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David Howells 4a7f62f919 rxrpc: Fix call timer start racing with call destruction
The rxrpc_call struct has a timer used to handle various timed events
relating to a call.  This timer can get started from the packet input
routines that are run in softirq mode with just the RCU read lock held.
Unfortunately, because only the RCU read lock is held - and neither ref or
other lock is taken - the call can start getting destroyed at the same time
a packet comes in addressed to that call.  This causes the timer - which
was already stopped - to get restarted.  Later, the timer dispatch code may
then oops if the timer got deallocated first.

Fix this by trying to take a ref on the rxrpc_call struct and, if
successful, passing that ref along to the timer.  If the timer was already
running, the ref is discarded.

The timer completion routine can then pass the ref along to the call's work
item when it queues it.  If the timer or work item where already
queued/running, the extra ref is discarded.

Fixes: a158bdd324 ("rxrpc: Fix call timeouts")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
Tested-by: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Link: http://lists.infradead.org/pipermail/linux-afs/2022-March/005073.html
Link: https://lore.kernel.org/r/164865115696.2943015.11097991776647323586.stgit@warthog.procyon.org.uk
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-03-31 12:25:25 +02:00
arch x86,kprobes: Fix optprobe trampoline to generate complete pt_regs 2022-03-28 19:38:51 -07:00
block for-5.18/64bit-pi-2022-03-25 2022-03-26 12:01:35 -07:00
certs KEYS: Introduce link restriction for machine keys 2022-03-08 13:55:52 +02:00
crypto for-5.18/64bit-pi-2022-03-25 2022-03-26 12:01:35 -07:00
Documentation docs: netdev: move the netdev-FAQ to the process pages 2022-03-31 10:49:39 +02:00
drivers net: hns3: fix software vlan talbe of vlan 0 inconsistent with hardware 2022-03-31 11:39:59 +02:00
fs Driver core changes for 5.18-rc1 2022-03-28 12:41:28 -07:00
include rxrpc: Fix call timer start racing with call destruction 2022-03-31 12:25:25 +02:00
init Merge branch 'akpm' (patches from Andrew) 2022-03-24 14:14:07 -07:00
ipc fs: allocate inode by using alloc_inode_sb() 2022-03-22 15:57:03 -07:00
kernel kprobes: Use rethook for kretprobe if possible 2022-03-28 19:38:09 -07:00
lib memcpy updates for v5.18-rc1 2022-03-26 12:19:04 -07:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm: kfence: fix missing objcg housekeeping for SLAB 2022-03-27 18:47:00 -07:00
net rxrpc: Fix call timer start racing with call destruction 2022-03-31 12:25:25 +02:00
samples Livepatching changes for 5.18 2022-03-28 14:38:31 -07:00
scripts Driver core changes for 5.18-rc1 2022-03-28 12:41:28 -07:00
security Landlock updates for v5.18-rc1 2022-03-27 14:26:47 -07:00
sound xen: branch for v5.18-rc1 2022-03-28 14:32:39 -07:00
tools wireguard: selftests: simplify RNG seeding 2022-03-30 19:14:08 -07:00
usr reiserfs_xattr.h: add linux/reiserfs_xattr.h to UAPI compile-test coverage 2022-02-17 09:09:38 +01:00
virt KVM: compat: riscv: Prevent KVM_COMPAT from being selected 2022-03-11 19:02:15 +05:30
.clang-format genirq/msi: Make interrupt allocation less convoluted 2021-12-16 22:22:20 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap Char/Misc and other driver updates for 5.18-rc1 2022-03-28 12:27:35 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: replace a Microchip AT91 maintainer 2022-02-09 11:30:01 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS docs: netdev: move the netdev-FAQ to the process pages 2022-03-31 10:49:39 +02:00
Makefile array-bounds updates for v5.18-rc1 2022-03-26 12:30:44 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.