diff options
Diffstat (limited to 'arch/x86/kernel/cpu/perf_event_intel_ds.c')
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event_intel_ds.c | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c index 46211bcc813e..6a94277525c9 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_ds.c +++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c @@ -724,6 +724,7 @@ static int intel_pmu_pebs_fixup_ip(struct pt_regs *regs) unsigned long ip = regs->ip; int is_64bit = 0; void *kaddr; + int size; /* * We don't need to fixup if the PEBS assist is fault like @@ -758,11 +759,12 @@ static int intel_pmu_pebs_fixup_ip(struct pt_regs *regs) return 1; } + size = ip - to; if (!kernel_ip(ip)) { - int size, bytes; + int bytes; u8 *buf = this_cpu_read(insn_buffer); - size = ip - to; /* Must fit our buffer, see above */ + /* 'size' must fit our buffer, see above */ bytes = copy_from_user_nmi(buf, (void __user *)to, size); if (bytes != 0) return 0; @@ -780,11 +782,20 @@ static int intel_pmu_pebs_fixup_ip(struct pt_regs *regs) #ifdef CONFIG_X86_64 is_64bit = kernel_ip(to) || !test_thread_flag(TIF_IA32); #endif - insn_init(&insn, kaddr, is_64bit); + insn_init(&insn, kaddr, size, is_64bit); insn_get_length(&insn); + /* + * Make sure there was not a problem decoding the + * instruction and getting the length. This is + * doubly important because we have an infinite + * loop if insn.length=0. + */ + if (!insn.length) + break; to += insn.length; kaddr += insn.length; + size -= insn.length; } while (to < ip); if (to == ip) { |