diff options
| -rw-r--r-- | arch/x86/include/asm/idtentry.h | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/traps.c | 64 | ||||
| -rw-r--r-- | arch/x86/mm/extable.c | 15 |
3 files changed, 52 insertions, 29 deletions
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h index d203c541a65a..2fc6b0c58341 100644 --- a/arch/x86/include/asm/idtentry.h +++ b/arch/x86/include/asm/idtentry.h @@ -543,7 +543,6 @@ SYM_CODE_END(spurious_entries_start) DECLARE_IDTENTRY(X86_TRAP_DE, exc_divide_error); DECLARE_IDTENTRY(X86_TRAP_OF, exc_overflow); DECLARE_IDTENTRY(X86_TRAP_BR, exc_bounds); -DECLARE_IDTENTRY(X86_TRAP_UD, exc_invalid_op); DECLARE_IDTENTRY(X86_TRAP_NM, exc_device_not_available); DECLARE_IDTENTRY(X86_TRAP_OLD_MF, exc_coproc_segment_overrun); DECLARE_IDTENTRY(X86_TRAP_SPURIOUS, exc_spurious_interrupt_bug); @@ -561,6 +560,7 @@ DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_GP, exc_general_protection); DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_AC, exc_alignment_check); /* Raw exception entries which need extra work */ +DECLARE_IDTENTRY_RAW(X86_TRAP_UD, exc_invalid_op); DECLARE_IDTENTRY_RAW(X86_TRAP_BP, exc_int3); DECLARE_IDTENTRY_RAW_ERRORCODE(X86_TRAP_PF, exc_page_fault); diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 7febae381b91..af75109485c2 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -97,24 +97,6 @@ int is_valid_bugaddr(unsigned long addr) return ud == INSN_UD0 || ud == INSN_UD2; } -int fixup_bug(struct pt_regs *regs, int trapnr) -{ - if (trapnr != X86_TRAP_UD) - return 0; - - switch (report_bug(regs->ip, regs)) { - case BUG_TRAP_TYPE_NONE: - case BUG_TRAP_TYPE_BUG: - break; - - case BUG_TRAP_TYPE_WARN: - regs->ip += LEN_UD2; - return 1; - } - - return 0; -} - static nokprobe_inline int do_trap_no_signal(struct task_struct *tsk, int trapnr, const char *str, struct pt_regs *regs, long error_code) @@ -190,13 +172,6 @@ static void do_error_trap(struct pt_regs *regs, long error_code, char *str, { RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU"); - /* - * WARN*()s end up here; fix them up before we call the - * notifier chain. - */ - if (!user_mode(regs) && fixup_bug(regs, trapnr)) - return; - if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) != NOTIFY_STOP) { cond_local_irq_enable(regs); @@ -241,9 +216,46 @@ static inline void handle_invalid_op(struct pt_regs *regs) ILL_ILLOPN, error_get_trap_addr(regs)); } -DEFINE_IDTENTRY(exc_invalid_op) +DEFINE_IDTENTRY_RAW(exc_invalid_op) { + bool rcu_exit; + + /* + * Handle BUG/WARN like NMIs instead of like normal idtentries: + * if we bugged/warned in a bad RCU context, for example, the last + * thing we want is to BUG/WARN again in the idtentry code, ad + * infinitum. + */ + if (!user_mode(regs) && is_valid_bugaddr(regs->ip)) { + enum bug_trap_type type; + + nmi_enter(); + instrumentation_begin(); + trace_hardirqs_off_finish(); + type = report_bug(regs->ip, regs); + if (regs->flags & X86_EFLAGS_IF) + trace_hardirqs_on_prepare(); + instrumentation_end(); + nmi_exit(); + + if (type == BUG_TRAP_TYPE_WARN) { + /* Skip the ud2. */ + regs->ip += LEN_UD2; + return; + } + + /* + * Else, if this was a BUG and report_bug returns or if this + * was just a normal #UD, we want to continue onward and + * crash. + */ + } + + rcu_exit = idtentry_enter_cond_rcu(regs); + instrumentation_begin(); handle_invalid_op(regs); + instrumentation_end(); + idtentry_exit_cond_rcu(regs, rcu_exit); } DEFINE_IDTENTRY(exc_coproc_segment_overrun) diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c index b991aa4bdfae..1d6cb07f4f86 100644 --- a/arch/x86/mm/extable.c +++ b/arch/x86/mm/extable.c @@ -204,8 +204,19 @@ void __init early_fixup_exception(struct pt_regs *regs, int trapnr) if (fixup_exception(regs, trapnr, regs->orig_ax, 0)) return; - if (fixup_bug(regs, trapnr)) - return; + if (trapnr == X86_TRAP_UD) { + if (report_bug(regs->ip, regs) == BUG_TRAP_TYPE_WARN) { + /* Skip the ud2. */ + regs->ip += LEN_UD2; + return; + } + + /* + * If this was a BUG and report_bug returns or if this + * was just a normal #UD, we want to continue onward and + * crash. + */ + } fail: early_printk("PANIC: early exception 0x%02x IP %lx:%lx error %lx cr2 0x%lx\n", |