Linux kernel ============ The Linux kernel is the core of any Linux operating system. It manages hardware, system resources, and provides the fundamental services for all other software. Quick Start ----------- * Report a bug: See Documentation/admin-guide/reporting-issues.rst * Get the latest kernel: https://kernel.org * Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst * Join the community: https://lore.kernel.org/ Essential Documentation ----------------------- All users should be familiar with: * Building requirements: Documentation/process/changes.rst * Code of Conduct: Documentation/process/code-of-conduct.rst * License: See COPYING Documentation can be built with make htmldocs or viewed online at: https://www.kernel.org/doc/html/latest/ Who Are You? ============ Find your role below: * New Kernel Developer - Getting started with kernel development * Academic Researcher - Studying kernel internals and architecture * Security Expert - Hardening and vulnerability analysis * Backport/Maintenance Engineer - Maintaining stable kernels * System Administrator - Configuring and troubleshooting * Maintainer - Leading subsystems and reviewing patches * Hardware Vendor - Writing drivers for new hardware * Distribution Maintainer - Packaging kernels for distros For Specific Users ================== New Kernel Developer -------------------- Welcome! Start your kernel development journey here: * Getting Started: Documentation/process/development-process.rst * Your First Patch: Documentation/process/submitting-patches.rst * Coding Style: Documentation/process/coding-style.rst * Build System: Documentation/kbuild/index.rst * Development Tools: Documentation/dev-tools/index.rst * Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst * Core APIs: Documentation/core-api/index.rst Academic Researcher ------------------- Explore the kernel's architecture and internals: * Researcher Guidelines: Documentation/process/researcher-guidelines.rst * Memory Management: Documentation/mm/index.rst * Scheduler: Documentation/scheduler/index.rst * Networking Stack: Documentation/networking/index.rst * Filesystems: Documentation/filesystems/index.rst * RCU (Read-Copy Update): Documentation/RCU/index.rst * Locking Primitives: Documentation/locking/index.rst * Power Management: Documentation/power/index.rst Security Expert --------------- Security documentation and hardening guides: * Security Documentation: Documentation/security/index.rst * LSM Development: Documentation/security/lsm-development.rst * Self Protection: Documentation/security/self-protection.rst * Reporting Vulnerabilities: Documentation/process/security-bugs.rst * CVE Procedures: Documentation/process/cve.rst * Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst * Security Features: Documentation/userspace-api/seccomp_filter.rst Backport/Maintenance Engineer ----------------------------- Maintain and stabilize kernel versions: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * Backporting Guide: Documentation/process/backporting.rst * Applying Patches: Documentation/process/applying-patches.rst * Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git for Maintainers: Documentation/maintainer/configure-git.rst System Administrator -------------------- Configure, tune, and troubleshoot Linux systems: * Admin Guide: Documentation/admin-guide/index.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst * Tracing/Debugging: Documentation/trace/index.rst * Performance Security: Documentation/admin-guide/perf-security.rst * Hardware Monitoring: Documentation/hwmon/index.rst Maintainer ---------- Lead kernel subsystems and manage contributions: * Maintainer Handbook: Documentation/maintainer/index.rst * Pull Requests: Documentation/maintainer/pull-requests.rst * Managing Patches: Documentation/maintainer/modifying-patches.rst * Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst * Development Process: Documentation/process/maintainer-handbooks.rst * Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git Configuration: Documentation/maintainer/configure-git.rst Hardware Vendor --------------- Write drivers and support new hardware: * Driver API Guide: Documentation/driver-api/index.rst * Driver Model: Documentation/driver-api/driver-model/driver.rst * Device Drivers: Documentation/driver-api/infrastructure.rst * Bus Types: Documentation/driver-api/driver-model/bus.rst * Device Tree Bindings: Documentation/devicetree/bindings/ * Power Management: Documentation/driver-api/pm/index.rst * DMA API: Documentation/core-api/dma-api.rst Distribution Maintainer ----------------------- Package and distribute the kernel: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * ABI Documentation: Documentation/ABI/README * Kernel Configuration: Documentation/kbuild/kconfig.rst * Module Signing: Documentation/admin-guide/module-signing.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst Communication and Support ========================= * Mailing Lists: https://lore.kernel.org/ * IRC: #kernelnewbies on irc.oftc.net * Bugzilla: https://bugzilla.kernel.org/ * MAINTAINERS file: Lists subsystem maintainers and mailing lists * Email Clients: Documentation/process/email-clients.rst
Clone this repository
For self-hosted knots, clone URLs may differ based on your setup.
Download tar.gz
Fix a memory leak in gpi_peripheral_config() where the original memory
pointed to by gchan->config could be lost if krealloc() fails.
The issue occurs when:
1. gchan->config points to previously allocated memory
2. krealloc() fails and returns NULL
3. The function directly assigns NULL to gchan->config, losing the
reference to the original memory
4. The original memory becomes unreachable and cannot be freed
Fix this by using a temporary variable to hold the krealloc() result
and only updating gchan->config when the allocation succeeds.
Found via static analysis and code review.
Fixes: 5d0c3533a19f ("dmaengine: qcom: Add GPI dma driver")
Cc: stable@vger.kernel.org
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Link: https://patch.msgid.link/20251029123421.91973-1-linmq006@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
After audio full duplex testing, playing the recorded file contains a few
playback frames from the previous time. The rz_dmac_terminate_all() does
not reset all the hardware descriptors queued previously, leading to the
wrong descriptor being picked up during the next DMA transfer. Fix the
above issue by resetting all the descriptor headers for a channel in
rz_dmac_terminate_all() as rz_dmac_lmdesc_recycle() points to the proper
descriptor header filled by the rz_dmac_prepare_descs_for_slave_sg().
Cc: stable@kernel.org
Fixes: 5000d37042a6 ("dmaengine: sh: Add DMAC driver for RZ/G2L SoC")
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Tested-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://patch.msgid.link/20251113195052.564338-1-biju.das.jz@bp.renesas.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
When device tree lacks optional "xlnx,addrwidth" property, the addr_width
variable remained uninitialized with garbage values, causing incorrect
DMA mask configuration and subsequent probe failure. The fix ensures a
fallback to the default 32-bit address width when this property is missing.
Signed-off-by: Suraj Gupta <suraj.gupta2@amd.com>
Fixes: b72db4005fe4 ("dmaengine: vdma: Add 64 bit addressing support to the driver")
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Reviewed-by: Folker Schwesinger <dev@folker-schwesinger.de>
Link: https://patch.msgid.link/20251021183006.3434495-1-suraj.gupta2@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
A use-after-free bug exists in the Tegra ADMA driver when audio streams
are terminated, particularly during XRUN conditions. The issue occurs
when the DMA buffer is freed by tegra_adma_terminate_all() before the
vchan completion tasklet finishes accessing it.
The race condition follows this sequence:
1. DMA transfer completes, triggering an interrupt that schedules the
completion tasklet (tasklet has not executed yet)
2. Audio playback stops, calling tegra_adma_terminate_all() which
frees the DMA buffer memory via kfree()
3. The scheduled tasklet finally executes, calling vchan_complete()
which attempts to access the already-freed memory
Since tasklets can execute at any time after being scheduled, there is
no guarantee that the buffer will remain valid when vchan_complete()
runs.
Fix this by properly synchronizing the virtual channel completion:
- Calling vchan_terminate_vdesc() in tegra_adma_stop() to mark the
descriptors as terminated instead of freeing the descriptor.
- Add the callback tegra_adma_synchronize() that calls
vchan_synchronize() which kills any pending tasklets and frees any
terminated descriptors.
Crash logs:
[ 337.427523] BUG: KASAN: use-after-free in vchan_complete+0x124/0x3b0
[ 337.427544] Read of size 8 at addr ffff000132055428 by task swapper/0/0
[ 337.427562] Call trace:
[ 337.427564] dump_backtrace+0x0/0x320
[ 337.427571] show_stack+0x20/0x30
[ 337.427575] dump_stack_lvl+0x68/0x84
[ 337.427584] print_address_description.constprop.0+0x74/0x2b8
[ 337.427590] kasan_report+0x1f4/0x210
[ 337.427598] __asan_load8+0xa0/0xd0
[ 337.427603] vchan_complete+0x124/0x3b0
[ 337.427609] tasklet_action_common.constprop.0+0x190/0x1d0
[ 337.427617] tasklet_action+0x30/0x40
[ 337.427623] __do_softirq+0x1a0/0x5c4
[ 337.427628] irq_exit+0x110/0x140
[ 337.427633] handle_domain_irq+0xa4/0xe0
[ 337.427640] gic_handle_irq+0x64/0x160
[ 337.427644] call_on_irq_stack+0x20/0x4c
[ 337.427649] do_interrupt_handler+0x7c/0x90
[ 337.427654] el1_interrupt+0x30/0x80
[ 337.427659] el1h_64_irq_handler+0x18/0x30
[ 337.427663] el1h_64_irq+0x7c/0x80
[ 337.427667] cpuidle_enter_state+0xe4/0x540
[ 337.427674] cpuidle_enter+0x54/0x80
[ 337.427679] do_idle+0x2e0/0x380
[ 337.427685] cpu_startup_entry+0x2c/0x70
[ 337.427690] rest_init+0x114/0x130
[ 337.427695] arch_call_rest_init+0x18/0x24
[ 337.427702] start_kernel+0x380/0x3b4
[ 337.427706] __primary_switched+0xc0/0xc8
Fixes: f46b195799b5 ("dmaengine: tegra-adma: Add support for Tegra210 ADMA")
Signed-off-by: Sheetal <sheetal@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Link: https://patch.msgid.link/20251110142445.3842036-1-sheetal@nvidia.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
When fsl_edma_alloc_chan_resources() fails after clk_prepare_enable(),
the error paths only free IRQs and destroy the TCD pool, but forget to
call clk_disable_unprepare(). This causes the channel clock to remain
enabled, leaking power and resources.
Fix it by disabling the channel clock in the error unwind path.
Fixes: d8d4355861d8 ("dmaengine: fsl-edma: add i.MX8ULP edma support")
Cc: stable@vger.kernel.org
Suggested-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Zhen Ni <zhen.ni@easystack.cn>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20251014090522.827726-1-zhen.ni@easystack.cn
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Add proper locking in mmp_pdma_residue() to prevent use-after-free when
accessing descriptor list and descriptor contents.
The race occurs when multiple threads call tx_status() while the tasklet
on another CPU is freeing completed descriptors:
CPU 0 CPU 1
----- -----
mmp_pdma_tx_status()
mmp_pdma_residue()
-> NO LOCK held
list_for_each_entry(sw, ..)
DMA interrupt
dma_do_tasklet()
-> spin_lock(&desc_lock)
list_move(sw->node, ...)
spin_unlock(&desc_lock)
| dma_pool_free(sw) <- FREED!
-> access sw->desc <- UAF!
This issue can be reproduced when running dmatest on the same channel with
multiple threads (threads_per_chan > 1).
Fix by protecting the chain_running list iteration and descriptor access
with the chan->desc_lock spinlock.
Signed-off-by: Juan Li <lijuan@linux.spacemit.com>
Signed-off-by: Guodong Xu <guodong@riscstar.com>
Link: https://patch.msgid.link/20251216-mmp-pdma-race-v1-1-976a224bb622@riscstar.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Make sure to drop the reference taken when looking up the UDMA platform
device.
Note that holding a reference to a platform device does not prevent its
driver data from going away so there is no point in keeping the
reference after the lookup helper returns.
Fixes: d70241913413 ("dmaengine: ti: k3-udma: Add glue layer for non DMAengine users")
Fixes: 1438cde8fe9c ("dmaengine: ti: k3-udma: add missing put_device() call in of_xudma_dev_get()")
Cc: stable@vger.kernel.org # 5.6: 1438cde8fe9c
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20251117161258.10679-17-johan@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Use a common exit path to drop the cross platform device reference on
errors for consistency with am335x.
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20251117161258.10679-16-johan@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Make sure to drop the reference taken when looking up the crossbar
platform device during am335x route allocation.
Fixes: 42dbdcc6bf96 ("dmaengine: ti-dma-crossbar: Add support for crossbar on AM33xx/AM43xx")
Cc: stable@vger.kernel.org # 4.4
Cc: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20251117161258.10679-15-johan@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Make sure to drop the reference taken when looking up the crossbar
platform device during dra7x route allocation.
Note that commit 615a4bfc426e ("dmaengine: ti: Add missing put_device in
ti_dra7_xbar_route_allocate") fixed the leak in the error paths but the
reference is still leaking on successful allocation.
Fixes: a074ae38f859 ("dmaengine: Add driver for TI DMA crossbar on DRA7x")
Fixes: 615a4bfc426e ("dmaengine: ti: Add missing put_device in ti_dra7_xbar_route_allocate")
Cc: stable@vger.kernel.org # 4.2: 615a4bfc426e
Cc: Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc: Miaoqian Lin <linmq006@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20251117161258.10679-14-johan@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Error labels should be named after what they do (and not after wherefrom
they are jumped to).
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Link: https://patch.msgid.link/20251117161258.10679-13-johan@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Make sure to drop the reference taken to the DMA master OF node also on
late route allocation failures.
Fixes: df7e762db5f6 ("dmaengine: Add STM32 DMAMUX driver")
Cc: stable@vger.kernel.org # 4.15
Cc: Pierre-Yves MORDRET <pierre-yves.mordret@foss.st.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Link: https://patch.msgid.link/20251117161258.10679-12-johan@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Make sure to drop the reference taken when looking up the DMA mux
platform device during route allocation.
Note that holding a reference to a device does not prevent its driver
data from going away so there is no point in keeping the reference.
Fixes: df7e762db5f6 ("dmaengine: Add STM32 DMAMUX driver")
Cc: stable@vger.kernel.org # 4.15
Cc: Pierre-Yves MORDRET <pierre-yves.mordret@foss.st.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Link: https://patch.msgid.link/20251117161258.10679-11-johan@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Make sure to drop the reference taken when looking up the ICU device
during probe also on probe failures (e.g. probe deferral).
Fixes: 7de873201c44 ("dmaengine: sh: rz-dmac: Add RZ/V2H(P) support")
Cc: stable@vger.kernel.org # 6.16
Cc: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
Link: https://patch.msgid.link/20251117161258.10679-10-johan@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Make sure to drop the reference taken when looking up the DMA mux
platform device during route allocation.
Note that holding a reference to a device does not prevent its driver
data from going away so there is no point in keeping the reference.
Fixes: 5d318b595982 ("dmaengine: Add dma router for pl08x in LPC32XX SoC")
Cc: stable@vger.kernel.org # 6.12
Cc: Piotr Wojtaszczyk <piotr.wojtaszczyk@timesys.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
Link: https://patch.msgid.link/20251117161258.10679-9-johan@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Make sure to drop the reference taken when looking up the DMA mux
platform device during route allocation.
Note that holding a reference to a device does not prevent its driver
data from going away so there is no point in keeping the reference.
Fixes: e5f4ae84be74 ("dmaengine: add driver for lpc18xx dmamux")
Cc: stable@vger.kernel.org # 4.3
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
Link: https://patch.msgid.link/20251117161258.10679-8-johan@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>