From: Sebastian Andrzej Siewior Date: Tue, 26 Feb 2019 14:53:49 +0100 Subject: [PATCH 240/351] x86: lazy-preempt: use proper return label on 32bit-x86 Origin: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit?id=2f573c1654480f0cf483d8970b1bbbd982643053 The lazy-preempt uses the wrong return label in case preemption isn't possible. This results crash while returning to the kernel. Use the correct return label if preemption isn' possible. Reported-by: Andri Yngvason Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/entry/entry_32.S | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 324b7539eaab..d8b40085c2b8 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -759,15 +759,15 @@ ENTRY(resume_kernel) # atleast preempt count == 0 ? cmpl $_PREEMPT_ENABLED,PER_CPU_VAR(__preempt_count) - jne restore_all + jne restore_all_kernel movl PER_CPU_VAR(current_task), %ebp cmpl $0,TASK_TI_preempt_lazy_count(%ebp) # non-zero preempt_lazy_count ? - jnz restore_all + jnz restore_all_kernel testl $_TIF_NEED_RESCHED_LAZY, TASK_TI_flags(%ebp) - jz restore_all - test_int_off: + jz restore_all_kernel +test_int_off: #endif testl $X86_EFLAGS_IF, PT_EFLAGS(%esp) # interrupts off (exception path) ? jz restore_all_kernel