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Wen Gu 38f0bdd548 net/smc: Transitional solution for clcsock race issue
[ Upstream commit c0bf3d8a943b6f2e912b7c1de03e2ef28e76f760 ]

We encountered a crash in smc_setsockopt() and it is caused by
accessing smc->clcsock after clcsock was released.

 BUG: kernel NULL pointer dereference, address: 0000000000000020
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 0 P4D 0
 Oops: 0000 [#1] PREEMPT SMP PTI
 CPU: 1 PID: 50309 Comm: nginx Kdump: loaded Tainted: G E     5.16.0-rc4+ #53
 RIP: 0010:smc_setsockopt+0x59/0x280 [smc]
 Call Trace:
  <TASK>
  __sys_setsockopt+0xfc/0x190
  __x64_sys_setsockopt+0x20/0x30
  do_syscall_64+0x34/0x90
  entry_SYSCALL_64_after_hwframe+0x44/0xae
 RIP: 0033:0x7f16ba83918e
  </TASK>

This patch tries to fix it by holding clcsock_release_lock and
checking whether clcsock has already been released before access.

In case that a crash of the same reason happens in smc_getsockopt()
or smc_switch_to_fallback(), this patch also checkes smc->clcsock
in them too. And the caller of smc_switch_to_fallback() will identify
whether fallback succeeds according to the return value.

Fixes: fd57770dd1 ("net/smc: wait for pending work before clcsock release_sock")
Link: https://lore.kernel.org/lkml/5dd7ffd1-28e2-24cc-9442-1defec27375e@linux.ibm.com/T/
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Acked-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-02-01 17:27:12 +01:00
Documentation psi: Fix uaf issue when psi trigger is destroyed while being polled 2022-02-01 17:27:01 +01:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
arch powerpc/perf: Fix power_pmu_disable to call clear_pmi_irq_pending only if PMI is pending 2022-02-01 17:27:12 +01:00
block block: add bio_start_io_acct_time() to control start_time 2022-02-01 17:27:03 +01:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto crypto: jitter - consider 32 LSB for APT 2022-01-27 11:04:31 +01:00
drivers ibmvnic: don't spin in tasklet 2022-02-01 17:27:12 +01:00
fs io_uring: fix bug in slow unregistering of nodes 2022-02-01 17:27:11 +01:00
include perf: Fix perf_event_read_local() time 2022-02-01 17:27:10 +01:00
init init: make unknown command line param message clearer 2021-11-18 19:17:11 +01:00
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-11-25 09:48:42 +01:00
kernel sched/pelt: Relax the sync of util_sum with util_avg 2022-02-01 17:27:10 +01:00
lib lib/test_meminit: destroy cache in kmem_cache_alloc_bulk() test 2022-01-27 11:05:44 +01:00
mm memcg: better bounds on the memcg stats updates 2022-01-29 10:58:24 +01:00
net net/smc: Transitional solution for clcsock race issue 2022-02-01 17:27:12 +01:00
samples samples: bpf: Fix 'unknown warning group' build warning on Clang 2022-01-27 11:03:29 +01:00
scripts scripts: sphinx-pre-install: Fix ctex support on Debian 2022-01-27 11:05:44 +01:00
security selinux: fix potential memleak in selinux_add_opt() 2022-01-27 11:03:43 +01:00
sound ASoC: mediatek: mt8183: fix device_node leak 2022-01-27 11:05:04 +01:00
tools mm/hmm.c: allow VM_MIXEDMAP to work with hmm_range_fault 2022-01-27 11:05:43 +01:00
usr kbuild: remove include/linux/cyclades.h from header file check 2022-02-01 17:27:04 +01:00
virt Revert "KVM: SVM: avoid infinite loop on NPF from bad address" 2022-02-01 17:27:01 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
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.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
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 drm fixes for 5.15 final 2021-10-28 12:17:01 -07:00
Makefile Linux 5.15.18 2022-01-29 10:58:25 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

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.