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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-10-02 12:17:24 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-10-02 12:17:24 -0700 |
| commit | 3f1fe48a36b0b6722dc3fd421d93512bac138e9a (patch) | |
| tree | b767d7f6e26bc64334d3f14f8422d187239dc45d /Documentation/process/debugging/index.rst | |
| download | linux-stable-3f1fe48a36b0b6722dc3fd421d93512bac138e9a.tar.gz linux-stable-3f1fe48a36b0b6722dc3fd421d93512bac138e9a.zip | |
Merge tag 'io_uring-7.3-20261002' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linuxgrafted
Pull io_uring fixes from Jens Axboe:
- Fix a task_work add use-after-free with SQPOLL.
The sqpoll thread could pop and complete the last request while
io_req_normal_work_add() was still looking at them after the mpscq
push.
Use the same approach as DEFER_TASKRUN to protect from that, holding
an RCU read lock across the add, and have exit wait for an RCU grace
period for SQPOLL rings as well.
- CQE32 ring fixes: correct the free entry check for 32b CQEs, zero the
big_cqe for aux CQEs, and only post the dummy skip CQE on CQE_MIXED
rings
- Mark the source filter table as COW when cloning bpf filters, so
registering another filter on the source doesn't modify the shared
table in place
- Initialize the task context before running the BPF loop
- Requeue zcrx multishot receives stopped by a local resource
- End a TX_TIMESTAMP multishot cmd when the CQ is full (lollipopkit)
* tag 'io_uring-7.3-20261002' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux:
io_uring: fix task_work add use-after-free with SQPOLL
io_uring/cmd_net: end TX_TIMESTAMP multishot when the CQ is full
io_uring/zcrx: requeue multishot receives stopped by a local resource
io_uring: initialize task context before running the BPF loop
io_uring: zero big_cqe for aux CQEs on CQE32 rings
io_uring: fix free entry check for 32b CQEs on CQE32 rings
io_uring: only post the dummy skip CQE on CQE_MIXED rings
io_uring/bpf_filter: mark source as COW when cloning filters
Diffstat (limited to 'Documentation/process/debugging/index.rst')
| -rw-r--r-- | Documentation/process/debugging/index.rst | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/Documentation/process/debugging/index.rst b/Documentation/process/debugging/index.rst new file mode 100644 index 000000000..357243e18 --- /dev/null +++ b/Documentation/process/debugging/index.rst @@ -0,0 +1,71 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================================ +Debugging advice for Linux Kernel developers +============================================ + +general guides +-------------- + +.. toctree:: + :maxdepth: 1 + + driver_development_debugging_guide + gdb-kernel-debugging + kgdb + userspace_debugging_guide + +subsystem specific guides +------------------------- + +.. toctree:: + :maxdepth: 1 + + media_specific_debugging_guide + +General debugging advice +======================== + +Depending on the issue, a different set of tools is available to track down the +problem or even to realize whether there is one in the first place. + +As a first step you have to figure out what kind of issue you want to debug. +Depending on the answer, your methodology and choice of tools may vary. + +Do I need to debug with limited access? +--------------------------------------- + +Do you have limited access to the machine or are you unable to stop the running +execution? + +In this case your debugging capability depends on built-in debugging support of +provided distribution kernel. +The :doc:`/process/debugging/userspace_debugging_guide` provides a brief +overview over a range of possible debugging tools in that situation. You can +check the capability of your kernel, in most cases, by looking into config file +within the /boot directory. + +Do I have root access to the system? +------------------------------------ + +Are you easily able to replace the module in question or to install a new +kernel? + +In that case your range of available tools is a lot bigger, you can find the +tools in the :doc:`/process/debugging/driver_development_debugging_guide`. + +Is timing a factor? +------------------- + +It is important to understand if the problem you want to debug manifests itself +consistently (i.e. given a set of inputs you always get the same, incorrect +output), or inconsistently. If it manifests itself inconsistently, some timing +factor might be at play. If inserting delays into the code does change the +behavior, then quite likely timing is a factor. + +When timing does alter the outcome of the code execution using a simple +printk() for debugging purposes may not work, a similar alternative is to use +trace_printk() , which logs the debug messages to the trace file instead of the +kernel log. + +**Copyright** ©2024 : Collabora |
