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linux/net/smc
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Wen Gu c0bf3d8a94 net/smc: Transitional solution for clcsock race issue 
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>
2022-01-24 12:06:08 +00:00
..
af_smc.c net/smc: Transitional solution for clcsock race issue 2022-01-24 12:06:08 +00:00
Kconfig treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
Makefile net/smc: Introduce tracepoint for fallback 2021-11-01 13:39:14 +00:00
smc_cdc.c net/smc: Introduce a new conn->lgr validity check helper 2022-01-13 13:14:53 +00:00
smc_cdc.h net/smc: fix kernel panic caused by race of smc_sock 2021-12-28 12:42:45 +00:00
smc_clc.c net/smc: Introduce a new conn->lgr validity check helper 2022-01-13 13:14:53 +00:00
smc_clc.h net/smc: add v2 format of CLC decline message 2021-10-16 14:58:13 +01:00
smc_close.c net/smc: Keep smc_close_final rc during active close 2021-12-02 12:14:36 +00:00
smc_close.h
smc_core.c net/smc: Fix hung_task when removing SMC-R devices 2022-01-16 12:30:28 +00:00
smc_core.h net/smc: Resolve the race between SMC-R link access and clear 2022-01-13 13:14:53 +00:00
smc_diag.c net/smc: Introduce a new conn->lgr validity check helper 2022-01-13 13:14:53 +00:00
smc_ib.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2021-12-31 14:35:40 +00:00
smc_ib.h net/smc: Introduce net namespace support for linkgroup 2022-01-02 12:07:39 +00:00
smc_ism.c net: Don't include filter.h from net/sock.h 2021-12-29 08:48:14 -08:00
smc_ism.h net/smc: keep static copy of system EID 2021-09-14 12:49:10 +01:00
smc_llc.c net/smc: Print net namespace in log 2022-01-02 12:07:39 +00:00
smc_llc.h net/smc: extend LLC layer for SMC-Rv2 2021-10-16 14:58:13 +01:00
smc_netlink.c net/smc: add generic netlink support for system EID 2021-09-14 12:49:10 +01:00
smc_netlink.h net/smc: add support for user defined EIDs 2021-09-14 12:49:10 +01:00
smc_netns.h net/smc: introduce list of pnetids for Ethernet devices 2020-09-28 15:19:03 -07:00
smc_pnet.c net/smc: fix possible NULL deref in smc_pnet_add_eth() 2022-01-12 14:45:29 +00:00
smc_pnet.h net/smc: determine proposed ISM devices 2020-09-28 15:19:03 -07:00
smc_rx.c net/smc: Introduce tracepoints for tx and rx msg 2021-11-01 13:39:14 +00:00
smc_rx.h
smc_stats.c net/smc: Fix ENODATA tests in smc_nl_get_fback_stats() 2021-06-21 12:16:58 -07:00
smc_stats.h net/smc: Make SMC statistics network namespace aware 2021-06-16 12:54:02 -07:00
smc_tracepoint.c net/smc: Introduce tracepoint for smcr link down 2021-11-01 13:39:14 +00:00
smc_tracepoint.h net/smc: Add net namespace for tracepoints 2022-01-02 12:07:39 +00:00
smc_tx.c net/smc: Introduce tracepoints for tx and rx msg 2021-11-01 13:39:14 +00:00
smc_tx.h
smc_wr.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-12-30 12:12:12 -08:00
smc_wr.h net/smc: Remove unused function declaration 2022-01-15 22:57:21 +00:00
smc.h net/smc: Resolve the race between link group access and termination 2022-01-13 12:55:40 +00:00