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H A D | Kconfig | diff e29aad08b1da7772b362537be32335c0394e65fe Mon Oct 09 17:13:48 CEST 2023 Uros Bizjak <ubizjak@gmail.com> x86/percpu: Disable named address spaces for KASAN
-fsanitize=kernel-address (KASAN) is at the moment incompatible with named address spaces - see GCC PR sanitizer/111736:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111736
GCC is doing a KASAN check on a percpu address which it shouldn't do, and didn't used to do because we did the access using inline asm.
But now that GCC does the accesses as normal (albeit special address space) memory accesses, the KASAN code triggers on them too, and it all goes to hell in a handbasket very quickly.
Those percpu accessor functions need to disable any KASAN checking or other sanitizer checking. Not on the percpu address, because that's not a "real" address, it's obviously just the offset from the segment register.
And GCC should probably not have generated such code in the first place, so arguably this is a bug with -fsanitize=kernel-address.
The patch also removes a stale dependency on CONFIG_SMP.
Reported-by: kernel test robot <oliver.sang@intel.com> Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20231009151409.53656-1-ubizjak@gmail.com
Closes: https://lore.kernel.org/oe-lkp/202310071301.a5113890-oliver.sang@intel.com
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