RE: [PATCH 02/11] x86: tboot: avoid Wstringop-overread-warning

2021-03-24 Thread David Laight
From: David Laight > Sent: 24 March 2021 09:12 > > From: Martin Sebor > > Sent: 22 March 2021 22:08 > ... > > In GCC 11, all access warnings expect objects to be either declared > > or allocated. Pointers with constant values are taken to point to > > nothing valid (as Arnd mentioned above, this

RE: [PATCH 02/11] x86: tboot: avoid Wstringop-overread-warning

2021-03-24 Thread David Laight
From: Martin Sebor > Sent: 22 March 2021 22:08 ... > In GCC 11, all access warnings expect objects to be either declared > or allocated. Pointers with constant values are taken to point to > nothing valid (as Arnd mentioned above, this is to detect invalid > accesses to members of structs at

Re: [PATCH 02/11] x86: tboot: avoid Wstringop-overread-warning

2021-03-22 Thread Ingo Molnar
* Martin Sebor wrote: > > I.e. the real workaround might be to turn off the > > -Wstringop-overread-warning, > > until GCC-11 gets fixed? > > In GCC 10 -Wstringop-overread is a subset of -Wstringop-overflow. > GCC 11 breaks it out as a separate warning to make it easier to > control. Both

Re: [PATCH 02/11] x86: tboot: avoid Wstringop-overread-warning

2021-03-22 Thread Arnd Bergmann
On Mon, Mar 22, 2021 at 11:09 PM Martin Sebor wrote: > On 3/22/21 2:29 PM, Ingo Molnar wrote: > > * Arnd Bergmann wrote: > > > > I.e. the real workaround might be to turn off the > > -Wstringop-overread-warning, > > until GCC-11 gets fixed? > > In GCC 10 -Wstringop-overread is a subset of

Re: [PATCH 02/11] x86: tboot: avoid Wstringop-overread-warning

2021-03-22 Thread Martin Sebor
On 3/22/21 2:29 PM, Ingo Molnar wrote: * Arnd Bergmann wrote: From: Arnd Bergmann gcc-11 warns about using string operations on pointers that are defined at compile time as offsets from a NULL pointer. Unfortunately that also happens on the result of fix_to_virt(), which is a compile-time

Re: [PATCH 02/11] x86: tboot: avoid Wstringop-overread-warning

2021-03-22 Thread Arnd Bergmann
On Mon, Mar 22, 2021 at 9:29 PM Ingo Molnar wrote: > * Arnd Bergmann wrote: > > From: Arnd Bergmann > This is indeed rather ugly - and the other patch that removes a debug > check seems counterproductive as well. > > Do we know how many genuine bugs -Wstringop-overread-warning has > caught or

Re: [PATCH 02/11] x86: tboot: avoid Wstringop-overread-warning

2021-03-22 Thread Ingo Molnar
* Arnd Bergmann wrote: > From: Arnd Bergmann > > gcc-11 warns about using string operations on pointers that are > defined at compile time as offsets from a NULL pointer. Unfortunately > that also happens on the result of fix_to_virt(), which is a > compile-time constant for a constantn

[PATCH 02/11] x86: tboot: avoid Wstringop-overread-warning

2021-03-22 Thread Arnd Bergmann
From: Arnd Bergmann gcc-11 warns about using string operations on pointers that are defined at compile time as offsets from a NULL pointer. Unfortunately that also happens on the result of fix_to_virt(), which is a compile-time constant for a constantn input: arch/x86/kernel/tboot.c: In