[Sat Mar 2 10:32:33 PST 1996 KERNEL_BUG-HOWTO lm@sgi.com (Larry McVoy)] This is how to track down a bug if you know nothing about kernel hacking. It's a brute force approach but it works pretty well. You need: . A reproducible bug - it has to happen predictably (sorry) . All the kernel tar files from a revision that worked to the revision that doesn't You will then do: . Rebuild a revision that you believe works, install, and verify that. . Do a binary search over the kernels to figure out which one introduced the bug. I.e., suppose 1.3.28 didn't have the bug, but you know that 1.3.69 does. Pick a kernel in the middle and build that, like 1.3.50. Build & test; if it works, pick the mid point between .50 and .69, else the mid point between .28 and .50. . You'll narrow it down to the kernel that introduced the bug. You can probably do better than this but it gets tricky. . Narrow it down to a subdirectory - Copy kernel that works into "test". Let's say that 3.62 works, but 3.63 doesn't. So you diff -r those two kernels and come up with a list of directories that changed. For each of those directories: Copy the non-working directory next to the working directory as "dir.63". One directory at time, try moving the working directory to "dir.62" and mv dir.63 dir"time, try mv dir dir.62 mv dir.63 dir find dir -name '*.[oa]' -print | xargs rm -f And then rebuild and retest. Assuming that all related changes were contained in the sub directory, this should isolate the change to a directory. Problems: changes in header files may have occurred; I've found in my case that they were self explanatory - you may or may not want to give up when that happens. . Narrow it down to a file - You can apply the same technique to each file in the directory, hoping that the changes in that file are self contained. . Narrow it down to a routine - You can take the old file and the new file and manually create a merged file that has #ifdef VER62 routine() { ... } #else routine() { ... } #endif And then walk through that file, one routine at a time and prefix it with #define VER62 /* both routines here */ #undef VER62 Then recompile, retest, move the ifdefs until you find the one that makes the difference. Finally, you take all the info that you have, kernel revisions, bug description, the extent to which you have narrowed it down, and pass that off to whomever you believe is the maintainer of that section. A post to linux.dev.kernel isn't such a bad idea if you've done some work to narrow it down. If you get it down to a routine, you'll probably get a fix in 24 hours. My apologies to Linus and the other kernel hackers for describing this brute force approach, it's hardly what a kernel hack would do. However, it does work and it lets non-hackers help bug fix. And it is cool because Linux snapshots will let you do this - something that you can't do with vender supplied releases.