* Re: [PATCH 1/1] IB/rxe: avoid double kfree_skb [not found] <1524146512-4188-1-git-send-email-yanjun.zhu@oracle.com> @ 2018-04-20 2:19 ` Doug Ledford 2018-04-20 5:46 ` Yanjun Zhu 0 siblings, 1 reply; 5+ messages in thread From: Doug Ledford @ 2018-04-20 2:19 UTC (permalink / raw) To: Zhu Yanjun, monis, jgg, linux-rdma; +Cc: netdev [-- Attachment #1: Type: text/plain, Size: 4795 bytes --] On Thu, 2018-04-19 at 10:01 -0400, Zhu Yanjun wrote: > When skb is dropped by iptables rules, the skb is freed at the same time > -EPERM is returned. So in softroce, it is not necessary to free skb again. > Or else, crash will occur. > > The steps to reproduce: > > server client > --------- --------- > |1.1.1.1|<----rxe-channel--->|1.1.1.2| > --------- --------- > > On server: rping -s -a 1.1.1.1 -v -C 10000 -S 512 > On client: rping -c -a 1.1.1.1 -v -C 10000 -S 512 > > The kernel configs CONFIG_DEBUG_KMEMLEAK and > CONFIG_DEBUG_OBJECTS are enabled on both server and client. > > When rping runs, run the following command in server: > > iptables -I OUTPUT -p udp --dport 4791 -j DROP > > Without this patch, crash will occur. > > CC: Srinivas Eeda <srinivas.eeda@oracle.com> > CC: Junxiao Bi <junxiao.bi@oracle.com> > Signed-off-by: Zhu Yanjun <yanjun.zhu@oracle.com> > Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com> I have no reason to doubt your analysis, but if there are a bunch of error paths for net_xmit and they all return with your skb still being valid and holding a reference, and then one oddball that returns with your skb already gone, that just sounds like a mistake waiting to happen (not to mention a bajillion special cases sprinkled everywhere to deal with this apparent inconsistency). Can we get a netdev@ confirmation on this being the right solution? > --- > drivers/infiniband/sw/rxe/rxe_net.c | 3 +++ > drivers/infiniband/sw/rxe/rxe_req.c | 5 +++-- > drivers/infiniband/sw/rxe/rxe_resp.c | 9 ++++++--- > 3 files changed, 12 insertions(+), 5 deletions(-) > > diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c > index 9da6e37..2094434 100644 > --- a/drivers/infiniband/sw/rxe/rxe_net.c > +++ b/drivers/infiniband/sw/rxe/rxe_net.c > @@ -511,6 +511,9 @@ int rxe_send(struct rxe_pkt_info *pkt, struct sk_buff *skb) > > if (unlikely(net_xmit_eval(err))) { > pr_debug("error sending packet: %d\n", err); > + /* -EPERM means the skb is dropped and freed. */ > + if (err == -EPERM) > + return -EPERM; > return -EAGAIN; > } > > diff --git a/drivers/infiniband/sw/rxe/rxe_req.c b/drivers/infiniband/sw/rxe/rxe_req.c > index 7bdaf71..9d2efec 100644 > --- a/drivers/infiniband/sw/rxe/rxe_req.c > +++ b/drivers/infiniband/sw/rxe/rxe_req.c > @@ -727,8 +727,9 @@ int rxe_requester(void *arg) > > rollback_state(wqe, qp, &rollback_wqe, rollback_psn); > > - if (ret == -EAGAIN) { > - kfree_skb(skb); > + if ((ret == -EAGAIN) || (ret == -EPERM)) { > + if (ret == -EAGAIN) > + kfree_skb(skb); > rxe_run_task(&qp->req.task, 1); > goto exit; > } > diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c > index a65c996..6bdf9b2 100644 > --- a/drivers/infiniband/sw/rxe/rxe_resp.c > +++ b/drivers/infiniband/sw/rxe/rxe_resp.c > @@ -742,7 +742,8 @@ static enum resp_states read_reply(struct rxe_qp *qp, > err = rxe_xmit_packet(rxe, qp, &ack_pkt, skb); > if (err) { > pr_err("Failed sending RDMA reply.\n"); > - kfree_skb(skb); > + if (err != -EPERM) > + kfree_skb(skb); > return RESPST_ERR_RNR; > } > > @@ -956,7 +957,8 @@ static int send_ack(struct rxe_qp *qp, struct rxe_pkt_info *pkt, > err = rxe_xmit_packet(rxe, qp, &ack_pkt, skb); > if (err) { > pr_err_ratelimited("Failed sending ack\n"); > - kfree_skb(skb); > + if (err != -EPERM) > + kfree_skb(skb); > } > > err1: > @@ -1141,7 +1143,8 @@ static enum resp_states duplicate_request(struct rxe_qp *qp, > if (rc) { > pr_err("Failed resending result. This flow is not handled - skb ignored\n"); > rxe_drop_ref(qp); > - kfree_skb(skb_copy); > + if (rc != -EPERM) > + kfree_skb(skb_copy); > rc = RESPST_CLEANUP; > goto out; > } > -- > 2.7.4 > -- Doug Ledford <dledford@redhat.com> GPG KeyID: B826A3330E572FDD Key fingerprint = AE6B 1BDA 122B 23B4 265B 1274 B826 A333 0E57 2FDD [-- Attachment #2: This is a digitally signed message part --] [-- Type: application/pgp-signature, Size: 833 bytes --] ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 1/1] IB/rxe: avoid double kfree_skb 2018-04-20 2:19 ` [PATCH 1/1] IB/rxe: avoid double kfree_skb Doug Ledford @ 2018-04-20 5:46 ` Yanjun Zhu 2018-04-24 8:34 ` Yanjun Zhu 0 siblings, 1 reply; 5+ messages in thread From: Yanjun Zhu @ 2018-04-20 5:46 UTC (permalink / raw) To: Doug Ledford, monis, jgg, linux-rdma; +Cc: netdev On 2018/4/20 10:19, Doug Ledford wrote: > On Thu, 2018-04-19 at 10:01 -0400, Zhu Yanjun wrote: >> When skb is dropped by iptables rules, the skb is freed at the same time >> -EPERM is returned. So in softroce, it is not necessary to free skb again. >> Or else, crash will occur. >> >> The steps to reproduce: >> >> server client >> --------- --------- >> |1.1.1.1|<----rxe-channel--->|1.1.1.2| >> --------- --------- >> >> On server: rping -s -a 1.1.1.1 -v -C 10000 -S 512 >> On client: rping -c -a 1.1.1.1 -v -C 10000 -S 512 >> >> The kernel configs CONFIG_DEBUG_KMEMLEAK and >> CONFIG_DEBUG_OBJECTS are enabled on both server and client. >> >> When rping runs, run the following command in server: >> >> iptables -I OUTPUT -p udp --dport 4791 -j DROP >> >> Without this patch, crash will occur. >> >> CC: Srinivas Eeda <srinivas.eeda@oracle.com> >> CC: Junxiao Bi <junxiao.bi@oracle.com> >> Signed-off-by: Zhu Yanjun <yanjun.zhu@oracle.com> >> Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com> > I have no reason to doubt your analysis, but if there are a bunch of > error paths for net_xmit and they all return with your skb still being > valid and holding a reference, and then one oddball that returns with > your skb already gone, that just sounds like a mistake waiting to happen > (not to mention a bajillion special cases sprinkled everywhere to deal > with this apparent inconsistency). > > Can we get a netdev@ confirmation on this being the right solution? Yes. I agree with you. After iptables rule "iptables -I OUTPUT -p udp --dport 4791 -j DROP", the skb is freed in this function /* Returns 1 if okfn() needs to be executed by the caller, * -EPERM for NF_DROP, 0 otherwise. Caller must hold rcu_read_lock. */ int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state, const struct nf_hook_entries *e, unsigned int s) { unsigned int verdict; int ret; for (; s < e->num_hook_entries; s++) { verdict = nf_hook_entry_hookfn(&e->hooks[s], skb, state); switch (verdict & NF_VERDICT_MASK) { case NF_ACCEPT: break; case NF_DROP: kfree_skb(skb); <----here, skb is freed ret = NF_DROP_GETERR(verdict); if (ret == 0) ret = -EPERM; return ret; case NF_QUEUE: ret = nf_queue(skb, state, e, s, verdict); if (ret == 1) continue; return ret; default: /* Implicit handling for NF_STOLEN, as well as any other * non conventional verdicts. */ return 0; } } return 1; } EXPORT_SYMBOL(nf_hook_slow); If I am wrong, please correct me. And my test environment is still there, any solution can be verified in it. Zhu Yanjun > >> --- >> drivers/infiniband/sw/rxe/rxe_net.c | 3 +++ >> drivers/infiniband/sw/rxe/rxe_req.c | 5 +++-- >> drivers/infiniband/sw/rxe/rxe_resp.c | 9 ++++++--- >> 3 files changed, 12 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c >> index 9da6e37..2094434 100644 >> --- a/drivers/infiniband/sw/rxe/rxe_net.c >> +++ b/drivers/infiniband/sw/rxe/rxe_net.c >> @@ -511,6 +511,9 @@ int rxe_send(struct rxe_pkt_info *pkt, struct sk_buff *skb) >> >> if (unlikely(net_xmit_eval(err))) { >> pr_debug("error sending packet: %d\n", err); >> + /* -EPERM means the skb is dropped and freed. */ >> + if (err == -EPERM) >> + return -EPERM; >> return -EAGAIN; >> } >> >> diff --git a/drivers/infiniband/sw/rxe/rxe_req.c b/drivers/infiniband/sw/rxe/rxe_req.c >> index 7bdaf71..9d2efec 100644 >> --- a/drivers/infiniband/sw/rxe/rxe_req.c >> +++ b/drivers/infiniband/sw/rxe/rxe_req.c >> @@ -727,8 +727,9 @@ int rxe_requester(void *arg) >> >> rollback_state(wqe, qp, &rollback_wqe, rollback_psn); >> >> - if (ret == -EAGAIN) { >> - kfree_skb(skb); >> + if ((ret == -EAGAIN) || (ret == -EPERM)) { >> + if (ret == -EAGAIN) >> + kfree_skb(skb); >> rxe_run_task(&qp->req.task, 1); >> goto exit; >> } >> diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c >> index a65c996..6bdf9b2 100644 >> --- a/drivers/infiniband/sw/rxe/rxe_resp.c >> +++ b/drivers/infiniband/sw/rxe/rxe_resp.c >> @@ -742,7 +742,8 @@ static enum resp_states read_reply(struct rxe_qp *qp, >> err = rxe_xmit_packet(rxe, qp, &ack_pkt, skb); >> if (err) { >> pr_err("Failed sending RDMA reply.\n"); >> - kfree_skb(skb); >> + if (err != -EPERM) >> + kfree_skb(skb); >> return RESPST_ERR_RNR; >> } >> >> @@ -956,7 +957,8 @@ static int send_ack(struct rxe_qp *qp, struct rxe_pkt_info *pkt, >> err = rxe_xmit_packet(rxe, qp, &ack_pkt, skb); >> if (err) { >> pr_err_ratelimited("Failed sending ack\n"); >> - kfree_skb(skb); >> + if (err != -EPERM) >> + kfree_skb(skb); >> } >> >> err1: >> @@ -1141,7 +1143,8 @@ static enum resp_states duplicate_request(struct rxe_qp *qp, >> if (rc) { >> pr_err("Failed resending result. This flow is not handled - skb ignored\n"); >> rxe_drop_ref(qp); >> - kfree_skb(skb_copy); >> + if (rc != -EPERM) >> + kfree_skb(skb_copy); >> rc = RESPST_CLEANUP; >> goto out; >> } >> -- >> 2.7.4 >> ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 1/1] IB/rxe: avoid double kfree_skb 2018-04-20 5:46 ` Yanjun Zhu @ 2018-04-24 8:34 ` Yanjun Zhu 2018-04-25 6:56 ` Yanjun Zhu 0 siblings, 1 reply; 5+ messages in thread From: Yanjun Zhu @ 2018-04-24 8:34 UTC (permalink / raw) To: Doug Ledford, monis, jgg, linux-rdma; +Cc: netdev Hi, all rxe_send ip_local_out __ip_local_out nf_hook_slow In the above call process, nf_hook_slow drops and frees skb, then -EPERM is returned when iptables rules(iptables -I OUTPUT -p udp --dport 4791 -j DROP) is set. If skb->users is not changed in softroce, kfree_skb should not be called in this module. I will make further investigations about other error handler after ip_local_out. If I am wrong, please correct me. Any reply is appreciated. Zhu Yanjun On 2018/4/20 13:46, Yanjun Zhu wrote: > > > On 2018/4/20 10:19, Doug Ledford wrote: >> On Thu, 2018-04-19 at 10:01 -0400, Zhu Yanjun wrote: >>> When skb is dropped by iptables rules, the skb is freed at the same >>> time >>> -EPERM is returned. So in softroce, it is not necessary to free skb >>> again. >>> Or else, crash will occur. >>> >>> The steps to reproduce: >>> >>> server client >>> --------- --------- >>> |1.1.1.1|<----rxe-channel--->|1.1.1.2| >>> --------- --------- >>> >>> On server: rping -s -a 1.1.1.1 -v -C 10000 -S 512 >>> On client: rping -c -a 1.1.1.1 -v -C 10000 -S 512 >>> >>> The kernel configs CONFIG_DEBUG_KMEMLEAK and >>> CONFIG_DEBUG_OBJECTS are enabled on both server and client. >>> >>> When rping runs, run the following command in server: >>> >>> iptables -I OUTPUT -p udp --dport 4791 -j DROP >>> >>> Without this patch, crash will occur. >>> >>> CC: Srinivas Eeda <srinivas.eeda@oracle.com> >>> CC: Junxiao Bi <junxiao.bi@oracle.com> >>> Signed-off-by: Zhu Yanjun <yanjun.zhu@oracle.com> >>> Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com> >> I have no reason to doubt your analysis, but if there are a bunch of >> error paths for net_xmit and they all return with your skb still being >> valid and holding a reference, and then one oddball that returns with >> your skb already gone, that just sounds like a mistake waiting to happen >> (not to mention a bajillion special cases sprinkled everywhere to deal >> with this apparent inconsistency). >> >> Can we get a netdev@ confirmation on this being the right solution? > Yes. I agree with you. > After iptables rule "iptables -I OUTPUT -p udp --dport 4791 -j DROP", > the skb is freed in this function > > /* Returns 1 if okfn() needs to be executed by the caller, > * -EPERM for NF_DROP, 0 otherwise. Caller must hold rcu_read_lock. */ > int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state, > const struct nf_hook_entries *e, unsigned int s) > { > unsigned int verdict; > int ret; > > for (; s < e->num_hook_entries; s++) { > verdict = nf_hook_entry_hookfn(&e->hooks[s], skb, state); > switch (verdict & NF_VERDICT_MASK) { > case NF_ACCEPT: > break; > case NF_DROP: > kfree_skb(skb); <----here, skb is freed > ret = NF_DROP_GETERR(verdict); > if (ret == 0) > ret = -EPERM; > return ret; > case NF_QUEUE: > ret = nf_queue(skb, state, e, s, verdict); > if (ret == 1) > continue; > return ret; > default: > /* Implicit handling for NF_STOLEN, as well as > any other > * non conventional verdicts. > */ > return 0; > } > } > > return 1; > } > EXPORT_SYMBOL(nf_hook_slow); > > If I am wrong, please correct me. > > And my test environment is still there, any solution can be verified > in it. > > Zhu Yanjun >> >>> --- >>> drivers/infiniband/sw/rxe/rxe_net.c | 3 +++ >>> drivers/infiniband/sw/rxe/rxe_req.c | 5 +++-- >>> drivers/infiniband/sw/rxe/rxe_resp.c | 9 ++++++--- >>> 3 files changed, 12 insertions(+), 5 deletions(-) >>> >>> diff --git a/drivers/infiniband/sw/rxe/rxe_net.c >>> b/drivers/infiniband/sw/rxe/rxe_net.c >>> index 9da6e37..2094434 100644 >>> --- a/drivers/infiniband/sw/rxe/rxe_net.c >>> +++ b/drivers/infiniband/sw/rxe/rxe_net.c >>> @@ -511,6 +511,9 @@ int rxe_send(struct rxe_pkt_info *pkt, struct >>> sk_buff *skb) >>> if (unlikely(net_xmit_eval(err))) { >>> pr_debug("error sending packet: %d\n", err); >>> + /* -EPERM means the skb is dropped and freed. */ >>> + if (err == -EPERM) >>> + return -EPERM; >>> return -EAGAIN; >>> } >>> diff --git a/drivers/infiniband/sw/rxe/rxe_req.c >>> b/drivers/infiniband/sw/rxe/rxe_req.c >>> index 7bdaf71..9d2efec 100644 >>> --- a/drivers/infiniband/sw/rxe/rxe_req.c >>> +++ b/drivers/infiniband/sw/rxe/rxe_req.c >>> @@ -727,8 +727,9 @@ int rxe_requester(void *arg) >>> rollback_state(wqe, qp, &rollback_wqe, >>> rollback_psn); >>> - if (ret == -EAGAIN) { >>> - kfree_skb(skb); >>> + if ((ret == -EAGAIN) || (ret == -EPERM)) { >>> + if (ret == -EAGAIN) >>> + kfree_skb(skb); >>> rxe_run_task(&qp->req.task, 1); >>> goto exit; >>> } >>> diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c >>> b/drivers/infiniband/sw/rxe/rxe_resp.c >>> index a65c996..6bdf9b2 100644 >>> --- a/drivers/infiniband/sw/rxe/rxe_resp.c >>> +++ b/drivers/infiniband/sw/rxe/rxe_resp.c >>> @@ -742,7 +742,8 @@ static enum resp_states read_reply(struct rxe_qp >>> *qp, >>> err = rxe_xmit_packet(rxe, qp, &ack_pkt, skb); >>> if (err) { >>> pr_err("Failed sending RDMA reply.\n"); >>> - kfree_skb(skb); >>> + if (err != -EPERM) >>> + kfree_skb(skb); >>> return RESPST_ERR_RNR; >>> } >>> @@ -956,7 +957,8 @@ static int send_ack(struct rxe_qp *qp, struct >>> rxe_pkt_info *pkt, >>> err = rxe_xmit_packet(rxe, qp, &ack_pkt, skb); >>> if (err) { >>> pr_err_ratelimited("Failed sending ack\n"); >>> - kfree_skb(skb); >>> + if (err != -EPERM) >>> + kfree_skb(skb); >>> } >>> err1: >>> @@ -1141,7 +1143,8 @@ static enum resp_states >>> duplicate_request(struct rxe_qp *qp, >>> if (rc) { >>> pr_err("Failed resending result. >>> This flow is not handled - skb ignored\n"); >>> rxe_drop_ref(qp); >>> - kfree_skb(skb_copy); >>> + if (rc != -EPERM) >>> + kfree_skb(skb_copy); >>> rc = RESPST_CLEANUP; >>> goto out; >>> } >>> -- >>> 2.7.4 >>> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 1/1] IB/rxe: avoid double kfree_skb 2018-04-24 8:34 ` Yanjun Zhu @ 2018-04-25 6:56 ` Yanjun Zhu 2018-04-27 16:24 ` Doug Ledford 0 siblings, 1 reply; 5+ messages in thread From: Yanjun Zhu @ 2018-04-25 6:56 UTC (permalink / raw) To: Doug Ledford, monis, jgg, linux-rdma; +Cc: netdev Hi, all rxe_send [rdma_rxe] ip_local_out __ip_local_out ip_output ip_finish_output ip_finish_output2 dev_queue_xmit __dev_queue_xmit dev_hard_start_xmit e1000_xmit_frame [e1000] When skb is sent, it will pass the above functions. I checked all the above functions. If error occurs in the above functions after ip_local_out, kfree_skb will be called. So when ip_local_out returns an error, skb should be freed. It is not necessary to call kfree_skb in soft roce module again. If I am wrong, please correct me. Zhu Yanjun On 2018/4/24 16:34, Yanjun Zhu wrote: > Hi, all > > rxe_send > ip_local_out > __ip_local_out > nf_hook_slow > > In the above call process, nf_hook_slow drops and frees skb, then > -EPERM is returned when iptables rules(iptables -I OUTPUT -p udp > --dport 4791 -j DROP) is set. > > If skb->users is not changed in softroce, kfree_skb should not be > called in this module. > > I will make further investigations about other error handler after > ip_local_out. > If I am wrong, please correct me. > > Any reply is appreciated. > > Zhu Yanjun > On 2018/4/20 13:46, Yanjun Zhu wrote: >> >> >> On 2018/4/20 10:19, Doug Ledford wrote: >>> On Thu, 2018-04-19 at 10:01 -0400, Zhu Yanjun wrote: >>>> When skb is dropped by iptables rules, the skb is freed at the same >>>> time >>>> -EPERM is returned. So in softroce, it is not necessary to free skb >>>> again. >>>> Or else, crash will occur. >>>> >>>> The steps to reproduce: >>>> >>>> server client >>>> --------- --------- >>>> |1.1.1.1|<----rxe-channel--->|1.1.1.2| >>>> --------- --------- >>>> >>>> On server: rping -s -a 1.1.1.1 -v -C 10000 -S 512 >>>> On client: rping -c -a 1.1.1.1 -v -C 10000 -S 512 >>>> >>>> The kernel configs CONFIG_DEBUG_KMEMLEAK and >>>> CONFIG_DEBUG_OBJECTS are enabled on both server and client. >>>> >>>> When rping runs, run the following command in server: >>>> >>>> iptables -I OUTPUT -p udp --dport 4791 -j DROP >>>> >>>> Without this patch, crash will occur. >>>> >>>> CC: Srinivas Eeda <srinivas.eeda@oracle.com> >>>> CC: Junxiao Bi <junxiao.bi@oracle.com> >>>> Signed-off-by: Zhu Yanjun <yanjun.zhu@oracle.com> >>>> Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com> >>> I have no reason to doubt your analysis, but if there are a bunch of >>> error paths for net_xmit and they all return with your skb still being >>> valid and holding a reference, and then one oddball that returns with >>> your skb already gone, that just sounds like a mistake waiting to >>> happen >>> (not to mention a bajillion special cases sprinkled everywhere to deal >>> with this apparent inconsistency). >>> >>> Can we get a netdev@ confirmation on this being the right solution? >> Yes. I agree with you. >> After iptables rule "iptables -I OUTPUT -p udp --dport 4791 -j >> DROP", the skb is freed in this function >> >> /* Returns 1 if okfn() needs to be executed by the caller, >> * -EPERM for NF_DROP, 0 otherwise. Caller must hold rcu_read_lock. */ >> int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state, >> const struct nf_hook_entries *e, unsigned int s) >> { >> unsigned int verdict; >> int ret; >> >> for (; s < e->num_hook_entries; s++) { >> verdict = nf_hook_entry_hookfn(&e->hooks[s], skb, >> state); >> switch (verdict & NF_VERDICT_MASK) { >> case NF_ACCEPT: >> break; >> case NF_DROP: >> kfree_skb(skb); <----here, skb is freed >> ret = NF_DROP_GETERR(verdict); >> if (ret == 0) >> ret = -EPERM; >> return ret; >> case NF_QUEUE: >> ret = nf_queue(skb, state, e, s, verdict); >> if (ret == 1) >> continue; >> return ret; >> default: >> /* Implicit handling for NF_STOLEN, as well >> as any other >> * non conventional verdicts. >> */ >> return 0; >> } >> } >> >> return 1; >> } >> EXPORT_SYMBOL(nf_hook_slow); >> >> If I am wrong, please correct me. >> >> And my test environment is still there, any solution can be verified >> in it. >> >> Zhu Yanjun >>> >>>> --- >>>> drivers/infiniband/sw/rxe/rxe_net.c | 3 +++ >>>> drivers/infiniband/sw/rxe/rxe_req.c | 5 +++-- >>>> drivers/infiniband/sw/rxe/rxe_resp.c | 9 ++++++--- >>>> 3 files changed, 12 insertions(+), 5 deletions(-) >>>> >>>> diff --git a/drivers/infiniband/sw/rxe/rxe_net.c >>>> b/drivers/infiniband/sw/rxe/rxe_net.c >>>> index 9da6e37..2094434 100644 >>>> --- a/drivers/infiniband/sw/rxe/rxe_net.c >>>> +++ b/drivers/infiniband/sw/rxe/rxe_net.c >>>> @@ -511,6 +511,9 @@ int rxe_send(struct rxe_pkt_info *pkt, struct >>>> sk_buff *skb) >>>> if (unlikely(net_xmit_eval(err))) { >>>> pr_debug("error sending packet: %d\n", err); >>>> + /* -EPERM means the skb is dropped and freed. */ >>>> + if (err == -EPERM) >>>> + return -EPERM; >>>> return -EAGAIN; >>>> } >>>> diff --git a/drivers/infiniband/sw/rxe/rxe_req.c >>>> b/drivers/infiniband/sw/rxe/rxe_req.c >>>> index 7bdaf71..9d2efec 100644 >>>> --- a/drivers/infiniband/sw/rxe/rxe_req.c >>>> +++ b/drivers/infiniband/sw/rxe/rxe_req.c >>>> @@ -727,8 +727,9 @@ int rxe_requester(void *arg) >>>> rollback_state(wqe, qp, &rollback_wqe, >>>> rollback_psn); >>>> - if (ret == -EAGAIN) { >>>> - kfree_skb(skb); >>>> + if ((ret == -EAGAIN) || (ret == -EPERM)) { >>>> + if (ret == -EAGAIN) >>>> + kfree_skb(skb); >>>> rxe_run_task(&qp->req.task, 1); >>>> goto exit; >>>> } >>>> diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c >>>> b/drivers/infiniband/sw/rxe/rxe_resp.c >>>> index a65c996..6bdf9b2 100644 >>>> --- a/drivers/infiniband/sw/rxe/rxe_resp.c >>>> +++ b/drivers/infiniband/sw/rxe/rxe_resp.c >>>> @@ -742,7 +742,8 @@ static enum resp_states read_reply(struct >>>> rxe_qp *qp, >>>> err = rxe_xmit_packet(rxe, qp, &ack_pkt, skb); >>>> if (err) { >>>> pr_err("Failed sending RDMA reply.\n"); >>>> - kfree_skb(skb); >>>> + if (err != -EPERM) >>>> + kfree_skb(skb); >>>> return RESPST_ERR_RNR; >>>> } >>>> @@ -956,7 +957,8 @@ static int send_ack(struct rxe_qp *qp, struct >>>> rxe_pkt_info *pkt, >>>> err = rxe_xmit_packet(rxe, qp, &ack_pkt, skb); >>>> if (err) { >>>> pr_err_ratelimited("Failed sending ack\n"); >>>> - kfree_skb(skb); >>>> + if (err != -EPERM) >>>> + kfree_skb(skb); >>>> } >>>> err1: >>>> @@ -1141,7 +1143,8 @@ static enum resp_states >>>> duplicate_request(struct rxe_qp *qp, >>>> if (rc) { >>>> pr_err("Failed resending result. >>>> This flow is not handled - skb ignored\n"); >>>> rxe_drop_ref(qp); >>>> - kfree_skb(skb_copy); >>>> + if (rc != -EPERM) >>>> + kfree_skb(skb_copy); >>>> rc = RESPST_CLEANUP; >>>> goto out; >>>> } >>>> -- >>>> 2.7.4 >>>> >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-rdma" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 1/1] IB/rxe: avoid double kfree_skb 2018-04-25 6:56 ` Yanjun Zhu @ 2018-04-27 16:24 ` Doug Ledford 0 siblings, 0 replies; 5+ messages in thread From: Doug Ledford @ 2018-04-27 16:24 UTC (permalink / raw) To: Yanjun Zhu, monis, jgg, linux-rdma; +Cc: netdev [-- Attachment #1: Type: text/plain, Size: 9640 bytes --] On Wed, 2018-04-25 at 14:56 +0800, Yanjun Zhu wrote: > Hi, all > > rxe_send [rdma_rxe] > ip_local_out > __ip_local_out > ip_output > ip_finish_output > ip_finish_output2 > dev_queue_xmit > __dev_queue_xmit > dev_hard_start_xmit > e1000_xmit_frame [e1000] > > When skb is sent, it will pass the above functions. I checked all the > above functions. If error occurs in the above functions after > ip_local_out, kfree_skb will be called. > So when ip_local_out returns an error, skb should be freed. It is not > necessary to call kfree_skb in soft roce module again. > > If I am wrong, please correct me. No one from netdev has spoken up, and I don't see where you are wrong, so I've applied this to for-rc. Thanks. > Zhu Yanjun > On 2018/4/24 16:34, Yanjun Zhu wrote: > > Hi, all > > > > rxe_send > > ip_local_out > > __ip_local_out > > nf_hook_slow > > > > In the above call process, nf_hook_slow drops and frees skb, then > > -EPERM is returned when iptables rules(iptables -I OUTPUT -p udp > > --dport 4791 -j DROP) is set. > > > > If skb->users is not changed in softroce, kfree_skb should not be > > called in this module. > > > > I will make further investigations about other error handler after > > ip_local_out. > > If I am wrong, please correct me. > > > > Any reply is appreciated. > > > > Zhu Yanjun > > On 2018/4/20 13:46, Yanjun Zhu wrote: > > > > > > > > > On 2018/4/20 10:19, Doug Ledford wrote: > > > > On Thu, 2018-04-19 at 10:01 -0400, Zhu Yanjun wrote: > > > > > When skb is dropped by iptables rules, the skb is freed at the same > > > > > time > > > > > -EPERM is returned. So in softroce, it is not necessary to free skb > > > > > again. > > > > > Or else, crash will occur. > > > > > > > > > > The steps to reproduce: > > > > > > > > > > server client > > > > > --------- --------- > > > > > |1.1.1.1|<----rxe-channel--->|1.1.1.2| > > > > > --------- --------- > > > > > > > > > > On server: rping -s -a 1.1.1.1 -v -C 10000 -S 512 > > > > > On client: rping -c -a 1.1.1.1 -v -C 10000 -S 512 > > > > > > > > > > The kernel configs CONFIG_DEBUG_KMEMLEAK and > > > > > CONFIG_DEBUG_OBJECTS are enabled on both server and client. > > > > > > > > > > When rping runs, run the following command in server: > > > > > > > > > > iptables -I OUTPUT -p udp --dport 4791 -j DROP > > > > > > > > > > Without this patch, crash will occur. > > > > > > > > > > CC: Srinivas Eeda <srinivas.eeda@oracle.com> > > > > > CC: Junxiao Bi <junxiao.bi@oracle.com> > > > > > Signed-off-by: Zhu Yanjun <yanjun.zhu@oracle.com> > > > > > Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com> > > > > > > > > I have no reason to doubt your analysis, but if there are a bunch of > > > > error paths for net_xmit and they all return with your skb still being > > > > valid and holding a reference, and then one oddball that returns with > > > > your skb already gone, that just sounds like a mistake waiting to > > > > happen > > > > (not to mention a bajillion special cases sprinkled everywhere to deal > > > > with this apparent inconsistency). > > > > > > > > Can we get a netdev@ confirmation on this being the right solution? > > > > > > Yes. I agree with you. > > > After iptables rule "iptables -I OUTPUT -p udp --dport 4791 -j > > > DROP", the skb is freed in this function > > > > > > /* Returns 1 if okfn() needs to be executed by the caller, > > > * -EPERM for NF_DROP, 0 otherwise. Caller must hold rcu_read_lock. */ > > > int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state, > > > const struct nf_hook_entries *e, unsigned int s) > > > { > > > unsigned int verdict; > > > int ret; > > > > > > for (; s < e->num_hook_entries; s++) { > > > verdict = nf_hook_entry_hookfn(&e->hooks[s], skb, > > > state); > > > switch (verdict & NF_VERDICT_MASK) { > > > case NF_ACCEPT: > > > break; > > > case NF_DROP: > > > kfree_skb(skb); <----here, skb is freed > > > ret = NF_DROP_GETERR(verdict); > > > if (ret == 0) > > > ret = -EPERM; > > > return ret; > > > case NF_QUEUE: > > > ret = nf_queue(skb, state, e, s, verdict); > > > if (ret == 1) > > > continue; > > > return ret; > > > default: > > > /* Implicit handling for NF_STOLEN, as well > > > as any other > > > * non conventional verdicts. > > > */ > > > return 0; > > > } > > > } > > > > > > return 1; > > > } > > > EXPORT_SYMBOL(nf_hook_slow); > > > > > > If I am wrong, please correct me. > > > > > > And my test environment is still there, any solution can be verified > > > in it. > > > > > > Zhu Yanjun > > > > > > > > > --- > > > > > drivers/infiniband/sw/rxe/rxe_net.c | 3 +++ > > > > > drivers/infiniband/sw/rxe/rxe_req.c | 5 +++-- > > > > > drivers/infiniband/sw/rxe/rxe_resp.c | 9 ++++++--- > > > > > 3 files changed, 12 insertions(+), 5 deletions(-) > > > > > > > > > > diff --git a/drivers/infiniband/sw/rxe/rxe_net.c > > > > > b/drivers/infiniband/sw/rxe/rxe_net.c > > > > > index 9da6e37..2094434 100644 > > > > > --- a/drivers/infiniband/sw/rxe/rxe_net.c > > > > > +++ b/drivers/infiniband/sw/rxe/rxe_net.c > > > > > @@ -511,6 +511,9 @@ int rxe_send(struct rxe_pkt_info *pkt, struct > > > > > sk_buff *skb) > > > > > if (unlikely(net_xmit_eval(err))) { > > > > > pr_debug("error sending packet: %d\n", err); > > > > > + /* -EPERM means the skb is dropped and freed. */ > > > > > + if (err == -EPERM) > > > > > + return -EPERM; > > > > > return -EAGAIN; > > > > > } > > > > > diff --git a/drivers/infiniband/sw/rxe/rxe_req.c > > > > > b/drivers/infiniband/sw/rxe/rxe_req.c > > > > > index 7bdaf71..9d2efec 100644 > > > > > --- a/drivers/infiniband/sw/rxe/rxe_req.c > > > > > +++ b/drivers/infiniband/sw/rxe/rxe_req.c > > > > > @@ -727,8 +727,9 @@ int rxe_requester(void *arg) > > > > > rollback_state(wqe, qp, &rollback_wqe, > > > > > rollback_psn); > > > > > - if (ret == -EAGAIN) { > > > > > - kfree_skb(skb); > > > > > + if ((ret == -EAGAIN) || (ret == -EPERM)) { > > > > > + if (ret == -EAGAIN) > > > > > + kfree_skb(skb); > > > > > rxe_run_task(&qp->req.task, 1); > > > > > goto exit; > > > > > } > > > > > diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c > > > > > b/drivers/infiniband/sw/rxe/rxe_resp.c > > > > > index a65c996..6bdf9b2 100644 > > > > > --- a/drivers/infiniband/sw/rxe/rxe_resp.c > > > > > +++ b/drivers/infiniband/sw/rxe/rxe_resp.c > > > > > @@ -742,7 +742,8 @@ static enum resp_states read_reply(struct > > > > > rxe_qp *qp, > > > > > err = rxe_xmit_packet(rxe, qp, &ack_pkt, skb); > > > > > if (err) { > > > > > pr_err("Failed sending RDMA reply.\n"); > > > > > - kfree_skb(skb); > > > > > + if (err != -EPERM) > > > > > + kfree_skb(skb); > > > > > return RESPST_ERR_RNR; > > > > > } > > > > > @@ -956,7 +957,8 @@ static int send_ack(struct rxe_qp *qp, struct > > > > > rxe_pkt_info *pkt, > > > > > err = rxe_xmit_packet(rxe, qp, &ack_pkt, skb); > > > > > if (err) { > > > > > pr_err_ratelimited("Failed sending ack\n"); > > > > > - kfree_skb(skb); > > > > > + if (err != -EPERM) > > > > > + kfree_skb(skb); > > > > > } > > > > > err1: > > > > > @@ -1141,7 +1143,8 @@ static enum resp_states > > > > > duplicate_request(struct rxe_qp *qp, > > > > > if (rc) { > > > > > pr_err("Failed resending result. > > > > > This flow is not handled - skb ignored\n"); > > > > > rxe_drop_ref(qp); > > > > > - kfree_skb(skb_copy); > > > > > + if (rc != -EPERM) > > > > > + kfree_skb(skb_copy); > > > > > rc = RESPST_CLEANUP; > > > > > goto out; > > > > > } > > > > > -- > > > > > 2.7.4 > > > > > > > > > > > -- > > > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in > > > the body of a message to majordomo@vger.kernel.org > > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- Doug Ledford <dledford@redhat.com> GPG KeyID: B826A3330E572FDD Key fingerprint = AE6B 1BDA 122B 23B4 265B 1274 B826 A333 0E57 2FDD [-- Attachment #2: This is a digitally signed message part --] [-- Type: application/pgp-signature, Size: 833 bytes --] ^ permalink raw reply [flat|nested] 5+ messages in thread
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2018-04-20 2:19 ` [PATCH 1/1] IB/rxe: avoid double kfree_skb Doug Ledford
2018-04-20 5:46 ` Yanjun Zhu
2018-04-24 8:34 ` Yanjun Zhu
2018-04-25 6:56 ` Yanjun Zhu
2018-04-27 16:24 ` Doug Ledford
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