aboutsummaryrefslogtreecommitdiffstats
path: root/fs/proc
diff options
context:
space:
mode:
authorAlexey Dobriyan <adobriyan@sw.ru>2008-02-08 07:18:37 -0500
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-08 12:22:24 -0500
commit2d3a4e3666325a9709cc8ea2e88151394e8f20fc (patch)
treec3e75289de8c824f5e2bb2e97d4b6853d48da3f3 /fs/proc
parentc6caeb7c4544608e8ae62731334661fc396c7f85 (diff)
proc: fix ->open'less usage due to ->proc_fops flip
Typical PDE creation code looks like: pde = create_proc_entry("foo", 0, NULL); if (pde) pde->proc_fops = &foo_proc_fops; Notice that PDE is first created, only then ->proc_fops is set up to final value. This is a problem because right after creation a) PDE is fully visible in /proc , and b) ->proc_fops are proc_file_operations which do not have ->open callback. So, it's possible to ->read without ->open (see one class of oopses below). The fix is new API called proc_create() which makes sure ->proc_fops are set up before gluing PDE to main tree. Typical new code looks like: pde = proc_create("foo", 0, NULL, &foo_proc_fops); if (!pde) return -ENOMEM; Fix most networking users for a start. In the long run, create_proc_entry() for regular files will go. BUG: unable to handle kernel NULL pointer dereference at virtual address 00000024 printing eip: c1188c1b *pdpt = 000000002929e001 *pde = 0000000000000000 Oops: 0002 [#1] PREEMPT SMP DEBUG_PAGEALLOC last sysfs file: /sys/block/sda/sda1/dev Modules linked in: foo af_packet ipv6 cpufreq_ondemand loop serio_raw psmouse k8temp hwmon sr_mod cdrom Pid: 24679, comm: cat Not tainted (2.6.24-rc3-mm1 #2) EIP: 0060:[<c1188c1b>] EFLAGS: 00210002 CPU: 0 EIP is at mutex_lock_nested+0x75/0x25d EAX: 000006fe EBX: fffffffb ECX: 00001000 EDX: e9340570 ESI: 00000020 EDI: 00200246 EBP: e9340570 ESP: e8ea1ef8 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 Process cat (pid: 24679, ti=E8EA1000 task=E9340570 task.ti=E8EA1000) Stack: 00000000 c106f7ce e8ee05b4 00000000 00000001 458003d0 f6fb6f20 fffffffb 00000000 c106f7aa 00001000 c106f7ce 08ae9000 f6db53f0 00000020 00200246 00000000 00000002 00000000 00200246 00200246 e8ee05a0 fffffffb e8ee0550 Call Trace: [<c106f7ce>] seq_read+0x24/0x28a [<c106f7aa>] seq_read+0x0/0x28a [<c106f7ce>] seq_read+0x24/0x28a [<c106f7aa>] seq_read+0x0/0x28a [<c10818b8>] proc_reg_read+0x60/0x73 [<c1081858>] proc_reg_read+0x0/0x73 [<c105a34f>] vfs_read+0x6c/0x8b [<c105a6f3>] sys_read+0x3c/0x63 [<c10025f2>] sysenter_past_esp+0x5f/0xa5 [<c10697a7>] destroy_inode+0x24/0x33 ======================= INFO: lockdep is turned off. Code: 75 21 68 e1 1a 19 c1 68 87 00 00 00 68 b8 e8 1f c1 68 25 73 1f c1 e8 84 06 e9 ff e8 52 b8 e7 ff 83 c4 10 9c 5f fa e8 28 89 ea ff <f0> fe 4e 04 79 0a f3 90 80 7e 04 00 7e f8 eb f0 39 76 34 74 33 EIP: [<c1188c1b>] mutex_lock_nested+0x75/0x25d SS:ESP 0068:e8ea1ef8 [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/proc')
-rw-r--r--fs/proc/generic.c40
-rw-r--r--fs/proc/proc_net.c7
-rw-r--r--fs/proc/root.c1
3 files changed, 38 insertions, 10 deletions
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index b9dd3628d43a..68971e66cd41 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -562,7 +562,7 @@ static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp
562 return 0; 562 return 0;
563} 563}
564 564
565static struct proc_dir_entry *proc_create(struct proc_dir_entry **parent, 565static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
566 const char *name, 566 const char *name,
567 mode_t mode, 567 mode_t mode,
568 nlink_t nlink) 568 nlink_t nlink)
@@ -605,7 +605,7 @@ struct proc_dir_entry *proc_symlink(const char *name,
605{ 605{
606 struct proc_dir_entry *ent; 606 struct proc_dir_entry *ent;
607 607
608 ent = proc_create(&parent,name, 608 ent = __proc_create(&parent, name,
609 (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1); 609 (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
610 610
611 if (ent) { 611 if (ent) {
@@ -630,7 +630,7 @@ struct proc_dir_entry *proc_mkdir_mode(const char *name, mode_t mode,
630{ 630{
631 struct proc_dir_entry *ent; 631 struct proc_dir_entry *ent;
632 632
633 ent = proc_create(&parent, name, S_IFDIR | mode, 2); 633 ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
634 if (ent) { 634 if (ent) {
635 if (proc_register(parent, ent) < 0) { 635 if (proc_register(parent, ent) < 0) {
636 kfree(ent); 636 kfree(ent);
@@ -664,7 +664,7 @@ struct proc_dir_entry *create_proc_entry(const char *name, mode_t mode,
664 nlink = 1; 664 nlink = 1;
665 } 665 }
666 666
667 ent = proc_create(&parent,name,mode,nlink); 667 ent = __proc_create(&parent, name, mode, nlink);
668 if (ent) { 668 if (ent) {
669 if (proc_register(parent, ent) < 0) { 669 if (proc_register(parent, ent) < 0) {
670 kfree(ent); 670 kfree(ent);
@@ -674,6 +674,38 @@ struct proc_dir_entry *create_proc_entry(const char *name, mode_t mode,
674 return ent; 674 return ent;
675} 675}
676 676
677struct proc_dir_entry *proc_create(const char *name, mode_t mode,
678 struct proc_dir_entry *parent,
679 const struct file_operations *proc_fops)
680{
681 struct proc_dir_entry *pde;
682 nlink_t nlink;
683
684 if (S_ISDIR(mode)) {
685 if ((mode & S_IALLUGO) == 0)
686 mode |= S_IRUGO | S_IXUGO;
687 nlink = 2;
688 } else {
689 if ((mode & S_IFMT) == 0)
690 mode |= S_IFREG;
691 if ((mode & S_IALLUGO) == 0)
692 mode |= S_IRUGO;
693 nlink = 1;
694 }
695
696 pde = __proc_create(&parent, name, mode, nlink);
697 if (!pde)
698 goto out;
699 pde->proc_fops = proc_fops;
700 if (proc_register(parent, pde) < 0)
701 goto out_free;
702 return pde;
703out_free:
704 kfree(pde);
705out:
706 return NULL;
707}
708
677void free_proc_entry(struct proc_dir_entry *de) 709void free_proc_entry(struct proc_dir_entry *de)
678{ 710{
679 unsigned int ino = de->low_ino; 711 unsigned int ino = de->low_ino;
diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c
index 4823c9677fac..14e9b5aaf863 100644
--- a/fs/proc/proc_net.c
+++ b/fs/proc/proc_net.c
@@ -67,12 +67,7 @@ EXPORT_SYMBOL_GPL(seq_release_net);
67struct proc_dir_entry *proc_net_fops_create(struct net *net, 67struct proc_dir_entry *proc_net_fops_create(struct net *net,
68 const char *name, mode_t mode, const struct file_operations *fops) 68 const char *name, mode_t mode, const struct file_operations *fops)
69{ 69{
70 struct proc_dir_entry *res; 70 return proc_create(name, mode, net->proc_net, fops);
71
72 res = create_proc_entry(name, mode, net->proc_net);
73 if (res)
74 res->proc_fops = fops;
75 return res;
76} 71}
77EXPORT_SYMBOL_GPL(proc_net_fops_create); 72EXPORT_SYMBOL_GPL(proc_net_fops_create);
78 73
diff --git a/fs/proc/root.c b/fs/proc/root.c
index 81f99e691f99..ef0fb57fc9ef 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -232,6 +232,7 @@ void pid_ns_release_proc(struct pid_namespace *ns)
232EXPORT_SYMBOL(proc_symlink); 232EXPORT_SYMBOL(proc_symlink);
233EXPORT_SYMBOL(proc_mkdir); 233EXPORT_SYMBOL(proc_mkdir);
234EXPORT_SYMBOL(create_proc_entry); 234EXPORT_SYMBOL(create_proc_entry);
235EXPORT_SYMBOL(proc_create);
235EXPORT_SYMBOL(remove_proc_entry); 236EXPORT_SYMBOL(remove_proc_entry);
236EXPORT_SYMBOL(proc_root); 237EXPORT_SYMBOL(proc_root);
237EXPORT_SYMBOL(proc_root_fs); 238EXPORT_SYMBOL(proc_root_fs);