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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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take that to kern_mount_data()-using callers
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.
The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.
New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time. Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.
The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.
Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.
Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.
===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
// but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}
@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}
@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
*off = E
|
*off += E
|
func(..., off, ...)
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E = *off
)
...+>
}
@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}
@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
*off = E
|
*off += E
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func(..., off, ...)
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E = *off
)
...+>
}
@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}
@ fops0 @
identifier fops;
@@
struct file_operations fops = {
...
};
@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
.llseek = llseek_f,
...
};
@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
.read = read_f,
...
};
@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
.write = write_f,
...
};
@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
.open = open_f,
...
};
// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
... .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};
@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
... .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};
// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
... .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};
// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};
// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};
@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+ .llseek = default_llseek, /* write accesses f_pos */
};
// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////
@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
.write = write_f,
.read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};
@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};
@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};
@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>
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I removed 3 unused assignments. The first two get reset on the first
statement of their functions. For "err" in root.c we don't return an
error and we don't use the variable again.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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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>
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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simple_set_mnt() is defined as returning 'int' but always returns 0.
Callers assume simple_set_mnt() never fails and don't properly cleanup if
it were to _ever_ fail. For instance, get_sb_single() and get_sb_nodev()
should:
up_write(sb->s_unmount);
deactivate_super(sb);
if simple_set_mnt() fails.
Since simple_set_mnt() never fails, would be cleaner if it did not
return anything.
[akpm@linux-foundation.org: fix build]
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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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>
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Now that everything was moved to their more or less expected places,
apply rm(1).
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
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kmem_cache creation code will panic, don't return anything.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
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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>
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Remove proc_root export. Creation and removal works well if parent PDE is
supplied as NULL -- it worked always that way.
So, one useless export removed and consistency added, some drivers created
PDEs with &proc_root as parent but removed them as NULL and so on.
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>
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Use creation by full path: "driver/foo".
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>
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Use creation by full path instead: "fs/foo".
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>
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Remove proc_bus export and variable itself. Using pathnames works fine
and is slightly more understandable and greppable.
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>
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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>
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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>
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proc_kill_inodes() can clear ->i_fop in the middle of vfs_readdir resulting in
NULL dereference during "file->f_op->readdir(file, buf, filler)".
The solution is to remove proc_kill_inodes() completely:
a) we don't have tricky modules implementing their tricky readdir hooks which
could keeping this revoke from hell.
b) In a situation when module is gone but PDE still alive, standard
readdir will return only "." and "..", because pde->next was cleared by
remove_proc_entry().
c) the race proc_kill_inode() destined to prevent is not completely
fixed, just race window made smaller, because vfs_readdir() is run
without sb_lock held and without file_list_lock held. Effectively,
->i_fop is cleared at random moment, which can't fix properly anything.
BUG: unable to handle kernel NULL pointer dereference at virtual address 00000018
printing eip: c1061205 *pdpt = 0000000005b22001 *pde = 0000000000000000
Oops: 0000 [#1] PREEMPT SMP
Modules linked in: foo af_packet ipv6 cpufreq_ondemand loop serio_raw sr_mod k8temp cdrom hwmon amd_rng
Pid: 2033, comm: find Not tainted (2.6.24-rc1-b1d08ac064268d0ae2281e98bf5e82627e0f0c56 #2)
EIP: 0060:[<c1061205>] EFLAGS: 00010246 CPU: 0
EIP is at vfs_readdir+0x47/0x74
EAX: c6b6a780 EBX: 00000000 ECX: c1061040 EDX: c5decf94
ESI: c6b6a780 EDI: fffffffe EBP: c9797c54 ESP: c5decf78
DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process find (pid: 2033, ti=c5dec000 task=c64bba90 task.ti=c5dec000)
Stack: c5decf94 c1061040 fffffff7 0805ffbc 00000000 c6b6a780 c1061295 0805ffbc
00000000 00000400 00000000 00000004 0805ffbc 4588eff4 c5dec000 c10026ba
00000004 0805ffbc 00000400 0805ffbc 4588eff4 bfdc6c70 000000dc 0000007b
Call Trace:
[<c1061040>] filldir64+0x0/0xc5
[<c1061295>] sys_getdents64+0x63/0xa5
[<c10026ba>] sysenter_past_esp+0x5f/0x85
=======================
Code: 49 83 78 18 00 74 43 8d 6b 74 bf fe ff ff ff 89 e8 e8 b8 c0 12 00 f6 83 2c 01 00 00 10 75 22 8b 5e 10 8b 4c 24 04 89 f0 8b 14 24 <ff> 53 18 f6 46 1a 04 89 c7 75 0b 8b 56 0c 8b 46 08 e8 c8 66 00
EIP: [<c1061205>] vfs_readdir+0x47/0x74 SS:ESP 0068:c5decf78
hch: "Nice, getting rid of this is a very good step formwards.
Unfortunately we have another copy of this junk in
security/selinux/selinuxfs.c:sel_remove_entries() which would need the
same treatment."
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Acked-by: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
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>
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It appears we overlooked support for removing generic proc files
when we added support for multiple proc super blocks. Handle
that now.
[akpm@linux-foundation.org: coding-style cleanups]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Alexey Dobriyan <adobriyan@sw.ru>
Acked-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The namespace's proc_mnt must be kern_mount-ed to make this pointer always
valid, independently of whether the user space mounted the proc or not. This
solves raced in proc_flush_task, etc. with the proc_mnt switching from NULL
to not-NULL.
The initialization is done after the init's pid is created and hashed to make
proc_get_sb() finr it and get for root inode.
Sice the namespace holds the vfsmnt, vfsmnt holds the superblock and the
superblock holds the namespace we must explicitly break this circle to destroy
all the stuff. This is done after the init of the namespace dies. Running a
few steps forward - when init exits it will kill all its children, so no
proc_mnt will be needed after its death.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Paul Menage <menage@google.com>
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>
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Each pid namespace have to be visible through its own proc mount. Thus we
need to have per-namespace proc trees with their own superblocks.
We cannot easily show different pid namespace via one global proc tree, since
each pid refers to different tasks in different namespaces. E.g. pid 1
refers to the init task in the initial namespace and to some other task when
seeing from another namespace. Moreover - pid, exisintg in one namespace may
not exist in the other.
This approach has one move advantage is that the tasks from the init namespace
can see what tasks live in another namespace by reading entries from another
proc tree.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Paul Menage <menage@google.com>
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>
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This patch makes /proc/net per network namespace. It modifies the global
variables proc_net and proc_net_stat to be per network namespace.
The proc_net file helpers are modified to take a network namespace argument,
and all of their callers are fixed to pass &init_net for that argument.
This ensures that all of the /proc/net files are only visible and
usable in the initial network namespace until the code behind them
has been updated to be handle multiple network namespaces.
Making /proc/net per namespace is necessary as at least some files
in /proc/net depend upon the set of network devices which is per
network namespace, and even more files in /proc/net have contents
that are relevant to a single network namespace.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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We're using #ifdef CONFIG_SYSCTL, but we should be using CONFIG_PROC_SYSCTL,
so we get
fs/built-in.o: In function `proc_root_init':
/usr/src/linux/fs/proc/root.c:83: undefined reference to `proc_sys_init'
Fix that up and remove an ifdef-in-C.
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Helge Hafting <helgehaf@aitel.hist.no>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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With this change the sysctl inodes can be cached and nothing needs to be done
when removing a sysctl table.
For a cost of 2K code we will save about 4K of static tables (when we remove
de from ctl_table) and 70K in proc_dir_entries that we will not allocate, or
about half that on a 32bit arch.
The speed feels about the same, even though we can now cache the sysctl
dentries :(
We get the core advantage that we don't need to have a 1 to 1 mapping between
ctl table entries and proc files. Making it possible to have /proc/sys vary
depending on the namespace you are in. The currently merged namespaces don't
have an issue here but the network namespace under /proc/sys/net needs to have
different directories depending on which network adapters are visible. By
simply being a cache different directories being visible depending on who you
are is trivial to implement.
[akpm@osdl.org: fix uninitialised var]
[akpm@osdl.org: fix ARM build]
[bunk@stusta.de: make things static]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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binfmt_misc has a mount point in the middle of the sysctl and that mount point
is created as a proc_generic directory.
Doing it that way gets in the way of cleaning up the sysctl proc support as it
continues the existence of a horrible hack. So instead simply create the
directory as an ordinary sysctl directory. At least that removes the magic
special case.
[akpm@osdl.org: warning fix]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Many struct inode_operations in the kernel can be "const". Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data. In addition it'll catch accidental writes at compile time to
these shared resources.
Signed-off-by: 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>
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Many struct file_operations in the kernel can be "const". Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data. In addition it'll catch accidental writes at compile time to
these shared resources.
Signed-off-by: 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>
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Helper functions in base.c like proc_pident_readdir and proc_pident_lookup
assume the directories have an associated task, and cannot currently be used
on the /proc root directory because it does not have such a task.
This small changes allows for base.c to be simplified and later when multiple
pid spaces are introduced it makes getting the needed context information
trivial.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
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Extend the get_sb() filesystem operation to take an extra argument that
permits the VFS to pass in the target vfsmount that defines the mountpoint.
The filesystem is then required to manually set the superblock and root dentry
pointers. For most filesystems, this should be done with simple_set_mnt()
which will set the superblock pointer and then set the root dentry to the
superblock's s_root (as per the old default behaviour).
The get_sb() op now returns an integer as there's now no need to return the
superblock pointer.
This patch permits a superblock to be implicitly shared amongst several mount
points, such as can be done with NFS to avoid potential inode aliasing. In
such a case, simple_set_mnt() would not be called, and instead the mnt_root
and mnt_sb would be set directly.
The patch also makes the following changes:
(*) the get_sb_*() convenience functions in the core kernel now take a vfsmount
pointer argument and return an integer, so most filesystems have to change
very little.
(*) If one of the convenience function is not used, then get_sb() should
normally call simple_set_mnt() to instantiate the vfsmount. This will
always return 0, and so can be tail-called from get_sb().
(*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the
dcache upon superblock destruction rather than shrink_dcache_anon().
This is required because the superblock may now have multiple trees that
aren't actually bound to s_root, but that still need to be cleaned up. The
currently called functions assume that the whole tree is rooted at s_root,
and that anonymous dentries are not the roots of trees which results in
dentries being left unculled.
However, with the way NFS superblock sharing are currently set to be
implemented, these assumptions are violated: the root of the filesystem is
simply a dummy dentry and inode (the real inode for '/' may well be
inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries
with child trees.
[*] Anonymous until discovered from another tree.
(*) The documentation has been adjusted, including the additional bit of
changing ext2_* into foo_* in the documentation.
[akpm@osdl.org: convert ipath_fs, do other stuff]
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Nathan Scott <nathans@sgi.com>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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1) it should use nr_processes(), not nr_threads; otherwise we are getting
very confused find(1) and friends, among other things.
2) better do that at stat() time than at every damn lookup in procfs root.
Patch had been sitting in FC4 kernels for many months now...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Function prototypes belong into header files.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
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