| Message ID | 20220830030555.373860-1-liuyacan@corp.netease.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net,v2] net/smc: Fix possible access to freed memory in link clear | expand |
> > From: liuyacan <liuyacan@corp.netease.com> > > > > After modifying the QP to the Error state, all RX WR would be > > completed with WC in IB_WC_WR_FLUSH_ERR status. Current > > implementation does not wait for it is done, but free the link > > directly. So there is a risk that accessing the freed link in > > tasklet context. > > > > Here is a crash example: > > > > BUG: unable to handle page fault for address: ffffffff8f220860 > > #PF: supervisor write access in kernel mode > > #PF: error_code(0x0002) - not-present page > > PGD f7300e067 P4D f7300e067 PUD f7300f063 PMD 8c4e45063 PTE 800ffff08c9df060 > > Oops: 0002 [#1] SMP PTI > > CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: G S OE 5.10.0-0607+ #23 > > Hardware name: Inspur NF5280M4/YZMB-00689-101, BIOS 4.1.20 07/09/2018 > > RIP: 0010:native_queued_spin_lock_slowpath+0x176/0x1b0 > > Code: f3 90 48 8b 32 48 85 f6 74 f6 eb d5 c1 ee 12 83 e0 03 83 ee 01 48 c1 e0 05 48 63 f6 48 05 00 c8 02 00 48 03 04 f5 00 09 98 8e <48> 89 10 8b 42 08 85 c0 75 09 f3 90 8b 42 08 85 c0 74 f7 48 8b 32 > > RSP: 0018:ffffb3b6c001ebd8 EFLAGS: 00010086 > > RAX: ffffffff8f220860 RBX: 0000000000000246 RCX: 0000000000080000 > > RDX: ffff91db1f86c800 RSI: 000000000000173c RDI: ffff91db62bace00 > > RBP: ffff91db62bacc00 R08: 0000000000000000 R09: c00000010000028b > > R10: 0000000000055198 R11: ffffb3b6c001ea58 R12: ffff91db80e05010 > > R13: 000000000000000a R14: 0000000000000006 R15: 0000000000000040 > > FS: 0000000000000000(0000) GS:ffff91db1f840000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: ffffffff8f220860 CR3: 00000001f9580004 CR4: 00000000003706e0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > Call Trace: > > <IRQ> > > _raw_spin_lock_irqsave+0x30/0x40 > > mlx5_ib_poll_cq+0x4c/0xc50 [mlx5_ib] > > smc_wr_rx_tasklet_fn+0x56/0xa0 [smc] > > tasklet_action_common.isra.21+0x66/0x100 > > __do_softirq+0xd5/0x29c > > asm_call_irq_on_stack+0x12/0x20 > > </IRQ> > > do_softirq_own_stack+0x37/0x40 > > irq_exit_rcu+0x9d/0xa0 > > sysvec_call_function_single+0x34/0x80 > > asm_sysvec_call_function_single+0x12/0x20 > > > > Signed-off-by: liuyacan <liuyacan@corp.netease.com> > > --- > > net/smc/smc_core.c | 2 ++ > > net/smc/smc_core.h | 2 ++ > > net/smc/smc_wr.c | 12 ++++++++++++ > > net/smc/smc_wr.h | 3 +++ > > 4 files changed, 19 insertions(+) > > > > diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c > > index ff49a11f5..b632a33f1 100644 > > --- a/net/smc/smc_core.c > > +++ b/net/smc/smc_core.c > > @@ -752,6 +752,7 @@ int smcr_link_init(struct smc_link_group *lgr, struct smc_link *lnk, > > atomic_inc(&lnk->smcibdev->lnk_cnt); > > refcount_set(&lnk->refcnt, 1); /* link refcnt is set to 1 */ > > lnk->clearing = 0; > > + lnk->rx_drained = 0; > > lnk->path_mtu = lnk->smcibdev->pattr[lnk->ibport - 1].active_mtu; > > lnk->link_id = smcr_next_link_id(lgr); > > lnk->lgr = lgr; > > @@ -1269,6 +1270,7 @@ void smcr_link_clear(struct smc_link *lnk, bool log) > > smcr_buf_unmap_lgr(lnk); > > smcr_rtoken_clear_link(lnk); > > smc_ib_modify_qp_error(lnk); > > + smc_wr_drain_cq(lnk); > > smc_wr_free_link(lnk); > > smc_ib_destroy_queue_pair(lnk); > > smc_ib_dealloc_protection_domain(lnk); > > diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h > > index fe8b524ad..0a469a3e7 100644 > > --- a/net/smc/smc_core.h > > +++ b/net/smc/smc_core.h > > @@ -117,6 +117,7 @@ struct smc_link { > > u64 wr_rx_id; /* seq # of last recv WR */ > > u32 wr_rx_cnt; /* number of WR recv buffers */ > > unsigned long wr_rx_tstamp; /* jiffies when last buf rx */ > > + wait_queue_head_t wr_rx_drain_wait; /* wait for WR drain */ > > > > struct ib_reg_wr wr_reg; /* WR register memory region */ > > wait_queue_head_t wr_reg_wait; /* wait for wr_reg result */ > > @@ -138,6 +139,7 @@ struct smc_link { > > u8 link_idx; /* index in lgr link array */ > > u8 link_is_asym; /* is link asymmetric? */ > > u8 clearing : 1; /* link is being cleared */ > > + u8 rx_drained : 1; /* link is drained */ > > refcount_t refcnt; /* link reference count */ > > struct smc_link_group *lgr; /* parent link group */ > > struct work_struct link_down_wrk; /* wrk to bring link down */ > > diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c > > index 26f8f240d..f9992896a 100644 > > --- a/net/smc/smc_wr.c > > +++ b/net/smc/smc_wr.c > > @@ -465,6 +465,10 @@ static inline void smc_wr_rx_process_cqes(struct ib_wc wc[], int num) > > case IB_WC_RNR_RETRY_EXC_ERR: > > case IB_WC_WR_FLUSH_ERR: > > smcr_link_down_cond_sched(link); > > + if (link->clearing && wc[i]->wr_id == link->wr_rx_id) { > > + link->rx_drained = 1; > > + wake_up(&link->wr_rx_drain_wait); > > + } > > I am wondering if we should wait for all the wc comes back? I think yes, so other processes can safely destroy qp. > > > break; > > default: > > smc_wr_rx_post(link); /* refill WR RX */ > > @@ -631,6 +635,13 @@ static void smc_wr_init_sge(struct smc_link *lnk) > > lnk->wr_reg.access = IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_WRITE; > > } > > > > +void smc_wr_drain_cq(struct smc_link *lnk) > > +{ > > + wait_event_interruptible_timeout(lnk->wr_rx_drain_wait, > > + (lnk->drained == 1), > > + SMC_WR_RX_WAIT_DRAIN_TIME); > > +} > > Should we wait for it with timeout? It should eventually be wake up > normally before freeing link. Waiting for SMC_WR_RX_WAIT_DRAIN_TIME (2s) > may also have this issue, although the probability of occurrence is > greatly reduced. Indeed, there should logically probably be a perpetual wait here. I'm just worried if it will get stuck for some unknown reason. > > Cheers, > Tony Lu Regards, Yacan
On 30.08.22 07:58, liuyacan@corp.netease.com wrote: >>> From: liuyacan <liuyacan@corp.netease.com> >>> >>> After modifying the QP to the Error state, all RX WR would be >>> completed with WC in IB_WC_WR_FLUSH_ERR status. Current >>> implementation does not wait for it is done, but free the link >>> directly. So there is a risk that accessing the freed link in >>> tasklet context. >>> >>> Here is a crash example: >>> >>> BUG: unable to handle page fault for address: ffffffff8f220860 >>> #PF: supervisor write access in kernel mode >>> #PF: error_code(0x0002) - not-present page >>> PGD f7300e067 P4D f7300e067 PUD f7300f063 PMD 8c4e45063 PTE 800ffff08c9df060 >>> Oops: 0002 [#1] SMP PTI >>> CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: G S OE 5.10.0-0607+ #23 >>> Hardware name: Inspur NF5280M4/YZMB-00689-101, BIOS 4.1.20 07/09/2018 >>> RIP: 0010:native_queued_spin_lock_slowpath+0x176/0x1b0 >>> Code: f3 90 48 8b 32 48 85 f6 74 f6 eb d5 c1 ee 12 83 e0 03 83 ee 01 48 c1 e0 05 48 63 f6 48 05 00 c8 02 00 48 03 04 f5 00 09 98 8e <48> 89 10 8b 42 08 85 c0 75 09 f3 90 8b 42 08 85 c0 74 f7 48 8b 32 >>> RSP: 0018:ffffb3b6c001ebd8 EFLAGS: 00010086 >>> RAX: ffffffff8f220860 RBX: 0000000000000246 RCX: 0000000000080000 >>> RDX: ffff91db1f86c800 RSI: 000000000000173c RDI: ffff91db62bace00 >>> RBP: ffff91db62bacc00 R08: 0000000000000000 R09: c00000010000028b >>> R10: 0000000000055198 R11: ffffb3b6c001ea58 R12: ffff91db80e05010 >>> R13: 000000000000000a R14: 0000000000000006 R15: 0000000000000040 >>> FS: 0000000000000000(0000) GS:ffff91db1f840000(0000) knlGS:0000000000000000 >>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>> CR2: ffffffff8f220860 CR3: 00000001f9580004 CR4: 00000000003706e0 >>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >>> Call Trace: >>> <IRQ> >>> _raw_spin_lock_irqsave+0x30/0x40 >>> mlx5_ib_poll_cq+0x4c/0xc50 [mlx5_ib] >>> smc_wr_rx_tasklet_fn+0x56/0xa0 [smc] >>> tasklet_action_common.isra.21+0x66/0x100 >>> __do_softirq+0xd5/0x29c >>> asm_call_irq_on_stack+0x12/0x20 >>> </IRQ> >>> do_softirq_own_stack+0x37/0x40 >>> irq_exit_rcu+0x9d/0xa0 >>> sysvec_call_function_single+0x34/0x80 >>> asm_sysvec_call_function_single+0x12/0x20 >>> >>> Signed-off-by: liuyacan <liuyacan@corp.netease.com> >>> --- >>> net/smc/smc_core.c | 2 ++ >>> net/smc/smc_core.h | 2 ++ >>> net/smc/smc_wr.c | 12 ++++++++++++ >>> net/smc/smc_wr.h | 3 +++ >>> 4 files changed, 19 insertions(+) >>> >>> diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c >>> index ff49a11f5..b632a33f1 100644 >>> --- a/net/smc/smc_core.c >>> +++ b/net/smc/smc_core.c >>> @@ -752,6 +752,7 @@ int smcr_link_init(struct smc_link_group *lgr, struct smc_link *lnk, >>> atomic_inc(&lnk->smcibdev->lnk_cnt); >>> refcount_set(&lnk->refcnt, 1); /* link refcnt is set to 1 */ >>> lnk->clearing = 0; >>> + lnk->rx_drained = 0; >>> lnk->path_mtu = lnk->smcibdev->pattr[lnk->ibport - 1].active_mtu; >>> lnk->link_id = smcr_next_link_id(lgr); >>> lnk->lgr = lgr; >>> @@ -1269,6 +1270,7 @@ void smcr_link_clear(struct smc_link *lnk, bool log) >>> smcr_buf_unmap_lgr(lnk); >>> smcr_rtoken_clear_link(lnk); >>> smc_ib_modify_qp_error(lnk); >>> + smc_wr_drain_cq(lnk); >>> smc_wr_free_link(lnk); >>> smc_ib_destroy_queue_pair(lnk); >>> smc_ib_dealloc_protection_domain(lnk); >>> diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h >>> index fe8b524ad..0a469a3e7 100644 >>> --- a/net/smc/smc_core.h >>> +++ b/net/smc/smc_core.h >>> @@ -117,6 +117,7 @@ struct smc_link { >>> u64 wr_rx_id; /* seq # of last recv WR */ >>> u32 wr_rx_cnt; /* number of WR recv buffers */ >>> unsigned long wr_rx_tstamp; /* jiffies when last buf rx */ >>> + wait_queue_head_t wr_rx_drain_wait; /* wait for WR drain */ >>> >>> struct ib_reg_wr wr_reg; /* WR register memory region */ >>> wait_queue_head_t wr_reg_wait; /* wait for wr_reg result */ >>> @@ -138,6 +139,7 @@ struct smc_link { >>> u8 link_idx; /* index in lgr link array */ >>> u8 link_is_asym; /* is link asymmetric? */ >>> u8 clearing : 1; /* link is being cleared */ >>> + u8 rx_drained : 1; /* link is drained */ >>> refcount_t refcnt; /* link reference count */ >>> struct smc_link_group *lgr; /* parent link group */ >>> struct work_struct link_down_wrk; /* wrk to bring link down */ >>> diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c >>> index 26f8f240d..f9992896a 100644 >>> --- a/net/smc/smc_wr.c >>> +++ b/net/smc/smc_wr.c >>> @@ -465,6 +465,10 @@ static inline void smc_wr_rx_process_cqes(struct ib_wc wc[], int num) >>> case IB_WC_RNR_RETRY_EXC_ERR: >>> case IB_WC_WR_FLUSH_ERR: >>> smcr_link_down_cond_sched(link); >>> + if (link->clearing && wc[i]->wr_id == link->wr_rx_id) { >>> + link->rx_drained = 1; >>> + wake_up(&link->wr_rx_drain_wait); >>> + } >> >> I am wondering if we should wait for all the wc comes back? > > I think yes, so other processes can safely destroy qp. > >> >>> break; >>> default: >>> smc_wr_rx_post(link); /* refill WR RX */ >>> @@ -631,6 +635,13 @@ static void smc_wr_init_sge(struct smc_link *lnk) >>> lnk->wr_reg.access = IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_WRITE; >>> } >>> >>> +void smc_wr_drain_cq(struct smc_link *lnk) >>> +{ >>> + wait_event_interruptible_timeout(lnk->wr_rx_drain_wait, >>> + (lnk->drained == 1), >>> + SMC_WR_RX_WAIT_DRAIN_TIME); >>> +} >> >> Should we wait for it with timeout? It should eventually be wake up >> normally before freeing link. Waiting for SMC_WR_RX_WAIT_DRAIN_TIME (2s) >> may also have this issue, although the probability of occurrence is >> greatly reduced. > > Indeed, there should logically probably be a perpetual wait here. I'm just worried if it > will get stuck for some unknown reason. > >> >> Cheers, >> Tony Lu > > Regards, > Yacan > Thank you very much for working on a fix, Yacan. Some comments to make reviewers' lives easier: Please use your real name for the Signed-Off tag and Mail sender (Is it Yacan Liu ?) (Please use the same Mail address for all your posts. In April there was a post from yacanliu@163.com. Not this one) Important: Add a Fixes tag, when sending fixes to NET Is this mail really a reply to your v2? Or rather a reply to Tony's comments on v1? Kind regards Alexandra
On Tue, Aug 30, 2022 at 01:58:06PM +0800, liuyacan@corp.netease.com wrote: > > > From: liuyacan <liuyacan@corp.netease.com> > > > > > > After modifying the QP to the Error state, all RX WR would be > > > completed with WC in IB_WC_WR_FLUSH_ERR status. Current > > > implementation does not wait for it is done, but free the link > > > directly. So there is a risk that accessing the freed link in > > > tasklet context. > > > > > > Here is a crash example: > > > > > > BUG: unable to handle page fault for address: ffffffff8f220860 > > > #PF: supervisor write access in kernel mode > > > #PF: error_code(0x0002) - not-present page > > > PGD f7300e067 P4D f7300e067 PUD f7300f063 PMD 8c4e45063 PTE 800ffff08c9df060 > > > Oops: 0002 [#1] SMP PTI > > > CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: G S OE 5.10.0-0607+ #23 > > > Hardware name: Inspur NF5280M4/YZMB-00689-101, BIOS 4.1.20 07/09/2018 > > > RIP: 0010:native_queued_spin_lock_slowpath+0x176/0x1b0 > > > Code: f3 90 48 8b 32 48 85 f6 74 f6 eb d5 c1 ee 12 83 e0 03 83 ee 01 48 c1 e0 05 48 63 f6 48 05 00 c8 02 00 48 03 04 f5 00 09 98 8e <48> 89 10 8b 42 08 85 c0 75 09 f3 90 8b 42 08 85 c0 74 f7 48 8b 32 > > > RSP: 0018:ffffb3b6c001ebd8 EFLAGS: 00010086 > > > RAX: ffffffff8f220860 RBX: 0000000000000246 RCX: 0000000000080000 > > > RDX: ffff91db1f86c800 RSI: 000000000000173c RDI: ffff91db62bace00 > > > RBP: ffff91db62bacc00 R08: 0000000000000000 R09: c00000010000028b > > > R10: 0000000000055198 R11: ffffb3b6c001ea58 R12: ffff91db80e05010 > > > R13: 000000000000000a R14: 0000000000000006 R15: 0000000000000040 > > > FS: 0000000000000000(0000) GS:ffff91db1f840000(0000) knlGS:0000000000000000 > > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > > CR2: ffffffff8f220860 CR3: 00000001f9580004 CR4: 00000000003706e0 > > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > Call Trace: > > > <IRQ> > > > _raw_spin_lock_irqsave+0x30/0x40 > > > mlx5_ib_poll_cq+0x4c/0xc50 [mlx5_ib] > > > smc_wr_rx_tasklet_fn+0x56/0xa0 [smc] > > > tasklet_action_common.isra.21+0x66/0x100 > > > __do_softirq+0xd5/0x29c > > > asm_call_irq_on_stack+0x12/0x20 > > > </IRQ> > > > do_softirq_own_stack+0x37/0x40 > > > irq_exit_rcu+0x9d/0xa0 > > > sysvec_call_function_single+0x34/0x80 > > > asm_sysvec_call_function_single+0x12/0x20 > > > > > > Signed-off-by: liuyacan <liuyacan@corp.netease.com> > > > --- > > > net/smc/smc_core.c | 2 ++ > > > net/smc/smc_core.h | 2 ++ > > > net/smc/smc_wr.c | 12 ++++++++++++ > > > net/smc/smc_wr.h | 3 +++ > > > 4 files changed, 19 insertions(+) > > > > > > diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c > > > index ff49a11f5..b632a33f1 100644 > > > --- a/net/smc/smc_core.c > > > +++ b/net/smc/smc_core.c > > > @@ -752,6 +752,7 @@ int smcr_link_init(struct smc_link_group *lgr, struct smc_link *lnk, > > > atomic_inc(&lnk->smcibdev->lnk_cnt); > > > refcount_set(&lnk->refcnt, 1); /* link refcnt is set to 1 */ > > > lnk->clearing = 0; > > > + lnk->rx_drained = 0; > > > lnk->path_mtu = lnk->smcibdev->pattr[lnk->ibport - 1].active_mtu; > > > lnk->link_id = smcr_next_link_id(lgr); > > > lnk->lgr = lgr; > > > @@ -1269,6 +1270,7 @@ void smcr_link_clear(struct smc_link *lnk, bool log) > > > smcr_buf_unmap_lgr(lnk); > > > smcr_rtoken_clear_link(lnk); > > > smc_ib_modify_qp_error(lnk); > > > + smc_wr_drain_cq(lnk); > > > smc_wr_free_link(lnk); > > > smc_ib_destroy_queue_pair(lnk); > > > smc_ib_dealloc_protection_domain(lnk); > > > diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h > > > index fe8b524ad..0a469a3e7 100644 > > > --- a/net/smc/smc_core.h > > > +++ b/net/smc/smc_core.h > > > @@ -117,6 +117,7 @@ struct smc_link { > > > u64 wr_rx_id; /* seq # of last recv WR */ > > > u32 wr_rx_cnt; /* number of WR recv buffers */ > > > unsigned long wr_rx_tstamp; /* jiffies when last buf rx */ > > > + wait_queue_head_t wr_rx_drain_wait; /* wait for WR drain */ > > > > > > struct ib_reg_wr wr_reg; /* WR register memory region */ > > > wait_queue_head_t wr_reg_wait; /* wait for wr_reg result */ > > > @@ -138,6 +139,7 @@ struct smc_link { > > > u8 link_idx; /* index in lgr link array */ > > > u8 link_is_asym; /* is link asymmetric? */ > > > u8 clearing : 1; /* link is being cleared */ > > > + u8 rx_drained : 1; /* link is drained */ > > > refcount_t refcnt; /* link reference count */ > > > struct smc_link_group *lgr; /* parent link group */ > > > struct work_struct link_down_wrk; /* wrk to bring link down */ > > > diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c > > > index 26f8f240d..f9992896a 100644 > > > --- a/net/smc/smc_wr.c > > > +++ b/net/smc/smc_wr.c > > > @@ -465,6 +465,10 @@ static inline void smc_wr_rx_process_cqes(struct ib_wc wc[], int num) > > > case IB_WC_RNR_RETRY_EXC_ERR: > > > case IB_WC_WR_FLUSH_ERR: > > > smcr_link_down_cond_sched(link); > > > + if (link->clearing && wc[i]->wr_id == link->wr_rx_id) { > > > + link->rx_drained = 1; > > > + wake_up(&link->wr_rx_drain_wait); > > > + } > > > > I am wondering if we should wait for all the wc comes back? > > I think yes, so other processes can safely destroy qp. > > > > > > break; > > > default: > > > smc_wr_rx_post(link); /* refill WR RX */ > > > @@ -631,6 +635,13 @@ static void smc_wr_init_sge(struct smc_link *lnk) > > > lnk->wr_reg.access = IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_WRITE; > > > } > > > > > > +void smc_wr_drain_cq(struct smc_link *lnk) > > > +{ > > > + wait_event_interruptible_timeout(lnk->wr_rx_drain_wait, > > > + (lnk->drained == 1), > > > + SMC_WR_RX_WAIT_DRAIN_TIME); > > > +} > > > > Should we wait for it with timeout? It should eventually be wake up > > normally before freeing link. Waiting for SMC_WR_RX_WAIT_DRAIN_TIME (2s) > > may also have this issue, although the probability of occurrence is > > greatly reduced. > > Indeed, there should logically probably be a perpetual wait here. I'm just worried if it > will get stuck for some unknown reason. IMHO, it's better to get stuck rather than to hide unknown issues. So I think timeout is unnecessary. Cheers, Tony Lu
> >>> From: liuyacan <liuyacan@corp.netease.com> > >>> > >>> After modifying the QP to the Error state, all RX WR would be > >>> completed with WC in IB_WC_WR_FLUSH_ERR status. Current > >>> implementation does not wait for it is done, but free the link > >>> directly. So there is a risk that accessing the freed link in > >>> tasklet context. > >>> > >>> Here is a crash example: > >>> > >>> BUG: unable to handle page fault for address: ffffffff8f220860 > >>> #PF: supervisor write access in kernel mode > >>> #PF: error_code(0x0002) - not-present page > >>> PGD f7300e067 P4D f7300e067 PUD f7300f063 PMD 8c4e45063 PTE 800ffff08c9df060 > >>> Oops: 0002 [#1] SMP PTI > >>> CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: G S OE 5.10.0-0607+ #23 > >>> Hardware name: Inspur NF5280M4/YZMB-00689-101, BIOS 4.1.20 07/09/2018 > >>> RIP: 0010:native_queued_spin_lock_slowpath+0x176/0x1b0 > >>> Code: f3 90 48 8b 32 48 85 f6 74 f6 eb d5 c1 ee 12 83 e0 03 83 ee 01 48 c1 e0 05 48 63 f6 48 05 00 c8 02 00 48 03 04 f5 00 09 98 8e <48> 89 10 8b 42 08 85 c0 75 09 f3 90 8b 42 08 85 c0 74 f7 48 8b 32 > >>> RSP: 0018:ffffb3b6c001ebd8 EFLAGS: 00010086 > >>> RAX: ffffffff8f220860 RBX: 0000000000000246 RCX: 0000000000080000 > >>> RDX: ffff91db1f86c800 RSI: 000000000000173c RDI: ffff91db62bace00 > >>> RBP: ffff91db62bacc00 R08: 0000000000000000 R09: c00000010000028b > >>> R10: 0000000000055198 R11: ffffb3b6c001ea58 R12: ffff91db80e05010 > >>> R13: 000000000000000a R14: 0000000000000006 R15: 0000000000000040 > >>> FS: 0000000000000000(0000) GS:ffff91db1f840000(0000) knlGS:0000000000000000 > >>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > >>> CR2: ffffffff8f220860 CR3: 00000001f9580004 CR4: 00000000003706e0 > >>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > >>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > >>> Call Trace: > >>> <IRQ> > >>> _raw_spin_lock_irqsave+0x30/0x40 > >>> mlx5_ib_poll_cq+0x4c/0xc50 [mlx5_ib] > >>> smc_wr_rx_tasklet_fn+0x56/0xa0 [smc] > >>> tasklet_action_common.isra.21+0x66/0x100 > >>> __do_softirq+0xd5/0x29c > >>> asm_call_irq_on_stack+0x12/0x20 > >>> </IRQ> > >>> do_softirq_own_stack+0x37/0x40 > >>> irq_exit_rcu+0x9d/0xa0 > >>> sysvec_call_function_single+0x34/0x80 > >>> asm_sysvec_call_function_single+0x12/0x20 > >>> > >>> Signed-off-by: liuyacan <liuyacan@corp.netease.com> > >>> --- > >>> net/smc/smc_core.c | 2 ++ > >>> net/smc/smc_core.h | 2 ++ > >>> net/smc/smc_wr.c | 12 ++++++++++++ > >>> net/smc/smc_wr.h | 3 +++ > >>> 4 files changed, 19 insertions(+) > >>> > >>> diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c > >>> index ff49a11f5..b632a33f1 100644 > >>> --- a/net/smc/smc_core.c > >>> +++ b/net/smc/smc_core.c > >>> @@ -752,6 +752,7 @@ int smcr_link_init(struct smc_link_group *lgr, struct smc_link *lnk, > >>> atomic_inc(&lnk->smcibdev->lnk_cnt); > >>> refcount_set(&lnk->refcnt, 1); /* link refcnt is set to 1 */ > >>> lnk->clearing = 0; > >>> + lnk->rx_drained = 0; > >>> lnk->path_mtu = lnk->smcibdev->pattr[lnk->ibport - 1].active_mtu; > >>> lnk->link_id = smcr_next_link_id(lgr); > >>> lnk->lgr = lgr; > >>> @@ -1269,6 +1270,7 @@ void smcr_link_clear(struct smc_link *lnk, bool log) > >>> smcr_buf_unmap_lgr(lnk); > >>> smcr_rtoken_clear_link(lnk); > >>> smc_ib_modify_qp_error(lnk); > >>> + smc_wr_drain_cq(lnk); > >>> smc_wr_free_link(lnk); > >>> smc_ib_destroy_queue_pair(lnk); > >>> smc_ib_dealloc_protection_domain(lnk); > >>> diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h > >>> index fe8b524ad..0a469a3e7 100644 > >>> --- a/net/smc/smc_core.h > >>> +++ b/net/smc/smc_core.h > >>> @@ -117,6 +117,7 @@ struct smc_link { > >>> u64 wr_rx_id; /* seq # of last recv WR */ > >>> u32 wr_rx_cnt; /* number of WR recv buffers */ > >>> unsigned long wr_rx_tstamp; /* jiffies when last buf rx */ > >>> + wait_queue_head_t wr_rx_drain_wait; /* wait for WR drain */ > >>> > >>> struct ib_reg_wr wr_reg; /* WR register memory region */ > >>> wait_queue_head_t wr_reg_wait; /* wait for wr_reg result */ > >>> @@ -138,6 +139,7 @@ struct smc_link { > >>> u8 link_idx; /* index in lgr link array */ > >>> u8 link_is_asym; /* is link asymmetric? */ > >>> u8 clearing : 1; /* link is being cleared */ > >>> + u8 rx_drained : 1; /* link is drained */ > >>> refcount_t refcnt; /* link reference count */ > >>> struct smc_link_group *lgr; /* parent link group */ > >>> struct work_struct link_down_wrk; /* wrk to bring link down */ > >>> diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c > >>> index 26f8f240d..f9992896a 100644 > >>> --- a/net/smc/smc_wr.c > >>> +++ b/net/smc/smc_wr.c > >>> @@ -465,6 +465,10 @@ static inline void smc_wr_rx_process_cqes(struct ib_wc wc[], int num) > >>> case IB_WC_RNR_RETRY_EXC_ERR: > >>> case IB_WC_WR_FLUSH_ERR: > >>> smcr_link_down_cond_sched(link); > >>> + if (link->clearing && wc[i]->wr_id == link->wr_rx_id) { > >>> + link->rx_drained = 1; > >>> + wake_up(&link->wr_rx_drain_wait); > >>> + } > >> > >> I am wondering if we should wait for all the wc comes back? > > > > I think yes, so other processes can safely destroy qp. > > > >> > >>> break; > >>> default: > >>> smc_wr_rx_post(link); /* refill WR RX */ > >>> @@ -631,6 +635,13 @@ static void smc_wr_init_sge(struct smc_link *lnk) > >>> lnk->wr_reg.access = IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_WRITE; > >>> } > >>> > >>> +void smc_wr_drain_cq(struct smc_link *lnk) > >>> +{ > >>> + wait_event_interruptible_timeout(lnk->wr_rx_drain_wait, > >>> + (lnk->drained == 1), > >>> + SMC_WR_RX_WAIT_DRAIN_TIME); > >>> +} > >> > >> Should we wait for it with timeout? It should eventually be wake up > >> normally before freeing link. Waiting for SMC_WR_RX_WAIT_DRAIN_TIME (2s) > >> may also have this issue, although the probability of occurrence is > >> greatly reduced. > > > > Indeed, there should logically probably be a perpetual wait here. I'm just worried if it > > will get stuck for some unknown reason. > > > >> > >> Cheers, > >> Tony Lu > > > > Regards, > > Yacan > > > > Thank you very much for working on a fix, Yacan. > > Some comments to make reviewers' lives easier: > Please use your real name for the Signed-Off tag and Mail sender (Is it Yacan Liu ?) > (Please use the same Mail address for all your posts. In April there was a post from yacanliu@163.com. Not this one) > > Important: Add a Fixes tag, when sending fixes to NET OK. I updated in the latest version (v4) > Is this mail really a reply to your v2? Or rather a reply to Tony's comments on v1? It should be v1. But now v1~v3 are abandoned. > > Kind regards > Alexandra Regards, Yacan
> > > > From: liuyacan <liuyacan@corp.netease.com> > > > > > > > > After modifying the QP to the Error state, all RX WR would be > > > > completed with WC in IB_WC_WR_FLUSH_ERR status. Current > > > > implementation does not wait for it is done, but free the link > > > > directly. So there is a risk that accessing the freed link in > > > > tasklet context. > > > > > > > > Here is a crash example: > > > > > > > > BUG: unable to handle page fault for address: ffffffff8f220860 > > > > #PF: supervisor write access in kernel mode > > > > #PF: error_code(0x0002) - not-present page > > > > PGD f7300e067 P4D f7300e067 PUD f7300f063 PMD 8c4e45063 PTE 800ffff08c9df060 > > > > Oops: 0002 [#1] SMP PTI > > > > CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: G S OE 5.10.0-0607+ #23 > > > > Hardware name: Inspur NF5280M4/YZMB-00689-101, BIOS 4.1.20 07/09/2018 > > > > RIP: 0010:native_queued_spin_lock_slowpath+0x176/0x1b0 > > > > Code: f3 90 48 8b 32 48 85 f6 74 f6 eb d5 c1 ee 12 83 e0 03 83 ee 01 48 c1 e0 05 48 63 f6 48 05 00 c8 02 00 48 03 04 f5 00 09 98 8e <48> 89 10 8b 42 08 85 c0 75 09 f3 90 8b 42 08 85 c0 74 f7 48 8b 32 > > > > RSP: 0018:ffffb3b6c001ebd8 EFLAGS: 00010086 > > > > RAX: ffffffff8f220860 RBX: 0000000000000246 RCX: 0000000000080000 > > > > RDX: ffff91db1f86c800 RSI: 000000000000173c RDI: ffff91db62bace00 > > > > RBP: ffff91db62bacc00 R08: 0000000000000000 R09: c00000010000028b > > > > R10: 0000000000055198 R11: ffffb3b6c001ea58 R12: ffff91db80e05010 > > > > R13: 000000000000000a R14: 0000000000000006 R15: 0000000000000040 > > > > FS: 0000000000000000(0000) GS:ffff91db1f840000(0000) knlGS:0000000000000000 > > > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > > > CR2: ffffffff8f220860 CR3: 00000001f9580004 CR4: 00000000003706e0 > > > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > > Call Trace: > > > > <IRQ> > > > > _raw_spin_lock_irqsave+0x30/0x40 > > > > mlx5_ib_poll_cq+0x4c/0xc50 [mlx5_ib] > > > > smc_wr_rx_tasklet_fn+0x56/0xa0 [smc] > > > > tasklet_action_common.isra.21+0x66/0x100 > > > > __do_softirq+0xd5/0x29c > > > > asm_call_irq_on_stack+0x12/0x20 > > > > </IRQ> > > > > do_softirq_own_stack+0x37/0x40 > > > > irq_exit_rcu+0x9d/0xa0 > > > > sysvec_call_function_single+0x34/0x80 > > > > asm_sysvec_call_function_single+0x12/0x20 > > > > > > > > Signed-off-by: liuyacan <liuyacan@corp.netease.com> > > > > --- > > > > net/smc/smc_core.c | 2 ++ > > > > net/smc/smc_core.h | 2 ++ > > > > net/smc/smc_wr.c | 12 ++++++++++++ > > > > net/smc/smc_wr.h | 3 +++ > > > > 4 files changed, 19 insertions(+) > > > > > > > > diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c > > > > index ff49a11f5..b632a33f1 100644 > > > > --- a/net/smc/smc_core.c > > > > +++ b/net/smc/smc_core.c > > > > @@ -752,6 +752,7 @@ int smcr_link_init(struct smc_link_group *lgr, struct smc_link *lnk, > > > > atomic_inc(&lnk->smcibdev->lnk_cnt); > > > > refcount_set(&lnk->refcnt, 1); /* link refcnt is set to 1 */ > > > > lnk->clearing = 0; > > > > + lnk->rx_drained = 0; > > > > lnk->path_mtu = lnk->smcibdev->pattr[lnk->ibport - 1].active_mtu; > > > > lnk->link_id = smcr_next_link_id(lgr); > > > > lnk->lgr = lgr; > > > > @@ -1269,6 +1270,7 @@ void smcr_link_clear(struct smc_link *lnk, bool log) > > > > smcr_buf_unmap_lgr(lnk); > > > > smcr_rtoken_clear_link(lnk); > > > > smc_ib_modify_qp_error(lnk); > > > > + smc_wr_drain_cq(lnk); > > > > smc_wr_free_link(lnk); > > > > smc_ib_destroy_queue_pair(lnk); > > > > smc_ib_dealloc_protection_domain(lnk); > > > > diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h > > > > index fe8b524ad..0a469a3e7 100644 > > > > --- a/net/smc/smc_core.h > > > > +++ b/net/smc/smc_core.h > > > > @@ -117,6 +117,7 @@ struct smc_link { > > > > u64 wr_rx_id; /* seq # of last recv WR */ > > > > u32 wr_rx_cnt; /* number of WR recv buffers */ > > > > unsigned long wr_rx_tstamp; /* jiffies when last buf rx */ > > > > + wait_queue_head_t wr_rx_drain_wait; /* wait for WR drain */ > > > > > > > > struct ib_reg_wr wr_reg; /* WR register memory region */ > > > > wait_queue_head_t wr_reg_wait; /* wait for wr_reg result */ > > > > @@ -138,6 +139,7 @@ struct smc_link { > > > > u8 link_idx; /* index in lgr link array */ > > > > u8 link_is_asym; /* is link asymmetric? */ > > > > u8 clearing : 1; /* link is being cleared */ > > > > + u8 rx_drained : 1; /* link is drained */ > > > > refcount_t refcnt; /* link reference count */ > > > > struct smc_link_group *lgr; /* parent link group */ > > > > struct work_struct link_down_wrk; /* wrk to bring link down */ > > > > diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c > > > > index 26f8f240d..f9992896a 100644 > > > > --- a/net/smc/smc_wr.c > > > > +++ b/net/smc/smc_wr.c > > > > @@ -465,6 +465,10 @@ static inline void smc_wr_rx_process_cqes(struct ib_wc wc[], int num) > > > > case IB_WC_RNR_RETRY_EXC_ERR: > > > > case IB_WC_WR_FLUSH_ERR: > > > > smcr_link_down_cond_sched(link); > > > > + if (link->clearing && wc[i]->wr_id == link->wr_rx_id) { > > > > + link->rx_drained = 1; > > > > + wake_up(&link->wr_rx_drain_wait); > > > > + } > > > > > > I am wondering if we should wait for all the wc comes back? > > > > I think yes, so other processes can safely destroy qp. > > > > > > > > > break; > > > > default: > > > > smc_wr_rx_post(link); /* refill WR RX */ > > > > @@ -631,6 +635,13 @@ static void smc_wr_init_sge(struct smc_link *lnk) > > > > lnk->wr_reg.access = IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_WRITE; > > > > } > > > > > > > > +void smc_wr_drain_cq(struct smc_link *lnk) > > > > +{ > > > > + wait_event_interruptible_timeout(lnk->wr_rx_drain_wait, > > > > + (lnk->drained == 1), > > > > + SMC_WR_RX_WAIT_DRAIN_TIME); > > > > +} > > > > > > Should we wait for it with timeout? It should eventually be wake up > > > normally before freeing link. Waiting for SMC_WR_RX_WAIT_DRAIN_TIME (2s) > > > may also have this issue, although the probability of occurrence is > > > greatly reduced. > > > > Indeed, there should logically probably be a perpetual wait here. I'm just worried if it > > will get stuck for some unknown reason. > > IMHO, it's better to get stuck rather than to hide unknown issues. So I > think timeout is unnecessary. Ok, I accept your suggestion, thank you! > > Cheers, > Tony Lu Regards, Yacan
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c index ff49a11f5..b632a33f1 100644 --- a/net/smc/smc_core.c +++ b/net/smc/smc_core.c @@ -752,6 +752,7 @@ int smcr_link_init(struct smc_link_group *lgr, struct smc_link *lnk, atomic_inc(&lnk->smcibdev->lnk_cnt); refcount_set(&lnk->refcnt, 1); /* link refcnt is set to 1 */ lnk->clearing = 0; + lnk->rx_drained = 0; lnk->path_mtu = lnk->smcibdev->pattr[lnk->ibport - 1].active_mtu; lnk->link_id = smcr_next_link_id(lgr); lnk->lgr = lgr; @@ -1269,6 +1270,7 @@ void smcr_link_clear(struct smc_link *lnk, bool log) smcr_buf_unmap_lgr(lnk); smcr_rtoken_clear_link(lnk); smc_ib_modify_qp_error(lnk); + smc_wr_drain_cq(lnk); smc_wr_free_link(lnk); smc_ib_destroy_queue_pair(lnk); smc_ib_dealloc_protection_domain(lnk); diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h index fe8b524ad..0a469a3e7 100644 --- a/net/smc/smc_core.h +++ b/net/smc/smc_core.h @@ -117,6 +117,7 @@ struct smc_link { u64 wr_rx_id; /* seq # of last recv WR */ u32 wr_rx_cnt; /* number of WR recv buffers */ unsigned long wr_rx_tstamp; /* jiffies when last buf rx */ + wait_queue_head_t wr_rx_drain_wait; /* wait for WR drain */ struct ib_reg_wr wr_reg; /* WR register memory region */ wait_queue_head_t wr_reg_wait; /* wait for wr_reg result */ @@ -138,6 +139,7 @@ struct smc_link { u8 link_idx; /* index in lgr link array */ u8 link_is_asym; /* is link asymmetric? */ u8 clearing : 1; /* link is being cleared */ + u8 rx_drained : 1; /* link is drained */ refcount_t refcnt; /* link reference count */ struct smc_link_group *lgr; /* parent link group */ struct work_struct link_down_wrk; /* wrk to bring link down */ diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c index 26f8f240d..3f782837b 100644 --- a/net/smc/smc_wr.c +++ b/net/smc/smc_wr.c @@ -465,6 +465,10 @@ static inline void smc_wr_rx_process_cqes(struct ib_wc wc[], int num) case IB_WC_RNR_RETRY_EXC_ERR: case IB_WC_WR_FLUSH_ERR: smcr_link_down_cond_sched(link); + if (link->clearing && wc[i].wr_id == link->wr_rx_id) { + link->rx_drained = 1; + wake_up(&link->wr_rx_drain_wait); + } break; default: smc_wr_rx_post(link); /* refill WR RX */ @@ -631,6 +635,13 @@ static void smc_wr_init_sge(struct smc_link *lnk) lnk->wr_reg.access = IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_WRITE; } +void smc_wr_drain_cq(struct smc_link *lnk) +{ + wait_event_interruptible_timeout(lnk->wr_rx_drain_wait, + (lnk->rx_drained == 1), + SMC_WR_RX_WAIT_DRAIN_TIME); +} + void smc_wr_free_link(struct smc_link *lnk) { struct ib_device *ibdev; @@ -889,6 +900,7 @@ int smc_wr_create_link(struct smc_link *lnk) atomic_set(&lnk->wr_tx_refcnt, 0); init_waitqueue_head(&lnk->wr_reg_wait); atomic_set(&lnk->wr_reg_refcnt, 0); + init_waitqueue_head(&lnk->wr_rx_drain_wait); return rc; dma_unmap: diff --git a/net/smc/smc_wr.h b/net/smc/smc_wr.h index a54e90a11..2a7ebdba3 100644 --- a/net/smc/smc_wr.h +++ b/net/smc/smc_wr.h @@ -27,6 +27,8 @@ #define SMC_WR_TX_PEND_PRIV_SIZE 32 +#define SMC_WR_RX_WAIT_DRAIN_TIME (2 * HZ) + struct smc_wr_tx_pend_priv { u8 priv[SMC_WR_TX_PEND_PRIV_SIZE]; }; @@ -101,6 +103,7 @@ static inline int smc_wr_rx_post(struct smc_link *link) int smc_wr_create_link(struct smc_link *lnk); int smc_wr_alloc_link_mem(struct smc_link *lnk); int smc_wr_alloc_lgr_mem(struct smc_link_group *lgr); +void smc_wr_drain_cq(struct smc_link *lnk); void smc_wr_free_link(struct smc_link *lnk); void smc_wr_free_link_mem(struct smc_link *lnk); void smc_wr_free_lgr_mem(struct smc_link_group *lgr);