Do all Linux distros use the same kernel?

By "the same kernel", I mean the one which was originally created by Torvalds and then updated by people here: http://www.kernel.org

Is it true that different distros all keep the kernel unchanged(of course they will update the kernel when there is a new version from the above site), and only make changes to the various utilities of their own?

All distros use the same "Linux" kernel, however all distros make slight changes to it in order make the kernel work best for them, however these changes will almost always get uploaded back to the top where Linus will merge them himself. So all use the Linux kernel, however they all have a few different lines of code in them to make them work best for that distro. It is also worth noting that distros will ship with the version of the kernel that they see fit for each version. Some distros choose a newer kernel then others. The main pro of a new kernel are improvements in driver's and hardware compatibility. The con is a loss in stability as all new code has bugs in it. So you trade features for stability. This is why distros known for being more stable will usually always ship an older kernel than the more risky distros. To find what kernel you are running enter:

uname -r

This will show you what you are running in the version of Ubuntu you have on your computer currently. Hope you enjoy!

Yes and No will be the answer.

"The Linux kernel" is a fairly complicated piece of software which can be compiled in a number of different ways. Basically, a configuration file is set up with a laundry-list of options, and this file subsequently determines exactly which blocks of source-code are or are not included in "the Linux kernel" for your system. (The same process also determines which kernel modules are built.)

Generally speaking, a distro writer will do all of that "heavy lifting" for you:

They'll compile one or more kernels, using config options that they have carefully selected, and include those (in binary form) in their distributions. They might even include custom patches.

So, the answer to your question is both 'yes' and 'no'.

• Yes, several distros might use "Linux version X.Y.Z."
• No, they might not use the same configuration options when building it.

Courtesy: sundialsvcs' comment here.

Also check out this post on stackoverflow for some more related information.