答复: [????] Re: ??: [PATCH][v2] x86/sgx: Use list_for_each_entry_srcu() for mm_list traversal

答复: [????] Re: ??: [PATCH][v2] x86/sgx: Use list_for_each_entry_srcu() for mm_list traversal

[Li,Rongqing(ACG CCN)]

> On Tue, Apr 14, 2026 at 07:47:54AM +0000, Li,Rongqing(ACG CCN) wrote:
> >
> >
> > > From: Li RongQing <lirongqing@baidu.com>
> > >
> > > In commit 1728ab54b4be ("x86/sgx: Add a page reclaimer") (v5.11),
> > > list_for_each_entry_rcu() was used to traverse the enclave's mm_list.
> > > However, this is incorrect because the list is protected by a
> > > Sleepable RCU (SRCU) lock (encl->srcu).
> > >
> > > Since commit 28875945ba98 ("rcu: Add support for consolidated-RCU
> > > reader
> > > checking") (v5.4), RCU lockdep checking has become stricter. When
> > > CONFIG_PROVE_RCU is enabled, using the standard
> > > list_for_each_entry_rcu() while only holding an SRCU lock triggers
> > > "suspicious RCU usage" false positive warnings, as it does not recognize SRCU
> read-side critical sections.
> > >
> > > Fix this by switching to list_for_each_entry_srcu(), which was
> > > introduced specifically for this purpose in commit ae2212a7216b
> > > ("rculist: Introduce list/hlist_for_each_entry_srcu() macros") (v5.10).
> > > This correctly associates the traversal with the SRCU lock and
> > > eliminates the lockdep warnings.
> > >
> > > Fixes: 1728ab54b4be ("x86/sgx: Add a page reclaimer")
> > > Signed-off-by: Li RongQing <lirongqing@baidu.com>
> > > Acked-by: Kai Huang <kai.huang@intel.com>
> > > ---
> >
> > Ping
> >
> > thanks
> >
> > [Li,Rongqing]
> >
> >
> >
> > > Diff with v1: rewrite changelog
> > >
> > >  arch/x86/kernel/cpu/sgx/encl.c | 12 ++++++++----
> > > arch/x86/kernel/cpu/sgx/main.c |  3 ++-
> > >  2 files changed, 10 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/arch/x86/kernel/cpu/sgx/encl.c
> > > b/arch/x86/kernel/cpu/sgx/encl.c index ac60ebd..91362d7 100644
> > > --- a/arch/x86/kernel/cpu/sgx/encl.c
> > > +++ b/arch/x86/kernel/cpu/sgx/encl.c
> > > @@ -822,7 +822,8 @@ static struct sgx_encl_mm
> > > *sgx_encl_find_mm(struct sgx_encl *encl,
> > >
> > >  	idx = srcu_read_lock(&encl->srcu);
> > >
> > > -	list_for_each_entry_rcu(tmp, &encl->mm_list, list) {
> > > +	list_for_each_entry_srcu(tmp, &encl->mm_list, list,
> > > +			srcu_read_lock_held(&encl->srcu)) {
> > >  		if (tmp->mm == mm) {
> > >  			encl_mm = tmp;
> > >  			break;
> > > @@ -933,7 +934,8 @@ const cpumask_t *sgx_encl_cpumask(struct
> > > sgx_encl
> > > *encl)
> > >
> > >  	idx = srcu_read_lock(&encl->srcu);
> > >
> > > -	list_for_each_entry_rcu(encl_mm, &encl->mm_list, list) {
> > > +	list_for_each_entry_srcu(encl_mm, &encl->mm_list, list,
> > > +			srcu_read_lock_held(&encl->srcu)) {
> > >  		if (!mmget_not_zero(encl_mm->mm))
> > >  			continue;
> > >
> > > @@ -1018,7 +1020,8 @@ static struct mem_cgroup
> > > *sgx_encl_get_mem_cgroup(struct sgx_encl *encl)
> > >  	 */
> > >  	idx = srcu_read_lock(&encl->srcu);
> > >
> > > -	list_for_each_entry_rcu(encl_mm, &encl->mm_list, list) {
> > > +	list_for_each_entry_srcu(encl_mm, &encl->mm_list, list,
> > > +			srcu_read_lock_held(&encl->srcu)) {
> > >  		if (!mmget_not_zero(encl_mm->mm))
> > >  			continue;
> > >
> > > @@ -1212,7 +1215,8 @@ void sgx_zap_enclave_ptes(struct sgx_encl
> > > *encl, unsigned long addr)
> > >
> > >  		idx = srcu_read_lock(&encl->srcu);
> > >
> > > -		list_for_each_entry_rcu(encl_mm, &encl->mm_list, list) {
> > > +		list_for_each_entry_srcu(encl_mm, &encl->mm_list, list,
> > > +				srcu_read_lock_held(&encl->srcu)) {
> > >  			if (!mmget_not_zero(encl_mm->mm))
> > >  				continue;
> > >
> > > diff --git a/arch/x86/kernel/cpu/sgx/main.c
> > > b/arch/x86/kernel/cpu/sgx/main.c index 38b7fd2..581e0c4 100644
> > > --- a/arch/x86/kernel/cpu/sgx/main.c
> > > +++ b/arch/x86/kernel/cpu/sgx/main.c
> > > @@ -120,7 +120,8 @@ static bool sgx_reclaimer_age(struct
> > > sgx_epc_page
> > > *epc_page)
> > >
> > >  	idx = srcu_read_lock(&encl->srcu);
> > >
> > > -	list_for_each_entry_rcu(encl_mm, &encl->mm_list, list) {
> > > +	list_for_each_entry_srcu(encl_mm, &encl->mm_list, list,
> > > +			srcu_read_lock_held(&encl->srcu)) {
> > >  		if (!mmget_not_zero(encl_mm->mm))
> > >  			continue;
> > >
> > > --
> > > 2.9.4
> >
> 
> 
> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
> 

Thanks for your review.

And ping

[Li,Rongqing] 


> BR, Jarkko