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From: Kees Cook <keescook@chromium.org>
To: kernel test robot <oliver.sang@intel.com>
Cc: oe-lkp@lists.linux.dev, lkp@intel.com,
	Linux Memory Management List <linux-mm@kvack.org>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Nicolas Schier <nicolas@fjasle.eu>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	linux-kbuild@vger.kernel.org, llvm@lists.linux.dev,
	linux-hardening@vger.kernel.org
Subject: Re: [linux-next:master] [kbuild]  df8fc4e934: BUG:unable_to_handle_page_fault_for_address
Date: Tue, 13 Jun 2023 13:46:54 -0700	[thread overview]
Message-ID: <202306131342.51A51F651C@keescook> (raw)
In-Reply-To: <202306102333.8f5a7443-oliver.sang@intel.com>

On Sun, Jun 11, 2023 at 09:41:30PM +0800, kernel test robot wrote:
> the issue we found below is by clang-15, but we confirmed clang-15 we use is
> commit 8dfdcc7b7b in llvm-project. it supports the flag already.

Interesting! Thanks for the report.

> [  228.605608][    C1] BUG: unable to handle page fault for address: 04090300
> [...]
> [ 228.608262][ C1] EIP: string (lib/vsprintf.c:644 lib/vsprintf.c:726) 
> [...]
> [ 228.608262][ C1] Call Trace:
> [ 228.608262][ C1]  <SOFTIRQ>
> [ 228.608262][ C1] vsnprintf (lib/vsprintf.c:2817) 
> [ 228.608262][ C1] vprintk_store (kernel/printk/printk.c:2191) 
> [ 228.608262][ C1] vprintk_emit (kernel/printk/printk.c:2288) 
> [ 228.608262][ C1] vprintk_default (kernel/printk/printk.c:2318) 
> [ 228.608262][ C1] vprintk (kernel/printk/printk_safe.c:50) 
> [ 228.608262][ C1] _printk (kernel/printk/printk.c:2331) 
> [ 228.608262][ C1] __ubsan_handle_out_of_bounds (lib/ubsan.c:209 lib/ubsan.c:343) 

This is a crash within the UBSAN handler! That's very unexpected.

> [ 228.608262][ C1] get_string (drivers/usb/gadget/composite.c:1314) 
> [ 228.608262][ C1] composite_setup (drivers/usb/gadget/composite.c:1871) 
> [ 228.608262][ C1] dummy_timer (drivers/usb/gadget/udc/dummy_hcd.c:?) 

And the out-of-bounds condition got triggered in dummy_hcd.

I also see this is happening in SOFTIRQ context. I wonder if there is a
problem with UBSAN vs SOFTIRQ. Again, I'd find that surprising...

I'll see what I can find...

-- 
Kees Cook


  reply	other threads:[~2023-06-13 20:46 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-11 13:41 kernel test robot
2023-06-13 20:46 ` Kees Cook [this message]
2023-06-13 20:58   ` Kees Cook

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