Bug 36692
| Summary: | Kernel fails to execute init on multi-arch initramfs | ||
|---|---|---|---|
| Product: | Memory Management | Reporter: | Mathias Krause (minipli) |
| Component: | Other | Assignee: | Andrew Morton (akpm) |
| Status: | RESOLVED CODE_FIX | ||
| Severity: | normal | ||
| Priority: | P1 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Kernel Version: | 2.6.12 onwards | Subsystem: | |
| Regression: | No | Bisected commit-id: | |
I've a x86 multi-arch initramfs containing a 64 bit init as /sbin/init and a 32 bit version as /bin/init. Also I've an empty text file /init (non-executable) to pass the check in init/main.c:kernel_init() to not call prepare_namespace() (otherwise booting would be impossible because the kernel complains not to find its rootfs). This setup should be bootable with either a 64 bit kernel with no compat support and also with a plain 32 bit kernel because the hardcoded list in init/main.c:init_post() should make /sbin/init succeed on the 64 bit kernel and make it fail, but skip over to /bin/init on a 32 bit kernel. The latter doesn't happen because the failed execution attempt of /sbin/init changed the address limit from KERNEL_DS to USER_DS in fs/exec.c:search_binary_handler() so all references to the filenames ("/etc/init", "/bin/init" and "/bin/sh") won't be allowed because they life in kernelland not userland. Patch for this bug is available at [1] but nobody seemed to care so far :( [1] http://marc.info/?l=linux-kernel&m=130677271530393&w=2