The dmesg command allows you to review the messages that are stored in the
ring buffer. Some Linux distributions have strict requirements for
dmesg, and you need to use sudo to use dmesg.
The action we used to delete the old release somehow cannot find the
release tag in forked repo and cause the workflow failed.
To solve this issue, simply setting `fail-if-no-release` option to false
will do the trick.
Since Linux v3.14, the read, write and seek operations of "struct file" are
guaranteed for thread safety [1][2]. This patch added an explanation.
Here are the potential problems:
chardev.c:
- Move the "msg_ptr" pointer into the read function to remove unnecessary usage.
- List the clear states of "already_open" by using mnemonic enumeration.
chardev2.c:
- The "buffer" in the write function is user space data. It cannot use in the
kernel space.
- Reduce the redundant type transformation.
- List the states of "already_open". Same as chardev.c.
[1] https://lore.kernel.org/lkml/20140303210359.26624.qmail@science.horizon.com/T/#u
[2] 9c225f2655
Parameters are case-sensitive, so myintArray is different from myintarray, and people who are running the example with copy/paste will find it doesn't work as described in the text.
Cppcheck[1] is integrated into CI pipeline for running static analysis.
However, Cppcheck is known to report false-positive, and we have to
suppress some warnings in advance.
[1] https://cppcheck.sourceforge.io/
The "alloc_chrdev_region" function will dynamically choose the
major number and store it at "dev". It is unnecessary to initialize
the "dev" before the "alloc_chrdev_region" function.
p + pre remains at em as we want to use the parent element here (however rem
could be used too, just requires a bigger value). I am setting it to 110% size,
otherwise some code blocks have relatively small text. The smaller code blocks
do appear bigger.
This new foreground + background color maintains the minimum of 7:1 contrast ratio as specified by WCAG (this has 7.36:1) and is the same colors Firefox reading mode uses when choosing the sepia theme.
Fonts are too small by default, using responsive units (em) let's me increase them, I am unsure where or if there is font-size specified for parent anywhere but it seems to have been manually decreased.
Increased max-width slightly to adjust for new size and more standard line-height, so the doc doesn't feel significantly longer, still maintains good eye travel.
In file {chardev,chardev2,sleep}.c, the variable to determine
the exclusive access was of integer type, which led to race
condition.
This patch rewrote the above with atomic CAS respectively
to eliminate the race.
Close#93
chardev2.c demonstrates the ioctl operation with static major
number MAJOR_NUM, but there also exists "Major," the dynamic
one, which results in registration and deregistration on different
device. Once the module remove, it cannot insert again:
$ sudo insmod chardev2.ko
$ sudo rmmod chardev2
$ cat /proc/devices
Character devices:
...
100 char_dev
$ sudo insmod chardev2.ko
insmod: ERROR: could not insert module chardev2.ko: Device or resource busy
This patch removed the use of dynamic major number.
