bnxt_en: Fix NULL pointer crash in bnxt_ptp_enable during error cleanup

When bnxt_init_one() fails during initialization (e.g.,
bnxt_init_int_mode returns -ENODEV), the error path calls
bnxt_free_hwrm_resources() which destroys the DMA pool and sets
bp->hwrm_dma_pool to NULL. Subsequently, bnxt_ptp_clear() is called,
which invokes ptp_clock_unregister().

Since commit a60fc32 ("ptp: rework ptp_clock_unregister() to
disable events"), ptp_clock_unregister() now calls
ptp_disable_all_events(), which in turn invokes the driver's .enable()
callback (bnxt_ptp_enable()) to disable PTP events before completing the
unregistration.

bnxt_ptp_enable() attempts to send HWRM commands via bnxt_ptp_cfg_pin()
and bnxt_ptp_cfg_event(), both of which call hwrm_req_init(). This
function tries to allocate from bp->hwrm_dma_pool, causing a NULL
pointer dereference:

  bnxt_en 0000:01:00.0 (unnamed net_device) (uninitialized): bnxt_init_int_mode err: ffffffed
  KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
  Call Trace:
   __hwrm_req_init (drivers/net/ethernet/broadcom/bnxt/bnxt_hwrm.c:72)
   bnxt_ptp_enable (drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c:323 drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c:517)
   ptp_disable_all_events (drivers/ptp/ptp_chardev.c:66)
   ptp_clock_unregister (drivers/ptp/ptp_clock.c:518)
   bnxt_ptp_clear (drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c:1134)
   bnxt_init_one (drivers/net/ethernet/broadcom/bnxt/bnxt.c:16889)

Lines are against commit f8f9c1f ("Linux 6.19-rc3")

Fix this by clearing and unregistering ptp (bnxt_ptp_clear()) before
freeing HWRM resources.

Suggested-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: Breno Leitao <leitao@debian.org>
Fixes: a60fc32 ("ptp: rework ptp_clock_unregister() to disable events")
Cc: stable@vger.kernel.org
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Link: https://patch.msgid.link/20260106-bnxt-v3-1-71f37e11446a@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: leitao

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -16891,12 +16891,12 @@ static int bnxt_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 init_err_pci_clean:
 	bnxt_hwrm_func_drv_unrgtr(bp);
-	bnxt_free_hwrm_resources(bp);
-	bnxt_hwmon_uninit(bp);
-	bnxt_ethtool_free(bp);
 	bnxt_ptp_clear(bp);
 	kfree(bp->ptp_cfg);
 	bp->ptp_cfg = NULL;
+	bnxt_free_hwrm_resources(bp);
+	bnxt_hwmon_uninit(bp);
+	bnxt_ethtool_free(bp);
 	kfree(bp->fw_health);
 	bp->fw_health = NULL;
 	bnxt_cleanup_pci(bp);