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
Makefile
smc.h	net/smc: Resolve the race between link group access and termination	2022-01-13 12:55:40 +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
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
smc_llc.c	net/smc: Print net namespace in log	2022-01-02 12:07:39 +00:00
smc_llc.h
smc_netlink.c
smc_netlink.h
smc_netns.h
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
smc_rx.c
smc_rx.h
smc_stats.c
smc_stats.h
smc_tracepoint.c
smc_tracepoint.h	net/smc: Add net namespace for tracepoints	2022-01-02 12:07:39 +00:00
smc_tx.c
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