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dkim=pass header.d=infradead.org header.s=desiato.20200630 header.b="S/lY5GPt"; spf=none (imf06.hostedemail.com: domain of peterz@infradead.org has no SPF policy when checking 90.155.92.199) smtp.mailfrom=peterz@infradead.org; dmarc=none X-Stat-Signature: pjg8xkp4n1xdf7t638se6mpqwr9cdg6o X-Rspamd-Queue-Id: 4F0C418003C X-Rspamd-Server: rspam07 X-Rspam-User: X-HE-Tag: 1666776663-244375 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Oct 26, 2022 at 12:17:55AM +0200, Alexander Potapenko wrote: > Make sure usercopy hooks from linux/instrumented.h are invoked for > copy_from_user_nmi(). > This fixes KMSAN false positives reported when dumping opcodes for a > stack trace. > > Cc: Andrew Morton > Cc: Dave Hansen > Cc: Kees Cook > Cc: x86@kernel.org > Signed-off-by: Alexander Potapenko > --- > arch/x86/lib/usercopy.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/x86/lib/usercopy.c b/arch/x86/lib/usercopy.c > index f1bb186171562..24b48af274173 100644 > --- a/arch/x86/lib/usercopy.c > +++ b/arch/x86/lib/usercopy.c > @@ -6,6 +6,7 @@ > > #include > #include > +#include > > #include > > @@ -44,7 +45,9 @@ copy_from_user_nmi(void *to, const void __user *from, unsigned long n) > * called from other contexts. > */ > pagefault_disable(); > + instrument_copy_from_user_before(to, from, n); > ret = raw_copy_from_user(to, from, n); > + instrument_copy_from_user_after(to, from, n, ret); > pagefault_enable(); > > return ret; Is all that instrumentation NMI safe? ISTR having seen locks in some of that *SAN stuff. Also did this want: Fixes: 59298997df89 ("x86/uaccess: avoid check_object_size() in copy_from_user_nmi()") ?