* [PATCH] proc: fix dentry/inode overinstantiating under /proc/${pid}/net [not found] ` <CAPmgiUJsd-gdq=JG1rF8BHfpADeS45rcVWwnC2qKE=7W1EryiQ@mail.gmail.com> @ 2022-03-20 16:23 ` Alexey Dobriyan 2022-03-21 9:15 ` hui li 0 siblings, 1 reply; 4+ messages in thread From: Alexey Dobriyan @ 2022-03-20 16:23 UTC (permalink / raw) To: akpm; +Cc: viro, linux-kernel, hui li, linux-fsdevel When a process exits, /proc/${pid}, and /proc/${pid}/net dentries are flushed. However some leaf dentries like /proc/${pid}/net/arp_cache aren't. That's because respective PDEs have proc_misc_d_revalidate() hook which returns 1 and leaves dentries/inodes in the LRU. Force revalidation/lookup on everything under /proc/${pid}/net by inheriting proc_net_dentry_ops. Fixes: c6c75deda813 ("proc: fix lookup in /proc/net subdirectories after setns(2)") Reported-by: hui li <juanfengpy@gmail.com> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> --- fs/proc/generic.c | 4 ++++ fs/proc/proc_net.c | 3 +++ 2 files changed, 7 insertions(+) --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -448,6 +448,10 @@ static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent, proc_set_user(ent, (*parent)->uid, (*parent)->gid); ent->proc_dops = &proc_misc_dentry_ops; + /* Revalidate everything under /proc/${pid}/net */ + if ((*parent)->proc_dops == &proc_net_dentry_ops) { + pde_force_lookup(ent); + } out: return ent; --- a/fs/proc/proc_net.c +++ b/fs/proc/proc_net.c @@ -376,6 +376,9 @@ static __net_init int proc_net_ns_init(struct net *net) proc_set_user(netd, uid, gid); + /* Seed dentry revalidation for /proc/${pid}/net */ + pde_force_lookup(netd); + err = -EEXIST; net_statd = proc_net_mkdir(net, "stat", netd); if (!net_statd) ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] proc: fix dentry/inode overinstantiating under /proc/${pid}/net 2022-03-20 16:23 ` [PATCH] proc: fix dentry/inode overinstantiating under /proc/${pid}/net Alexey Dobriyan @ 2022-03-21 9:15 ` hui li 2022-03-21 10:40 ` Alexey Dobriyan 0 siblings, 1 reply; 4+ messages in thread From: hui li @ 2022-03-21 9:15 UTC (permalink / raw) To: Alexey Dobriyan; +Cc: akpm, viro, linux-kernel, linux-fsdevel proc_misc_dentry_ops is a general ops for dentry under /proc, except for "/proc/${pid}/net"，other dentries may also use there own ops too, so I think change proc_misc_d_delete may be better? see patch under: https://lkml.org/lkml/2022/3/17/319 Alexey Dobriyan <adobriyan@gmail.com> 于2022年3月21日周一 00:24写道： > > When a process exits, /proc/${pid}, and /proc/${pid}/net dentries are flushed. > However some leaf dentries like /proc/${pid}/net/arp_cache aren't. > That's because respective PDEs have proc_misc_d_revalidate() hook which > returns 1 and leaves dentries/inodes in the LRU. > > Force revalidation/lookup on everything under /proc/${pid}/net by inheriting > proc_net_dentry_ops. > > Fixes: c6c75deda813 ("proc: fix lookup in /proc/net subdirectories after setns(2)") > Reported-by: hui li <juanfengpy@gmail.com> > Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> > --- > > fs/proc/generic.c | 4 ++++ > fs/proc/proc_net.c | 3 +++ > 2 files changed, 7 insertions(+) > > --- a/fs/proc/generic.c > +++ b/fs/proc/generic.c > @@ -448,6 +448,10 @@ static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent, > proc_set_user(ent, (*parent)->uid, (*parent)->gid); > > ent->proc_dops = &proc_misc_dentry_ops; > + /* Revalidate everything under /proc/${pid}/net */ > + if ((*parent)->proc_dops == &proc_net_dentry_ops) { > + pde_force_lookup(ent); > + } > > out: > return ent; > --- a/fs/proc/proc_net.c > +++ b/fs/proc/proc_net.c > @@ -376,6 +376,9 @@ static __net_init int proc_net_ns_init(struct net *net) > > proc_set_user(netd, uid, gid); > > + /* Seed dentry revalidation for /proc/${pid}/net */ > + pde_force_lookup(netd); > + > err = -EEXIST; > net_statd = proc_net_mkdir(net, "stat", netd); > if (!net_statd) ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] proc: fix dentry/inode overinstantiating under /proc/${pid}/net 2022-03-21 9:15 ` hui li @ 2022-03-21 10:40 ` Alexey Dobriyan 2022-03-21 11:50 ` cael 0 siblings, 1 reply; 4+ messages in thread From: Alexey Dobriyan @ 2022-03-21 10:40 UTC (permalink / raw) To: hui li; +Cc: akpm, viro, linux-kernel, linux-fsdevel On Mon, Mar 21, 2022 at 05:15:02PM +0800, hui li wrote: > Alexey Dobriyan <adobriyan@gmail.com> 于2022年3月21日周一 00:24写道： > > > > When a process exits, /proc/${pid}, and /proc/${pid}/net dentries are flushed. > > However some leaf dentries like /proc/${pid}/net/arp_cache aren't. > > That's because respective PDEs have proc_misc_d_revalidate() hook which > > returns 1 and leaves dentries/inodes in the LRU. > > > > Force revalidation/lookup on everything under /proc/${pid}/net by inheriting > > proc_net_dentry_ops. > > > > Fixes: c6c75deda813 ("proc: fix lookup in /proc/net subdirectories after setns(2)") > > Reported-by: hui li <juanfengpy@gmail.com> > > Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> > > --- > > > > fs/proc/generic.c | 4 ++++ > > fs/proc/proc_net.c | 3 +++ > > 2 files changed, 7 insertions(+) > > > > --- a/fs/proc/generic.c > > +++ b/fs/proc/generic.c > > @@ -448,6 +448,10 @@ static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent, > > proc_set_user(ent, (*parent)->uid, (*parent)->gid); > > > > ent->proc_dops = &proc_misc_dentry_ops; > > + /* Revalidate everything under /proc/${pid}/net */ > > + if ((*parent)->proc_dops == &proc_net_dentry_ops) { > > + pde_force_lookup(ent); > > + } > > > > out: > > return ent; > > --- a/fs/proc/proc_net.c > > +++ b/fs/proc/proc_net.c > > @@ -376,6 +376,9 @@ static __net_init int proc_net_ns_init(struct net *net) > > > > proc_set_user(netd, uid, gid); > > > > + /* Seed dentry revalidation for /proc/${pid}/net */ > > + pde_force_lookup(netd); > > + > > err = -EEXIST; > > net_statd = proc_net_mkdir(net, "stat", netd); > > if (!net_statd) > proc_misc_dentry_ops is a general ops for dentry under /proc, except > for "/proc/${pid}/net"，other dentries may also use there own ops too, > so I think change proc_misc_d_delete may be better? > see patch under: https://lkml.org/lkml/2022/3/17/319 I don't think so. proc_misc_d_delete covers "everything else" part under /proc/ and /proc/net which are 2 separate trees. Now /proc/net/ requires revalidation because of commit c6c75deda81344c3a95d1d1f606d5cee109e5d54 proc: fix lookup in /proc/net subdirectories after setns(2) so the bug is that the above commit was applied only partially. In particular, /proc/*/net/stat/arp_cache was created with proc_create_seq_data(), avoiding proc_net_* APIs. And there is probably the same "lookup after setns find wrong file" if you search hard enough in /proc/*/net/ This is the logic. Please test on your systems. ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] proc: fix dentry/inode overinstantiating under /proc/${pid}/net 2022-03-21 10:40 ` Alexey Dobriyan @ 2022-03-21 11:50 ` cael 0 siblings, 0 replies; 4+ messages in thread From: cael @ 2022-03-21 11:50 UTC (permalink / raw) To: Alexey Dobriyan; +Cc: akpm, viro, linux-kernel, linux-fsdevel I see, I will test on my system. Alexey Dobriyan <adobriyan@gmail.com> 于2022年3月21日周一 18:40写道： > > On Mon, Mar 21, 2022 at 05:15:02PM +0800, hui li wrote: > > Alexey Dobriyan <adobriyan@gmail.com> 于2022年3月21日周一 00:24写道： > > > > > > When a process exits, /proc/${pid}, and /proc/${pid}/net dentries are flushed. > > > However some leaf dentries like /proc/${pid}/net/arp_cache aren't. > > > That's because respective PDEs have proc_misc_d_revalidate() hook which > > > returns 1 and leaves dentries/inodes in the LRU. > > > > > > Force revalidation/lookup on everything under /proc/${pid}/net by inheriting > > > proc_net_dentry_ops. > > > > > > Fixes: c6c75deda813 ("proc: fix lookup in /proc/net subdirectories after setns(2)") > > > Reported-by: hui li <juanfengpy@gmail.com> > > > Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> > > > --- > > > > > > fs/proc/generic.c | 4 ++++ > > > fs/proc/proc_net.c | 3 +++ > > > 2 files changed, 7 insertions(+) > > > > > > --- a/fs/proc/generic.c > > > +++ b/fs/proc/generic.c > > > @@ -448,6 +448,10 @@ static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent, > > > proc_set_user(ent, (*parent)->uid, (*parent)->gid); > > > > > > ent->proc_dops = &proc_misc_dentry_ops; > > > + /* Revalidate everything under /proc/${pid}/net */ > > > + if ((*parent)->proc_dops == &proc_net_dentry_ops) { > > > + pde_force_lookup(ent); > > > + } > > > > > > out: > > > return ent; > > > --- a/fs/proc/proc_net.c > > > +++ b/fs/proc/proc_net.c > > > @@ -376,6 +376,9 @@ static __net_init int proc_net_ns_init(struct net *net) > > > > > > proc_set_user(netd, uid, gid); > > > > > > + /* Seed dentry revalidation for /proc/${pid}/net */ > > > + pde_force_lookup(netd); > > > + > > > err = -EEXIST; > > > net_statd = proc_net_mkdir(net, "stat", netd); > > > if (!net_statd) > > > proc_misc_dentry_ops is a general ops for dentry under /proc, except > > for "/proc/${pid}/net"，other dentries may also use there own ops too, > > so I think change proc_misc_d_delete may be better? > > see patch under: https://lkml.org/lkml/2022/3/17/319 > > I don't think so. > > proc_misc_d_delete covers "everything else" part under /proc/ and > /proc/net which are 2 separate trees. Now /proc/net/ requires > revalidation because of > > commit c6c75deda81344c3a95d1d1f606d5cee109e5d54 > proc: fix lookup in /proc/net subdirectories after setns(2) > > so the bug is that the above commit was applied only partially. > In particular, /proc/*/net/stat/arp_cache was created with > proc_create_seq_data(), avoiding proc_net_* APIs. > > And there is probably the same "lookup after setns find wrong file" > if you search hard enough in /proc/*/net/ > > This is the logic. Please test on your systems. ^ permalink raw reply [flat|nested] 4+ messages in thread
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2022-03-20 16:23 ` [PATCH] proc: fix dentry/inode overinstantiating under /proc/${pid}/net Alexey Dobriyan
2022-03-21 9:15 ` hui li
2022-03-21 10:40 ` Alexey Dobriyan
2022-03-21 11:50 ` cael
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