full list: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.... (very "slow" at the very end of the development cycle)
example merge: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux....
example commit: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux....
I picked some of the longer ones on the first page just for contrast with your impression, many have shorter commit messages, but they all have a commit message with some explanation.
But I sympathize. I often spend more time on commit messages than the actual changes...
My worst commit-message-to-code-changed ratio is a commit in the kernel with a 1307 char/175 word commit message, and a single character change...
Link for the curious?
https://github.com/torvalds/linux/commit/949e9b827eb4736d96d...
I wish I could upvote this more than once.