* [PATCH net v2] net/smc: fix wrong list_del in smc_lgr_cleanup_early
@ 2021-12-01 2:31 Dust Li
2021-12-01 2:46 ` Jakub Kicinski
0 siblings, 1 reply; 2+ messages in thread
From: Dust Li @ 2021-12-01 2:31 UTC (permalink / raw)
To: Karsten Graul, David S . Miller, Jakub Kicinski, Ursula Braun
Cc: Tony Lu, Wen Gu, linux-s390, netdev
smc_lgr_cleanup_early() meant to delete the link
group from the link group list, but it deleted
the list head by mistake.
This may cause memory corruption since we didn't
remove the real link group from the list and later
memseted the link group structure.
We got a list corruption panic when testing:
[ 231.277259] list_del corruption. prev->next should be ffff8881398a8000, but was 0000000000000000
[ 231.278222] ------------[ cut here ]------------
[ 231.278726] kernel BUG at lib/list_debug.c:53!
[ 231.279326] invalid opcode: 0000 [#1] SMP NOPTI
[ 231.279803] CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.10.46+ #435
[ 231.280466] Hardware name: Alibaba Cloud ECS, BIOS 8c24b4c 04/01/2014
[ 231.281248] Workqueue: events smc_link_down_work
[ 231.281732] RIP: 0010:__list_del_entry_valid+0x70/0x90
[ 231.282258] Code: 4c 60 82 e8 7d cc 6a 00 0f 0b 48 89 fe 48 c7 c7 88 4c
60 82 e8 6c cc 6a 00 0f 0b 48 89 fe 48 c7 c7 c0 4c 60 82 e8 5b cc 6a 00 <0f>
0b 48 89 fe 48 c7 c7 00 4d 60 82 e8 4a cc 6a 00 0f 0b cc cc cc
[ 231.284146] RSP: 0018:ffffc90000033d58 EFLAGS: 00010292
[ 231.284685] RAX: 0000000000000054 RBX: ffff8881398a8000 RCX: 0000000000000000
[ 231.285415] RDX: 0000000000000001 RSI: ffff88813bc18040 RDI: ffff88813bc18040
[ 231.286141] RBP: ffffffff8305ad40 R08: 0000000000000003 R09: 0000000000000001
[ 231.286873] R10: ffffffff82803da0 R11: ffffc90000033b90 R12: 0000000000000001
[ 231.287606] R13: 0000000000000000 R14: ffff8881398a8000 R15: 0000000000000003
[ 231.288337] FS: 0000000000000000(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000
[ 231.289160] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 231.289754] CR2: 0000000000e72058 CR3: 000000010fa96006 CR4: 00000000003706f0
[ 231.290485] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 231.291211] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 231.291940] Call Trace:
[ 231.292211] smc_lgr_terminate_sched+0x53/0xa0
[ 231.292677] smc_switch_conns+0x75/0x6b0
[ 231.293085] ? update_load_avg+0x1a6/0x590
[ 231.293517] ? ttwu_do_wakeup+0x17/0x150
[ 231.293907] ? update_load_avg+0x1a6/0x590
[ 231.294317] ? newidle_balance+0xca/0x3d0
[ 231.294716] smcr_link_down+0x50/0x1a0
[ 231.295090] ? __wake_up_common_lock+0x77/0x90
[ 231.295534] smc_link_down_work+0x46/0x60
[ 231.295933] process_one_work+0x18b/0x350
Fixes: a0a62ee15a829 ("net/smc: separate locks for SMCD and SMCR link group lists")
Signed-off-by: Dust Li <dust.li@linux.alibaba.com>
Acked-by: Karsten Graul <kgraul@linux.ibm.com>
---
v2:
- Remove unused lgr_list
---
net/smc/smc_core.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index bb52c8b5f148..8759f9fd8113 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -625,18 +625,16 @@ int smcd_nl_get_lgr(struct sk_buff *skb, struct netlink_callback *cb)
void smc_lgr_cleanup_early(struct smc_connection *conn)
{
struct smc_link_group *lgr = conn->lgr;
- struct list_head *lgr_list;
spinlock_t *lgr_lock;
if (!lgr)
return;
smc_conn_free(conn);
- lgr_list = smc_lgr_list_head(lgr, &lgr_lock);
spin_lock_bh(lgr_lock);
/* do not use this link group for new connections */
- if (!list_empty(lgr_list))
- list_del_init(lgr_list);
+ if (!list_empty(&lgr->list))
+ list_del_init(&lgr->list);
spin_unlock_bh(lgr_lock);
__smc_lgr_terminate(lgr, true);
}
--
2.19.1.3.ge56e4f7
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net v2] net/smc: fix wrong list_del in smc_lgr_cleanup_early
2021-12-01 2:31 [PATCH net v2] net/smc: fix wrong list_del in smc_lgr_cleanup_early Dust Li
@ 2021-12-01 2:46 ` Jakub Kicinski
0 siblings, 0 replies; 2+ messages in thread
From: Jakub Kicinski @ 2021-12-01 2:46 UTC (permalink / raw)
To: Dust Li
Cc: Karsten Graul, David S . Miller, Ursula Braun, Tony Lu, Wen Gu,
linux-s390, netdev
On Wed, 1 Dec 2021 10:31:47 +0800 Dust Li wrote:
> smc_lgr_cleanup_early() meant to delete the link
> group from the link group list, but it deleted
> the list head by mistake.
>
> This may cause memory corruption since we didn't
> remove the real link group from the list and later
> memseted the link group structure.
> We got a list corruption panic when testing:
>
> [ 231.277259] list_del corruption. prev->next should be ffff8881398a8000, but was 0000000000000000
> [ 231.278222] ------------[ cut here ]------------
> [ 231.278726] kernel BUG at lib/list_debug.c:53!
> [ 231.279326] invalid opcode: 0000 [#1] SMP NOPTI
> [ 231.279803] CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.10.46+ #435
> [ 231.280466] Hardware name: Alibaba Cloud ECS, BIOS 8c24b4c 04/01/2014
> [ 231.281248] Workqueue: events smc_link_down_work
> [ 231.281732] RIP: 0010:__list_del_entry_valid+0x70/0x90
> [ 231.282258] Code: 4c 60 82 e8 7d cc 6a 00 0f 0b 48 89 fe 48 c7 c7 88 4c
> 60 82 e8 6c cc 6a 00 0f 0b 48 89 fe 48 c7 c7 c0 4c 60 82 e8 5b cc 6a 00 <0f>
> 0b 48 89 fe 48 c7 c7 00 4d 60 82 e8 4a cc 6a 00 0f 0b cc cc cc
> [ 231.284146] RSP: 0018:ffffc90000033d58 EFLAGS: 00010292
> [ 231.284685] RAX: 0000000000000054 RBX: ffff8881398a8000 RCX: 0000000000000000
> [ 231.285415] RDX: 0000000000000001 RSI: ffff88813bc18040 RDI: ffff88813bc18040
> [ 231.286141] RBP: ffffffff8305ad40 R08: 0000000000000003 R09: 0000000000000001
> [ 231.286873] R10: ffffffff82803da0 R11: ffffc90000033b90 R12: 0000000000000001
> [ 231.287606] R13: 0000000000000000 R14: ffff8881398a8000 R15: 0000000000000003
> [ 231.288337] FS: 0000000000000000(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000
> [ 231.289160] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 231.289754] CR2: 0000000000e72058 CR3: 000000010fa96006 CR4: 00000000003706f0
> [ 231.290485] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 231.291211] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [ 231.291940] Call Trace:
> [ 231.292211] smc_lgr_terminate_sched+0x53/0xa0
> [ 231.292677] smc_switch_conns+0x75/0x6b0
> [ 231.293085] ? update_load_avg+0x1a6/0x590
> [ 231.293517] ? ttwu_do_wakeup+0x17/0x150
> [ 231.293907] ? update_load_avg+0x1a6/0x590
> [ 231.294317] ? newidle_balance+0xca/0x3d0
> [ 231.294716] smcr_link_down+0x50/0x1a0
> [ 231.295090] ? __wake_up_common_lock+0x77/0x90
> [ 231.295534] smc_link_down_work+0x46/0x60
> [ 231.295933] process_one_work+0x18b/0x350
>
> Fixes: a0a62ee15a829 ("net/smc: separate locks for SMCD and SMCR link group lists")
> Signed-off-by: Dust Li <dust.li@linux.alibaba.com>
> Acked-by: Karsten Graul <kgraul@linux.ibm.com>
> net/smc/smc_core.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
> index bb52c8b5f148..8759f9fd8113 100644
> --- a/net/smc/smc_core.c
> +++ b/net/smc/smc_core.c
> @@ -625,18 +625,16 @@ int smcd_nl_get_lgr(struct sk_buff *skb, struct netlink_callback *cb)
> void smc_lgr_cleanup_early(struct smc_connection *conn)
> {
> struct smc_link_group *lgr = conn->lgr;
> - struct list_head *lgr_list;
> spinlock_t *lgr_lock;
>
> if (!lgr)
> return;
>
> smc_conn_free(conn);
> - lgr_list = smc_lgr_list_head(lgr, &lgr_lock);
> spin_lock_bh(lgr_lock);
> /* do not use this link group for new connections */
> - if (!list_empty(lgr_list))
> - list_del_init(lgr_list);
> + if (!list_empty(&lgr->list))
> + list_del_init(&lgr->list);
> spin_unlock_bh(lgr_lock);
> __smc_lgr_terminate(lgr, true);
> }
clang has something to say about that:
net/smc/smc_core.c:634:15: warning: variable 'lgr_lock' is uninitialized when used here [-Wuninitialized]
spin_lock_bh(lgr_lock);
^~~~~~~~
net/smc/smc_core.c:628:22: note: initialize the variable 'lgr_lock' to silence this warning
spinlock_t *lgr_lock;
^
= NULL
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