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SubjectRe: [PATCH 00/13] [v4] x86, pkeys: two protection keys bug fixes

* Dave Hansen <dave.hansen@linux.intel.com> wrote:

> Hi x86 maintainers,
>
> This set has been seen quite a few changes and additions since the
> last post. Details below.
>
> Changes from v3:
> * Reordered patches following Ingo's recommendations: Introduce
> failing selftests first, then the kernel code to fix the test
> failure.
> * Increase verbosity and accuracy of do_not_expect_pk_fault()
> messages.
> * Removed abort() use from tests. Crashing is not nice.
> * Remove some dead debugging code, fixing dprint_in_signal.
> * Fix deadlocks from using printf() and friends in signal
> handlers.
>
> Changes from v2:
> * Clarified commit message in patch 1/9 taking some feedback from
> Shuah.
>
> Changes from v1:
> * Added Fixes: and cc'd stable. No code changes.
>
> --
>
> This fixes two bugs, and adds selftests to make sure they stay fixed:
>
> 1. pkey 0 was not usable via mprotect_pkey() because it had never
> been explicitly allocated.
> 2. mprotect(PROT_EXEC) memory could sometimes be left with the
> implicit exec-only protection key assigned.
>
> I already posted #1 previously. I'm including them both here because
> I don't think it's been picked up in case folks want to pull these
> all in a single bundle.
>
> Dave Hansen (13):
> x86/pkeys/selftests: give better unexpected fault error messages
> x86/pkeys/selftests: Stop using assert()
> x86/pkeys/selftests: remove dead debugging code, fix dprint_in_signal
> x86/pkeys/selftests: avoid printf-in-signal deadlocks
> x86/pkeys/selftests: Allow faults on unknown keys
> x86/pkeys/selftests: Factor out "instruction page"
> x86/pkeys/selftests: Add PROT_EXEC test
> x86/pkeys/selftests: Fix pkey exhaustion test off-by-one
> x86/pkeys: Override pkey when moving away from PROT_EXEC
> x86/pkeys/selftests: Fix pointer math
> x86/pkeys/selftests: Save off 'prot' for allocations
> x86/pkeys/selftests: Add a test for pkey 0
> x86/pkeys: Do not special case protection key 0
>
> arch/x86/include/asm/mmu_context.h | 2 +-
> arch/x86/include/asm/pkeys.h | 18 +-
> arch/x86/mm/pkeys.c | 21 +-
> tools/testing/selftests/x86/pkey-helpers.h | 20 +-
> tools/testing/selftests/x86/protection_keys.c | 187 +++++++++++++-----
> 5 files changed, 173 insertions(+), 75 deletions(-)

So this series is looking good to me in principle, but trying to build it I got
warnings and errors - see the build log below.

Note that this is on a box with "Ubuntu 18.04 LTS (Bionic Beaver)".

Thanks,

Ingo

================>

gcc -m32 -o /home/mingo/tip/tools/testing/selftests/x86/protection_keys_32 -O2 -g -std=gnu99 -pthread -Wall -no-pie -DCAN_BUILD_32 -DCAN_BUILD_64 protection_keys.c -lrt -ldl -lm
protection_keys.c:232:0: warning: "SEGV_BNDERR" redefined
#define SEGV_BNDERR 3 /* failed address bound checks */

In file included from /usr/include/signal.h:58:0,
from protection_keys.c:33:
/usr/include/bits/siginfo-consts.h:117:0: note: this is the location of the previous definition
# define SEGV_BNDERR SEGV_BNDERR

protection_keys.c:233:0: warning: "SEGV_PKUERR" redefined
#define SEGV_PKUERR 4

In file included from /usr/include/signal.h:58:0,
from protection_keys.c:33:
/usr/include/bits/siginfo-consts.h:119:0: note: this is the location of the previous definition
# define SEGV_PKUERR SEGV_PKUERR

protection_keys.c:387:5: error: conflicting types for ‘pkey_get’
u32 pkey_get(int pkey, unsigned long flags)
^~~~~~~~
In file included from /usr/include/bits/mman-linux.h:115:0,
from /usr/include/bits/mman.h:45,
from /usr/include/sys/mman.h:41,
from protection_keys.c:37:
/usr/include/bits/mman-shared.h:64:5: note: previous declaration of ‘pkey_get’ was here
int pkey_get (int __key) __THROW;
^~~~~~~~
protection_keys.c:409:5: error: conflicting types for ‘pkey_set’
int pkey_set(int pkey, unsigned long rights, unsigned long flags)
^~~~~~~~
In file included from /usr/include/bits/mman-linux.h:115:0,
from /usr/include/bits/mman.h:45,
from /usr/include/sys/mman.h:41,
from protection_keys.c:37:
/usr/include/bits/mman-shared.h:60:5: note: previous declaration of ‘pkey_set’ was here
int pkey_set (int __key, unsigned int __access_rights) __THROW;
^~~~~~~~
Makefile:67: recipe for target '/home/mingo/tip/tools/testing/selftests/x86/protection_keys_32' failed
make: *** [/home/mingo/tip/tools/testing/selftests/x86/protection_keys_32] Error 1

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