Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
New issues: - [High] Module parameter updates can silently fail to reach the hardware during driver probe due to the behavior of driver_find_next_device(). Pre-existing issues: - [High] Potential Use-After-Free in qcom_scm_get() and its callers due to unprotected devres pointers. -- commit 03814e83233282a25e37723ed4eb68479514c4e0 Author: Albert Esteve <[email protected]> firmware: qcom: scm: drop the __scm global Stop publishing a driver-wide singleton. Mark the instance ready with scm->available, look it up from the platform driver for module-parameter stores, and use platform_get_drvdata() on shutdown. > diff --git a/drivers/firmware/qcom/qcom_scm.c > b/drivers/firmware/qcom/qcom_scm.c > index 73e9752e3cca1..68cd8dc622c6f 100644 > --- a/drivers/firmware/qcom/qcom_scm.c > +++ b/drivers/firmware/qcom/qcom_scm.c [ ... ] > @@ -2657,7 +2658,7 @@ static void qcom_scm_qtee_init(struct qcom_scm *scm) > bool qcom_scm_is_available(struct qcom_scm *scm) > { > /* Paired with smp_store_release() in qcom_scm_probe */ > - return scm && scm == smp_load_acquire(&__scm); > + return scm && smp_load_acquire(&scm->available); [Severity: High] This is a pre-existing issue, but does this introduce a new use-after-free dereference site? Looking at qcom_scm_get(), it acquires a device reference, retrieves the devres-managed scm pointer, and immediately drops the reference: struct qcom_scm *qcom_scm_get(void) { ... scm = dev_get_drvdata(dev); put_device(dev); if (!qcom_scm_is_available(scm)) return NULL; ... } If the device is concurrently unbound (e.g., via dynamic DT overlay removal), device_unbind_cleanup() will synchronously free all devres allocations, including the scm pointer. Right after this in qcom_scm_get(), calling qcom_scm_is_available(scm) will now dereference scm->available on the freed pointer. Can the pointer be safeguarded before dereferencing it here? > } > EXPORT_SYMBOL_GPL(qcom_scm_is_available); > > @@ -2817,7 +2818,7 @@ static int set_download_mode(const char *val, const > struct kernel_param *kp) > > download_mode = ret; > /* Pairs with smp_store_release() in qcom_scm_probe(). */ > - scm = smp_load_acquire(&__scm); > + scm = qcom_scm_get(); [Severity: High] Could this cause module parameter updates to silently fail during driver probe? If a user or script updates the download_mode module parameter via sysfs while qcom_scm_probe() is executing, set_download_mode() will call qcom_scm_get(). Because qcom_scm_get() uses driver_find_next_device(), which relies on klist_devices, it will return NULL until driver_bound() adds the device to the list after probe completes. Since this skips the hardware update when qcom_scm_get() returns NULL, would the global download_mode variable become permanently desynchronized from the hardware state? > if (scm) > qcom_scm_set_download_mode(scm, download_mode); > > @@ -2858,7 +2859,7 @@ static int set_minidump_dest(const char *val, const > struct kernel_param *kp) > minidump_dest = minidump_dest_map[i].val; > > /* Pairs with smp_store_release() in qcom_scm_probe(). */ > - scm = smp_load_acquire(&__scm); > + scm = qcom_scm_get(); [Severity: High] Similarly to the download_mode parameter, could writing to minidump_dest via sysfs during probe fail to reach the hardware? Since qcom_scm_get() will return NULL before driver_bound() finishes, it appears the minidump_sram write could be completely missed. > if (scm && scm->minidump_sram && (download_mode & QCOM_DLOAD_MINIDUMP)) > writel_relaxed(minidump_dest, scm->minidump_sram); -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=3
