| Message ID | 20221018013906.3890007-1-qiang1.zhang@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | srcu: Export srcu_check_nmi_safety() to modules | expand |
On Tue, Oct 18, 2022 at 09:39:06AM +0800, Zqiang wrote: > When enable CONFIG_PROVE_RCU and built modules, the following > error appear: > > ERROR: modpost: "srcu_check_nmi_safety" [kernel/rcu/rcutorture.ko] undefined! > ERROR: modpost: "srcu_check_nmi_safety" [kernel/rcu/rcuscale.ko] undefined! > > This commit fix it by exporting the srcu_check_nmi_safety(). > > Signed-off-by: Zqiang <qiang1.zhang@intel.com> Acked-by: Joel Fernandes (Google) <joel@joelfernandes.org> thanks, - Joel > --- > kernel/rcu/srcutree.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c > index 382236dd5e46..bcd629f5f902 100644 > --- a/kernel/rcu/srcutree.c > +++ b/kernel/rcu/srcutree.c > @@ -651,6 +651,7 @@ void srcu_check_nmi_safety(struct srcu_struct *ssp, bool nmi_safe) > } > WARN_ONCE(old_nmi_safe_mask != nmi_safe_mask, "CPU %d old state %d new state %d\n", sdp->cpu, old_nmi_safe_mask, nmi_safe_mask); > } > +EXPORT_SYMBOL_GPL(srcu_check_nmi_safety); > #endif /* CONFIG_PROVE_RCU */ > > /* > -- > 2.25.1 >
On Tue, Oct 18, 2022 at 09:39:06AM +0800, Zqiang wrote: > When enable CONFIG_PROVE_RCU and built modules, the following > error appear: > > ERROR: modpost: "srcu_check_nmi_safety" [kernel/rcu/rcutorture.ko] undefined! > ERROR: modpost: "srcu_check_nmi_safety" [kernel/rcu/rcuscale.ko] undefined! > > This commit fix it by exporting the srcu_check_nmi_safety(). > > Signed-off-by: Zqiang <qiang1.zhang@intel.com> Paul, whichever way you prefer, editing the commit or adding this one on top. Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Thanks. > --- > kernel/rcu/srcutree.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c > index 382236dd5e46..bcd629f5f902 100644 > --- a/kernel/rcu/srcutree.c > +++ b/kernel/rcu/srcutree.c > @@ -651,6 +651,7 @@ void srcu_check_nmi_safety(struct srcu_struct *ssp, bool nmi_safe) > } > WARN_ONCE(old_nmi_safe_mask != nmi_safe_mask, "CPU %d old state %d new state %d\n", sdp->cpu, old_nmi_safe_mask, nmi_safe_mask); > } > +EXPORT_SYMBOL_GPL(srcu_check_nmi_safety); > #endif /* CONFIG_PROVE_RCU */ > > /* > -- > 2.25.1 >
On Tue, Oct 18, 2022 at 12:45:33PM +0200, Frederic Weisbecker wrote: > On Tue, Oct 18, 2022 at 09:39:06AM +0800, Zqiang wrote: > > When enable CONFIG_PROVE_RCU and built modules, the following > > error appear: > > > > ERROR: modpost: "srcu_check_nmi_safety" [kernel/rcu/rcutorture.ko] undefined! > > ERROR: modpost: "srcu_check_nmi_safety" [kernel/rcu/rcuscale.ko] undefined! > > > > This commit fix it by exporting the srcu_check_nmi_safety(). > > > > Signed-off-by: Zqiang <qiang1.zhang@intel.com> > > Paul, whichever way you prefer, editing the commit or adding this > one on top. > > Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Thank you all! This is what I currently have, folded into Frederic's original. Thoughts? Thanx, Paul ------------------------------------------------------------------------ commit 88a6ff77b433f1f60af01fc94430eaad448ca491 Author: Frederic Weisbecker <frederic@kernel.org> Date: Thu Oct 13 19:22:44 2022 +0200 srcu: Debug NMI safety even on archs that don't require it Currently the NMI safety debugging is only performed on architectures that don't support NMI-safe this_cpu_inc(). Reorder the code so that other architectures like x86 also detect bad uses. [ paulmck: Apply kernel test robot, Stephen Rothwell, and Zqiang feedback. ] Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> diff --git a/include/linux/srcu.h b/include/linux/srcu.h index 565f60d574847..f0814ffca34bb 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -52,8 +52,6 @@ int init_srcu_struct(struct srcu_struct *ssp); #else /* Dummy definition for things like notifiers. Actual use gets link error. */ struct srcu_struct { }; -int __srcu_read_lock_nmisafe(struct srcu_struct *ssp, bool chknmisafe) __acquires(ssp); -void __srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx, bool chknmisafe) __releases(ssp); #endif void call_srcu(struct srcu_struct *ssp, struct rcu_head *head, @@ -66,6 +64,20 @@ unsigned long get_state_synchronize_srcu(struct srcu_struct *ssp); unsigned long start_poll_synchronize_srcu(struct srcu_struct *ssp); bool poll_state_synchronize_srcu(struct srcu_struct *ssp, unsigned long cookie); +#ifdef CONFIG_NEED_SRCU_NMI_SAFE +int __srcu_read_lock_nmisafe(struct srcu_struct *ssp) __acquires(ssp); +void __srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx) __releases(ssp); +#else +static inline int __srcu_read_lock_nmisafe(struct srcu_struct *ssp) +{ + return __srcu_read_lock(ssp); +} +static inline void __srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx) +{ + __srcu_read_unlock(ssp, idx); +} +#endif /* CONFIG_NEED_SRCU_NMI_SAFE */ + #ifdef CONFIG_SRCU void srcu_init(void); #else /* #ifdef CONFIG_SRCU */ @@ -106,6 +118,18 @@ static inline int srcu_read_lock_held(const struct srcu_struct *ssp) #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ +#define SRCU_NMI_UNKNOWN 0x0 +#define SRCU_NMI_UNSAFE 0x1 +#define SRCU_NMI_SAFE 0x2 + +#if defined(CONFIG_PROVE_RCU) && defined(CONFIG_TREE_SRCU) +void srcu_check_nmi_safety(struct srcu_struct *ssp, bool nmi_safe); +#else +static inline void srcu_check_nmi_safety(struct srcu_struct *ssp, + bool nmi_safe) { } +#endif + + /** * srcu_dereference_check - fetch SRCU-protected pointer for later dereferencing * @p: the pointer to fetch and protect for later dereferencing @@ -163,6 +187,7 @@ static inline int srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp) { int retval; + srcu_check_nmi_safety(ssp, false); retval = __srcu_read_lock(ssp); rcu_lock_acquire(&(ssp)->dep_map); return retval; @@ -179,10 +204,8 @@ static inline int srcu_read_lock_nmisafe(struct srcu_struct *ssp) __acquires(ssp { int retval; - if (IS_ENABLED(CONFIG_NEED_SRCU_NMI_SAFE)) - retval = __srcu_read_lock_nmisafe(ssp, true); - else - retval = __srcu_read_lock(ssp); + srcu_check_nmi_safety(ssp, true); + retval = __srcu_read_lock_nmisafe(ssp); rcu_lock_acquire(&(ssp)->dep_map); return retval; } @@ -193,6 +216,7 @@ srcu_read_lock_notrace(struct srcu_struct *ssp) __acquires(ssp) { int retval; + srcu_check_nmi_safety(ssp, false); retval = __srcu_read_lock(ssp); return retval; } @@ -208,6 +232,7 @@ static inline void srcu_read_unlock(struct srcu_struct *ssp, int idx) __releases(ssp) { WARN_ON_ONCE(idx & ~0x1); + srcu_check_nmi_safety(ssp, false); rcu_lock_release(&(ssp)->dep_map); __srcu_read_unlock(ssp, idx); } @@ -223,17 +248,16 @@ static inline void srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx) __releases(ssp) { WARN_ON_ONCE(idx & ~0x1); + srcu_check_nmi_safety(ssp, true); rcu_lock_release(&(ssp)->dep_map); - if (IS_ENABLED(CONFIG_NEED_SRCU_NMI_SAFE)) - __srcu_read_unlock_nmisafe(ssp, idx, true); - else - __srcu_read_unlock(ssp, idx); + __srcu_read_unlock_nmisafe(ssp, idx); } /* Used by tracing, cannot be traced and cannot call lockdep. */ static inline notrace void srcu_read_unlock_notrace(struct srcu_struct *ssp, int idx) __releases(ssp) { + srcu_check_nmi_safety(ssp, false); __srcu_read_unlock(ssp, idx); } diff --git a/include/linux/srcutiny.h b/include/linux/srcutiny.h index efd808a23f8d8..a2f620f8c5592 100644 --- a/include/linux/srcutiny.h +++ b/include/linux/srcutiny.h @@ -87,16 +87,4 @@ static inline void srcu_torture_stats_print(struct srcu_struct *ssp, data_race(READ_ONCE(ssp->srcu_lock_nesting[!idx])), data_race(READ_ONCE(ssp->srcu_lock_nesting[idx]))); } - -static inline int __srcu_read_lock_nmisafe(struct srcu_struct *ssp, bool chknmisafe) -{ - BUG(); - return 0; -} - -static inline void __srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx, bool chknmisafe) -{ - BUG(); -} - #endif diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h index 35ffdedf86ccb..c689a81752c9a 100644 --- a/include/linux/srcutree.h +++ b/include/linux/srcutree.h @@ -43,10 +43,6 @@ struct srcu_data { struct srcu_struct *ssp; }; -#define SRCU_NMI_UNKNOWN 0x0 -#define SRCU_NMI_NMI_UNSAFE 0x1 -#define SRCU_NMI_NMI_SAFE 0x2 - /* * Node in SRCU combining tree, similar in function to rcu_data. */ @@ -159,7 +155,4 @@ void synchronize_srcu_expedited(struct srcu_struct *ssp); void srcu_barrier(struct srcu_struct *ssp); void srcu_torture_stats_print(struct srcu_struct *ssp, char *tt, char *tf); -int __srcu_read_lock_nmisafe(struct srcu_struct *ssp, bool chknmisafe) __acquires(ssp); -void __srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx, bool chknmisafe) __releases(ssp); - #endif diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index 272830a87e566..ca4b5dcec675b 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -631,17 +631,16 @@ void cleanup_srcu_struct(struct srcu_struct *ssp) } EXPORT_SYMBOL_GPL(cleanup_srcu_struct); +#ifdef CONFIG_PROVE_RCU /* * Check for consistent NMI safety. */ -static void srcu_check_nmi_safety(struct srcu_struct *ssp, bool nmi_safe) +void srcu_check_nmi_safety(struct srcu_struct *ssp, bool nmi_safe) { int nmi_safe_mask = 1 << nmi_safe; int old_nmi_safe_mask; struct srcu_data *sdp; - if (!IS_ENABLED(CONFIG_PROVE_RCU)) - return; /* NMI-unsafe use in NMI is a bad sign */ WARN_ON_ONCE(!nmi_safe && in_nmi()); sdp = raw_cpu_ptr(ssp->sda); @@ -652,6 +651,8 @@ static void srcu_check_nmi_safety(struct srcu_struct *ssp, bool nmi_safe) } WARN_ONCE(old_nmi_safe_mask != nmi_safe_mask, "CPU %d old state %d new state %d\n", sdp->cpu, old_nmi_safe_mask, nmi_safe_mask); } +EXPORT_SYMBOL_GPL(srcu_check_nmi_safety); +#endif /* CONFIG_PROVE_RCU */ /* * Counts the new reader in the appropriate per-CPU element of the @@ -665,7 +666,6 @@ int __srcu_read_lock(struct srcu_struct *ssp) idx = READ_ONCE(ssp->srcu_idx) & 0x1; this_cpu_inc(ssp->sda->srcu_lock_count[idx].counter); smp_mb(); /* B */ /* Avoid leaking the critical section. */ - srcu_check_nmi_safety(ssp, false); return idx; } EXPORT_SYMBOL_GPL(__srcu_read_lock); @@ -679,7 +679,6 @@ void __srcu_read_unlock(struct srcu_struct *ssp, int idx) { smp_mb(); /* C */ /* Avoid leaking the critical section. */ this_cpu_inc(ssp->sda->srcu_unlock_count[idx].counter); - srcu_check_nmi_safety(ssp, false); } EXPORT_SYMBOL_GPL(__srcu_read_unlock); @@ -690,7 +689,7 @@ EXPORT_SYMBOL_GPL(__srcu_read_unlock); * srcu_struct, but in an NMI-safe manner using RMW atomics. * Returns an index that must be passed to the matching srcu_read_unlock(). */ -int __srcu_read_lock_nmisafe(struct srcu_struct *ssp, bool chknmisafe) +int __srcu_read_lock_nmisafe(struct srcu_struct *ssp) { int idx; struct srcu_data *sdp = raw_cpu_ptr(ssp->sda); @@ -698,8 +697,6 @@ int __srcu_read_lock_nmisafe(struct srcu_struct *ssp, bool chknmisafe) idx = READ_ONCE(ssp->srcu_idx) & 0x1; atomic_long_inc(&sdp->srcu_lock_count[idx]); smp_mb__after_atomic(); /* B */ /* Avoid leaking the critical section. */ - if (chknmisafe) - srcu_check_nmi_safety(ssp, true); return idx; } EXPORT_SYMBOL_GPL(__srcu_read_lock_nmisafe); @@ -709,14 +706,12 @@ EXPORT_SYMBOL_GPL(__srcu_read_lock_nmisafe); * element of the srcu_struct. Note that this may well be a different * CPU than that which was incremented by the corresponding srcu_read_lock(). */ -void __srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx, bool chknmisafe) +void __srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx) { struct srcu_data *sdp = raw_cpu_ptr(ssp->sda); smp_mb__before_atomic(); /* C */ /* Avoid leaking the critical section. */ atomic_long_inc(&sdp->srcu_unlock_count[idx]); - if (chknmisafe) - srcu_check_nmi_safety(ssp, true); } EXPORT_SYMBOL_GPL(__srcu_read_unlock_nmisafe); @@ -1163,7 +1158,7 @@ static unsigned long srcu_gp_start_if_needed(struct srcu_struct *ssp, * SRCU read-side critical section so that the grace-period * sequence number cannot wrap around in the meantime. */ - idx = __srcu_read_lock_nmisafe(ssp, false); + idx = __srcu_read_lock_nmisafe(ssp); ss_state = smp_load_acquire(&ssp->srcu_size_state); if (ss_state < SRCU_SIZE_WAIT_CALL) sdp = per_cpu_ptr(ssp->sda, 0); @@ -1196,7 +1191,7 @@ static unsigned long srcu_gp_start_if_needed(struct srcu_struct *ssp, srcu_funnel_gp_start(ssp, sdp, s, do_norm); else if (needexp) srcu_funnel_exp_start(ssp, sdp_mynode, s); - __srcu_read_unlock_nmisafe(ssp, idx, false); + __srcu_read_unlock_nmisafe(ssp, idx); return s; } @@ -1500,13 +1495,13 @@ void srcu_barrier(struct srcu_struct *ssp) /* Initial count prevents reaching zero until all CBs are posted. */ atomic_set(&ssp->srcu_barrier_cpu_cnt, 1); - idx = __srcu_read_lock_nmisafe(ssp, false); + idx = __srcu_read_lock_nmisafe(ssp); if (smp_load_acquire(&ssp->srcu_size_state) < SRCU_SIZE_WAIT_BARRIER) srcu_barrier_one_cpu(ssp, per_cpu_ptr(ssp->sda, 0)); else for_each_possible_cpu(cpu) srcu_barrier_one_cpu(ssp, per_cpu_ptr(ssp->sda, cpu)); - __srcu_read_unlock_nmisafe(ssp, idx, false); + __srcu_read_unlock_nmisafe(ssp, idx); /* Remove the initial count, at which point reaching zero can happen. */ if (atomic_dec_and_test(&ssp->srcu_barrier_cpu_cnt))
On Tue, Oct 18, 2022 at 1:50 PM Paul E. McKenney <paulmck@kernel.org> wrote: > > On Tue, Oct 18, 2022 at 12:45:33PM +0200, Frederic Weisbecker wrote: > > On Tue, Oct 18, 2022 at 09:39:06AM +0800, Zqiang wrote: > > > When enable CONFIG_PROVE_RCU and built modules, the following > > > error appear: > > > > > > ERROR: modpost: "srcu_check_nmi_safety" [kernel/rcu/rcutorture.ko] undefined! > > > ERROR: modpost: "srcu_check_nmi_safety" [kernel/rcu/rcuscale.ko] undefined! > > > > > > This commit fix it by exporting the srcu_check_nmi_safety(). > > > > > > Signed-off-by: Zqiang <qiang1.zhang@intel.com> > > > > Paul, whichever way you prefer, editing the commit or adding this > > one on top. > > > > Reviewed-by: Frederic Weisbecker <frederic@kernel.org> > > Thank you all! > > This is what I currently have, folded into Frederic's original. > > Thoughts? Looks good to me, has this caught any issues yet? Thanks.
diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index 382236dd5e46..bcd629f5f902 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -651,6 +651,7 @@ void srcu_check_nmi_safety(struct srcu_struct *ssp, bool nmi_safe) } WARN_ONCE(old_nmi_safe_mask != nmi_safe_mask, "CPU %d old state %d new state %d\n", sdp->cpu, old_nmi_safe_mask, nmi_safe_mask); } +EXPORT_SYMBOL_GPL(srcu_check_nmi_safety); #endif /* CONFIG_PROVE_RCU */ /*
When enable CONFIG_PROVE_RCU and built modules, the following error appear: ERROR: modpost: "srcu_check_nmi_safety" [kernel/rcu/rcutorture.ko] undefined! ERROR: modpost: "srcu_check_nmi_safety" [kernel/rcu/rcuscale.ko] undefined! This commit fix it by exporting the srcu_check_nmi_safety(). Signed-off-by: Zqiang <qiang1.zhang@intel.com> --- kernel/rcu/srcutree.c | 1 + 1 file changed, 1 insertion(+)