| Message ID | 20240320101851.2589698-1-glider@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2,1/3] mm: kmsan: implement kmsan_memmove() | expand |
On Wed, 20 Mar 2024 at 03:18, Alexander Potapenko <glider@google.com> wrote: > > Provide a hook that can be used by custom memcpy implementations to tell > KMSAN that the metadata needs to be copied. Without that, false positive > reports are possible in the cases where KMSAN fails to intercept memory > initialization. Thanks, the series looks fine to me now with the updated 3/3. I assume it will go through Andrew's -mm tree? Linus
On Wed, Mar 20, 2024 at 5:05 PM Linus Torvalds <torvalds@linux-foundation.org> wrote: > > On Wed, 20 Mar 2024 at 03:18, Alexander Potapenko <glider@google.com> wrote: > > > > Provide a hook that can be used by custom memcpy implementations to tell > > KMSAN that the metadata needs to be copied. Without that, false positive > > reports are possible in the cases where KMSAN fails to intercept memory > > initialization. > > Thanks, the series looks fine to me now with the updated 3/3. > > I assume it will go through Andrew's -mm tree? > > Linus Yes, I think this makes the most sense.
On Wed, 20 Mar 2024 at 11:18, Alexander Potapenko <glider@google.com> wrote: > > Provide a hook that can be used by custom memcpy implementations to tell > KMSAN that the metadata needs to be copied. Without that, false positive > reports are possible in the cases where KMSAN fails to intercept memory > initialization. > > Link: https://lore.kernel.org/all/3b7dbd88-0861-4638-b2d2-911c97a4cadf@I-love.SAKURA.ne.jp/ > Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> > Signed-off-by: Alexander Potapenko <glider@google.com> > Cc: Dmitry Vyukov <dvyukov@google.com> > Cc: Marco Elver <elver@google.com> > Cc: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Marco Elver <elver@google.com> > --- > include/linux/kmsan-checks.h | 15 +++++++++++++++ > mm/kmsan/hooks.c | 11 +++++++++++ > 2 files changed, 26 insertions(+) > > diff --git a/include/linux/kmsan-checks.h b/include/linux/kmsan-checks.h > index c4cae333deec5..e1082dc40abc2 100644 > --- a/include/linux/kmsan-checks.h > +++ b/include/linux/kmsan-checks.h > @@ -61,6 +61,17 @@ void kmsan_check_memory(const void *address, size_t size); > void kmsan_copy_to_user(void __user *to, const void *from, size_t to_copy, > size_t left); > > +/** > + * kmsan_memmove() - Notify KMSAN about a data copy within kernel. > + * @to: destination address in the kernel. > + * @from: source address in the kernel. > + * @size: number of bytes to copy. > + * > + * Invoked after non-instrumented version (e.g. implemented using assembly > + * code) of memmove()/memcpy() is called, in order to copy KMSAN's metadata. > + */ > +void kmsan_memmove(void *to, const void *from, size_t to_copy); > + > #else > > static inline void kmsan_poison_memory(const void *address, size_t size, > @@ -78,6 +89,10 @@ static inline void kmsan_copy_to_user(void __user *to, const void *from, > { > } > > +static inline void kmsan_memmove(void *to, const void *from, size_t to_copy) > +{ > +} > + > #endif > > #endif /* _LINUX_KMSAN_CHECKS_H */ > diff --git a/mm/kmsan/hooks.c b/mm/kmsan/hooks.c > index 5d6e2dee5692a..364f778ee226d 100644 > --- a/mm/kmsan/hooks.c > +++ b/mm/kmsan/hooks.c > @@ -285,6 +285,17 @@ void kmsan_copy_to_user(void __user *to, const void *from, size_t to_copy, > } > EXPORT_SYMBOL(kmsan_copy_to_user); > > +void kmsan_memmove(void *to, const void *from, size_t size) > +{ > + if (!kmsan_enabled || kmsan_in_runtime()) > + return; > + > + kmsan_enter_runtime(); > + kmsan_internal_memmove_metadata(to, (void *)from, size); > + kmsan_leave_runtime(); > +} > +EXPORT_SYMBOL(kmsan_memmove); > + > /* Helper function to check an URB. */ > void kmsan_handle_urb(const struct urb *urb, bool is_out) > { > -- > 2.44.0.291.gc1ea87d7ee-goog >
diff --git a/include/linux/kmsan-checks.h b/include/linux/kmsan-checks.h index c4cae333deec5..e1082dc40abc2 100644 --- a/include/linux/kmsan-checks.h +++ b/include/linux/kmsan-checks.h @@ -61,6 +61,17 @@ void kmsan_check_memory(const void *address, size_t size); void kmsan_copy_to_user(void __user *to, const void *from, size_t to_copy, size_t left); +/** + * kmsan_memmove() - Notify KMSAN about a data copy within kernel. + * @to: destination address in the kernel. + * @from: source address in the kernel. + * @size: number of bytes to copy. + * + * Invoked after non-instrumented version (e.g. implemented using assembly + * code) of memmove()/memcpy() is called, in order to copy KMSAN's metadata. + */ +void kmsan_memmove(void *to, const void *from, size_t to_copy); + #else static inline void kmsan_poison_memory(const void *address, size_t size, @@ -78,6 +89,10 @@ static inline void kmsan_copy_to_user(void __user *to, const void *from, { } +static inline void kmsan_memmove(void *to, const void *from, size_t to_copy) +{ +} + #endif #endif /* _LINUX_KMSAN_CHECKS_H */ diff --git a/mm/kmsan/hooks.c b/mm/kmsan/hooks.c index 5d6e2dee5692a..364f778ee226d 100644 --- a/mm/kmsan/hooks.c +++ b/mm/kmsan/hooks.c @@ -285,6 +285,17 @@ void kmsan_copy_to_user(void __user *to, const void *from, size_t to_copy, } EXPORT_SYMBOL(kmsan_copy_to_user); +void kmsan_memmove(void *to, const void *from, size_t size) +{ + if (!kmsan_enabled || kmsan_in_runtime()) + return; + + kmsan_enter_runtime(); + kmsan_internal_memmove_metadata(to, (void *)from, size); + kmsan_leave_runtime(); +} +EXPORT_SYMBOL(kmsan_memmove); + /* Helper function to check an URB. */ void kmsan_handle_urb(const struct urb *urb, bool is_out) {
Provide a hook that can be used by custom memcpy implementations to tell KMSAN that the metadata needs to be copied. Without that, false positive reports are possible in the cases where KMSAN fails to intercept memory initialization. Link: https://lore.kernel.org/all/3b7dbd88-0861-4638-b2d2-911c97a4cadf@I-love.SAKURA.ne.jp/ Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Marco Elver <elver@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> --- include/linux/kmsan-checks.h | 15 +++++++++++++++ mm/kmsan/hooks.c | 11 +++++++++++ 2 files changed, 26 insertions(+)