The patch titled proc: fix ->open'less usage due to ->proc_fops flip has been added to the -mm tree. Its filename is proc-fix-openless-usage-due-to-proc_fops-flip.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: proc: fix ->open'less usage due to ->proc_fops flip From: Alexey Dobriyan <adobriyan@xxxxx> 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 Signed-off-by: Alexey Dobriyan <adobriyan@xxxxx> Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> Cc: Oleg Nesterov <oleg@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/proc/generic.c | 40 ++++++++++++++++++++++++++++++++++---- fs/proc/proc_net.c | 7 ------ fs/proc/root.c | 1 include/linux/proc_fs.h | 6 ++++- 4 files changed, 43 insertions(+), 11 deletions(-) diff -puN fs/proc/generic.c~proc-fix-openless-usage-due-to-proc_fops-flip fs/proc/generic.c --- a/fs/proc/generic.c~proc-fix-openless-usage-due-to-proc_fops-flip +++ a/fs/proc/generic.c @@ -562,7 +562,7 @@ static int proc_register(struct proc_dir return 0; } -static struct proc_dir_entry *proc_create(struct proc_dir_entry **parent, +static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent, const char *name, mode_t mode, nlink_t nlink) @@ -605,7 +605,7 @@ struct proc_dir_entry *proc_symlink(cons { struct proc_dir_entry *ent; - ent = proc_create(&parent,name, + ent = __proc_create(&parent,name, (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1); if (ent) { @@ -630,7 +630,7 @@ struct proc_dir_entry *proc_mkdir_mode(c { struct proc_dir_entry *ent; - ent = proc_create(&parent, name, S_IFDIR | mode, 2); + ent = __proc_create(&parent, name, S_IFDIR | mode, 2); if (ent) { if (proc_register(parent, ent) < 0) { kfree(ent); @@ -664,7 +664,7 @@ struct proc_dir_entry *create_proc_entry nlink = 1; } - ent = proc_create(&parent,name,mode,nlink); + ent = __proc_create(&parent,name,mode,nlink); if (ent) { if (proc_register(parent, ent) < 0) { kfree(ent); @@ -674,6 +674,38 @@ struct proc_dir_entry *create_proc_entry return ent; } +struct proc_dir_entry *proc_create(const char *name, mode_t mode, + struct proc_dir_entry *parent, + const struct file_operations *proc_fops) +{ + struct proc_dir_entry *pde; + nlink_t nlink; + + if (S_ISDIR(mode)) { + if ((mode & S_IALLUGO) == 0) + mode |= S_IRUGO | S_IXUGO; + nlink = 2; + } else { + if ((mode & S_IFMT) == 0) + mode |= S_IFREG; + if ((mode & S_IALLUGO) == 0) + mode |= S_IRUGO; + nlink = 1; + } + + pde = __proc_create(&parent, name, mode, nlink); + if (!pde) + goto out; + pde->proc_fops = proc_fops; + if (proc_register(parent, pde) < 0) + goto out_free; + return pde; +out_free: + kfree(pde); +out: + return NULL; +} + void free_proc_entry(struct proc_dir_entry *de) { unsigned int ino = de->low_ino; diff -puN fs/proc/proc_net.c~proc-fix-openless-usage-due-to-proc_fops-flip fs/proc/proc_net.c --- a/fs/proc/proc_net.c~proc-fix-openless-usage-due-to-proc_fops-flip +++ a/fs/proc/proc_net.c @@ -67,12 +67,7 @@ EXPORT_SYMBOL_GPL(seq_release_net); struct proc_dir_entry *proc_net_fops_create(struct net *net, const char *name, mode_t mode, const struct file_operations *fops) { - struct proc_dir_entry *res; - - res = create_proc_entry(name, mode, net->proc_net); - if (res) - res->proc_fops = fops; - return res; + return proc_create(name, mode, net->proc_net, fops); } EXPORT_SYMBOL_GPL(proc_net_fops_create); diff -puN fs/proc/root.c~proc-fix-openless-usage-due-to-proc_fops-flip fs/proc/root.c --- a/fs/proc/root.c~proc-fix-openless-usage-due-to-proc_fops-flip +++ a/fs/proc/root.c @@ -232,6 +232,7 @@ void pid_ns_release_proc(struct pid_name EXPORT_SYMBOL(proc_symlink); EXPORT_SYMBOL(proc_mkdir); EXPORT_SYMBOL(create_proc_entry); +EXPORT_SYMBOL(proc_create); EXPORT_SYMBOL(remove_proc_entry); EXPORT_SYMBOL(proc_root); EXPORT_SYMBOL(proc_root_fs); diff -puN include/linux/proc_fs.h~proc-fix-openless-usage-due-to-proc_fops-flip include/linux/proc_fs.h --- a/include/linux/proc_fs.h~proc-fix-openless-usage-due-to-proc_fops-flip +++ a/include/linux/proc_fs.h @@ -126,6 +126,7 @@ void de_put(struct proc_dir_entry *de); extern struct proc_dir_entry *create_proc_entry(const char *name, mode_t mode, struct proc_dir_entry *parent); +struct proc_dir_entry *proc_create(const char *name, mode_t mode, struct proc_dir_entry *parent, const struct file_operations *proc_fops); extern void remove_proc_entry(const char *name, struct proc_dir_entry *parent); extern struct vfsmount *proc_mnt; @@ -218,7 +219,10 @@ static inline void proc_flush_task(struc static inline struct proc_dir_entry *create_proc_entry(const char *name, mode_t mode, struct proc_dir_entry *parent) { return NULL; } - +static inline struct proc_dir_entry *proc_create(const char *name, mode_t mode, struct proc_dir_entry *parent, const struct file_operations *proc_fops) +{ + return NULL; +} #define remove_proc_entry(name, parent) do {} while (0) static inline struct proc_dir_entry *proc_symlink(const char *name, _ Patches currently in -mm which might be from adobriyan@xxxxx are gregkh-driver-block-device-genhd-fixup-kobj_to_dev-macro.patch gregkh-driver-kobject-convert-hvcs-to-use-kref-not-kobject-hvcs-fixup-container_of-usage.patch proc-remove-module_license.patch proc-less-lock-operations-during-lookup.patch proc-simplify-function-prototypes.patch proc-remove-useless-check-on-symlink-removal.patch proc-detect-duplicate-names-on-registration.patch proc-detect-duplicate-names-on-registration-fix.patch proc-fix-openless-usage-due-to-proc_fops-flip.patch fixup-container_of-usage.patch single_open-seq_release-leak-diagnostics.patch - To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html