With -fprofile-update=atomic in global CFLAGS_GCOV, GCC still cannot
constant-fold the skb_ext_total_length() loop when it is inlined into a
profiled caller. The existing __no_profile on skb_ext_total_length()
itself is insufficient because after __always_inline expansion the code
resides in the caller's body, which still carries GCOV instrumentation.
Mark skb_extensions_init() with __no_profile so the BUILD_BUG_ON checks
can be evaluated at compile time. Also mark it noinline to prevent the
compiler from inlining it into skb_init() (which lacks __no_profile),
which would re-expose the function body to GCOV instrumentation.
Add __init since skb_extensions_init() is only called from __init
skb_init(). Previously it was implicitly inlined into the .init.text
section; with noinline it would otherwise remain in permanent .text,
wasting memory after boot.
Build-tested with both CONFIG_GCOV_PROFILE_ALL=y and
CONFIG_KCOV_INSTRUMENT_ALL=y.
Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
Link: https://patch.msgid.link/20260410162150.3105738-3-khorenko@virtuozzo.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
29b1ee8788