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Nir Dotan 146820cc24 ip6mr: Fix notifiers call on mroute_clean_tables()
When the MC route socket is closed, mroute_clean_tables() is called to
cleanup existing routes. Mistakenly notifiers call was put on the cleanup
of the unresolved MC route entries cache.
In a case where the MC socket closes before an unresolved route expires,
the notifier call leads to a crash, caused by the driver trying to
increment a non initialized refcount_t object [1] and then when handling
is done, to decrement it [2]. This was detected by a test recently added in
commit 6d4efada3b ("selftests: forwarding: Add multicast routing test").

Fix that by putting notifiers call on the resolved entries traversal,
instead of on the unresolved entries traversal.

[1]

[  245.748967] refcount_t: increment on 0; use-after-free.
[  245.754829] WARNING: CPU: 3 PID: 3223 at lib/refcount.c:153 refcount_inc_checked+0x2b/0x30
...
[  245.802357] Hardware name: Mellanox Technologies Ltd. MSN2740/SA001237, BIOS 5.6.5 06/07/2016
[  245.811873] RIP: 0010:refcount_inc_checked+0x2b/0x30
...
[  245.907487] Call Trace:
[  245.910231]  mlxsw_sp_router_fib_event.cold.181+0x42/0x47 [mlxsw_spectrum]
[  245.917913]  notifier_call_chain+0x45/0x7
[  245.922484]  atomic_notifier_call_chain+0x15/0x20
[  245.927729]  call_fib_notifiers+0x15/0x30
[  245.932205]  mroute_clean_tables+0x372/0x3f
[  245.936971]  ip6mr_sk_done+0xb1/0xc0
[  245.940960]  ip6_mroute_setsockopt+0x1da/0x5f0
...

[2]

[  246.128487] refcount_t: underflow; use-after-free.
[  246.133859] WARNING: CPU: 0 PID: 7 at lib/refcount.c:187 refcount_sub_and_test_checked+0x4c/0x60
[  246.183521] Hardware name: Mellanox Technologies Ltd. MSN2740/SA001237, BIOS 5.6.5 06/07/2016
...
[  246.193062] Workqueue: mlxsw_core_ordered mlxsw_sp_router_fibmr_event_work [mlxsw_spectrum]
[  246.202394] RIP: 0010:refcount_sub_and_test_checked+0x4c/0x60
...
[  246.298889] Call Trace:
[  246.301617]  refcount_dec_and_test_checked+0x11/0x20
[  246.307170]  mlxsw_sp_router_fibmr_event_work.cold.196+0x47/0x78 [mlxsw_spectrum]
[  246.315531]  process_one_work+0x1fa/0x3f0
[  246.320005]  worker_thread+0x2f/0x3e0
[  246.324083]  kthread+0x118/0x130
[  246.327683]  ? wq_update_unbound_numa+0x1b0/0x1b0
[  246.332926]  ? kthread_park+0x80/0x80
[  246.337013]  ret_from_fork+0x1f/0x30

Fixes: 088aa3eec2 ("ip6mr: Support fib notifications")
Signed-off-by: Nir Dotan <nird@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-27 23:16:07 -08:00
arch Quite a few fixes for x86: nested virtualization save/restore, AMD nested virtualization 2019-01-27 09:21:00 -08:00
block blk-wbt: Declare local functions static 2019-01-24 11:09:21 -07:00
certs kbuild: remove redundant target cleaning on failure 2019-01-06 09:46:51 +09:00
crypto crypto: sm3 - fix undefined shift by >= width of value 2019-01-10 21:37:32 +08:00
Documentation drm fixes. msm, sun4i, amdgpu, i915 gvt 2019-01-25 12:19:10 +13:00
drivers net: stmmac: dwmac-rk: fix error handling in rk_gmac_powerup() 2019-01-27 23:03:38 -08:00
firmware kbuild: change filechk to surround the given command with { } 2019-01-06 09:46:51 +09:00
fs a set of small smb3 fixes, some fixing various crediting issues discovered during xfstest runs, five for stable 2019-01-26 15:38:22 -08:00
include Fix a xen-swiotlb regression on arm64 2019-01-27 09:18:05 -08:00
init kbuild: Disable LD_DEAD_CODE_DATA_ELIMINATION with ftrace & GCC <= 4.7 2019-01-14 10:37:09 +09:00
ipc ipc: IPCMNI limit check for semmni 2018-10-31 08:54:14 -07:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-01-21 12:52:31 +13:00
lib XArray updates for 5.0-rc3 2019-01-22 17:08:30 +13:00
LICENSES This is a fairly typical cycle for documentation. There's some welcome 2018-10-24 18:01:11 +01:00
mm for-linus-20190125 2019-01-26 12:42:41 -08:00
net ip6mr: Fix notifiers call on mroute_clean_tables() 2019-01-27 23:16:07 -08:00
samples samples/bpf: workaround clang asm goto compilation errors 2019-01-15 20:57:30 +01:00
scripts Bug fixes for gcc-plugins 2019-01-21 13:07:03 +13:00
security Merge branch 'fixes-v5.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-01-17 16:54:58 +12:00
sound sound fixes for 5.0-rc4 2019-01-25 05:55:26 +13:00
tools Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec 2019-01-27 10:30:01 -08:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt KVM: validate userspace input in kvm_clear_dirty_log_protect() 2019-01-11 18:38:07 +01:00
.clang-format clang-format: Update .clang-format with the latest for_each macro list 2019-01-19 19:26:06 +01:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support for DT binding schema checks 2018-12-13 09:41:32 -06:00
.mailmap A few early MIPS fixes for 4.21: 2019-01-05 12:48:25 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Add CREDITS entry for Shaohua Li 2019-01-04 14:27:09 -07:00
Kbuild kbuild: use assignment instead of define ... endef for filechk_* rules 2019-01-06 10:22:35 +09:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-01-27 08:59:12 -08:00
Makefile Linux 5.0-rc3 2019-01-21 13:14:44 +13:00
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.