[PATCH 5.11 195/210] x86/traps: Correct exc_general_protection() and math_error() return paths

Greg Kroah-Hartman
2021-04-12T09:43:28Z

From: Thomas Tai <thomas.tai@oracle.com>

commit 632a1c209b8773cb0119fe3aada9f1db14fa357c upstream.

Commit

334872a09198 ("x86/traps: Attempt to fixup exceptions in vDSO before signaling")

added return statements which bypass calling cond_local_irq_disable().

According to

ca4c6a9858c2 ("x86/traps: Make interrupt enable/disable symmetric in C code"),

cond_local_irq_disable() is needed because the asm return code no longer
disables interrupts. Follow the existing code as an example to use "goto
exit" instead of "return" statement.

[ bp: Massage commit message. ]

Fixes: 334872a09198 ("x86/traps: Attempt to fixup exceptions in vDSO before signaling")
Signed-off-by: Thomas Tai <thomas.tai@oracle.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Link: https://lkml.kernel.org/r/1617902914-83245-1-git-send-email-thomas.tai@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/traps.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -556,7 +556,7 @@ DEFINE_IDTENTRY_ERRORCODE(exc_general_pr
tsk->thread.trap_nr = X86_TRAP_GP;

if (fixup_vdso_exception(regs, X86_TRAP_GP, error_code, 0))
- return;
+ goto exit;

show_signal(tsk, SIGSEGV, "", desc, regs, error_code);
force_sig(SIGSEGV);
@@ -1057,7 +1057,7 @@ static void math_error(struct pt_regs *r
goto exit;

if (fixup_vdso_exception(regs, trapnr, 0, 0))
- return;
+ goto exit;

force_sig_fault(SIGFPE, si_code,
(void __user *)uprobe_get_trap_addr(regs));