This patch series addresses a collection of critical race conditions, memory leaks, use-after-free bugs, and resource management issues within the Amlogic Meson video decoder (meson-vdec) driver and associated components.
The primary focus is tightening session lifecycles, safely synchronising the V4L2 m2m framework callbacks, hardening work queue operations (esparser_queue_work), and correcting buffer validations to prevent stability issues like KASAN out-of-bounds errors or stream-on timeouts. Summary of Changes: * Race Conditions & Synchronisation: Fixes multi-threading and execution races across stream-on, stream-off, job abort, and teardown pathways. * Memory Lifecycle: Eliminates memory leaks and use-after-free vulnerabilities by safely pinning, canceling, and sequencing device removals. * VP9 & Buffer Hardening: Addresses payload handling bugs in the ES parser, properly tracks ongoing buffers via atomic counters, and prevents invalid memory writes. * Platform/DMA Adjustments: Adjusts DMA segment configurations, canvas handling, and buffer sizes to match modern hardware demands. Note on an outstanding issue: An execution deadlock occurs in the driver workqueue path during high stress or long playback sessions. This stall is triggered when the Amlogic hardware internal video FIFO buffer becomes completely full. When esparser_queue_all_src runs, the capacity validation check is tripped due to a design limitation in how buffer exhaustion is handled. This blocks progress and leaves the workqueue worker waiting indefinitely on a core mutex lock. The resulting hung task call trace shows the worker thread blocking on the internal lock: Workqueue: events esparser_queue_all_src [meson_vdec] ... __mutex_lock mutex_lock_nested esparser_queue_all_src I have tried to address this issue, but the underlying deadlock persists under extreme conditions. Any feedback on this new appock is welcome. Testing was done using v4l2-compliance and active decoding pipelines on Meson platforms (like Hardkernel ODROID-N2+ and ODROID-C4) SBCs. The v4l2-compliance tests passed successfully via: $ v4l2-compliance -s -v -d /dev/video0 Pipelines were validated using the following GStreamer script. [1] https://gist.github.com/moonlinux/08295ba1f17ce7155550773f2d2cb6e5 Previous changes: v6: https://lore.kernel.org/all/[email protected]/ Thanks -Annad Anand Moon (19): media: meson: vdec: Fix m2m device lifetime and cleanup path media: meson: vdec: Fix STREAMON / STREAMOFF race conditions and session teardown media: meson: vdec: Fix lifecycle leaks and race conditions in recycle_thread media: meson: vdec: Fix use-after-free race between teardown and ISR routines media: meson: vdec: Fix race condition and synchronize esparser IRQ media: meson: vdec: Fix race condition by canceling work sync media: meson: vdec: Refactor esparser work queue and fix teardown race media: meson: vdec: Fix concurrent execution races and unsafe teardown media: meson: vdec: Fix vp9 header update failure on invalid payloads media: meson: vdec: Fix race conditions and leaks in esparser pipeline media: meson: vdec: Update core m2m stream state during transitions media: meson: vdec: Coordinate m2m task execution inside async loop media: meson: vdec: Fix race conditions in job abort sequence media: meson: vdec: Correct atomic counter placement in dst_buf_done media: meson: vdec: Fix concurrent firmware loading race and hardware timeout media: meson: vdec: Configure DMA mask and segment size in probe media: meson: canvas: Fix Use-After-Free by linking canvas provider device media: meson: vdec: Increase VIFIFO buffer size to 32 MiB gpu: drm: meson: Fix DMA segment size limits and maximize allocation boundaries drivers/gpu/drm/meson/meson_drv.c | 6 + drivers/soc/amlogic/meson-canvas.c | 14 +- drivers/staging/media/meson/vdec/esparser.c | 127 +++++-- drivers/staging/media/meson/vdec/vdec.c | 320 ++++++++++++++---- drivers/staging/media/meson/vdec/vdec.h | 8 +- drivers/staging/media/meson/vdec/vdec_1.c | 16 +- .../staging/media/meson/vdec/vdec_helpers.c | 3 + 7 files changed, 388 insertions(+), 106 deletions(-) base-commit: a13c140cc289c0b7b3770bce5b3ad42ab35074aa -- 2.50.1
