pdsc_reset_prepare() and pdsc_reset_done()'s pdsc_map_bars() error path clear/iounmap cmd_regs without devcmd_lock, and pdsc_legacy_firmware_update()'s download loop derefs cmd_regs after dropping and retaking the lock without re-checking. An FLR concurrent with a devlink flash can unmap cmd_regs under an in-flight devcmd, causing a NULL deref or a write to unmapped MMIO. Take devcmd_lock across the BAR unmap/remap, and re-check cmd_regs in the download loop. Only the PF maps cmd_regs and runs devcmd, so skip the unmap on a VF, as pdsc_remove() and pdsc_reset_done() already do. A reset that completes entirely within the unlocked window is not a correctness problem for the image: the device clears its update session, so a resumed download is rejected, and it verifies the staged image before writing a flash slot, reporting PDS_RC_BAD_FW rather than activating it. pdsc_unmap_bars() also clears info_regs, intr_status and intr_ctrl. The interrupt and start/stop readers of those are quiesced before the unmap by pdsc_fw_down(), which frees the interrupts and tears down the queues. The debugfs readers are not, since those files outlive a reset; that is pre-existing and out of scope here. Fixes: e96094c1d11c ("pds_core: Clear BARs on reset") Reported-by: sashiko-bot Closes: https://sashiko.dev/#/patchset/20260708212222.296202-1-nikhil.rao%40amd.com?part=3 Assisted-by: Claude:claude-opus-4.8 Signed-off-by: Nikhil P. Rao --- drivers/net/ethernet/amd/pds_core/fw.c | 10 +++++++++- drivers/net/ethernet/amd/pds_core/main.c | 8 +++++++- 2 files changed, 16 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/amd/pds_core/fw.c b/drivers/net/ethernet/amd/pds_core/fw.c index 5ccf017f6af4..19899bf38d40 100644 --- a/drivers/net/ethernet/amd/pds_core/fw.c +++ b/drivers/net/ethernet/amd/pds_core/fw.c @@ -171,8 +171,10 @@ pdsc_legacy_firmware_update(struct pdsc *pdsc, dev_info(pdsc->dev, "Installing firmware\n"); - if (!pdsc->cmd_regs) + if (!pdsc->cmd_regs) { + NL_SET_ERR_MSG_MOD(extack, "BARs not mapped"); return -ENXIO; + } dl = priv_to_devlink(pdsc); devlink_flash_update_status_notify(dl, "Preparing to flash", @@ -198,6 +200,12 @@ pdsc_legacy_firmware_update(struct pdsc *pdsc, copy_sz = min_t(unsigned int, buf_sz, fw->size - offset); mutex_lock(&pdsc->devcmd_lock); + if (!pdsc->cmd_regs) { + mutex_unlock(&pdsc->devcmd_lock); + err = -ENXIO; + NL_SET_ERR_MSG_MOD(extack, "Device reset during flash"); + goto err_out; + } memcpy_toio(&pdsc->cmd_regs->data, fw->data + offset, copy_sz); err = pdsc_devcmd_fw_download_locked(pdsc, data_addr, offset, copy_sz); diff --git a/drivers/net/ethernet/amd/pds_core/main.c b/drivers/net/ethernet/amd/pds_core/main.c index bb79e7476370..6e1079f9ba0f 100644 --- a/drivers/net/ethernet/amd/pds_core/main.c +++ b/drivers/net/ethernet/amd/pds_core/main.c @@ -513,7 +513,11 @@ static void pdsc_reset_prepare(struct pci_dev *pdev) pdsc_auxbus_dev_del(pdsc, pdsc, &pdsc->padev); } - pdsc_unmap_bars(pdsc); + if (!pdev->is_virtfn) { + mutex_lock(&pdsc->devcmd_lock); + pdsc_unmap_bars(pdsc); + mutex_unlock(&pdsc->devcmd_lock); + } pci_release_regions(pdev); if (pci_is_enabled(pdev)) pci_disable_device(pdev); @@ -543,7 +547,9 @@ static void pdsc_reset_done(struct pci_dev *pdev) return; } + mutex_lock(&pdsc->devcmd_lock); err = pdsc_map_bars(pdsc); + mutex_unlock(&pdsc->devcmd_lock); if (err) return; } -- 2.43.0