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David Howells dde9f09558 afs: Fix handling of an abort from a service handler
When an AFS service handler function aborts a call, AF_RXRPC marks the call
as complete - which means that it's not going to get any more packets from
the receiver.  This is a problem because reception of the final ACK is what
triggers afs_deliver_to_call() to drop the final ref on the afs_call
object.

Instead, aborted AFS service calls may then just sit around waiting for
ever or until they're displaced by a new call on the same connection
channel or a connection-level abort.

Fix this by calling afs_set_call_complete() to finalise the afs_call struct
representing the call.

However, we then need to drop the ref that stops the call from being
deallocated.  We can do this in afs_set_call_complete(), as the work queue
is holding a separate ref of its own, but then we shouldn't do it in
afs_process_async_call() and afs_delete_async_call().

call->drop_ref is set to indicate that a ref needs dropping for a call and
this is dealt with when we transition a call to AFS_CALL_COMPLETE.

But then we also need to get rid of the ref that pins an asynchronous
client call.  We can do this by the same mechanism, setting call->drop_ref
for an async client call too.

We can also get rid of call->incoming since nothing ever sets it and only
one thing ever checks it (futilely).


A trace of the rxrpc_call and afs_call struct ref counting looks like:

          <idle>-0     [001] ..s5   164.764892: rxrpc_call: c=00000002 SEE u=3 sp=rxrpc_new_incoming_call+0x473/0xb34 a=00000000442095b5
          <idle>-0     [001] .Ns5   164.766001: rxrpc_call: c=00000002 QUE u=4 sp=rxrpc_propose_ACK+0xbe/0x551 a=00000000442095b5
          <idle>-0     [001] .Ns4   164.766005: rxrpc_call: c=00000002 PUT u=3 sp=rxrpc_new_incoming_call+0xa3f/0xb34 a=00000000442095b5
          <idle>-0     [001] .Ns7   164.766433: afs_call: c=00000002 WAKE  u=2 o=11 sp=rxrpc_notify_socket+0x196/0x33c
     kworker/1:2-1810  [001] ...1   164.768409: rxrpc_call: c=00000002 SEE u=3 sp=rxrpc_process_call+0x25/0x7ae a=00000000442095b5
     kworker/1:2-1810  [001] ...1   164.769439: rxrpc_tx_packet: c=00000002 e9f1a7a8:95786a88:00000008:09c5 00000001 00000000 02 22 ACK CallAck
     kworker/1:2-1810  [001] ...1   164.769459: rxrpc_call: c=00000002 PUT u=2 sp=rxrpc_process_call+0x74f/0x7ae a=00000000442095b5
     kworker/1:2-1810  [001] ...1   164.770794: afs_call: c=00000002 QUEUE u=3 o=12 sp=afs_deliver_to_call+0x449/0x72c
     kworker/1:2-1810  [001] ...1   164.770829: afs_call: c=00000002 PUT   u=2 o=12 sp=afs_process_async_call+0xdb/0x11e
     kworker/1:2-1810  [001] ...2   164.771084: rxrpc_abort: c=00000002 95786a88:00000008 s=0 a=1 e=1 K-1
     kworker/1:2-1810  [001] ...1   164.771461: rxrpc_tx_packet: c=00000002 e9f1a7a8:95786a88:00000008:09c5 00000002 00000000 04 00 ABORT CallAbort
     kworker/1:2-1810  [001] ...1   164.771466: afs_call: c=00000002 PUT   u=1 o=12 sp=SRXAFSCB_ProbeUuid+0xc1/0x106

The abort generated in SRXAFSCB_ProbeUuid(), labelled "K-1", indicates that
the local filesystem/cache manager didn't recognise the UUID as its own.

Fixes: 2067b2b3f4 ("afs: Fix the CB.ProbeUuid service handler to reply correctly")
Signed-off-by: David Howells <dhowells@redhat.com>
2020-03-13 23:04:35 +00:00
arch arm64: dts: ls1043a: FMan erratum A050385 2020-03-06 21:55:32 -08:00
block block-5.6-2020-02-05 2020-02-06 06:15:23 +00:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2020-02-20 15:15:16 -08:00
Documentation linux-next: DOC: RDS: Fix a typo in rds.txt 2020-03-09 10:06:07 -07:00
drivers net: mvmdio: avoid error message for optional IRQ 2020-03-12 00:03:30 -07:00
fs afs: Fix handling of an abort from a service handler 2020-03-13 23:04:35 +00:00
include afs: Fix some tracing details 2020-03-13 23:04:34 +00:00
init Tracing updates: 2020-02-26 10:34:42 -08:00
ipc Revert "ipc,sem: remove uneeded sem_undo_list lock usage in exit_sem()" 2020-02-21 11:22:15 -08:00
kernel cgroup: memcg: net: do not associate sock with unrelated cgroup 2020-03-10 15:33:05 -07:00
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LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm net: memcg: late association of sock to memcg 2020-03-10 15:33:05 -07:00
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Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.