This fixes a problem seen by a number of people running UML on newer host kernels. init would hang with an infinite segfault loop.
It turns out that the host kernel was providing a AT_SYSINFO_EHDR of 0xffffe000, which faked UML into believing that the host VDSO page could be reused. However, AT_SYSINFO pointed into the middle of the address space, and was unmapped as a result. Because UML was providing AT_SYSINFO_EHDR and AT_SYSINFO to its own processes, these would branch to nowhere when trying to use the VDSO. The fix is to also check the location of AT_SYSINFO when deciding whether to use the host's VDSO. Signed-off-by: Jeff Dike <[EMAIL PROTECTED]> -- arch/um/os-Linux/elf_aux.c | 3 +++ 1 file changed, 3 insertions(+) Index: linux-2.6.17/arch/um/os-Linux/elf_aux.c =================================================================== --- linux-2.6.17.orig/arch/um/os-Linux/elf_aux.c 2007-02-23 15:00:51.000000000 -0500 +++ linux-2.6.17/arch/um/os-Linux/elf_aux.c 2007-02-23 15:09:58.000000000 -0500 @@ -39,6 +39,9 @@ __init void scan_elf_aux( char **envp) switch ( auxv->a_type ) { case AT_SYSINFO: __kernel_vsyscall = auxv->a_un.a_val; + /* See if the page is under TASK_SIZE */ + if (__kernel_vsyscall < (unsigned long) envp) + __kernel_vsyscall = 0; break; case AT_SYSINFO_EHDR: vsyscall_ehdr = auxv->a_un.a_val; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/