diff mbox series

rcu: tiny: record kvfree_call_rcu() call stack for KASAN

Message ID 20220527170743.04c21d235467.I1f79da0f90fb9b557ec34932136c656bc64b8fbf@changeid (mailing list archive)
State Accepted
Commit 393c712686b22968aa190a665bc81411dced71f8
Headers show
Series rcu: tiny: record kvfree_call_rcu() call stack for KASAN | expand

Commit Message

Johannes Berg May 27, 2022, 3:07 p.m. UTC
From: Johannes Berg <johannes.berg@intel.com>

When running KASAN with Tiny RCU (e.g. under ARCH=um, where
a working KASAN patch is now available), we don't get any
information on the original kfree_rcu() (or similar) caller
when a problem is reported, as Tiny RCU doesn't record this.

Add the recording, which required pulling kvfree_call_rcu()
out of line for the KASAN case since the recording function
(kasan_record_aux_stack_noalloc) is neither exported, nor
can we include kasan.h into rcutiny.h.

without KASAN, the patch has no size impact (ARCH=um kernel):
    text       data         bss         dec        hex    filename
 6151515    4423154    33148520    43723189    29b29b5    linux
 6151515    4423154    33148520    43723189    29b29b5    linux + patch

with KASAN, the impact on my build was minimal:
    text       data         bss         dec        hex    filename
13915539    7388050    33282304    54585893    340ea25    linux
13911266    7392114    33282304    54585684    340e954    linux + patch
   -4273      +4064         +-0        -209

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 include/linux/rcutiny.h | 11 ++++++++++-
 kernel/rcu/tiny.c       | 14 ++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

Comments

Dmitry Vyukov May 27, 2022, 3:13 p.m. UTC | #1
On Fri, 27 May 2022 at 17:07, Johannes Berg <johannes@sipsolutions.net> wrote:
>
> From: Johannes Berg <johannes.berg@intel.com>
>
> When running KASAN with Tiny RCU (e.g. under ARCH=um, where
> a working KASAN patch is now available), we don't get any
> information on the original kfree_rcu() (or similar) caller
> when a problem is reported, as Tiny RCU doesn't record this.
>
> Add the recording, which required pulling kvfree_call_rcu()
> out of line for the KASAN case since the recording function
> (kasan_record_aux_stack_noalloc) is neither exported, nor
> can we include kasan.h into rcutiny.h.
>
> without KASAN, the patch has no size impact (ARCH=um kernel):
>     text       data         bss         dec        hex    filename
>  6151515    4423154    33148520    43723189    29b29b5    linux
>  6151515    4423154    33148520    43723189    29b29b5    linux + patch
>
> with KASAN, the impact on my build was minimal:
>     text       data         bss         dec        hex    filename
> 13915539    7388050    33282304    54585893    340ea25    linux
> 13911266    7392114    33282304    54585684    340e954    linux + patch
>    -4273      +4064         +-0        -209
>
> Signed-off-by: Johannes Berg <johannes.berg@intel.com>

From KASAN perspective:

Acked-by: Dmitry Vyukov <dvyukov@google.com>

What tree should it go into? mm? rcu? +Paul

> ---
>  include/linux/rcutiny.h | 11 ++++++++++-
>  kernel/rcu/tiny.c       | 14 ++++++++++++++
>  2 files changed, 24 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
> index 5fed476f977f..d84e13f2c384 100644
> --- a/include/linux/rcutiny.h
> +++ b/include/linux/rcutiny.h
> @@ -38,7 +38,7 @@ static inline void synchronize_rcu_expedited(void)
>   */
>  extern void kvfree(const void *addr);
>
> -static inline void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> +static inline void __kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
>  {
>         if (head) {
>                 call_rcu(head, func);
> @@ -51,6 +51,15 @@ static inline void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
>         kvfree((void *) func);
>  }
>
> +#ifdef CONFIG_KASAN_GENERIC
> +void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func);
> +#else
> +static inline void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> +{
> +       __kvfree_call_rcu(head, func);
> +}
> +#endif
> +
>  void rcu_qs(void);
>
>  static inline void rcu_softirq_qs(void)
> diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
> index 340b3f8b090d..58ff3721d975 100644
> --- a/kernel/rcu/tiny.c
> +++ b/kernel/rcu/tiny.c
> @@ -217,6 +217,20 @@ bool poll_state_synchronize_rcu(unsigned long oldstate)
>  }
>  EXPORT_SYMBOL_GPL(poll_state_synchronize_rcu);
>
> +#ifdef CONFIG_KASAN_GENERIC
> +void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> +{
> +       if (head) {
> +               void *ptr = (void *) head - (unsigned long) func;
> +
> +               kasan_record_aux_stack_noalloc(ptr);
> +       }
> +
> +       __kvfree_call_rcu(head, func);
> +}
> +EXPORT_SYMBOL_GPL(kvfree_call_rcu);
> +#endif
> +
>  void __init rcu_init(void)
>  {
>         open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
> --
> 2.36.1
>
> --
> You received this message because you are subscribed to the Google Groups "kasan-dev" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to kasan-dev+unsubscribe@googlegroups.com.
> To view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/20220527170743.04c21d235467.I1f79da0f90fb9b557ec34932136c656bc64b8fbf%40changeid.
Paul E. McKenney May 27, 2022, 3:24 p.m. UTC | #2
On Fri, May 27, 2022 at 05:13:18PM +0200, Dmitry Vyukov wrote:
> On Fri, 27 May 2022 at 17:07, Johannes Berg <johannes@sipsolutions.net> wrote:
> >
> > From: Johannes Berg <johannes.berg@intel.com>
> >
> > When running KASAN with Tiny RCU (e.g. under ARCH=um, where
> > a working KASAN patch is now available), we don't get any
> > information on the original kfree_rcu() (or similar) caller
> > when a problem is reported, as Tiny RCU doesn't record this.
> >
> > Add the recording, which required pulling kvfree_call_rcu()
> > out of line for the KASAN case since the recording function
> > (kasan_record_aux_stack_noalloc) is neither exported, nor
> > can we include kasan.h into rcutiny.h.
> >
> > without KASAN, the patch has no size impact (ARCH=um kernel):
> >     text       data         bss         dec        hex    filename
> >  6151515    4423154    33148520    43723189    29b29b5    linux
> >  6151515    4423154    33148520    43723189    29b29b5    linux + patch
> >
> > with KASAN, the impact on my build was minimal:
> >     text       data         bss         dec        hex    filename
> > 13915539    7388050    33282304    54585893    340ea25    linux
> > 13911266    7392114    33282304    54585684    340e954    linux + patch
> >    -4273      +4064         +-0        -209
> >
> > Signed-off-by: Johannes Berg <johannes.berg@intel.com>
> 
> >From KASAN perspective:
> 
> Acked-by: Dmitry Vyukov <dvyukov@google.com>
> 
> What tree should it go into? mm? rcu? +Paul

If Johannes is johill on IRC, I already agreed to take it.  If not,
we might have dueling patches.

Ah, "Berg" -> "Hill".  I never would have figured that out without
this hint.  ;-)

							Thanx, Paul

> > ---
> >  include/linux/rcutiny.h | 11 ++++++++++-
> >  kernel/rcu/tiny.c       | 14 ++++++++++++++
> >  2 files changed, 24 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
> > index 5fed476f977f..d84e13f2c384 100644
> > --- a/include/linux/rcutiny.h
> > +++ b/include/linux/rcutiny.h
> > @@ -38,7 +38,7 @@ static inline void synchronize_rcu_expedited(void)
> >   */
> >  extern void kvfree(const void *addr);
> >
> > -static inline void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> > +static inline void __kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> >  {
> >         if (head) {
> >                 call_rcu(head, func);
> > @@ -51,6 +51,15 @@ static inline void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> >         kvfree((void *) func);
> >  }
> >
> > +#ifdef CONFIG_KASAN_GENERIC
> > +void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func);
> > +#else
> > +static inline void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> > +{
> > +       __kvfree_call_rcu(head, func);
> > +}
> > +#endif
> > +
> >  void rcu_qs(void);
> >
> >  static inline void rcu_softirq_qs(void)
> > diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
> > index 340b3f8b090d..58ff3721d975 100644
> > --- a/kernel/rcu/tiny.c
> > +++ b/kernel/rcu/tiny.c
> > @@ -217,6 +217,20 @@ bool poll_state_synchronize_rcu(unsigned long oldstate)
> >  }
> >  EXPORT_SYMBOL_GPL(poll_state_synchronize_rcu);
> >
> > +#ifdef CONFIG_KASAN_GENERIC
> > +void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> > +{
> > +       if (head) {
> > +               void *ptr = (void *) head - (unsigned long) func;
> > +
> > +               kasan_record_aux_stack_noalloc(ptr);
> > +       }
> > +
> > +       __kvfree_call_rcu(head, func);
> > +}
> > +EXPORT_SYMBOL_GPL(kvfree_call_rcu);
> > +#endif
> > +
> >  void __init rcu_init(void)
> >  {
> >         open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
> > --
> > 2.36.1
> >
> > --
> > You received this message because you are subscribed to the Google Groups "kasan-dev" group.
> > To unsubscribe from this group and stop receiving emails from it, send an email to kasan-dev+unsubscribe@googlegroups.com.
> > To view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/20220527170743.04c21d235467.I1f79da0f90fb9b557ec34932136c656bc64b8fbf%40changeid.
Paul E. McKenney May 28, 2022, 11:52 p.m. UTC | #3
On Fri, May 27, 2022 at 08:24:03AM -0700, Paul E. McKenney wrote:
> On Fri, May 27, 2022 at 05:13:18PM +0200, Dmitry Vyukov wrote:
> > On Fri, 27 May 2022 at 17:07, Johannes Berg <johannes@sipsolutions.net> wrote:
> > >
> > > From: Johannes Berg <johannes.berg@intel.com>
> > >
> > > When running KASAN with Tiny RCU (e.g. under ARCH=um, where
> > > a working KASAN patch is now available), we don't get any
> > > information on the original kfree_rcu() (or similar) caller
> > > when a problem is reported, as Tiny RCU doesn't record this.
> > >
> > > Add the recording, which required pulling kvfree_call_rcu()
> > > out of line for the KASAN case since the recording function
> > > (kasan_record_aux_stack_noalloc) is neither exported, nor
> > > can we include kasan.h into rcutiny.h.
> > >
> > > without KASAN, the patch has no size impact (ARCH=um kernel):
> > >     text       data         bss         dec        hex    filename
> > >  6151515    4423154    33148520    43723189    29b29b5    linux
> > >  6151515    4423154    33148520    43723189    29b29b5    linux + patch
> > >
> > > with KASAN, the impact on my build was minimal:
> > >     text       data         bss         dec        hex    filename
> > > 13915539    7388050    33282304    54585893    340ea25    linux
> > > 13911266    7392114    33282304    54585684    340e954    linux + patch
> > >    -4273      +4064         +-0        -209
> > >
> > > Signed-off-by: Johannes Berg <johannes.berg@intel.com>
> > 
> > >From KASAN perspective:
> > 
> > Acked-by: Dmitry Vyukov <dvyukov@google.com>
> > 
> > What tree should it go into? mm? rcu? +Paul
> 
> If Johannes is johill on IRC, I already agreed to take it.  If not,
> we might have dueling patches.
> 
> Ah, "Berg" -> "Hill".  I never would have figured that out without
> this hint.  ;-)

And applied with Dmitry's ack.  It will show up on -rcu after my next
rebase.

							Thanx, Paul

> > > ---
> > >  include/linux/rcutiny.h | 11 ++++++++++-
> > >  kernel/rcu/tiny.c       | 14 ++++++++++++++
> > >  2 files changed, 24 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
> > > index 5fed476f977f..d84e13f2c384 100644
> > > --- a/include/linux/rcutiny.h
> > > +++ b/include/linux/rcutiny.h
> > > @@ -38,7 +38,7 @@ static inline void synchronize_rcu_expedited(void)
> > >   */
> > >  extern void kvfree(const void *addr);
> > >
> > > -static inline void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> > > +static inline void __kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> > >  {
> > >         if (head) {
> > >                 call_rcu(head, func);
> > > @@ -51,6 +51,15 @@ static inline void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> > >         kvfree((void *) func);
> > >  }
> > >
> > > +#ifdef CONFIG_KASAN_GENERIC
> > > +void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func);
> > > +#else
> > > +static inline void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> > > +{
> > > +       __kvfree_call_rcu(head, func);
> > > +}
> > > +#endif
> > > +
> > >  void rcu_qs(void);
> > >
> > >  static inline void rcu_softirq_qs(void)
> > > diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
> > > index 340b3f8b090d..58ff3721d975 100644
> > > --- a/kernel/rcu/tiny.c
> > > +++ b/kernel/rcu/tiny.c
> > > @@ -217,6 +217,20 @@ bool poll_state_synchronize_rcu(unsigned long oldstate)
> > >  }
> > >  EXPORT_SYMBOL_GPL(poll_state_synchronize_rcu);
> > >
> > > +#ifdef CONFIG_KASAN_GENERIC
> > > +void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> > > +{
> > > +       if (head) {
> > > +               void *ptr = (void *) head - (unsigned long) func;
> > > +
> > > +               kasan_record_aux_stack_noalloc(ptr);
> > > +       }
> > > +
> > > +       __kvfree_call_rcu(head, func);
> > > +}
> > > +EXPORT_SYMBOL_GPL(kvfree_call_rcu);
> > > +#endif
> > > +
> > >  void __init rcu_init(void)
> > >  {
> > >         open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
> > > --
> > > 2.36.1
> > >
> > > --
> > > You received this message because you are subscribed to the Google Groups "kasan-dev" group.
> > > To unsubscribe from this group and stop receiving emails from it, send an email to kasan-dev+unsubscribe@googlegroups.com.
> > > To view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/20220527170743.04c21d235467.I1f79da0f90fb9b557ec34932136c656bc64b8fbf%40changeid.
diff mbox series

Patch

diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index 5fed476f977f..d84e13f2c384 100644
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -38,7 +38,7 @@  static inline void synchronize_rcu_expedited(void)
  */
 extern void kvfree(const void *addr);
 
-static inline void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
+static inline void __kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
 {
 	if (head) {
 		call_rcu(head, func);
@@ -51,6 +51,15 @@  static inline void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
 	kvfree((void *) func);
 }
 
+#ifdef CONFIG_KASAN_GENERIC
+void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func);
+#else
+static inline void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
+{
+	__kvfree_call_rcu(head, func);
+}
+#endif
+
 void rcu_qs(void);
 
 static inline void rcu_softirq_qs(void)
diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
index 340b3f8b090d..58ff3721d975 100644
--- a/kernel/rcu/tiny.c
+++ b/kernel/rcu/tiny.c
@@ -217,6 +217,20 @@  bool poll_state_synchronize_rcu(unsigned long oldstate)
 }
 EXPORT_SYMBOL_GPL(poll_state_synchronize_rcu);
 
+#ifdef CONFIG_KASAN_GENERIC
+void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
+{
+	if (head) {
+		void *ptr = (void *) head - (unsigned long) func;
+
+		kasan_record_aux_stack_noalloc(ptr);
+	}
+
+	__kvfree_call_rcu(head, func);
+}
+EXPORT_SYMBOL_GPL(kvfree_call_rcu);
+#endif
+
 void __init rcu_init(void)
 {
 	open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);