The E810 device has support for a "low latency" firmware interface to access and read the Tx timestamps. This interface does not use the standard Tx timestamp logic, due to the latency overhead of proxying sideband command requests over the firmware AdminQ. The logic still makes use of the Tx timestamp tracking structure, ice_ptp_tx, as it uses the same "ready" bitmap to track which Tx timestamps. Unfortunately, the ice_ptp_ts_irq() function does not check if the tracker is initialized before its first access. This results in NULL dereference or use-after-free bugs similar to the following: [245977.278756] BUG: kernel NULL pointer dereference, address: 0000000000000000 [245977.278774] RIP: 0010:_find_first_bit+0x19/0x40 [245977.278796] Call Trace: [245977.278809] ? ice_misc_intr+0x364/0x380 [ice] This can occur if a Tx timestamp interrupt races with the driver reset logic. Fix this by only checking the in_use bitmap (and other fields) if the tracker is marked as initialized. The reset flow will clear the init field under lock before it tears the tracker down, thus preventing any use-after-free or NULL access. Fixes: f9472aaabd1f ("ice: Process TSYN IRQ in a separate function") Signed-off-by: Jacob Keller --- drivers/net/ethernet/intel/ice/ice_ptp.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.c b/drivers/net/ethernet/intel/ice/ice_ptp.c index e358eb1d719f..fb0f6365a6d6 100644 --- a/drivers/net/ethernet/intel/ice/ice_ptp.c +++ b/drivers/net/ethernet/intel/ice/ice_ptp.c @@ -2701,16 +2701,19 @@ irqreturn_t ice_ptp_ts_irq(struct ice_pf *pf) */ if (hw->dev_caps.ts_dev_info.ts_ll_int_read) { struct ice_ptp_tx *tx = &pf->ptp.port.tx; - u8 idx; + u8 idx, last; if (!ice_pf_state_is_nominal(pf)) return IRQ_HANDLED; spin_lock(&tx->lock); - idx = find_next_bit_wrap(tx->in_use, tx->len, - tx->last_ll_ts_idx_read + 1); - if (idx != tx->len) - ice_ptp_req_tx_single_tstamp(tx, idx); + if (tx->init) { + last = tx->last_ll_ts_idx_read + 1; + idx = find_next_bit_wrap(tx->in_use, tx->len, + last); + if (idx != tx->len) + ice_ptp_req_tx_single_tstamp(tx, idx); + } spin_unlock(&tx->lock); return IRQ_HANDLED; -- 2.50.1