Commit-ID: 881125bfe65bb772f34f4fcb04a35dfe117e186a Gitweb: https://git.kernel.org/tip/881125bfe65bb772f34f4fcb04a35dfe117e186a Author: Josh Poimboeuf <jpoim...@redhat.com> AuthorDate: Tue, 7 Nov 2017 20:19:34 -0600 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Wed, 8 Nov 2017 10:21:49 +0100
x86/unwind: Disable KASAN checking in the ORC unwinder Fengguang reported a KASAN warning: Kprobe smoke test: started ================================================================== BUG: KASAN: stack-out-of-bounds in deref_stack_reg+0xb5/0x11a Read of size 8 at addr ffff8800001c7cd8 by task swapper/1 CPU: 0 PID: 1 Comm: swapper Not tainted 4.14.0-rc8 #26 Call Trace: <#DB> ... save_trace+0xd9/0x1d3 mark_lock+0x5f7/0xdc3 __lock_acquire+0x6b4/0x38ef lock_acquire+0x1a1/0x2aa _raw_spin_lock_irqsave+0x46/0x55 kretprobe_table_lock+0x1a/0x42 pre_handler_kretprobe+0x3f5/0x521 kprobe_int3_handler+0x19c/0x25f do_int3+0x61/0x142 int3+0x30/0x60 [...] The ORC unwinder got confused by some kprobes changes, which isn't surprising since the runtime code no longer matches vmlinux and the stack was modified for kretprobes. Until we have a way for generated code to register changes with the unwinder, these types of warnings are inevitable. So just disable KASAN checks for stack accesses in the ORC unwinder. Reported-by: Fengguang Wu <fengguang...@intel.com> Signed-off-by: Josh Poimboeuf <jpoim...@redhat.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thiago Jung Bauermann <bauer...@linux.vnet.ibm.com> Cc: Thomas Gleixner <t...@linutronix.de> Link: http://lkml.kernel.org/r/20171108021934.zbl6unh5hpugybc5@treble Signed-off-by: Ingo Molnar <mi...@kernel.org> --- arch/x86/kernel/unwind_orc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c index b95007e..a3f973b 100644 --- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -279,7 +279,7 @@ static bool deref_stack_reg(struct unwind_state *state, unsigned long addr, if (!stack_access_ok(state, addr, sizeof(long))) return false; - *val = READ_ONCE_TASK_STACK(state->task, *(unsigned long *)addr); + *val = READ_ONCE_NOCHECK(*(unsigned long *)addr); return true; }
