On 3/30/22 07:46, Greg KH wrote:
On Tue, Mar 29, 2022 at 03:02:56PM -0700, Tadeusz Struk wrote:Please apply this to stable 5.10.y, and 5.15.y ---8<--- From: Kees Cook<keescook@xxxxxxxxxxxx> Upstream commit: 1a2fb220edca ("skbuff: Extract list pointers to silence compiler warnings") Under both -Warray-bounds and the object_size sanitizer, the compiler is upset about accessing prev/next of sk_buff when the object it thinks it is coming from is sk_buff_head. The warning is a false positive due to the compiler taking a conservative approach, opting to warn at casting time rather than access time. However, in support of enabling -Warray-bounds globally (which has found many real bugs), arrange things for sk_buff so that the compiler can unambiguously see that there is no intention to access anything except prev/next. Introduce and cast to a separate struct sk_buff_list, which contains_only_ the first two fields, silencing the warnings:We don't have -Warray-bounds enabled on any stable kernel tree, so why is this needed? Where is this showing up as a problem?
The issue shows up and hinders testing stable kernels in test automations like syzkaller:
https://syzkaller.appspot.com/text?tag=Error&x=12b3aac3700000 Applying it to stable would enable more test coverage. -- Thanks, Tadeusz
