Hi Sasha,
Could you drop this? This prevents probing too much functions, and we will drop it from upstream. Anyway, commit a50480cb6d61 ("kprobes/x86: Blacklist non-attachable interrupt functions") fixes same issue. So please pick it instead of this.
Thank you,
On Wed, 27 Mar 2019 14:00:07 -0400 Sasha Levin sashal@kernel.org wrote:
From: Masami Hiramatsu mhiramat@kernel.org
[ Upstream commit 0eae81dc9f026d899c70f3931bf3bca6d7aa6938 ]
Prohibit probing on IRQ handlers in irqentry_text because if it interrupts user mode, at that point we haven't changed to kernel space yet and which eventually leads a double fault. E.g.
# echo p apic_timer_interrupt > kprobe_events # echo 1 > events/kprobes/enable PANIC: double fault, error_code: 0x0 CPU: 1 PID: 814 Comm: less Not tainted 4.20.0-rc3+ #30 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:error_entry+0x12/0xf0 [snip] Call Trace:
<ENTRY_TRAMPOLINE> ? native_iret+0x7/0x7 ? async_page_fault+0x8/0x30 ? trace_hardirqs_on_thunk+0x1c/0x1c ? error_entry+0x7c/0xf0 ? async_page_fault+0x8/0x30 ? native_iret+0x7/0x7 ? int3+0xa/0x20 ? trace_hardirqs_on_thunk+0x1c/0x1c ? error_entry+0x7c/0xf0 ? int3+0xa/0x20 ? apic_timer_interrupt+0x1/0x20 </ENTRY_TRAMPOLINE> Kernel panic - not syncing: Machine halted. Kernel Offset: disabled ---[ end Kernel panic - not syncing: Machine halted. ]---
Signed-off-by: Masami Hiramatsu mhiramat@kernel.org Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Andrea Righi righi.andrea@gmail.com Cc: Arnaldo Carvalho de Melo acme@redhat.com Cc: Jiri Olsa jolsa@redhat.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Mathieu Desnoyers mathieu.desnoyers@efficios.com Cc: Peter Zijlstra peterz@infradead.org Cc: Steven Rostedt rostedt@goodmis.org Cc: Thomas Gleixner tglx@linutronix.de Link: http://lkml.kernel.org/r/154998796400.31052.8406236614820687840.stgit@devbox Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org
arch/x86/kernel/kprobes/core.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 4ba75afba527..a034cb808e7e 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -1028,6 +1028,13 @@ NOKPROBE_SYMBOL(kprobe_fault_handler); int __init arch_populate_kprobe_blacklist(void) {
- int ret;
- ret = kprobe_add_area_blacklist((unsigned long)__irqentry_text_start,
(unsigned long)__irqentry_text_end);- if (ret)
return ret;- return kprobe_add_area_blacklist((unsigned long)__entry_text_start, (unsigned long)__entry_text_end);
}
2.19.1