linux-stable.git/net/9p, branch v6.2

Merge tag 'for-linus-6.2-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2023-01-12T23:02:20+00:00

Pull xen fixes from Juergen Gross:

 - two cleanup patches

 - a fix of a memory leak in the Xen pvfront driver

 - a fix of a locking issue in the Xen hypervisor console driver

* tag 'for-linus-6.2-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/pvcalls: free active map buffer on pvcalls_front_free_map
  hvc/xen: lock console list traversal
  x86/xen: Remove the unused function p2m_index()
  xen: make remove callback of xen driver void returned

Merge tag '9p-for-6.2-rc1' of https://github.com/martinetd/linux

2022-12-23T19:39:18+00:00

Pull 9p updates from Dominique Martinet:

 - improve p9_check_errors to check buffer size instead of msize when
   possible (e.g. not zero-copy)

 - some more syzbot and KCSAN fixes

 - minor headers include cleanup

* tag '9p-for-6.2-rc1' of https://github.com/martinetd/linux:
  9p/client: fix data race on req->status
  net/9p: fix response size check in p9_check_errors()
  net/9p: distinguish zero-copy requests
  9p/xen: do not memcpy header into req->rc
  9p: set req refcount to zero to avoid uninitialized usage
  9p/net: Remove unneeded idr.h #include
  9p/fs: Remove unneeded idr.h #include

Treewide: Stop corrupting socket's task_frag

2022-12-20T01:28:49+00:00

Since moving to memalloc_nofs_save/restore, SUNRPC has stopped setting the
GFP_NOIO flag on sk_allocation which the networking system uses to decide
when it is safe to use current->task_frag.  The results of this are
unexpected corruption in task_frag when SUNRPC is involved in memory
reclaim.

The corruption can be seen in crashes, but the root cause is often
difficult to ascertain as a crashing machine's stack trace will have no
evidence of being near NFS or SUNRPC code.  I believe this problem to
be much more pervasive than reports to the community may indicate.

Fix this by having kernel users of sockets that may corrupt task_frag due
to reclaim set sk_use_task_frag = false.  Preemptively correcting this
situation for users that still set sk_allocation allows them to convert to
memalloc_nofs_save/restore without the same unexpected corruptions that are
sure to follow, unlikely to show up in testing, and difficult to bisect.

CC: Philipp Reisner 
CC: Lars Ellenberg 
CC: "Christoph Böhmwalder" 
CC: Jens Axboe 
CC: Josef Bacik 
CC: Keith Busch 
CC: Christoph Hellwig 
CC: Sagi Grimberg 
CC: Lee Duncan 
CC: Chris Leech 
CC: Mike Christie 
CC: "James E.J. Bottomley" 
CC: "Martin K. Petersen" 
CC: Valentina Manea 
CC: Shuah Khan 
CC: Greg Kroah-Hartman 
CC: David Howells 
CC: Marc Dionne 
CC: Steve French 
CC: Christine Caulfield 
CC: David Teigland 
CC: Mark Fasheh 
CC: Joel Becker 
CC: Joseph Qi 
CC: Eric Van Hensbergen 
CC: Latchesar Ionkov 
CC: Dominique Martinet 
CC: Ilya Dryomov 
CC: Xiubo Li 
CC: Chuck Lever 
CC: Jeff Layton 
CC: Trond Myklebust 
CC: Anna Schumaker 
CC: Steffen Klassert 
CC: Herbert Xu 

Suggested-by: Guillaume Nault 
Signed-off-by: Benjamin Coddington 
Reviewed-by: Guillaume Nault 
Signed-off-by: Jakub Kicinski

xen: make remove callback of xen driver void returned

2022-12-15T15:06:10+00:00

Since commit fc7a6209d571 ("bus: Make remove callback return void")
forces bus_type::remove be void-returned, it doesn't make much sense for
any bus based driver implementing remove callbalk to return non-void to
its caller.

This change is for xen bus based drivers.

Acked-by: Juergen Gross 
Signed-off-by: Dawei Li 
Link: https://lore.kernel.org/r/TYCP286MB23238119AB4DF190997075C9CAE39@TYCP286MB2323.JPNP286.PROD.OUTLOOK.COM
Signed-off-by: Juergen Gross

9p/client: fix data race on req->status

2022-12-13T04:02:15+00:00

KCSAN reported a race between writing req->status in p9_client_cb and
accessing it in p9_client_rpc's wait_event.

Accesses to req itself is protected by the data barrier (writing req
fields, write barrier, writing status // reading status, read barrier,
reading other req fields), but status accesses themselves apparently
also must be annotated properly with WRITE_ONCE/READ_ONCE when we
access it without locks.

Follows:
 - error paths writing status in various threads all can notify
p9_client_rpc, so these all also need WRITE_ONCE
 - there's a similar read loop in trans_virtio for zc case that also
needs READ_ONCE
 - other reads in trans_fd should be protected by the trans_fd lock and
lists state machine, as corresponding writers all are within trans_fd
and should be under the same lock. If KCSAN complains on them we likely
will have something else to fix as well, so it's better to leave them
unmarked and look again if required.

Link: https://lkml.kernel.org/r/20221205124756.426350-1-asmadeus@codewreck.org
Reported-by: Naresh Kamboju 
Suggested-by: Marco Elver 
Acked-by: Marco Elver 
Reviewed-by: Christian Schoenebeck 
Signed-off-by: Dominique Martinet

Merge tag 'pull-iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2022-12-13T02:29:54+00:00

Pull iov_iter updates from Al Viro:
 "iov_iter work; most of that is about getting rid of direction
  misannotations and (hopefully) preventing more of the same for the
  future"

* tag 'pull-iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  use less confusing names for iov_iter direction initializers
  iov_iter: saner checks for attempt to copy to/from iterator
  [xen] fix "direction" argument of iov_iter_kvec()
  [vhost] fix 'direction' argument of iov_iter_{init,bvec}()
  [target] fix iov_iter_bvec() "direction" argument
  [s390] memcpy_real(): WRITE is "data source", not destination...
  [s390] zcore: WRITE is "data source", not destination...
  [infiniband] READ is "data destination", not source...
  [fsi] WRITE is "data source", not destination...
  [s390] copy_oldmem_kernel() - WRITE is "data source", not destination
  csum_and_copy_to_iter(): handle ITER_DISCARD
  get rid of unlikely() on page_copy_sane() calls

net/9p: fix response size check in p9_check_errors()

2022-12-05T22:31:18+00:00

Since commit 60ece0833b6c ("net/9p: allocate appropriate reduced message
buffers") it is no longer appropriate to check server's response size
against msize. Check against the previously allocated buffer capacity
instead.

- Omit this size check entirely for zero-copy messages, as those always
  allocate 4k (P9_ZC_HDR_SZ) linear buffers which are not used for actual
  payload and can be much bigger than 4k.

- Replace p9_debug() by pr_err() to make sure this message is always
  printed in case this error is triggered.

- Add 9p message type to error message to ease investigation.

Link: https://lkml.kernel.org/r/e0edec84b1c80119ae937ce854b4f5f6dbe2d08c.1669144861.git.linux_oss@crudebyte.com
Signed-off-by: Christian Schoenebeck 
Tested-by: Stefano Stabellini 
Reported-by: kernel test robot 
Signed-off-by: Dominique Martinet

net/9p: distinguish zero-copy requests

2022-12-05T22:30:55+00:00

Add boolean `zc` member to struct p9_fcall to distinguish zero-copy
messages (not using the linear `sdata` buffer for message payload) from
regular messages (which do copy message payload to `sdata` before being
further processed).

This new member is appended to end of structure to avoid inserting huge
padding in generated layout.

Link: https://lkml.kernel.org/r/8f2a5c12a446c3b544da64e0b1550e1fb2d6f972.1669144861.git.linux_oss@crudebyte.com
Signed-off-by: Christian Schoenebeck 
Tested-by: Stefano Stabellini 
Signed-off-by: Dominique Martinet

9p/xen: do not memcpy header into req->rc

2022-12-02T15:04:37+00:00

while 'h' is packed and can be assumed to match the request payload,
req->rc is a struct p9_fcall which is not packed and that memcpy
could be wrong.

Fix this by copying each fields individually instead.

Reported-by: Christian Schoenebeck 
Reviewed-by: Christian Schoenebeck 
Suggested-by: Stefano Stabellini 
Reviewed-by: Stefano Stabellini 
Link: https://lkml.kernel.org/r/alpine.DEB.2.22.394.2211211454540.1049131@ubuntu-linux-20-04-desktop
Link: https://lkml.kernel.org/r/20221122001025.119121-1-asmadeus@codewreck.org
Signed-off-by: Dominique Martinet

9p: set req refcount to zero to avoid uninitialized usage

2022-12-02T14:59:20+00:00

When a new request is allocated, the refcount will be zero if it is
reused, but if the request is newly allocated from slab, it is not fully
initialized before being added to idr.

If the p9_read_work got a response before the refcount initiated. It will
use a uninitialized req, which will result in a bad request data struct.

Here is the logs from syzbot.

Corrupted memory at 0xffff88807eade00b [ 0xff 0x07 0x00 0x00 0x00 0x00
0x00 0x00 . . . . . . . . ] (in kfence-#110):
 p9_fcall_fini net/9p/client.c:248 [inline]
 p9_req_put net/9p/client.c:396 [inline]
 p9_req_put+0x208/0x250 net/9p/client.c:390
 p9_client_walk+0x247/0x540 net/9p/client.c:1165
 clone_fid fs/9p/fid.h:21 [inline]
 v9fs_fid_xattr_set+0xe4/0x2b0 fs/9p/xattr.c:118
 v9fs_xattr_set fs/9p/xattr.c:100 [inline]
 v9fs_xattr_handler_set+0x6f/0x120 fs/9p/xattr.c:159
 __vfs_setxattr+0x119/0x180 fs/xattr.c:182
 __vfs_setxattr_noperm+0x129/0x5f0 fs/xattr.c:216
 __vfs_setxattr_locked+0x1d3/0x260 fs/xattr.c:277
 vfs_setxattr+0x143/0x340 fs/xattr.c:309
 setxattr+0x146/0x160 fs/xattr.c:617
 path_setxattr+0x197/0x1c0 fs/xattr.c:636
 __do_sys_setxattr fs/xattr.c:652 [inline]
 __se_sys_setxattr fs/xattr.c:648 [inline]
 __ia32_sys_setxattr+0xc0/0x160 fs/xattr.c:648
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 entry_SYSENTER_compat_after_hwframe+0x70/0x82

Below is a similar scenario, the scenario in the syzbot log looks more
complicated than this one, but this patch can fix it.

     T21124                   p9_read_work
======================== second trans =================================
p9_client_walk
  p9_client_rpc
    p9_client_prepare_req
      p9_tag_alloc
        req = kmem_cache_alloc(p9_req_cache, GFP_NOFS);
        tag = idr_alloc
        << preempted >>
        req->tc.tag = tag;
                            /* req->[refcount/tag] == uninitialized */
                            m->rreq = p9_tag_lookup(m->client, m->rc.tag);
                              /* increments uninitalized refcount */

        refcount_set(&req->refcount, 2);
                            /* cb drops one ref */
                            p9_client_cb(req)
                            /* reader thread drops its ref:
                               request is incorrectly freed */
                            p9_req_put(req)
    /* use after free and ref underflow */
    p9_req_put(req)

To fix it, we can initialize the refcount to zero before add to idr.

Link: https://lkml.kernel.org/r/20221201033310.18589-1-schspa@gmail.com
Cc: stable@vger.kernel.org # 6.0+ due to 6cda12864cb0 ("9p: Drop kref usage")
Fixes: 728356dedeff ("9p: Add refcount to p9_req_t")
Reported-by: syzbot+8f1060e2aaf8ca55220b@syzkaller.appspotmail.com
Signed-off-by: Schspa Shi 
Reviewed-by: Christian Schoenebeck 
Signed-off-by: Dominique Martinet