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net/smc: use smc_lgr_list.lock to protect smc_lgr_list.list iterate i…
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…n smcr_port_add

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: 1f90a05 ("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>
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@davem330
Guangguan Wang authored and davem330 committed Sep 10, 2023
1 parent 6912e72 commit f5146e3
Showing 1 changed file with 2 additions and 0 deletions.
2 changes: 2 additions & 0 deletions net/smc/smc_core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1662,6 +1662,7 @@ 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;

Expand All @@ -1680,6 +1681,7 @@ 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,
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