[PATCH 09/20] signal/vm86_32: Replace open coded BUG_ON with an actual BUG_ON

Eric W. Biederman
2021-10-20T17:45:22Z

The function save_v86_state is only called when userspace was
operating in vm86 mode before entering the kernel. Not having vm86
state in the task_struct should never happen. So transform the hand
rolled BUG_ON into an actual BUG_ON to make it clear what is
happening.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org
Cc: H Peter Anvin <hpa@zytor.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
arch/x86/kernel/vm86_32.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index e5a7a10a0164..63486da77272 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -106,10 +106,8 @@ void save_v86_state(struct kernel_vm86_regs *regs, int retval)
*/
local_irq_enable();

- if (!vm86 || !vm86->user_vm86) {
- pr_alert("no user_vm86: BAD\n");
- do_exit(SIGSEGV);
- }
+ BUG_ON(!vm86 || !vm86->user_vm86);
+
set_flags(regs->pt.flags, VEFLAGS, X86_EFLAGS_VIF | vm86->veflags_mask);
user = vm86->user_vm86;

--
2.20.1