avr32: Fix oops on unaligned user access
The unaligned address exception handler (and others) does not scan the
fixup tables before oopsing. This is bad because it means passing a
badly aligned pointer from user space might crash the kernel.
Fix this by scanning the fixup tables in _exception(). This should
resolve the issue for unaligned addresses as well as other less common
exceptions that might be happening during a userspace access. The page
fault handler already does fixup processing.
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
diff --git a/arch/avr32/kernel/traps.c b/arch/avr32/kernel/traps.c
index d547c8d..6e3d491 100644
--- a/arch/avr32/kernel/traps.c
+++ b/arch/avr32/kernel/traps.c
@@ -75,8 +75,17 @@
{
siginfo_t info;
- if (!user_mode(regs))
+ if (!user_mode(regs)) {
+ const struct exception_table_entry *fixup;
+
+ /* Are we prepared to handle this kernel fault? */
+ fixup = search_exception_tables(regs->pc);
+ if (fixup) {
+ regs->pc = fixup->fixup;
+ return;
+ }
die("Unhandled exception in kernel mode", regs, signr);
+ }
memset(&info, 0, sizeof(info));
info.si_signo = signr;
