Commit Graph

179 Commits

Author SHA1 Message Date
Andrew Lunn 15e522a7b1 net: 9p: kerneldoc fixes
Simple fixes which require no deep knowledge of the code.

Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Cc: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-13 17:20:39 -07:00
Sergey Alirzaev 388f6966b0 9pnet: allow making incomplete read requests
A user doesn't necessarily want to wait for all the requested data to
be available, since the waiting time for each request is unbounded.

The new method permits sending one read request at a time and getting
the response ASAP, allowing to use 9pnet with synthetic file systems
representing arbitrary data streams.

Link: http://lkml.kernel.org/r/20200205204053.12751-1-l29ah@cock.li
Signed-off-by: Sergey Alirzaev <l29ah@cock.li>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2020-03-27 09:29:56 +00:00
Lu Shuaibing 0ce772fe79 9p: Transport error uninitialized
The p9_tag_alloc() does not initialize the transport error t_err field.
The struct p9_req_t *req is allocated and stored in a struct p9_client
variable. The field t_err is never initialized before p9_conn_cancel()
checks its value.

KUMSAN(KernelUninitializedMemorySantizer, a new error detection tool)
reports this bug.

==================================================================
BUG: KUMSAN: use of uninitialized memory in p9_conn_cancel+0x2d9/0x3b0
Read of size 4 at addr ffff88805f9b600c by task kworker/1:2/1216

CPU: 1 PID: 1216 Comm: kworker/1:2 Not tainted 5.2.0-rc4+ #28
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
Workqueue: events p9_write_work
Call Trace:
 dump_stack+0x75/0xae
 __kumsan_report+0x17c/0x3e6
 kumsan_report+0xe/0x20
 p9_conn_cancel+0x2d9/0x3b0
 p9_write_work+0x183/0x4a0
 process_one_work+0x4d1/0x8c0
 worker_thread+0x6e/0x780
 kthread+0x1ca/0x1f0
 ret_from_fork+0x35/0x40

Allocated by task 1979:
 save_stack+0x19/0x80
 __kumsan_kmalloc.constprop.3+0xbc/0x120
 kmem_cache_alloc+0xa7/0x170
 p9_client_prepare_req.part.9+0x3b/0x380
 p9_client_rpc+0x15e/0x880
 p9_client_create+0x3d0/0xac0
 v9fs_session_init+0x192/0xc80
 v9fs_mount+0x67/0x470
 legacy_get_tree+0x70/0xd0
 vfs_get_tree+0x4a/0x1c0
 do_mount+0xba9/0xf90
 ksys_mount+0xa8/0x120
 __x64_sys_mount+0x62/0x70
 do_syscall_64+0x6d/0x1e0
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff88805f9b6008
 which belongs to the cache p9_req_t of size 144
The buggy address is located 4 bytes inside of
 144-byte region [ffff88805f9b6008, ffff88805f9b6098)
The buggy address belongs to the page:
page:ffffea00017e6d80 refcount:1 mapcount:0 mapping:ffff888068b63740 index:0xffff88805f9b7d90 compound_mapcount: 0
flags: 0x100000000010200(slab|head)
raw: 0100000000010200 ffff888068b66450 ffff888068b66450 ffff888068b63740
raw: ffff88805f9b7d90 0000000000100001 00000001ffffffff 0000000000000000
page dumped because: kumsan: bad access detected
==================================================================

Link: http://lkml.kernel.org/r/20190613070854.10434-1-shuaibinglu@126.com
Signed-off-by: Lu Shuaibing <shuaibinglu@126.com>
[dominique.martinet@cea.fr: grouped the added init with the others]
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2019-09-03 11:05:34 +00:00
Thomas Gleixner 1f32761322 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 188
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation this program is
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program if not write to free software
  foundation 51 franklin street fifth floor boston ma 02111 1301 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 27 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528170026.981318839@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:29:21 -07:00
zhengbin bb06c388fa 9p/net: fix memory leak in p9_client_create
If msize is less than 4096, we should close and put trans, destroy
tagpool, not just free client. This patch fixes that.

Link: http://lkml.kernel.org/m/1552464097-142659-1-git-send-email-zhengbin13@huawei.com
Cc: stable@vger.kernel.org
Fixes: 574d356b7a ("9p/net: put a lower bound on msize")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2019-03-13 11:50:04 +01:00
Dominique Martinet 574d356b7a 9p/net: put a lower bound on msize
If the requested msize is too small (either from command line argument
or from the server version reply), we won't get any work done.
If it's *really* too small, nothing will work, and this got caught by
syzbot recently (on a new kmem_cache_create_usercopy() call)

Just set a minimum msize to 4k in both code paths, until someone
complains they have a use-case for a smaller msize.

We need to check in both mount option and server reply individually
because the msize for the first version request would be unchecked
with just a global check on clnt->msize.

Link: http://lkml.kernel.org/r/1541407968-31350-1-git-send-email-asmadeus@codewreck.org
Reported-by: syzbot+0c1d61e4db7db94102ca@syzkaller.appspotmail.com
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Cc: stable@vger.kernel.org
2018-12-25 17:07:49 +09:00
Linus Torvalds 9931a07d51 Merge branch 'work.afs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull AFS updates from Al Viro:
 "AFS series, with some iov_iter bits included"

* 'work.afs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (26 commits)
  missing bits of "iov_iter: Separate type from direction and use accessor functions"
  afs: Probe multiple fileservers simultaneously
  afs: Fix callback handling
  afs: Eliminate the address pointer from the address list cursor
  afs: Allow dumping of server cursor on operation failure
  afs: Implement YFS support in the fs client
  afs: Expand data structure fields to support YFS
  afs: Get the target vnode in afs_rmdir() and get a callback on it
  afs: Calc callback expiry in op reply delivery
  afs: Fix FS.FetchStatus delivery from updating wrong vnode
  afs: Implement the YFS cache manager service
  afs: Remove callback details from afs_callback_break struct
  afs: Commit the status on a new file/dir/symlink
  afs: Increase to 64-bit volume ID and 96-bit vnode ID for YFS
  afs: Don't invoke the server to read data beyond EOF
  afs: Add a couple of tracepoints to log I/O errors
  afs: Handle EIO from delivery function
  afs: Fix TTL on VL server and address lists
  afs: Implement VL server rotation
  afs: Improve FS server rotation error handling
  ...
2018-11-01 19:58:52 -07:00
David Howells aa563d7bca iov_iter: Separate type from direction and use accessor functions
In the iov_iter struct, separate the iterator type from the iterator
direction and use accessor functions to access them in most places.

Convert a bunch of places to use switch-statements to access them rather
then chains of bitwise-AND statements.  This makes it easier to add further
iterator types.  Also, this can be more efficient as to implement a switch
of small contiguous integers, the compiler can use ~50% fewer compare
instructions than it has to use bitwise-and instructions.

Further, cease passing the iterator type into the iterator setup function.
The iterator function can set that itself.  Only the direction is required.

Signed-off-by: David Howells <dhowells@redhat.com>
2018-10-24 00:41:07 +01:00
Dan Carpenter 72ea032108 9p: potential NULL dereference
p9_tag_alloc() is supposed to return error pointers, but we accidentally
return a NULL here.  It would cause a NULL dereference in the caller.

Link: http://lkml.kernel.org/m/20180926103934.GA14535@mwanda
Fixes: 996d5b4db4 ("9p: Use a slab for allocating requests")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-10-10 09:13:20 +09:00
Tomas Bortoli 728356dede 9p: Add refcount to p9_req_t
To avoid use-after-free(s), use a refcount to keep track of the
usable references to any instantiated struct p9_req_t.

This commit adds p9_req_put(), p9_req_get() and p9_req_try_get() as
wrappers to kref_put(), kref_get() and kref_get_unless_zero().
These are used by the client and the transports to keep track of
valid requests' references.

p9_free_req() is added back and used as callback by kref_put().

Add SLAB_TYPESAFE_BY_RCU as it ensures that the memory freed by
kmem_cache_free() will not be reused for another type until the rcu
synchronisation period is over, so an address gotten under rcu read
lock is safe to inc_ref() without corrupting random memory while
the lock is held.

Link: http://lkml.kernel.org/r/1535626341-20693-1-git-send-email-asmadeus@codewreck.org
Co-developed-by: Dominique Martinet <dominique.martinet@cea.fr>
Signed-off-by: Tomas Bortoli <tomasbortoli@gmail.com>
Reported-by: syzbot+467050c1ce275af2a5b8@syzkaller.appspotmail.com
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-09-08 01:39:47 +09:00
Tomas Bortoli 43cbcbee99 9p: rename p9_free_req() function
In sight of the next patch to add a refcount in p9_req_t, rename
the p9_free_req() function in p9_release_req().

In the next patch the actual kfree will be moved to another function.

Link: http://lkml.kernel.org/r/20180811144254.23665-1-tomasbortoli@gmail.com
Signed-off-by: Tomas Bortoli <tomasbortoli@gmail.com>
Acked-by: Jun Piao <piaojun@huawei.com>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-09-08 01:39:47 +09:00
Dominique Martinet 91a76be37f 9p: add a per-client fcall kmem_cache
Having a specific cache for the fcall allocations helps speed up
end-to-end latency.

The caches will automatically be merged if there are multiple caches
of items with the same size so we do not need to try to share a cache
between different clients of the same size.

Since the msize is negotiated with the server, only allocate the cache
after that negotiation has happened - previous allocations or
allocations of different sizes (e.g. zero-copy fcall) are made with
kmalloc directly.

Some figures on two beefy VMs with Connect-IB (sriov) / trans=rdma,
with ior running 32 processes in parallel doing small 32 bytes IOs:
 - no alloc (4.18-rc7 request cache): 65.4k req/s
 - non-power of two alloc, no patch: 61.6k req/s
 - power of two alloc, no patch: 62.2k req/s
 - non-power of two alloc, with patch: 64.7k req/s
 - power of two alloc, with patch: 65.1k req/s

Link: http://lkml.kernel.org/r/1532943263-24378-2-git-send-email-asmadeus@codewreck.org
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
Acked-by: Jun Piao <piaojun@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Greg Kurz <groug@kaod.org>
2018-09-08 01:39:47 +09:00
Dominique Martinet 523adb6cc1 9p: embed fcall in req to round down buffer allocs
'msize' is often a power of two, or at least page-aligned, so avoiding
an overhead of two dozen bytes for each allocation will help the
allocator do its work and reduce memory fragmentation.

Link: http://lkml.kernel.org/r/1533825236-22896-1-git-send-email-asmadeus@codewreck.org
Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
Reviewed-by: Greg Kurz <groug@kaod.org>
Acked-by: Jun Piao <piaojun@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
2018-09-08 01:39:45 +09:00
Matthew Wilcox 996d5b4db4 9p: Use a slab for allocating requests
Replace the custom batch allocation with a slab.  Use an IDR to store
pointers to the active requests instead of an array.  We don't try to
handle P9_NOTAG specially; the IDR will happily shrink all the way back
once the TVERSION call has completed.

Link: http://lkml.kernel.org/r/20180711210225.19730-6-willy@infradead.org
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-08-29 13:39:57 +09:00
Stephen Hemminger c69f297d7f 9p: fix whitespace issues
Remove trailing whitespace and blank lines at EOF

Link: http://lkml.kernel.org/m/20180724192918.31165-11-sthemmin@microsoft.com
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-08-13 09:34:58 +09:00
Tomas Bortoli f984579a01 9p: validate PDU length
This commit adds length check for the PDU size.
The size contained in the header has to match the actual size,
except for TCP (trans_fd.c) where actual length is not known ahead
and the header's length will be checked only against the validity
range.

Link: http://lkml.kernel.org/r/20180723154404.2406-1-tomasbortoli@gmail.com
Signed-off-by: Tomas Bortoli <tomasbortoli@gmail.com>
Reported-by: syzbot+65c6b72f284a39d416b4@syzkaller.appspotmail.com
To: Eric Van Hensbergen <ericvh@gmail.com>
To: Ron Minnich <rminnich@sandia.gov>
To: Latchesar Ionkov <lucho@ionkov.net>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-08-13 09:34:58 +09:00
Matthew Wilcox 2557d0c57c 9p: Embed wait_queue_head into p9_req_t
On a 64-bit system, the wait_queue_head_t is 24 bytes while the pointer
to it is 8 bytes.  Growing the p9_req_t by 16 bytes is better than
performing a 24-byte memory allocation.

Link: http://lkml.kernel.org/r/20180711210225.19730-5-willy@infradead.org
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-08-13 09:21:44 +09:00
Matthew Wilcox f28cdf0430 9p: Replace the fidlist with an IDR
The p9_idpool being used to allocate the IDs uses an IDR to allocate
the IDs ... which we then keep in a doubly-linked list, rather than in
the IDR which allocated them.  We can use an IDR directly which saves
two pointers per p9_fid, and a tiny memory allocation per p9_client.

Link: http://lkml.kernel.org/r/20180711210225.19730-4-willy@infradead.org
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-08-13 09:21:44 +09:00
Matthew Wilcox b5303be2be 9p: Change p9_fid_create calling convention
Return NULL instead of ERR_PTR when we can't allocate a FID.  The ENOSPC
return value was getting all the way back to userspace, and that's
confusing for a userspace program which isn't expecting read() to tell it
there's no space left on the filesystem.  The best error we can return to
indicate a temporary failure caused by lack of client resources is ENOMEM.

Maybe it would be better to sleep until a FID is available, but that's
not a change I'm comfortable making.

Link: http://lkml.kernel.org/r/20180711210225.19730-3-willy@infradead.org
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Jun Piao <piaojun@huawei.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Yiwen Jiang <jiangyiwen@huwei.com>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-08-13 09:21:44 +09:00
Matthew Wilcox 2d58f63f72 9p: Fix comment on smp_wmb
The previous comment misled me into thinking the barrier wasn't needed
at all.

Link: http://lkml.kernel.org/r/20180711210225.19730-2-willy@infradead.org
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-08-13 09:21:44 +09:00
Tomas Bortoli 7913690dcc net/9p/client.c: version pointer uninitialized
The p9_client_version() does not initialize the version pointer. If the
call to p9pdu_readf() returns an error and version has not been allocated
in p9pdu_readf(), then the program will jump to the "error" label and will
try to free the version pointer. If version is not initialized, free()
will be called with uninitialized, garbage data and will provoke a crash.

Link: http://lkml.kernel.org/r/20180709222943.19503-1-tomasbortoli@gmail.com
Signed-off-by: Tomas Bortoli <tomasbortoli@gmail.com>
Reported-by: syzbot+65c6b72f284a39d416b4@syzkaller.appspotmail.com
Reviewed-by: Jun Piao <piaojun@huawei.com>
Reviewed-by: Yiwen Jiang <jiangyiwen@huawei.com>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-08-13 09:21:44 +09:00
piaojun 64ad31f328 net/9p/client.c: add missing '\n' at the end of p9_debug()
In p9_client_getattr_dotl(), we should add '\n' at the end of printing
log.

Link: http://lkml.kernel.org/r/5B44589A.50302@huawei.com
Signed-off-by: Jun Piao <piaojun@huawei.com>
Reviewed-by: Yiwen Jiang <jiangyiwen@huawei.com>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-08-13 09:21:44 +09:00
piaojun c290fba8c4 net/9p/client.c: put refcount of trans_mod in error case in parse_opts()
In my testing, the second mount will fail after umounting successfully.
The reason is that we put refcount of trans_mod in the correct case
rather than the error case in parse_opts() at last.  That will cause the
refcount decrease to -1, and when we try to get trans_mod again in
try_module_get(), we could only increase refcount to 0 which will cause
failure as follows:

parse_opts
  v9fs_get_trans_by_name
    try_module_get : return NULL to caller which cause error

So we should put refcount of trans_mod in error case.

Link: http://lkml.kernel.org/r/5B3F39A0.2030509@huawei.com
Fixes: 9421c3e641 ("net/9p/client.c: fix potential refcnt problem of trans module")
Signed-off-by: Jun Piao <piaojun@huawei.com>
Reviewed-by: Yiwen Jiang <jiangyiwen@huawei.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Dominique Martinet <dominique.martinet@cea.fr>
Tested-by: Dominique Martinet <dominique.martinet@cea.fr>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-14 11:11:09 -07:00
Chengguang Xu 8d856c72b4 net/9p: detect invalid options as much as possible
Currently when detecting invalid options in option parsing, some
options(e.g.  msize) just set errno and allow to continuously validate
other options so that it can detect invalid options as much as possible
and give proper error messages together.

This patch applies same rule to option 'trans' and 'version' when
detecting -EINVAL.

Link: http://lkml.kernel.org/r/1525340676-34072-1-git-send-email-cgxu519@gmx.com
Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-07 17:34:34 -07:00
Chengguang Xu 9421c3e641 net/9p/client.c: fix potential refcnt problem of trans module
When specifying trans_mod multiple times in a mount, it will cause an
inaccurate refcount of the trans module.  Also, in the error case of
option parsing, we should put the trans module if we have already got
it.

Link: http://lkml.kernel.org/r/1522154942-57339-1-git-send-email-cgxu519@gmx.com
Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-05 21:36:23 -07:00
Greg Kurz a85222435b net/9p: avoid -ERESTARTSYS leak to userspace
If it was interrupted by a signal, the 9p client may need to send some
more requests to the server for cleanup before returning to userspace.

To avoid such a last minute request to be interrupted right away, the
client memorizes if a signal is pending, clears TIF_SIGPENDING, handles
the request and calls recalc_sigpending() before returning.

Unfortunately, if the transmission of this cleanup request fails for any
reason, the transport returns an error and the client propagates it
right away, without calling recalc_sigpending().

This ends up with -ERESTARTSYS from the initially interrupted request
crawling up to syscall exit, with TIF_SIGPENDING cleared by the cleanup
request.  The specific signal handling code, which is responsible for
converting -ERESTARTSYS to -EINTR is not called, and userspace receives
the confusing errno value:

  open: Unknown error 512 (512)

This is really hard to hit in real life.  I discovered the issue while
working on hot-unplug of a virtio-9p-pci device with an instrumented
QEMU allowing to control request completion.

Both p9_client_zc_rpc() and p9_client_rpc() functions have this buggy
error path actually.  Their code flow is a bit obscure and the best
thing to do would probably be a full rewrite: to really ensure this
situation of clearing TIF_SIGPENDING and returning -ERESTARTSYS can
never happen.

But given the general lack of interest for the 9p code, I won't risk
breaking more things.  So this patch simply fixes the buggy paths in
both functions with a trivial label+goto.

Thanks to Laurent Dufour for his help and suggestions on how to find the
root cause and how to fix it.

Link: http://lkml.kernel.org/r/152062809886.10599.7361006774123053312.stgit@bahia.lan
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Yiwen Jiang <jiangyiwen@huawei.com>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Cc: David Miller <davem@davemloft.net>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-05 21:36:22 -07:00
Tuomas Tynkkynen 61b272c3aa 9p: Fix missing commas in mount options
Since commit c4fac91004 ("9p: Implement show_options"), the mount
options of 9p filesystems are printed out with some missing commas
between the individual options:

p9-scratch on /mnt/scratch type 9p (rw,dirsync,loose,access=clienttrans=virtio)

Add them back.

Cc: stable@vger.kernel.org # 4.13+
Fixes: c4fac91004 ("9p: Implement show_options")
Signed-off-by: Tuomas Tynkkynen <tuomas@tuxera.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-11-19 17:31:06 -05:00
Tuomas Tynkkynen 9523feac27 net/9p: Switch to wait_event_killable()
Because userspace gets Very Unhappy when calls like stat() and execve()
return -EINTR on 9p filesystem mounts. For instance, when bash is
looking in PATH for things to execute and some SIGCHLD interrupts
stat(), bash can throw a spurious 'command not found' since it doesn't
retry the stat().

In practice, hitting the problem is rare and needs a really
slow/bogged down 9p server.

Cc: stable@vger.kernel.org
Signed-off-by: Tuomas Tynkkynen <tuomas@tuxera.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-10-23 23:10:01 -04:00
David Howells c4fac91004 9p: Implement show_options
Implement the show_options superblock op for 9p as part of a bid to get
rid of s_options and generic_show_options() to make it easier to implement
a context-based mount where the mount options can be passed individually
over a file descriptor.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Ron Minnich <rminnich@sandia.gov>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: v9fs-developer@lists.sourceforge.net
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-07-11 06:08:58 -04:00
Al Viro 1c512a7ca9 net/9p: switch to copy_from_iter_full()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-04-21 13:57:22 -04:00
Al Viro 71d6ad0837 p9_client_readdir() fix
Don't assume that server is sane and won't return more data than
asked for.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-04-17 14:23:20 -04:00
Linus Torvalds 0710f3ff91 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc final vfs updates from Al Viro:
 "A few unrelated patches that got beating in -next.

  Everything else will have to go into the next window ;-/"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  hfs: fix hfs_readdir()
  selftest for default_file_splice_read() infoleak
  9p: constify ->d_name handling
2017-03-03 21:44:35 -08:00
Ingo Molnar 3f07c01441 sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h>
We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/signal.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:29 +01:00
Al Viro 7880b43bdf 9p: constify ->d_name handling
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-01-12 04:01:17 -05:00
Arnd Bergmann 287980e49f remove lots of IS_ERR_VALUE abuses
Most users of IS_ERR_VALUE() in the kernel are wrong, as they
pass an 'int' into a function that takes an 'unsigned long'
argument. This happens to work because the type is sign-extended
on 64-bit architectures before it gets converted into an
unsigned type.

However, anything that passes an 'unsigned short' or 'unsigned int'
argument into IS_ERR_VALUE() is guaranteed to be broken, as are
8-bit integers and types that are wider than 'unsigned long'.

Andrzej Hajda has already fixed a lot of the worst abusers that
were causing actual bugs, but it would be nice to prevent any
users that are not passing 'unsigned long' arguments.

This patch changes all users of IS_ERR_VALUE() that I could find
on 32-bit ARM randconfig builds and x86 allmodconfig. For the
moment, this doesn't change the definition of IS_ERR_VALUE()
because there are probably still architecture specific users
elsewhere.

Almost all the warnings I got are for files that are better off
using 'if (err)' or 'if (err < 0)'.
The only legitimate user I could find that we get a warning for
is the (32-bit only) freescale fman driver, so I did not remove
the IS_ERR_VALUE() there but changed the type to 'unsigned long'.
For 9pfs, I just worked around one user whose calling conventions
are so obscure that I did not dare change the behavior.

I was using this definition for testing:

 #define IS_ERR_VALUE(x) ((unsigned long*)NULL == (typeof (x)*)NULL && \
       unlikely((unsigned long long)(x) >= (unsigned long long)(typeof(x))-MAX_ERRNO))

which ends up making all 16-bit or wider types work correctly with
the most plausible interpretation of what IS_ERR_VALUE() was supposed
to return according to its users, but also causes a compile-time
warning for any users that do not pass an 'unsigned long' argument.

I suggested this approach earlier this year, but back then we ended
up deciding to just fix the users that are obviously broken. After
the initial warning that caused me to get involved in the discussion
(fs/gfs2/dir.c) showed up again in the mainline kernel, Linus
asked me to send the whole thing again.

[ Updated the 9p parts as per Al Viro  - Linus ]

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.org/lkml/2016/1/7/363
Link: https://lkml.org/lkml/2016/5/27/486
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> # For nvmem part
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-27 15:26:11 -07:00
Vincent Bernat 999b8b88c6 9p: ensure err is initialized to 0 in p9_client_read/write
Some use of those functions were providing unitialized values to those
functions. Notably, when reading 0 bytes from an empty file on a 9P
filesystem, the return code of read() was not 0.

Tested with this simple program:

    #include <assert.h>
    #include <sys/types.h>
    #include <sys/stat.h>
    #include <fcntl.h>
    #include <unistd.h>

    int main(int argc, const char **argv)
    {
        assert(argc == 2);
        char buffer[256];
        int fd = open(argv[1], O_RDONLY|O_NOCTTY);
        assert(fd >= 0);
        assert(read(fd, buffer, 0) == 0);
        return 0;
    }

Cc: stable@vger.kernel.org # v4.1
Signed-off-by: Vincent Bernat <vincent@bernat.im>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-08-22 21:35:02 -04:00
Al Viro 0f1db7dee2 9p: cope with bogus responses from server in p9_client_{read,write}
if server claims to have written/read more than we'd told it to,
warn and cap the claimed byte count to avoid advancing more than
we are ready to.
2015-07-04 16:17:39 -04:00
Al Viro 67e808fbb0 p9_client_write(): avoid double p9_free_req()
Braino in "9p: switch p9_client_write() to passing it struct iov_iter *";
if response is impossible to parse and we discard the request, get the
out of the loop right there.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-07-04 16:11:05 -04:00
Al Viro a84b69cb6e 9p: forgetting to cancel request on interrupted zero-copy RPC
If we'd already sent a request and decide to abort it, we *must*
issue TFLUSH properly and not just blindly reuse the tag, or
we'll get seriously screwed when response eventually arrives
and we confuse it for response to later request that had reused
the same tag.

Cc: stable@vger.kernel.org # v3.2 and later
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-07-04 16:04:19 -04:00
Al Viro 21c9f5ccb1 p9_client_attach(): set fid->uid correctly
it's almost always equal to current_fsuid(), but there's an exception -
if the first writeback fid is opened by non-root *and* that happens before
root has done any lookups in /, we end up doing attach for root.  The
current code leaves the resulting FID owned by root from the server POV
and by non-root from the client one.  Unfortunately, it means that e.g.
massive dcache eviction will leave that user buggered - they'll end
up redoing walks from / *and* picking that FID every time.  As soon as
they try to create something, the things will get nasty.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-04-11 22:28:28 -04:00
Al Viro e1200fe68f 9p: switch p9_client_read() to passing struct iov_iter *
... and make it loop

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-04-11 22:28:27 -04:00
Al Viro 070b3656cf 9p: switch p9_client_write() to passing it struct iov_iter *
... and make it loop until it's done

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-04-11 22:28:25 -04:00
Al Viro 4f3b35c157 net/9p: switch the guts of p9_client_{read,write}() to iov_iter
... and have get_user_pages_fast() mapping fewer pages than requested
to generate a short read/write.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-04-11 22:28:25 -04:00
Fabian Frederick d8282ea05a 9P: remove unnecessary break after return
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-15 16:27:00 -07:00
Simon Derr 0bfd6845c0 9P: Get rid of REQ_STATUS_FLSH
This request state is mostly useless, and properly implementing it
for RDMA would require an extra lock to be taken in handle_recv()
and in rdma_cancel() to avoid this race:

    handle_recv()           rdma_cancel()
        .                     .
        .                   if req->state == SENT
    req->state = RCVD         .
        .                           req->state = FLSH

So just get rid of it.

Signed-off-by: Simon Derr <simon.derr@bull.net>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
2014-03-25 16:38:15 -05:00
Simon Derr afd8d65411 9P: Add cancelled() to the transport functions.
And move transport-specific code out of net/9p/client.c

Signed-off-by: Simon Derr <simon.derr@bull.net>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
2014-03-25 16:38:11 -05:00
Rashika 05a782d416 net: Mark function as static in 9p/client.c
Mark function as static in net/9p/client.c because it is not used
outside this file.

This eliminates the following warning in net/9p/client.c:
net/9p/client.c:207:18: warning: no previous prototype for ‘p9_fcall_alloc’ [-Wmissing-prototypes]

Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
2014-03-25 16:38:09 -05:00
Dominique Martinet 2b6e72ed74 9P: Add memory barriers to protect request fields over cb/rpc threads handoff
We need barriers to guarantee this pattern works as intended:
[w] req->rc, 1		[r] req->status, 1
wmb			rmb
[w] req->status, 1	[r] req->rc

Where the wmb ensures that rc gets written before status,
and the rmb ensures that if you observe status == 1, rc is the new value.

Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
2014-03-25 16:37:59 -05:00
Eric Van Hensbergen f94741fd28 net/9p: remove virtio default hack and set appropriate bits instead
A few releases back a patch made virtio the default transport, however
it was done in a way which side-stepped the mechanism put in place to
allow for this selection.  This patch cleans that up while maintaining
virtio as the default transport.

Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
2013-11-23 16:13:36 -06:00
Linus Torvalds 2b76db6a0f for-linus-3.12-merge minor 9p fixes and tweaks for 3.12 merge window
The first fixes namespace issues which causes a kernel
 NULL pointer dereference, the second fixes uevent
 handling to work better with udev, and the third
 switches some code to use srlcpy instead of strncpy
 in order to be safer.
 
 All changes have been baking in for-next for at least
 2 weeks.
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Merge tag 'for-linus-3.12-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs

Pull 9p updates from Eric Van Hensbergen:
 "Minor 9p fixes and tweaks for 3.12 merge window

  The first fixes namespace issues which causes a kernel NULL pointer
  dereference, the second fixes uevent handling to work better with
  udev, and the third switches some code to use srlcpy instead of
  strncpy in order to be safer.

  All changes have been baking in for-next for at least 2 weeks"

* tag 'for-linus-3.12-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
  fs/9p: avoid accessing utsname after namespace has been torn down
  9p: send uevent after adding/removing mount_tag attribute
  fs: 9p: use strlcpy instead of strncpy
2013-09-11 12:34:13 -07:00