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rrc: defer manipulations of the RLC/PDCP arrays 

all calls that manipulate the RLC and/or PDCP arrays suffer
from a high deadlock risk if a PHY worker holds the RLC
AM Rx mutex at the same time when the stack wants to carry
out this reconfiguration.

this applies to RRC Reconfigs, but potentially also to RRC Connection
Reestablishment or even RRC Connection Setup, although this should
seldom be the case.

By breaking the call stack between RLC->PDCP->RRC->RCL and
carrying out the reconfig as a single task without holding the
RLC readlock the deadlock should not happen anymore.

This should fix issue #1593
This commit is contained in:
Andre Puschmann 2020-08-04 11:48:44 +02:00 committed by Francisco Paisana
parent 9146e6ddf1
commit 24dfb03b9d
1 changed files with 50 additions and 37 deletions
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87
srsue/src/stack/rrc/rrc.cc
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@ -905,7 +905,7 @@ bool rrc::con_reconfig(rrc_conn_recfg_s* reconfig)
nas_sdu->N_bytes = reconfig_r8->ded_info_nas_list[i].size();
nas->write_pdu(RB_ID_SRB1, std::move(nas_sdu));
} else {
rrc_log->error("Fatal Error: Couldn't allocate PDU in handle_rrc_con_reconfig().\n");
rrc_log->error("Fatal Error: Couldn't allocate PDU in %s.\n", __FUNCTION__);
return;
}
}
@ -946,14 +946,18 @@ void rrc::handle_rrc_con_reconfig(uint32_t lcid, rrc_conn_recfg_s* reconfig)
previous_phy_cfg = current_phy_cfg;
previous_mac_cfg = current_mac_cfg;
rrc_conn_recfg_r8_ies_s* reconfig_r8 = &reconfig->crit_exts.c1().rrc_conn_recfg_r8();
if (reconfig_r8->mob_ctrl_info_present) {
con_reconfig_ho(reconfig);
} else {
if (!con_reconfig(reconfig)) {
con_reconfig_failed();
// Execute in next iteration to break RLC/PDCP call stack
rrc_conn_recfg_s reconfig_ = *reconfig;
task_sched.defer_task([this, reconfig_]() mutable {
rrc_conn_recfg_r8_ies_s* reconfig_r8 = &reconfig_.crit_exts.c1().rrc_conn_recfg_r8();
if (reconfig_r8->mob_ctrl_info_present) {
con_reconfig_ho(&reconfig_);
} else {
if (!con_reconfig(&reconfig_)) {
con_reconfig_failed();
}
}
}
});
}
/* Actions upon reception of RRCConnectionRelease 5.3.8.3 */
@ -2220,48 +2224,57 @@ void rrc::apply_scell_config(rrc_conn_recfg_r8_ies_s* reconfig_r8)
void rrc::handle_con_setup(rrc_conn_setup_s* setup)
{
// Must enter CONNECT before stopping T300
state = RRC_STATE_CONNECTED;
t300.stop();
t302.stop();
rrc_log->console("RRC Connected\n");
// Execute in next iteration to break RLC/PDCP call stack
rrc_conn_setup_s setup_ = *setup;
task_sched.defer_task([this, setup_]() mutable {
// Must enter CONNECT before stopping T300
state = RRC_STATE_CONNECTED;
t300.stop();
t302.stop();
rrc_log->console("RRC Connected\n");
// Apply the Radio Resource configuration
apply_rr_config_dedicated(&setup->crit_exts.c1().rrc_conn_setup_r8().rr_cfg_ded);
// Apply the Radio Resource configuration
apply_rr_config_dedicated(&setup_.crit_exts.c1().rrc_conn_setup_r8().rr_cfg_ded);
nas->set_barring(srslte::barring_t::none);
nas->set_barring(srslte::barring_t::none);
if (dedicated_info_nas.get()) {
send_con_setup_complete(std::move(dedicated_info_nas));
} else {
rrc_log->error("Pending to transmit a ConnectionSetupComplete but no dedicatedInfoNAS was in queue\n");
}
if (dedicated_info_nas.get()) {
send_con_setup_complete(std::move(dedicated_info_nas));
} else {
rrc_log->error("Pending to transmit a ConnectionSetupComplete but no dedicatedInfoNAS was in queue\n");
}
});
}
/* Reception of RRCConnectionReestablishment by the UE 5.3.7.5 */
void rrc::handle_con_reest(rrc_conn_reest_s* setup)
void rrc::handle_con_reest(rrc_conn_reest_s* reest)
{
t301.stop();
// Execute in next iteration to break RLC/PDCP call stack
rrc_conn_reest_s reest_ = *reest;
task_sched.defer_task([this, reest_]() mutable {
t301.stop();
// Reestablish PDCP and RLC for SRB1
pdcp->reestablish(1);
rlc->reestablish(1);
// Reestablish PDCP and RLC for SRB1
pdcp->reestablish(1);
rlc->reestablish(1);
// Update RRC Integrity keys
int ncc = setup->crit_exts.c1().rrc_conn_reest_r8().next_hop_chaining_count;
usim->generate_as_keys_ho(meas_cells.serving_cell().get_pci(), meas_cells.serving_cell().get_earfcn(), ncc, &sec_cfg);
pdcp->config_security_all(sec_cfg);
// Update RRC Integrity keys
int ncc = reest_.crit_exts.c1().rrc_conn_reest_r8().next_hop_chaining_count;
usim->generate_as_keys_ho(
meas_cells.serving_cell().get_pci(), meas_cells.serving_cell().get_earfcn(), ncc, &sec_cfg);
pdcp->config_security_all(sec_cfg);
// Apply the Radio Resource configuration
apply_rr_config_dedicated(&setup->crit_exts.c1().rrc_conn_reest_r8().rr_cfg_ded);
// Apply the Radio Resource configuration
apply_rr_config_dedicated(&reest_.crit_exts.c1().rrc_conn_reest_r8().rr_cfg_ded);
// Resume SRB1
rlc->resume_bearer(1);
// Resume SRB1
rlc->resume_bearer(1);
// Send ConnectionSetupComplete message
send_con_restablish_complete();
// Send ConnectionSetupComplete message
send_con_restablish_complete();
reestablishment_successful = true;
reestablishment_successful = true;
});
}
void rrc::add_srb(srb_to_add_mod_s* srb_cnfg)