6.5-stable review patch. If anyone has any objections, please let me know.
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From: Guangguan Wang guangguan.wang@linux.alibaba.com
[ Upstream commit f5146e3ef0a9eea405874b36178c19a4863b8989 ]
While doing smcr_port_add, there maybe linkgroup add into or delete from smc_lgr_list.list at the same time, which may result kernel crash. So, use smc_lgr_list.lock to protect smc_lgr_list.list iterate in smcr_port_add.
The crash calltrace show below: BUG: kernel NULL pointer dereference, address: 0000000000000000 PGD 0 P4D 0 Oops: 0000 [#1] SMP NOPTI CPU: 0 PID: 559726 Comm: kworker/0:92 Kdump: loaded Tainted: G Hardware name: Alibaba Cloud Alibaba Cloud ECS, BIOS 449e491 04/01/2014 Workqueue: events smc_ib_port_event_work [smc] RIP: 0010:smcr_port_add+0xa6/0xf0 [smc] RSP: 0000:ffffa5a2c8f67de0 EFLAGS: 00010297 RAX: 0000000000000001 RBX: ffff9935e0650000 RCX: 0000000000000000 RDX: 0000000000000010 RSI: ffff9935e0654290 RDI: ffff9935c8560000 RBP: 0000000000000000 R08: 0000000000000000 R09: ffff9934c0401918 R10: 0000000000000000 R11: ffffffffb4a5c278 R12: ffff99364029aae4 R13: ffff99364029aa00 R14: 00000000ffffffed R15: ffff99364029ab08 FS: 0000000000000000(0000) GS:ffff994380600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000f06a10003 CR4: 0000000002770ef0 PKRU: 55555554 Call Trace: smc_ib_port_event_work+0x18f/0x380 [smc] process_one_work+0x19b/0x340 worker_thread+0x30/0x370 ? process_one_work+0x340/0x340 kthread+0x114/0x130 ? __kthread_cancel_work+0x50/0x50 ret_from_fork+0x1f/0x30
Fixes: 1f90a05d9ff9 ("net/smc: add smcr_port_add() and smcr_link_up() processing") Signed-off-by: Guangguan Wang guangguan.wang@linux.alibaba.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/smc/smc_core.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c index 6b78075404d7d..3e89bb9b7c56c 100644 --- a/net/smc/smc_core.c +++ b/net/smc/smc_core.c @@ -1654,6 +1654,7 @@ void smcr_port_add(struct smc_ib_device *smcibdev, u8 ibport) { struct smc_link_group *lgr, *n;
+ spin_lock_bh(&smc_lgr_list.lock); list_for_each_entry_safe(lgr, n, &smc_lgr_list.list, list) { struct smc_link *link;
@@ -1669,6 +1670,7 @@ void smcr_port_add(struct smc_ib_device *smcibdev, u8 ibport) if (link) smc_llc_add_link_local(link); } + spin_unlock_bh(&smc_lgr_list.lock); }
/* link is down - switch connections to alternate link,