ACK: [SRU][N][PATCH 0/1] Noble kernel 6.8.0-108 does not compile when KASAN enabled

[Masahiro Yamada]

On 3/20/26 00:14, Massimiliano Pellizzer wrote:
> BugLink: https://bugs.launchpad.net/bugs/2144914
>
> [ Impact ]
>
> When trying to compile Noble’s kernel 6.8.0-108 with KASAN enabled the following compile-time error appears:
>
> /build/noble/mm/kasan/common.c: In function '__kasan_unpoison_vmap_areas':
> /build/noble/mm/kasan/common.c:566:34: error: 'KASAN_VMALLOC_KEEP_TAG' undeclared (first use in this function); did you mean 'KASAN_VMALLOC_INIT'?
>    566 | if (WARN_ON_ONCE(flags & KASAN_VMALLOC_KEEP_TAG))
>        | ^~~~~~~~~~~~~~~~~~~~~~
> /build/noble/include/asm-generic/bug.h:111:32: note: in definition of macro 'WARN_ON_ONCE'
>    111 | int __ret_warn_on = !!(condition); \
>        | ^~~~~~~~~
> /build/noble/mm/kasan/common.c:566:34: note: each undeclared identifier is reported only once for each function it appears in
>    566 | if (WARN_ON_ONCE(flags & KASAN_VMALLOC_KEEP_TAG))
>        | ^~~~~~~~~~~~~~~~~~~~~~
> /build/noble/include/asm-generic/bug.h:111:32: note: in definition of macro 'WARN_ON_ONCE'
>    111 | int __ret_warn_on = !!(condition); \
>        | ^~~~~~~~~
>    CC [M] samples/ftrace/ftrace-direct-too.o
>
> [ Fix ]
>
> The error is due to an upstream stable update which missed the very first commit of the patchset:
> - https://lore.kernel.org/all/a2a1889754be3d97b8919cb2d3d099d12461f814.1765978969.git.m.wieczorretman@pm.me/T/#u
>
> To fix it, it is necessary to backport
> - 007f5da43b3d (“mm/kasan: fix incorrect unpoisoning in vrealloc for KASAN”).
>
> [ Test Case ]
>
> Compile the kernel with KASAN enabled.
>
> [ Regression Potential ]
>
> No regression potential. The kernel is already
> not compiling with kasan enabled.
> The fix allows the kernel to compile correctly.
>
>
> Jiayuan Chen (1):
>    mm/kasan: fix incorrect unpoisoning in vrealloc for KASAN
>
>   include/linux/kasan.h | 1 +
>   mm/kasan/hw_tags.c    | 2 +-
>   mm/kasan/shadow.c     | 4 +++-
>   3 files changed, 5 insertions(+), 2 deletions(-)
>

Acked-by: Masahiro Yamada <masahiro.yamada at canonical.com>