count with
sufficient memory (and a filesystem that is intentionally extremely
slow).

Admittedly it's not exactly easy.  To have more than four billion
references to a page requires a minimum of 32GB of kernel memory just
for the pointers to the pages, much less any metadata to keep track of
those pointers.  Jann needed a total of 140GB of memory and a specially
crafted filesystem that leaves all reads pending (in order to not ever
free the page references and just keep adding more).

Still, we have a fairly straightforward way to limit the two obvious
user-controllable sources of page references: direct-IO like page
references gotten through get_user_pages(), and the splice pipe page
duplication.  So let's just do that.

* branch page-refs:
  fs: prevent page refcount overflow in pipe_buf_get
  mm: prevent get_user_pages() from overflowing page refcount
  mm: add 'try_get_page()' helper function
  mm: make page ref count overflow check tighter and more explicit
2019-04-14 15:09:40 -07:00
Matthew Wilcox
15fab63e1e fs: prevent page refcount overflow in pipe_buf_get
Change pipe_buf_get() to return a bool indicating whether it succeeded
in raising the refcount of the page (if the thing in the pipe is a page).
This removes another mechanism for overflowing the page refcount.  All
callers converted to handle a failure.

Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-04-14 10:00:04 -07:00
Jens Axboe
3d6770fbd9 io_uring: drop io_file_put() 'file' argument
Since the fget/fput handling was reworked in commit 09bb839434, we
never call io_file_put() with state == NULL (and hence file != NULL)
anymore. Remove that case.

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-13 19:08:22 -06:00
Jens Axboe
917257daa0 io_uring: only test SQPOLL cpu after we've verified it
We currently call cpu_possible() even if we don't use the CPU. Move the
test under the SQ_AFF branch, which is the only place where we'll use
the value. Do the cpu_possible() test AFTER we've limited it to a max
of NR_CPUS. This avoids triggering the following warning:

WARNING: CPU: 1 PID: 7600 at include/linux/cpumask.h:121 cpu_max_bits_warn

if CONFIG_DEBUG_PER_CPU_MAPS is enabled.

While in there, also move the SQ thread idle period assignment inside
SETUP_SQPOLL, as we don't use it otherwise either.

Reported-by: syzbot+cd714a07c6de2bc34293@syzkaller.appspotmail.com
Fixes: 6c271ce2f1 ("io_uring: add submission polling")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-13 19:08:22 -06:00
Jens Axboe
0605863246 io_uring: park SQPOLL thread if it's percpu
kthread expects this, or we can throw a warning on exit:

WARNING: CPU: 0 PID: 7822 at kernel/kthread.c:399
__kthread_bind_mask+0x3b/0xc0 kernel/kthread.c:399
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 7822 Comm: syz-executor030 Not tainted 5.1.0-rc4-next-20190412
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x172/0x1f0 lib/dump_stack.c:113
  panic+0x2cb/0x72b kernel/panic.c:214
  __warn.cold+0x20/0x46 kernel/panic.c:576
  report_bug+0x263/0x2b0 lib/bug.c:186
  fixup_bug arch/x86/kernel/traps.c:179 [inline]
  fixup_bug arch/x86/kernel/traps.c:174 [inline]
  do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272
  do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:291
  invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973
RIP: 0010:__kthread_bind_mask+0x3b/0xc0 kernel/kthread.c:399
Code: 48 89 fb e8 f7 ab 24 00 4c 89 e6 48 89 df e8 ac e1 02 00 31 ff 49 89
c4 48 89 c6 e8 7f ad 24 00 4d 85 e4 75 15 e8 d5 ab 24 00 <0f> 0b e8 ce ab
24 00 5b 41 5c 41 5d 41 5e 5d c3 e8 c0 ab 24 00 4c
RSP: 0018:ffff8880a89bfbb8 EFLAGS: 00010293
RAX: ffff88808ca7a280 RBX: ffff8880a98e4380 RCX: ffffffff814bdd11
RDX: 0000000000000000 RSI: ffffffff814bdd1b RDI: 0000000000000007
RBP: ffff8880a89bfbd8 R08: ffff88808ca7a280 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff87691148 R14: ffff8880a98e43a0 R15: ffffffff81c91e10
  __kthread_bind kernel/kthread.c:412 [inline]
  kthread_unpark+0x123/0x160 kernel/kthread.c:480
  kthread_stop+0xfa/0x6c0 kernel/kthread.c:556
  io_sq_thread_stop fs/io_uring.c:2057 [inline]
  io_sq_thread_stop fs/io_uring.c:2052 [inline]
  io_finish_async+0xab/0x180 fs/io_uring.c:2064
  io_ring_ctx_free fs/io_uring.c:2534 [inline]
  io_ring_ctx_wait_and_kill+0x133/0x510 fs/io_uring.c:2591
  io_uring_release+0x42/0x50 fs/io_uring.c:2599
  __fput+0x2e5/0x8d0 fs/file_table.c:278
  ____fput+0x16/0x20 fs/file_table.c:309
  task_work_run+0x14a/0x1c0 kernel/task_work.c:113
  exit_task_work include/linux/task_work.h:22 [inline]
  do_exit+0x90a/0x2fa0 kernel/exit.c:876
  do_group_exit+0x135/0x370 kernel/exit.c:980
  __do_sys_exit_group kernel/exit.c:991 [inline]
  __se_sys_exit_group kernel/exit.c:989 [inline]
  __x64_sys_exit_group+0x44/0x50 kernel/exit.c:989
  do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

Reported-by: syzbot+6d4a92619eb0ad08602b@syzkaller.appspotmail.com
Fixes: 6c271ce2f1 ("io_uring: add submission polling")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-13 19:08:22 -06:00
Linus Torvalds
4443f8e6ac for-linus-20190412
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Merge tag 'for-linus-20190412' of git://git.kernel.dk/linux-block

Pull block fixes from Jens Axboe:
 "Set of fixes that should go into this round. This pull is larger than
  I'd like at this time, but there's really no specific reason for that.
  Some are fixes for issues that went into this merge window, others are
  not. Anyway, this contains:

   - Hardware queue limiting for virtio-blk/scsi (Dongli)

   - Multi-page bvec fixes for lightnvm pblk

   - Multi-bio dio error fix (Jason)

   - Remove the cache hint from the io_uring tool side, since we didn't
     move forward with that (me)

   - Make io_uring SETUP_SQPOLL root restricted (me)

   - Fix leak of page in error handling for pc requests (Jérôme)

   - Fix BFQ regression introduced in this merge window (Paolo)

   - Fix break logic for bio segment iteration (Ming)

   - Fix NVMe cancel request error handling (Ming)

   - NVMe pull request with two fixes (Christoph):
       - fix the initial CSN for nvme-fc (James)
       - handle log page offsets properly in the target (Keith)"

* tag 'for-linus-20190412' of git://git.kernel.dk/linux-block:
  block: fix the return errno for direct IO
  nvmet: fix discover log page when offsets are used
  nvme-fc: correct csn initialization and increments on error
  block: do not leak memory in bio_copy_user_iov()
  lightnvm: pblk: fix crash in pblk_end_partial_read due to multipage bvecs
  nvme: cancel request synchronously
  blk-mq: introduce blk_mq_complete_request_sync()
  scsi: virtio_scsi: limit number of hw queues by nr_cpu_ids
  virtio-blk: limit number of hw queues by nr_cpu_ids
  block, bfq: fix use after free in bfq_bfqq_expire
  io_uring: restrict IORING_SETUP_SQPOLL to root
  tools/io_uring: remove IOCQE_FLAG_CACHEHIT
  block: don't use for-inside-for in bio_for_each_segment_all
2019-04-13 16:23:16 -07:00
Linus Torvalds
b60bc0665e NFS client bugfixes for Linux 5.1
Highlights include:
 
 Stable fixes:
 - Fix a deadlock in close() due to incorrect draining of RDMA queues
 
 Bugfixes:
 - Revert "SUNRPC: Micro-optimise when the task is known not to be sleeping"
   as it is causing stack overflows
 - Fix a regression where NFSv4 getacl and fs_locations stopped working
 - Forbid setting AF_INET6 to "struct sockaddr_in"->sin_family.
 - Fix xfstests failures due to incorrect copy_file_range() return values
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Merge tag 'nfs-for-5.1-4' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client bugfixes from Trond Myklebust:
 "Highlights include:

  Stable fix:

   - Fix a deadlock in close() due to incorrect draining of RDMA queues

  Bugfixes:

   - Revert "SUNRPC: Micro-optimise when the task is known not to be
     sleeping" as it is causing stack overflows

   - Fix a regression where NFSv4 getacl and fs_locations stopped
     working

   - Forbid setting AF_INET6 to "struct sockaddr_in"->sin_family.

   - Fix xfstests failures due to incorrect copy_file_range() return
     values"

* tag 'nfs-for-5.1-4' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  Revert "SUNRPC: Micro-optimise when the task is known not to be sleeping"
  NFSv4.1 fix incorrect return value in copy_file_range
  xprtrdma: Fix helper that drains the transport
  NFS: Fix handling of reply page vector
  NFS: Forbid setting AF_INET6 to "struct sockaddr_in"->sin_family.
2019-04-13 14:47:06 -07:00
David Howells
eeba1e9cf3 afs: Fix in-progess ops to ignore server-level callback invalidation
The in-kernel afs filesystem client counts the number of server-level
callback invalidation events (CB.InitCallBackState* RPC operations) that it
receives from the server.  This is stored in cb_s_break in various
structures, including afs_server and afs_vnode.

If an inode is examined by afs_validate(), say, the afs_server copy is
compared, along with other break counters, to those in afs_vnode, and if
one or more of the counters do not match, it is considered that the
server's callback promise is broken.  At points where this happens,
AFS_VNODE_CB_PROMISED is cleared to indicate that the status must be
refetched from the server.

afs_validate() issues an FS.FetchStatus operation to get updated metadata -
and based on the updated data_version may invalidate the pagecache too.

However, the break counters are also used to determine whether to note a
new callback in the vnode (which would set the AFS_VNODE_CB_PROMISED flag)
and whether to cache the permit data included in the YFSFetchStatus record
by the server.


The problem comes when the server sends us a CB.InitCallBackState op.  The
first such instance doesn't cause cb_s_break to be incremented, but rather
causes AFS_SERVER_FL_NEW to be cleared - but thereafter, say some hours
after last use and all the volumes have been automatically unmounted and
the server has forgotten about the client[*], this *will* likely cause an
increment.

 [*] There are other circumstances too, such as the server restarting or
     needing to make space in its callback table.

Note that the server won't send us a CB.InitCallBackState op until we talk
to it again.

So what happens is:

 (1) A mount for a new volume is attempted, a inode is created for the root
     vnode and vnode->cb_s_break and AFS_VNODE_CB_PROMISED aren't set
     immediately, as we don't have a nominated server to talk to yet - and
     we may iterate through a few to find one.

 (2) Before the operation happens, afs_fetch_status(), say, notes in the
     cursor (fc.cb_break) the break counter sum from the vnode, volume and
     server counters, but the server->cb_s_break is currently 0.

 (3) We send FS.FetchStatus to the server.  The server sends us back
     CB.InitCallBackState.  We increment server->cb_s_break.

 (4) Our FS.FetchStatus completes.  The reply includes a callback record.

 (5) xdr_decode_AFSCallBack()/xdr_decode_YFSCallBack() check to see whether
     the callback promise was broken by checking the break counter sum from
     step (2) against the current sum.

     This fails because of step (3), so we don't set the callback record
     and, importantly, don't set AFS_VNODE_CB_PROMISED on the vnode.

This does not preclude the syscall from progressing, and we don't loop here
rechecking the status, but rather assume it's good enough for one round
only and will need to be rechecked next time.

 (6) afs_validate() it triggered on the vnode, probably called from
     d_revalidate() checking the parent directory.

 (7) afs_validate() notes that AFS_VNODE_CB_PROMISED isn't set, so doesn't
     update vnode->cb_s_break and assumes the vnode to be invalid.

 (8) afs_validate() needs to calls afs_fetch_status().  Go back to step (2)
     and repeat, every time the vnode is validated.

This primarily affects volume root dir vnodes.  Everything subsequent to
those inherit an already incremented cb_s_break upon mounting.


The issue is that we assume that the callback record and the cached permit
information in a reply from the server can't be trusted after getting a
server break - but this is wrong since the server makes sure things are
done in the right order, holding up our ops if necessary[*].

 [*] There is an extremely unlikely scenario where a reply from before the
     CB.InitCallBackState could get its delivery deferred till after - at
     which point we think we have a promise when we don't.  This, however,
     requires unlucky mass packet loss to one call.

AFS_SERVER_FL_NEW tries to paper over the cracks for the initial mount from
a server we've never contacted before, but this should be unnecessary.
It's also further insulated from the problem on an initial mount by
querying the server first with FS.GetCapabilities, which triggers the
CB.InitCallBackState.


Fix this by

 (1) Remove AFS_SERVER_FL_NEW.

 (2) In afs_calc_vnode_cb_break(), don't include cb_s_break in the
     calculation.

 (3) In afs_cb_is_broken(), don't include cb_s_break in the check.


Signed-off-by: David Howells <dhowells@redhat.com>
2019-04-13 08:37:37 +01:00
Marc Dionne
21bd68f196 afs: Unlock pages for __pagevec_release()
__pagevec_release() complains loudly if any page in the vector is still
locked.  The pages need to be locked for generic_error_remove_page(), but
that function doesn't actually unlock them.

Unlock the pages afterwards.

Signed-off-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Jonathan Billings <jsbillin@umich.edu>
2019-04-13 08:37:37 +01:00
David Howells
8022c4b95c afs: Differentiate abort due to unmarshalling from other errors
Differentiate an abort due to an unmarshalling error from an abort due to
other errors, such as ENETUNREACH.  It doesn't make sense to set abort code
RXGEN_*_UNMARSHAL in such a case, so use RX_USER_ABORT instead.

Signed-off-by: David Howells <dhowells@redhat.com>
2019-04-13 08:37:37 +01:00
Andi Kleen
d2abfa86ff afs: Avoid section confusion in CM_NAME
__tracepoint_str cannot be const because the tracepoint_str
section is not read-only. Remove the stray const.

Cc: dhowells@redhat.com
Cc: viro@zeniv.linux.org.uk
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2019-04-13 08:37:36 +01:00
Arnd Bergmann
ba25b81e3a afs: avoid deprecated get_seconds()
get_seconds() has a limited range on 32-bit architectures and is
deprecated because of that. While AFS uses the same limits for
its inode timestamps on the wire protocol, let's just use the
simpler current_time() as we do for other file systems.

This will still zero out the 'tv_nsec' field of the timestamps
internally.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David Howells <dhowells@redhat.com>
2019-04-13 08:37:36 +01:00
Marc Dionne
f7f1dd3162 afs: Check for rxrpc call completion in wait loop
Check the state of the rxrpc call backing an afs call in each iteration of
the call wait loop in case the rxrpc call has already been terminated at
the rxrpc layer.

Interrupt the wait loop and mark the afs call as complete if the rxrpc
layer call is complete.

There were cases where rxrpc errors were not passed up to afs, which could
result in this loop waiting forever for an afs call to transition to
AFS_CALL_COMPLETE while the rx call was already complete.

Signed-off-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-12 16:57:23 -07:00
Marc Dionne
4611da30d6 rxrpc: Make rxrpc_kernel_check_life() indicate if call completed
Make rxrpc_kernel_check_life() pass back the life counter through the
argument list and return true if the call has not yet completed.

Suggested-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-12 16:57:23 -07:00
Jason Yan
a89afe58f1 block: fix the return errno for direct IO
If the last bio returned is not dio->bio, the status of the bio will
not assigned to dio->bio if it is error. This will cause the whole IO
status wrong.

    ksoftirqd/21-117   [021] ..s.  4017.966090:   8,0    C   N 4883648 [0]
          <idle>-0     [018] ..s.  4017.970888:   8,0    C  WS 4924800 + 1024 [0]
          <idle>-0     [018] ..s.  4017.970909:   8,0    D  WS 4935424 + 1024 [<idle>]
          <idle>-0     [018] ..s.  4017.970924:   8,0    D  WS 4936448 + 321 [<idle>]
    ksoftirqd/21-117   [021] ..s.  4017.995033:   8,0    C   R 4883648 + 336 [65475]
    ksoftirqd/21-117   [021] d.s.  4018.001988: myprobe1: (blkdev_bio_end_io+0x0/0x168) bi_status=7
    ksoftirqd/21-117   [021] d.s.  4018.001992: myprobe: (aio_complete_rw+0x0/0x148) x0=0xffff802f2595ad80 res=0x12a000 res2=0x0

We always have to assign bio->bi_status to dio->bio.bi_status because we
will only check dio->bio.bi_status when we return the whole IO to
the upper layer.

Fixes: 542ff7bf18 ("block: new direct I/O implementation")
Cc: stable@vger.kernel.org
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-11 21:22:21 -06:00
Linus Torvalds
2d06b23581 for-5.1-rc4-tag
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Merge tag 'for-5.1-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

 - fix parsing of compression algorithm when set as a inode property,
   this could end up with eg. 'zst' or 'zli' in the value

 - don't allow trim on a filesystem with unreplayed log, this could
   cause data loss if there are pending updates to the block groups that
   would not be subject to trim after replay

* tag 'for-5.1-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: prop: fix vanished compression property after failed set
  btrfs: prop: fix zstd compression parameter validation
  Btrfs: do not allow trimming when a fs is mounted with the nologreplay option
2019-04-11 14:19:02 -07:00
Olga Kornievskaia
0769663b4f NFSv4.1 fix incorrect return value in copy_file_range
According to the NFSv4.2 spec if the input and output file is the
same file, operation should fail with EINVAL. However, linux
copy_file_range() system call has no such restrictions. Therefore,
in such case let's return EOPNOTSUPP and allow VFS to fallback
to doing do_splice_direct(). Also when copy_file_range is called
on an NFSv4.0 or 4.1 mount (ie., a server that doesn't support
COPY functionality), we also need to return EOPNOTSUPP and
fallback to a regular copy.

Fixes xfstest generic/075, generic/091, generic/112, generic/263
for all NFSv4.x versions.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-04-11 15:23:48 -04:00
Chuck Lever
29e7ca715f NFS: Fix handling of reply page vector
NFSv4 GETACL and FS_LOCATIONS requests stopped working in v5.1-rc.

These two need the extra padding to be added directly to the reply
length.

Reported-by: Olga Kornievskaia <aglo@umich.edu>
Fixes: 02ef04e432 ("NFS: Account for XDR pad of buf->pages")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Olga Kornievskaia <aglo@umich.edu>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-04-11 15:23:48 -04:00
Tetsuo Handa
7c2bd9a398 NFS: Forbid setting AF_INET6 to "struct sockaddr_in"->sin_family.
syzbot is reporting uninitialized value at rpc_sockaddr2uaddr() [1]. This
is because syzbot is setting AF_INET6 to "struct sockaddr_in"->sin_family
(which is embedded into user-visible "struct nfs_mount_data" structure)
despite nfs23_validate_mount_data() cannot pass sizeof(struct sockaddr_in6)
bytes of AF_INET6 address to rpc_sockaddr2uaddr().

Since "struct nfs_mount_data" structure is user-visible, we can't change
"struct nfs_mount_data" to use "struct sockaddr_storage". Therefore,
assuming that everybody is using AF_INET family when passing address via
"struct nfs_mount_data"->addr, reject if its sin_family is not AF_INET.

[1] https://syzkaller.appspot.com/bug?id=599993614e7cbbf66bc2656a919ab2a95fb5d75c

Reported-by: syzbot <syzbot+047a11c361b872896a4f@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-04-11 15:23:48 -04:00
Linus Torvalds
972acfb494 Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc fixes from Al Viro:
 "A few regression fixes from this cycle"

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  aio: use kmem_cache_free() instead of kfree()
  iov_iter: Fix build error without CONFIG_CRYPTO
  aio: Fix an error code in __io_submit_one()
2019-04-09 16:20:59 -10:00
Jens Axboe
3ec482d15c io_uring: restrict IORING_SETUP_SQPOLL to root
This options spawns a kernel side thread that will poll for submissions
(and completions, if IORING_SETUP_IOPOLL is set). As this allows a user
to potentially use more cycles outside of the normal hierarchy,
restrict the use of this feature to root.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-08 10:51:01 -06:00
Trond Myklebust
e6abc8caa6 nfsd: Don't release the callback slot unless it was actually held
If there are multiple callbacks queued, waiting for the callback
slot when the callback gets shut down, then they all currently
end up acting as if they hold the slot, and call
nfsd4_cb_sequence_done() resulting in interesting side-effects.

In addition, the 'retry_nowait' path in nfsd4_cb_sequence_done()
causes a loop back to nfsd4_cb_prepare() without first freeing the
slot, which causes a deadlock when nfsd41_cb_get_slot() gets called
a second time.

This patch therefore adds a boolean to track whether or not the
callback did pick up the slot, so that it can do the right thing
in these 2 cases.

Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2019-04-08 12:43:15 -04:00
Linus Torvalds
429fba106e for-linus-20190407
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Merge tag 'for-linus-20190407' of git://git.kernel.dk/linux-block

Pull block fixes from Jens Axboe:

 - Fixups for the pf/pcd queue handling (YueHaibing)

 - Revert of the three direct issue changes as they have been proven to
   cause an issue with dm-mpath (Bart)

 - Plug rq_count reset fix (Dongli)

 - io_uring double free in fileset registration error handling (me)

 - Make null_blk handle bad numa node passed in (John)

 - BFQ ifdef fix (Konstantin)

 - Flush queue leak fix (Shenghui)

 - Plug trace fix (Yufen)

* tag 'for-linus-20190407' of git://git.kernel.dk/linux-block:
  xsysace: Fix error handling in ace_setup
  null_blk: prevent crash from bad home_node value
  block: Revert v5.0 blk_mq_request_issue_directly() changes
  paride/pcd: Fix potential NULL pointer dereference and mem leak
  blk-mq: do not reset plug->rq_count before the list is sorted
  paride/pf: Fix potential NULL pointer dereference
  io_uring: fix double free in case of fileset regitration failure
  blk-mq: add trace block plug and unplug for multiple queues
  block: use blk_free_flush_queue() to free hctx->fq in blk_mq_init_hctx
  block/bfq: fix ifdef for CONFIG_BFQ_GROUP_IOSCHED=y
2019-04-07 13:28:36 -10:00
Kirill Smelkov
10dce8af34 fs: stream_open - opener for stream-like files so that read and write can run simultaneously without deadlock
Commit 9c225f2655 ("vfs: atomic f_pos accesses as per POSIX") added
locking for file.f_pos access and in particular made concurrent read and
write not possible - now both those functions take f_pos lock for the
whole run, and so if e.g. a read is blocked waiting for data, write will
deadlock waiting for that read to complete.

This caused regression for stream-like files where previously read and
write could run simultaneously, but after that patch could not do so
anymore. See e.g. commit 581d21a2d0 ("xenbus: fix deadlock on writes
to /proc/xen/xenbus") which fixes such regression for particular case of
/proc/xen/xenbus.

The patch that added f_pos lock in 2014 did so to guarantee POSIX thread
safety for read/write/lseek and added the locking to file descriptors of
all regular files. In 2014 that thread-safety problem was not new as it
was already discussed earlier in 2006.

However even though 2006'th version of Linus's patch was adding f_pos
locking "only for files that are marked seekable with FMODE_LSEEK (thus
avoiding the stream-like objects like pipes and sockets)", the 2014
version - the one that actually made it into the tree as 9c225f2655 -
is doing so irregardless of whether a file is seekable or not.

See

    https://lore.kernel.org/lkml/53022DB1.4070805@gmail.com/
    https://lwn.net/Articles/180387
    https://lwn.net/Articles/180396

for historic context.

The reason that it did so is, probably, that there are many files that
are marked non-seekable, but e.g. their read implementation actually
depends on knowing current position to correctly handle the read. Some
examples:

	kernel/power/user.c		snapshot_read
	fs/debugfs/file.c		u32_array_read
	fs/fuse/control.c		fuse_conn_waiting_read + ...
	drivers/hwmon/asus_atk0110.c	atk_debugfs_ggrp_read
	arch/s390/hypfs/inode.c		hypfs_read_iter
	...

Despite that, many nonseekable_open users implement read and write with
pure stream semantics - they don't depend on passed ppos at all. And for
those cases where read could wait for something inside, it creates a
situation similar to xenbus - the write could be never made to go until
read is done, and read is waiting for some, potentially external, event,
for potentially unbounded time -> deadlock.

Besides xenbus, there are 14 such places in the kernel that I've found
with semantic patch (see below):

	drivers/xen/evtchn.c:667:8-24: ERROR: evtchn_fops: .read() can deadlock .write()
	drivers/isdn/capi/capi.c:963:8-24: ERROR: capi_fops: .read() can deadlock .write()
	drivers/input/evdev.c:527:1-17: ERROR: evdev_fops: .read() can deadlock .write()
	drivers/char/pcmcia/cm4000_cs.c:1685:7-23: ERROR: cm4000_fops: .read() can deadlock .write()
	net/rfkill/core.c:1146:8-24: ERROR: rfkill_fops: .read() can deadlock .write()
	drivers/s390/char/fs3270.c:488:1-17: ERROR: fs3270_fops: .read() can deadlock .write()
	drivers/usb/misc/ldusb.c:310:1-17: ERROR: ld_usb_fops: .read() can deadlock .write()
	drivers/hid/uhid.c:635:1-17: ERROR: uhid_fops: .read() can deadlock .write()
	net/batman-adv/icmp_socket.c:80:1-17: ERROR: batadv_fops: .read() can deadlock .write()
	drivers/media/rc/lirc_dev.c:198:1-17: ERROR: lirc_fops: .read() can deadlock .write()
	drivers/leds/uleds.c:77:1-17: ERROR: uleds_fops: .read() can deadlock .write()
	drivers/input/misc/uinput.c:400:1-17: ERROR: uinput_fops: .read() can deadlock .write()
	drivers/infiniband/core/user_mad.c:985:7-23: ERROR: umad_fops: .read() can deadlock .write()
	drivers/gnss/core.c:45:1-17: ERROR: gnss_fops: .read() can deadlock .write()

In addition to the cases above another regression caused by f_pos
locking is that now FUSE filesystems that implement open with
FOPEN_NONSEEKABLE flag, can no longer implement bidirectional
stream-like files - for the same reason as above e.g. read can deadlock
write locking on file.f_pos in the kernel.

FUSE's FOPEN_NONSEEKABLE was added in 2008 in a7c1b990f7 ("fuse:
implement nonseekable open") to support OSSPD. OSSPD implements /dev/dsp
in userspace with FOPEN_NONSEEKABLE flag, with corresponding read and
write routines not depending on current position at all, and with both
read and write being potentially blocking operations:

See

    https://github.com/libfuse/osspd
    https://lwn.net/Articles/308445

    https://github.com/libfuse/osspd/blob/14a9cff0/osspd.c#L1406
    https://github.com/libfuse/osspd/blob/14a9cff0/osspd.c#L1438-L1477
    https://github.com/libfuse/osspd/blob/14a9cff0/osspd.c#L1479-L1510

Corresponding libfuse example/test also describes FOPEN_NONSEEKABLE as
"somewhat pipe-like files ..." with read handler not using offset.
However that test implements only read without write and cannot exercise
the deadlock scenario:

    https://github.com/libfuse/libfuse/blob/fuse-3.4.2-3-ga1bff7d/example/poll.c#L124-L131
    https://github.com/libfuse/libfuse/blob/fuse-3.4.2-3-ga1bff7d/example/poll.c#L146-L163
    https://github.com/libfuse/libfuse/blob/fuse-3.4.2-3-ga1bff7d/example/poll.c#L209-L216

I've actually hit the read vs write deadlock for real while implementing
my FUSE filesystem where there is /head/watch file, for which open
creates separate bidirectional socket-like stream in between filesystem
and its user with both read and write being later performed
simultaneously. And there it is semantically not easy to split the
stream into two separate read-only and write-only channels:

    https://lab.nexedi.com/kirr/wendelin.core/blob/f13aa600/wcfs/wcfs.go#L88-169

Let's fix this regression. The plan is:

1. We can't change nonseekable_open to include &~FMODE_ATOMIC_POS -
   doing so would break many in-kernel nonseekable_open users which
   actually use ppos in read/write handlers.

2. Add stream_open() to kernel to open stream-like non-seekable file
   descriptors. Read and write on such file descriptors would never use
   nor change ppos. And with that property on stream-like files read and
   write will be running without taking f_pos lock - i.e. read and write
   could be running simultaneously.

3. With semantic patch search and convert to stream_open all in-kernel
   nonseekable_open users for which read and write actually do not
   depend on ppos and where there is no other methods in file_operations
   which assume @offset access.

4. Add FOPEN_STREAM to fs/fuse/ and open in-kernel file-descriptors via
   steam_open if that bit is present in filesystem open reply.

   It was tempting to change fs/fuse/ open handler to use stream_open
   instead of nonseekable_open on just FOPEN_NONSEEKABLE flags, but
   grepping through Debian codesearch shows users of FOPEN_NONSEEKABLE,
   and in particular GVFS which actually uses offset in its read and
   write handlers

	https://codesearch.debian.net/search?q=-%3Enonseekable+%3D
	https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1080
	https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1247-1346
	https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1399-1481

   so if we would do such a change it will break a real user.

5. Add stream_open and FOPEN_STREAM handling to stable kernels starting
   from v3.14+ (the kernel where 9c225f2655 first appeared).

   This will allow to patch OSSPD and other FUSE filesystems that
   provide stream-like files to return FOPEN_STREAM | FOPEN_NONSEEKABLE
   in their open handler and this way avoid the deadlock on all kernel
   versions. This should work because fs/fuse/ ignores unknown open
   flags returned from a filesystem and so passing FOPEN_STREAM to a
   kernel that is not aware of this flag cannot hurt. In turn the kernel
   that is not aware of FOPEN_STREAM will be < v3.14 where just
   FOPEN_NONSEEKABLE is sufficient to implement streams without read vs
   write deadlock.

This patch adds stream_open, converts /proc/xen/xenbus to it and adds
semantic patch to automatically locate in-kernel places that are either
required to be converted due to read vs write deadlock, or that are just
safe to be converted because read and write do not use ppos and there
are no other funky methods in file_operations.

Regarding semantic patch I've verified each generated change manually -
that it is correct to convert - and each other nonseekable_open instance
left - that it is either not correct to convert there, or that it is not
converted due to current stream_open.cocci limitations.

The script also does not convert files that should be valid to convert,
but that currently have .llseek = noop_llseek or generic_file_llseek for
unknown reason despite file being opened with nonseekable_open (e.g.
drivers/input/mousedev.c)

Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yongzhi Pan <panyongzhi@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Tejun Heo <tj@kernel.org>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Nikolaus Rath <Nikolaus@rath.org>
Cc: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Kirill Smelkov <kirr@nexedi.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-04-06 07:01:55 -10:00
Linus Torvalds
f654f0fc0b Merge branch 'akpm' (patches from Andrew)
Merge misc fixes from Andrew Morton:
 "14 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  kernel/sysctl.c: fix out-of-bounds access when setting file-max
  mm/util.c: fix strndup_user() comment
  sh: fix multiple function definition build errors
  MAINTAINERS: add maintainer and replacing reviewer ARM/NUVOTON NPCM
  MAINTAINERS: fix bad pattern in ARM/NUVOTON NPCM
  mm: writeback: use exact memcg dirty counts
  psi: clarify the units used in pressure files
  mm/huge_memory.c: fix modifying of page protection by insert_pfn_pmd()
  hugetlbfs: fix memory leak for resv_map
  mm: fix vm_fault_t cast in VM_FAULT_GET_HINDEX()
  lib/lzo: fix bugs for very short or empty input
  include/linux/bitrev.h: fix constant bitrev
  kmemleak: powerpc: skip scanning holes in the .bss section
  lib/string.c: implement a basic bcmp
2019-04-05 17:08:55 -10:00