uml: kernel segfaults should dump proper registers
If there's a segfault inside the kernel, we want a dump of the registers at
the point of the segfault, not the registers at the point of calling panic or
the last userspace registers.
sig_handler_common_skas now uses a static register set in the case of a
SIGSEGV to avoid messing up the process registers if the segfault turns out to
be non-fatal.
The architecture sigcontext-to-pt_regs copying code was repurposed to copy
data out of the SEGV stack frame.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index c3e62e6..0c467fa 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -170,8 +170,10 @@
flush_tlb_kernel_vm();
return 0;
}
- else if(current->mm == NULL)
- panic("Segfault with no mm");
+ else if(current->mm == NULL) {
+ show_regs(container_of(regs, struct pt_regs, regs));
+ panic("Segfault with no mm");
+ }
if (SEGV_IS_FIXABLE(&fi) || SEGV_MAYBE_FIXABLE(&fi))
err = handle_page_fault(address, ip, is_write, is_user, &si.si_code);
@@ -194,9 +196,11 @@
else if(!is_user && arch_fixup(ip, regs))
return 0;
- if(!is_user)
+ if(!is_user) {
+ show_regs(container_of(regs, struct pt_regs, regs));
panic("Kernel mode fault at addr 0x%lx, ip 0x%lx",
address, ip);
+ }
if (err == -EACCES) {
si.si_signo = SIGBUS;