aboutsummaryrefslogtreecommitdiffstats
path: root/fs/proc/generic.c
AgeCommit message (Collapse)AuthorFilesLines
2012-12-25proc: Allow proc_free_inum to be called from any contextEric W. Biederman1-6/+7
While testing the pid namespace code I hit this nasty warning. [ 176.262617] ------------[ cut here ]------------ [ 176.263388] WARNING: at /home/eric/projects/linux/linux-userns-devel/kernel/softirq.c:160 local_bh_enable_ip+0x7a/0xa0() [ 176.265145] Hardware name: Bochs [ 176.265677] Modules linked in: [ 176.266341] Pid: 742, comm: bash Not tainted 3.7.0userns+ #18 [ 176.266564] Call Trace: [ 176.266564] [<ffffffff810a539f>] warn_slowpath_common+0x7f/0xc0 [ 176.266564] [<ffffffff810a53fa>] warn_slowpath_null+0x1a/0x20 [ 176.266564] [<ffffffff810ad9ea>] local_bh_enable_ip+0x7a/0xa0 [ 176.266564] [<ffffffff819308c9>] _raw_spin_unlock_bh+0x19/0x20 [ 176.266564] [<ffffffff8123dbda>] proc_free_inum+0x3a/0x50 [ 176.266564] [<ffffffff8111d0dc>] free_pid_ns+0x1c/0x80 [ 176.266564] [<ffffffff8111d195>] put_pid_ns+0x35/0x50 [ 176.266564] [<ffffffff810c608a>] put_pid+0x4a/0x60 [ 176.266564] [<ffffffff8146b177>] tty_ioctl+0x717/0xc10 [ 176.266564] [<ffffffff810aa4d5>] ? wait_consider_task+0x855/0xb90 [ 176.266564] [<ffffffff81086bf9>] ? default_spin_lock_flags+0x9/0x10 [ 176.266564] [<ffffffff810cab0a>] ? remove_wait_queue+0x5a/0x70 [ 176.266564] [<ffffffff811e37e8>] do_vfs_ioctl+0x98/0x550 [ 176.266564] [<ffffffff810b8a0f>] ? recalc_sigpending+0x1f/0x60 [ 176.266564] [<ffffffff810b9127>] ? __set_task_blocked+0x37/0x80 [ 176.266564] [<ffffffff810ab95b>] ? sys_wait4+0xab/0xf0 [ 176.266564] [<ffffffff811e3d31>] sys_ioctl+0x91/0xb0 [ 176.266564] [<ffffffff810a95f0>] ? task_stopped_code+0x50/0x50 [ 176.266564] [<ffffffff81939199>] system_call_fastpath+0x16/0x1b [ 176.266564] ---[ end trace 387af88219ad6143 ]--- It turns out that spin_unlock_bh(proc_inum_lock) is not safe when put_pid is called with another spinlock held and irqs disabled. For now take the easy path and use spin_lock_irqsave(proc_inum_lock) in proc_free_inum and spin_loc_irq in proc_alloc_inum(proc_inum_lock). Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2012-12-20Merge branch 'akpm' (Andrew's patch-bomb)Linus Torvalds1-6/+6
Merge the rest of Andrew's patches for -rc1: "A bunch of fixes and misc missed-out-on things. That'll do for -rc1. I still have a batch of IPC patches which still have a possible bug report which I'm chasing down." * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (25 commits) keys: use keyring_alloc() to create module signing keyring keys: fix unreachable code sendfile: allows bypassing of notifier events SGI-XP: handle non-fatal traps fat: fix incorrect function comment Documentation: ABI: remove testing/sysfs-devices-node proc: fix inconsistent lock state linux/kernel.h: fix DIV_ROUND_CLOSEST with unsigned divisors memcg: don't register hotcpu notifier from ->css_alloc() checkpatch: warn on uapi #includes that #include <uapi/... revert "rtc: recycle id when unloading a rtc driver" mm: clean up transparent hugepage sysfs error messages hfsplus: add error message for the case of failure of sync fs in delayed_sync_fs() method hfsplus: rework processing of hfs_btree_write() returned error hfsplus: rework processing errors in hfsplus_free_extents() hfsplus: avoid crash on failed block map free kcmp: include linux/ptrace.h drivers/rtc/rtc-imxdi.c: must include <linux/spinlock.h> mm: cma: WARN if freed memory is still in use exec: do not leave bprm->interp on stack ...
2012-12-20proc: fix inconsistent lock stateXiaotian Feng1-6/+6
Lockdep found an inconsistent lock state when rcu is processing delayed work in softirq. Currently, kernel is using spin_lock/spin_unlock to protect proc_inum_ida, but proc_free_inum is called by rcu in softirq context. Use spin_lock_bh/spin_unlock_bh fix following lockdep warning. ================================= [ INFO: inconsistent lock state ] 3.7.0 #36 Not tainted --------------------------------- inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. swapper/1/0 [HC0[0]:SC1[1]:HE1:SE0] takes: (proc_inum_lock){+.?...}, at: proc_free_inum+0x1c/0x50 {SOFTIRQ-ON-W} state was registered at: __lock_acquire+0x8ae/0xca0 lock_acquire+0x199/0x200 _raw_spin_lock+0x41/0x50 proc_alloc_inum+0x4c/0xd0 alloc_mnt_ns+0x49/0xc0 create_mnt_ns+0x25/0x70 mnt_init+0x161/0x1c7 vfs_caches_init+0x107/0x11a start_kernel+0x348/0x38c x86_64_start_reservations+0x131/0x136 x86_64_start_kernel+0x103/0x112 irq event stamp: 2993422 hardirqs last enabled at (2993422): _raw_spin_unlock_irqrestore+0x55/0x80 hardirqs last disabled at (2993421): _raw_spin_lock_irqsave+0x29/0x70 softirqs last enabled at (2993394): _local_bh_enable+0x13/0x20 softirqs last disabled at (2993395): call_softirq+0x1c/0x30 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(proc_inum_lock); <Interrupt> lock(proc_inum_lock); *** DEADLOCK *** no locks held by swapper/1/0. stack backtrace: Pid: 0, comm: swapper/1 Not tainted 3.7.0 #36 Call Trace: <IRQ> [<ffffffff810a40f1>] ? vprintk_emit+0x471/0x510 print_usage_bug+0x2a5/0x2c0 mark_lock+0x33b/0x5e0 __lock_acquire+0x813/0xca0 lock_acquire+0x199/0x200 _raw_spin_lock+0x41/0x50 proc_free_inum+0x1c/0x50 free_pid_ns+0x1c/0x50 put_pid_ns+0x2e/0x50 put_pid+0x4a/0x60 delayed_put_pid+0x12/0x20 rcu_process_callbacks+0x462/0x790 __do_softirq+0x1b4/0x3b0 call_softirq+0x1c/0x30 do_softirq+0x59/0xd0 irq_exit+0x54/0xd0 smp_apic_timer_interrupt+0x95/0xa3 apic_timer_interrupt+0x72/0x80 cpuidle_enter_tk+0x10/0x20 cpuidle_enter_state+0x17/0x50 cpuidle_idle_call+0x287/0x520 cpu_idle+0xba/0x130 start_secondary+0x2b3/0x2bc Signed-off-by: Xiaotian Feng <dannyfeng@tencent.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-20procfs: drop vmtruncateMarco Stornelli1-8/+1
Removed vmtruncate Signed-off-by: Marco Stornelli <marco.stornelli@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-11-20proc: Generalize proc inode allocationEric W. Biederman1-13/+13
Generalize the proc inode allocation so that it can be used without having to having to create a proc_dir_entry. This will allow namespace file descriptors to remain light weight entitities but still have the same inode number when the backing namespace is the same. Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2012-10-06proc: use kzalloc instead of kmalloc and memsetyan1-7/+6
Part of the memory will be written twice after this change, but that should be negligible. [akpm@linux-foundation.org: fix __proc_create() coding-style issues, remove unneeded zero-initialisations] Signed-off-by: yan <clouds.yan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-06proc: return -ENOMEM when inode allocation failedyan1-1/+1
If proc_get_inode() returns NULL then presumably it encountered memory exhaustion. proc_lookup_de() should return -ENOMEM in this case, not -EINVAL. Signed-off-by: yan <clouds.yan@gmail.com> Cc: Ryan Mallon <rmallon@gmail.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-14stop passing nameidata to ->lookup()Al Viro1-1/+1
Just the flags; only NFS cares even about that, but there are legitimate uses for such argument. And getting rid of that completely would require splitting ->lookup() into a couple of methods (at least), so let's leave that alone for now... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03switch procfs to umode_t useAl Viro1-4/+4
both proc_dir_entry ->mode and populating functions Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-11-02filesystems: add set_nlink()Miklos Szeredi1-1/+1
Replace remaining direct i_nlink updates with a new set_nlink() updater function. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2011-07-27proc: make struct proc_dir_entry::name a terminal array rather than a pointerDavid Howells1-2/+1
Since __proc_create() appends the name it is given to the end of the PDE structure that it allocates, there isn't a need to store a name pointer. Instead we can just replace the name pointer with a terminal char array of _unspecified_ length. The compiler will simply append the string to statically defined variables of PDE type overlapping any hole at the end of the structure and, unlike specifying an explicitly _zero_ length array, won't give a warning if you try to statically initialise it with a string of more than zero length. Also, whilst we're at it: (1) Move namelen to end just prior to name and reduce it to a single byte (name shouldn't be longer than NAME_MAX). (2) Move pde_unload_lock two places further on so that if it's four bytes in size on a 64-bit machine, it won't cause an unused hole in the PDE struct. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-16airo: correct proc entry creation interfacesAlexey Dobriyan1-0/+1
* use proc_mkdir_mode() instead of create_proc_entry(S_IFDIR|...), export proc_mkdir_mode() for that, oh well. * don't supply S_IFREG to proc_create_data(), it's unnecessary Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-03-23proc: make struct proc_dir_entry::namelen unsigned intAlexey Dobriyan1-4/+4
1. namelen is declared "unsigned short" which hints for "maybe space savings". Indeed in 2.4 struct proc_dir_entry looked like: struct proc_dir_entry { unsigned short low_ino; unsigned short namelen; Now, low_ino is "unsigned int", all savings were gone for a long time. "struct proc_dir_entry" is not that countless to worry about it's size, anyway. 2. converting from unsigned short to int/unsigned int can only create problems, we better play it safe. Space is not really conserved, because of natural alignment for the next field. sizeof(struct proc_dir_entry) remains the same. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13proc: less LOCK/UNLOCK in remove_proc_entry()Alexey Dobriyan1-4/+1
For the common case where a proc entry is being removed and nobody is in the process of using it, save a LOCK/UNLOCK pair. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13proc: ->low_ino cleanupAlexey Dobriyan1-10/+2
- ->low_ino is write-once field -- reading it under locks is unnecessary. - /proc/$PID stuff never reaches pde_put()/free_proc_entry() -- PROC_DYNAMIC_FIRST check never triggers. - in proc_get_inode(), inode number always matches proc dir entry, so save one parameter. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-07fs: dcache reduce branches in lookup pathNick Piggin1-1/+1
Reduce some branches and memory accesses in dcache lookup by adding dentry flags to indicate common d_ops are set, rather than having to check them. This saves a pointer memory access (dentry->d_op) in common path lookup situations, and saves another pointer load and branch in cases where we have d_op but not the particular operation. Patched with: git grep -E '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: change d_delete semanticsNick Piggin1-1/+1
Change d_delete from a dentry deletion notification to a dentry caching advise, more like ->drop_inode. Require it to be constant and idempotent, and not take d_lock. This is how all existing filesystems use the callback anyway. This makes fine grained dentry locking of dput and dentry lru scanning much simpler. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2010-08-09remove inode_setattrChristoph Hellwig1-6/+12
Replace inode_setattr with opencoded variants of it in all callers. This moves the remaining call to vmtruncate into the filesystem methods where it can be replaced with the proper truncate sequence. In a few cases it was obvious that we would never end up calling vmtruncate so it was left out in the opencoded variant: spufs: explicitly checks for ATTR_SIZE earlier btrfs,hugetlbfs,logfs,dlmfs: explicitly clears ATTR_SIZE earlier ufs: contains an opencoded simple_seattr + truncate that sets the filesize just above In addition to that ncpfs called inode_setattr with handcrafted iattrs, which allowed to trim down the opencoded variant. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-27proc: remove obsolete commentsAmerigo Wang1-15/+0
A quick test shows these comments are obsolete, so just remove them. Signed-off-by: WANG Cong <amwang@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo1-0/+1
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-06proc: warn on non-existing proc entriesAlexey Dobriyan1-2/+6
* warn if creation goes on to non-existent directory * warn if removal goes on from non-existing directory * warn if non-existing proc entry is removed Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06proc: do translation + unlink atomically at remove_proc_entry()Alexey Dobriyan1-12/+19
remove_proc_entry() does lock lookup parent unlock lock unlink proc entry from lists unlock which can be made bit more correct by doing parent translation + unlink without dropping lock. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-03some clean up in fs/procHelight.Xu1-0/+5
EXPORT_SYMBOL(proc_symlink); EXPORT_SYMBOL(proc_mkdir); EXPORT_SYMBOL(create_proc_entry); EXPORT_SYMBOL(proc_create_data); EXPORT_SYMBOL(remove_proc_entry); Those EXPORT_SYMBOL shouldn't be in fs/proc/root.c, should be in fs/proc/generic.c. Signed-off-by: Helight.Xu <helight.xu@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-12-16proc: rename de_get() to pde_get() and inline itAlexey Dobriyan1-8/+13
* de_get() is trivial -- make inline, save a few bits of code, drop "refcount is 0" check -- it should be done in some generic refcount code, don't recall it's was helpful * rename GET and PUT functions to pde_get(), pde_put() for cool prefix! * remove obvious and incorrent comments * in remove_proc_entry() use pde_put(), when I fixed PDE refcounting to be normal one, remove_proc_entry() was supposed to do "-1" and code now reflects that. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-31proc 1/2: do PDE usecounting even for ->read_proc, ->write_procAlexey Dobriyan1-10/+38
struct proc_dir_entry::owner is going to be removed. Now it's only necessary to protect PDEs which are using ->read_proc, ->write_proc hooks. However, ->owner assignments are racy and make it very easy for someone to switch ->owner on live PDE (as some subsystems do) without fixing refcounts and so on. http://bugzilla.kernel.org/show_bug.cgi?id=12454 So, ->owner is on death row. Proxy file operations exist already (proc_file_operations), just bump usecount when necessary. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2009-03-31proc: move fs/proc/inode-alloc.txt comment into a source fileRandy Dunlap1-0/+15
so that people will realize that it exists and can update it as needed. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2009-03-27constify dentry_operations: procfsAl Viro1-1/+1
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-01-05proc: stop using BKLAlexey Dobriyan1-6/+2
There are four BKL users in proc: de_put(), proc_lookup_de(), proc_readdir_de(), proc_root_readdir(), 1) de_put() ----------- de_put() is classic atomic_dec_and_test() refcount wrapper -- no BKL needed. BKL doesn't matter to possible refcount leak as well. 2) proc_lookup_de() ------------------- Walking PDE list is protected by proc_subdir_lock(), proc_get_inode() is potentially blocking, all callers of proc_lookup_de() eventually end up from ->lookup hooks which is protected by directory's ->i_mutex -- BKL doesn't protect anything. 3) proc_readdir_de() -------------------- "." and ".." part doesn't need BKL, walking PDE list is under proc_subdir_lock, calling filldir callback is potentially blocking because it writes to luserspace. All proc_readdir_de() callers eventually come from ->readdir hook which is under directory's ->i_mutex -- BKL doesn't protect anything. 4) proc_root_readdir_de() ------------------------- proc_root_readdir_de is ->readdir hook, see (3). Since readdir hooks doesn't use BKL anymore, switch to generic_file_llseek, since it also takes directory's i_mutex. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2008-10-23proc: use WARN() rather than printk+backtraceArjan van de Ven1-2/+1
Use WARN() rather than a printk() + backtrace(); this gives a more standard format message as well as complete information (including line numbers etc) that will be collected by kerneloops.org Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2008-09-13proc: more debugging for "already registered" caseAlexey Dobriyan1-2/+2
Print parent directory name as well. The aim is to catch non-creation of parent directory when proc_mkdir will return NULL and all subsequent registrations go directly in /proc instead of intended directory. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> [ Fixed insane printk string while at it. - Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-25[PATCH] proc: inode number fixletAlexey Dobriyan1-0/+1
Ouch, if number taken from IDA is too big, the intent was to signal an error, not check for overflow and still do overflowing addition. One still needs 2^28 proc entries to notice this. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-08-01[PATCH 2/2] proc: switch inode number allocation to IDAAlexey Dobriyan1-5/+5
proc doesn't use "associate pointer with id" feature of IDR, so switch to IDA. NOTE, NOTE, NOTE: Do not apply if release_inode_number() still mantions MAX_ID_MASK! Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-08-01[PATCH 1/2] proc: fix inode number bogorithmeticAlexey Dobriyan1-12/+9
Id which proc gets from IDR for inode number and id which proc removes from IDR do not match. E.g. 0x11a transforms into 0x8000011a. Which stayed unnoticed for a long time because, surprise, idr_remove() masks out that high bit before doing anything. All of this due to "| ~MAX_ID_MASK" in release_inode_number(). I still don't understand how it's supposed to work, because "| ~MASK" is not an inversion for "& MAX" operation. So, use just one nice, working addition. Make start offset unsigned int, while I'm at it. It's longness is not used anywhere. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-07-26Use WARN() in fs/proc/Arjan van de Ven1-4/+1
Use WARN() instead of a printk+WARN_ON() pair; this way the message becomes part of the warning section for better reporting/collection. This way, the entire if() {} section can collapse into the WARN() as well. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Acked-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25proc: always do ->releaseAlexey Dobriyan1-0/+14
Current two-stage scheme of removing PDE emphasizes one bug in proc: open rmmod remove_proc_entry close ->release won't be called because ->proc_fops were cleared. In simple cases it's small memory leak. For every ->open, ->release has to be done. List of openers is introduced which is traversed at remove_proc_entry() if neeeded. Discussions with Al long ago (sigh). Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-02netns: assign PDE->data before gluing entry into /proc treeDenis V. Lunev1-0/+17
In this unfortunate case, proc_mkdir_mode wrapper can't be used anymore and this is no way to reuse proc_create_data due to nlinks assignment. So, copy the code from proc_mkdir and assign PDE->data at the appropriate moment. Signed-off-by: Denis V. Lunev <den@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-29proc: introduce proc_create_data to setup de->dataDenis V. Lunev1-3/+5
This set of patches fixes an proc ->open'less usage due to ->proc_fops flip in the most part of the kernel code. The original OOPS is described in the commit 2d3a4e3666325a9709cc8ea2e88151394e8f20fc: 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. In addition to this, proc_create_data is introduced to fix reading from proc without PDE->data. The race is basically the same as above. create_proc_entries is replaced in the entire kernel code as new method is also simply better. This patch: The problem is the same as for de->proc_fops. Right now PDE becomes visible without data set. So, the entry could be looked up without data. This, in most cases, will simply OOPS. proc_create_data call is created to address this issue. proc_create now becomes a wrapper around it. Signed-off-by: Denis V. Lunev <den@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Bjorn Helgaas <bjorn.helgaas@hp.com> Cc: Chris Mason <chris.mason@oracle.com> Acked-by: David Howells <dhowells@redhat.com> Cc: Dmitry Torokhov <dtor@mail.ru> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Grant Grundler <grundler@parisc-linux.org> Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Jaroslav Kysela <perex@suse.cz> Cc: Jeff Garzik <jgarzik@pobox.com> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Karsten Keil <kkeil@suse.de> Cc: Kyle McMartin <kyle@parisc-linux.org> Cc: Len Brown <lenb@kernel.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Mauro Carvalho Chehab <mchehab@infradead.org> Cc: Mikael Starvik <starvik@axis.com> Cc: Nadia Derbey <Nadia.Derbey@bull.net> Cc: Neil Brown <neilb@suse.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Osterlund <petero2@telia.com> Cc: Pierre Peiffer <peifferp@gmail.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Takashi Iwai <tiwai@suse.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29proc: remove ->get_info infrastructureAlexey Dobriyan1-6/+1
Now that last dozen or so users of ->get_info were removed, ditch it too. Everyone sane shouldd have switched to seq_file interface long ago. P.S.: Co-existing 3 interfaces (->get_info/->read_proc/->proc_fops) for proc is long-standing crap, BTW, thus a) put ->read_proc/->write_proc/read_proc_entry() users on death row, b) new such users should be rejected, c) everyone is encouraged to convert his favourite ->read_proc user or I'll do it, lazy bastards. Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29proc: drop several "PDE valid/invalid" checksAlexey Dobriyan1-19/+14
proc-misc code is noticeably full of "if (de)" checks when PDE passed is always valid. Remove them. Addition of such check in proc_lookup_de() is for failed lookup case. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29proc: less special case in xlate codeAlexey Dobriyan1-3/+6
If valid "parent" is passed to proc_create/remove_proc_entry(), then name of PDE should consist of only one path component, otherwise creation or or removal will fail. However, if NULL is passed as parent then create/remove accept full path as a argument. This is arbitrary restriction -- all infrastructure is in place. So, patch allows the following to succeed: create_proc_entry("foo/bar", 0, pde_baz); remove_proc_entry("baz/foo/bar", &proc_root); Also makes the following to behave identically: create_proc_entry("foo/bar", 0, NULL); create_proc_entry("foo/bar", 0, &proc_root); Discrepancy noticed by Den Lunev (IIRC). Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29proc: simplify locking in remove_proc_entry()Alexey Dobriyan1-42/+40
proc_subdir_lock protects only modifying and walking through PDE lists, so after we've found PDE to remove and actually removed it from lists, there is no need to hold proc_subdir_lock for the rest of operation. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29proc: print more information when removing non-empty directoriesAlexey Dobriyan1-1/+6
This usually saves one recompile to insert similar printk like below. :) Sample nastygram: remove_proc_entry: removing non-empty directory '/proc/foo', leaking at least 'bar' ------------[ cut here ]------------ WARNING: at fs/proc/generic.c:776 remove_proc_entry+0x18a/0x200() Modules linked in: foo(-) container fan battery dock sbs ac sbshc backlight ipv6 loop af_packet amd_rng sr_mod i2c_amd8111 i2c_amd756 cdrom i2c_core button thermal processor Pid: 3034, comm: rmmod Tainted: G M 2.6.25-rc1 #5 Call Trace: [<ffffffff80231974>] warn_on_slowpath+0x64/0x90 [<ffffffff80232a6e>] printk+0x4e/0x60 [<ffffffff802d6c8a>] remove_proc_entry+0x18a/0x200 [<ffffffff8045cd88>] mutex_lock_nested+0x1c8/0x2d0 [<ffffffff8025f0f0>] __try_stop_module+0x0/0x40 [<ffffffff8025effd>] sys_delete_module+0x14d/0x200 [<ffffffff8045df3d>] lockdep_sys_exit_thunk+0x35/0x67 [<ffffffff8031c307>] __up_read+0x27/0xa0 [<ffffffff8045decc>] trace_hardirqs_on_thunk+0x35/0x3a [<ffffffff8020b6ab>] system_call_after_swapgs+0x7b/0x80 ---[ end trace 10ef850597e89c54 ]--- Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru> Cc: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-07[NET]: Make /proc/net a symlink on /proc/self/net (v3)Pavel Emelyanov1-9/+17
Current /proc/net is done with so called "shadows", but current implementation is broken and has little chances to get fixed. The problem is that dentries subtree of /proc/net directory has fancy revalidation rules to make processes living in different net namespaces see different entries in /proc/net subtree, but currently, tasks see in the /proc/net subdir the contents of any other namespace, depending on who opened the file first. The proposed fix is to turn /proc/net into a symlink, which points to /proc/self/net, which in turn shows what previously was in /proc/net - the network-related info, from the net namespace the appropriate task lives in. # ls -l /proc/net lrwxrwxrwx 1 root root 8 Mar 5 15:17 /proc/net -> self/net In other words - this behaves like /proc/mounts, but unlike "mounts", "net" is not a file, but a directory. Changes from v2: * Fixed discrepancy of /proc/net nlink count and selinux labeling screwup pointed out by Stephen. To get the correct nlink count the ->getattr callback for /proc/net is overridden to read one from the net->proc_net entry. To make selinux still work the net->proc_net entry is initialized properly, i.e. with the "net" name and the proc_net parent. Selinux fixes are Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Changes from v1: * Fixed a task_struct leak in get_proc_task_net, pointed out by Paul. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-02-08proc: fix ->open'less usage due to ->proc_fops flipAlexey Dobriyan1-4/+36
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>
2008-02-08proc: detect duplicate names on registrationZhang Rui1-0/+10
Print a warning if PDE is registered with a name which already exists in target directory. Bug report and a simple fix can be found here: http://bugzilla.kernel.org/show_bug.cgi?id=8798 [\n fixlet and no undescriptive variable usage --adobriyan] [akpm@linux-foundation.org: make printk comprehensible] Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08proc: remove useless check on symlink removalAlexey Dobriyan1-1/+1
proc symlinks always have valid ->data containing destination of symlink. No need to check it on removal -- proc_symlink() already done it. Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08proc: simplify function prototypesAlexey Dobriyan1-12/+6
Move code around so as to reduce the number of forward-declarations. Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08proc: less LOCK operations during lookupAlexey Dobriyan1-2/+2
Pseudo-code for lookup effectively is: LOCK kernel LOCK proc_subdir_lock find PDE UNLOCK proc_subdir_lock get inode LOCK proc_subdir_lock goto unlock UNLOCK proc_subdir_lock UNLOCK kernel We can get rid of LOCK/UNLOCK pair after getting inode simply by jumping to unlock_kernel() directly. Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-12-10proc: remove/Fix proc generic d_revalidateEric W. Biederman1-7/+0
Ultimately to implement /proc perfectly we need an implementation of d_revalidate because files and directories can be removed behind the back of the VFS, and d_revalidate is the only way we can let the VFS know that this has happened. Unfortunately the linux VFS can not cope with anything in the path to a mount point going away. So a proper d_revalidate method that calls d_drop also needs to call have_submounts which is moderately expensive, so you really don't want a d_revalidate method that unconditionally calls it, but instead only calls it when the backing object has really gone away. proc generic entries only disappear on module_unload (when not counting the fledgling network namespace) so it is quite rare that we actually encounter that case and has not actually caused us real world trouble yet. So until we get a proper test for keeping dentries in the dcache fix the current d_revalidate method by completely removing it. This returns us to the current status quo. So with CONFIG_NETNS=n things should look as they have always looked. For CONFIG_NETNS=y things work most of the time but there are a few rare corner cases that don't behave properly. As the network namespace is barely present in 2.6.24 this should not be a problem. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "Denis V. Lunev" <den@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-12-05proc: fix proc_dir_entry refcountingAlexey Dobriyan1-7/+2
Creating PDEs with refcount 0 and "deleted" flag has problems (see below). Switch to usual scheme: * PDE is created with refcount 1 * every de_get does +1 * every de_put() and remove_proc_entry() do -1 * once refcount reaches 0, PDE is freed. This elegantly fixes at least two following races (both observed) without introducing new locks, without abusing old locks, without spreading lock_kernel(): 1) PDE leak remove_proc_entry de_put ----------------- ------ [refcnt = 1] if (atomic_read(&de->count) == 0) if (atomic_dec_and_test(&de->count)) if (de->deleted) /* also not taken! */ free_proc_entry(de); else de->deleted = 1; [refcount=0, deleted=1] 2) use after free remove_proc_entry de_put ----------------- ------ [refcnt = 1] if (atomic_dec_and_test(&de->count)) if (atomic_read(&de->count) == 0) free_proc_entry(de); /* boom! */ if (de->deleted) free_proc_entry(de); BUG: unable to handle kernel paging request at virtual address 6b6b6b6b printing eip: c10acdda *pdpt = 00000000338f8001 *pde = 0000000000000000 Oops: 0000 [#1] PREEMPT SMP Modules linked in: af_packet ipv6 cpufreq_ondemand loop serio_raw psmouse k8temp hwmon sr_mod cdrom Pid: 23161, comm: cat Not tainted (2.6.24-rc2-8c0863403f109a43d7000b4646da4818220d501f #4) EIP: 0060:[<c10acdda>] EFLAGS: 00210097 CPU: 1 EIP is at strnlen+0x6/0x18 EAX: 6b6b6b6b EBX: 6b6b6b6b ECX: 6b6b6b6b EDX: fffffffe ESI: c128fa3b EDI: f380bf34 EBP: ffffffff ESP: f380be44 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 Process cat (pid: 23161, ti=f380b000 task=f38f2570 task.ti=f380b000) Stack: c10ac4f0 00000278 c12ce000 f43cd2a8 00000163 00000000 7da86067 00000400 c128fa20 00896b18 f38325a8 c128fe20 ffffffff 00000000 c11f291e 00000400 f75be300 c128fa20 f769c9a0 c10ac779 f380bf34 f7bfee70 c1018e6b f380bf34 Call Trace: [<c10ac4f0>] vsnprintf+0x2ad/0x49b [<c10ac779>] vscnprintf+0x14/0x1f [<c1018e6b>] vprintk+0xc5/0x2f9 [<c10379f1>] handle_fasteoi_irq+0x0/0xab [<c1004f44>] do_IRQ+0x9f/0xb7 [<c117db3b>] preempt_schedule_irq+0x3f/0x5b [<c100264e>] need_resched+0x1f/0x21 [<c10190ba>] printk+0x1b/0x1f [<c107c8ad>] de_put+0x3d/0x50 [<c107c8f8>] proc_delete_inode+0x38/0x41 [<c107c8c0>] proc_delete_inode+0x0/0x41 [<c1066298>] generic_delete_inode+0x5e/0xc6 [<c1065aa9>] iput+0x60/0x62 [<c1063c8e>] d_kill+0x2d/0x46 [<c1063fa9>] dput+0xdc/0xe4 [<c10571a1>] __fput+0xb0/0xcd [<c1054e49>] filp_close+0x48/0x4f [<c1055ee9>] sys_close+0x67/0xa5 [<c10026b6>] sysenter_past_esp+0x5f/0x85 ======================= Code: c9 74 0c f2 ae 74 05 bf 01 00 00 00 4f 89 fa 5f 89 d0 c3 85 c9 57 89 c7 89 d0 74 05 f2 ae 75 01 4f 89 f8 5f c3 89 c1 89 c8 eb 06 <80> 38 00 74 07 40 4a 83 fa ff 75 f4 29 c8 c3 90 90 90 57 83 c9 EIP: [<c10acdda>] strnlen+0x6/0x18 SS:ESP 0068:f380be44 Also, remove broken usage of ->deleted from reiserfs: if sget() succeeds, module is already pinned and remove_proc_entry() can't happen => nobody can mark PDE deleted. Dummy proc root in netns code is not marked with refcount 1. AFAICS, we never get it, it's just for proper /proc/net removal. I double checked CLONE_NETNS continues to work. Patch survives many hours of modprobe/rmmod/cat loops without new bugs which can be attributed to refcounting. Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>