proc: fix UAF in proc_get_inode()

Fix race between rmmod and /proc/XXX's inode instantiation.

The bug is that pde->proc_ops don't belong to /proc, it belongs to a
module, therefore dereferencing it

proc: fix UAF in proc_get_inode()

Fix race between rmmod and /proc/XXX's inode instantiation.

The bug is that pde->proc_ops don't belong to /proc, it belongs to a
module, therefore dereferencing it after /proc entry has been registered
is a bug unless use_pde/unuse_pde() pair has been used.

use_pde/unuse_pde can be avoided (2 atomic ops!) because pde->proc_ops
never changes so information necessary for inode instantiation can be
saved _before_ proc_register() in PDE itself and used later, avoiding
pde->proc_ops->... dereference.

rmmod lookup
sys_delete_module
proc_lookup_de
pde_get(de);
proc_get_inode(dir->i_sb, de);
mod->exit()
proc_remove
remove_proc_subtree
proc_entry_rundown(de);
free_module(mod);

if (S_ISREG(inode->i_mode))
if (de->proc_ops->proc_read_iter)
--> As module is already freed, will trigger UAF

BUG: unable to handle page fault for address: fffffbfff80a702b
PGD 817fc4067 P4D 817fc4067 PUD 817fc0067 PMD 102ef4067 PTE 0
Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 26 UID: 0 PID: 2667 Comm: ls Tainted: G
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
RIP: 0010:proc_get_inode+0x302/0x6e0
RSP: 0018:ffff88811c837998 EFLAGS: 00010a06
RAX: dffffc0000000000 RBX: ffffffffc0538140 RCX: 0000000000000007
RDX: 1ffffffff80a702b RSI: 0000000000000001 RDI: ffffffffc0538158
RBP: ffff8881299a6000 R08: 0000000067bbe1e5 R09: 1ffff11023906f20
R10: ffffffffb560ca07 R11: ffffffffb2b43a58 R12: ffff888105bb78f0
R13: ffff888100518048 R14: ffff8881299a6004 R15: 0000000000000001
FS: 00007f95b9686840(0000) GS:ffff8883af100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffbfff80a702b CR3: 0000000117dd2000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
proc_lookup_de+0x11f/0x2e0
__lookup_slow+0x188/0x350
walk_component+0x2ab/0x4f0
path_lookupat+0x120/0x660
filename_lookup+0x1ce/0x560
vfs_statx+0xac/0x150
__do_sys_newstat+0x96/0x110
do_syscall_64+0x5f/0x170
entry_SYSCALL_64_after_hwframe+0x76/0x7e

[[email protected]: don't do 2 atomic ops on the common path]
Link: https://lkml.kernel.org/r/3d25ded0-1739-447e-812b-e34da7990dcf@p183
Fixes: 778f3dd5a13c ("Fix procfs compat_ioctl regression")
Signed-off-by: Ye Bin <[email protected]>
Signed-off-by: Alexey Dobriyan <[email protected]>
Cc: Al Viro <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

Pass parent directory inode and expected name to ->d_revalidate()

->d_revalidate() often needs to access dentry parent and name; that has
to be done carefully, since the locking environment varies f

Pass parent directory inode and expected name to ->d_revalidate()

->d_revalidate() often needs to access dentry parent and name; that has
to be done carefully, since the locking environment varies from caller
to caller. We are not guaranteed that dentry in question will not be
moved right under us - not unless the filesystem is such that nothing
on it ever gets renamed.

It can be dealt with, but that results in boilerplate code that isn't
even needed - the callers normally have just found the dentry via dcache
lookup and want to verify that it's in the right place; they already
have the values of ->d_parent and ->d_name stable. There is a couple
of exceptions (overlayfs and, to less extent, ecryptfs), but for the
majority of calls that song and dance is not needed at all.

It's easier to make ecryptfs and overlayfs find and pass those values if
there's a ->d_revalidate() instance to be called, rather than doing that
in the instances.

This commit only changes the calling conventions; making use of supplied
values is left to followups.

NOTE: some instances need more than just the parent - things like CIFS
may need to build an entire path from filesystem root, so they need
more precautions than the usual boilerplate. This series doesn't
do anything to that need - these filesystems have to keep their locking
mechanisms (rename_lock loops, use of dentry_path_raw(), private rwsem
a-la v9fs).

One thing to keep in mind when using name is that name->name will normally
point into the pathname being resolved; the filename in question occupies
name->len bytes starting at name->name, and there is NUL somewhere after it,
but it the next byte might very well be '/' rather than '\0'. Do not
ignore name->len.

Reviewed-by: Jeff Layton <[email protected]>
Reviewed-by: Gabriel Krisman Bertazi <[email protected]>
Signed-off-by: Al Viro <[email protected]>

show more ...

proc: fold kmalloc() + strcpy() into kmemdup()

strcpy() will recalculate string length second time which is
unnecessary in this case.

Signed-off-by: Alexey Dobriyan <[email protected]>
Link: http

proc: fold kmalloc() + strcpy() into kmemdup()

strcpy() will recalculate string length second time which is
unnecessary in this case.

Signed-off-by: Alexey Dobriyan <[email protected]>
Link: https://lore.kernel.org/r/90af27c1-0b86-47a6-a6c8-61a58b8aa747@p183
Signed-off-by: Christian Brauner <[email protected]>

show more ...

proc: Remove usage of the deprecated ida_simple_xx() API

ida_alloc() and ida_free() should be preferred to the deprecated
ida_simple_get() and ida_simple_remove().

Note that the upper limit of ida_

proc: Remove usage of the deprecated ida_simple_xx() API

ida_alloc() and ida_free() should be preferred to the deprecated
ida_simple_get() and ida_simple_remove().

Note that the upper limit of ida_simple_get() is exclusive, but the one of
ida_alloc_max() is inclusive. So a -1 has been added when needed.

Signed-off-by: Christophe JAILLET <[email protected]>
Link: https://lore.kernel.org/r/ae10003feb87d240163d0854de95f09e1f00be7d.1717855701.git.christophe.jaillet@wanadoo.fr
Reviewed-by: Matthew Wilcox (Oracle) <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>

show more ...

proc: remove usage of the deprecated ida_simple_xx() API

ida_alloc() and ida_free() should be preferred to the deprecated
ida_simple_get() and ida_simple_remove().

Note that the upper limit of ida_

proc: remove usage of the deprecated ida_simple_xx() API

ida_alloc() and ida_free() should be preferred to the deprecated
ida_simple_get() and ida_simple_remove().

Note that the upper limit of ida_simple_get() is exclusive, but the one of
ida_alloc_max() is inclusive. So a -1 has been added when needed.

Link: https://lkml.kernel.org/r/ae10003feb87d240163d0854de95f09e1f00be7d.1717855701.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Christophe JAILLET <[email protected]>
Reviewed-by: Matthew Wilcox (Oracle) <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: Alistar Popple <[email protected]>
Cc: Christian Gromm <[email protected]>
Cc: Eddie James <[email protected]>
Cc: Jeremy Kerr <[email protected]>
Cc: Joel Stanley <[email protected]>
Cc: Parthiban Veerasooran <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

fs: pass the request_mask to generic_fillattr

generic_fillattr just fills in the entire stat struct indiscriminately
today, copying data from the inode. There is at least one attribute
(STATX_CHANGE

fs: pass the request_mask to generic_fillattr

generic_fillattr just fills in the entire stat struct indiscriminately
today, copying data from the inode. There is at least one attribute
(STATX_CHANGE_COOKIE) that can have side effects when it is reported,
and we're looking at adding more with the addition of multigrain
timestamps.

Add a request_mask argument to generic_fillattr and have most callers
just pass in the value that is passed to getattr. Have other callers
(e.g. ksmbd) just pass in STATX_BASIC_STATS. Also move the setting of
STATX_CHANGE_COOKIE into generic_fillattr.

Acked-by: Joseph Qi <[email protected]>
Reviewed-by: Xiubo Li <[email protected]>
Reviewed-by: "Paulo Alcantara (SUSE)" <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Signed-off-by: Jeff Layton <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>

show more ...

proc: remove mark_inode_dirty() in .setattr()

procfs' .setattr() has updated i_uid, i_gid and i_mode into proc dirent,
we don't need to call mark_inode_dirty() for delayed update, remove it.

Link:

proc: remove mark_inode_dirty() in .setattr()

procfs' .setattr() has updated i_uid, i_gid and i_mode into proc dirent,
we don't need to call mark_inode_dirty() for delayed update, remove it.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Chao Yu <[email protected]>
Reviewed-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

fs: port ->getattr() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just

fs: port ->getattr() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Christian Brauner (Microsoft) <[email protected]>

show more ...

fs: port ->setattr() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just

fs: port ->setattr() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Christian Brauner (Microsoft) <[email protected]>

show more ...

proc: fix dentry/inode overinstantiating under /proc/${pid}/net

When a process exits, /proc/${pid}, and /proc/${pid}/net dentries are
flushed. However some leaf dentries like /proc/${pid}/net/arp_c

proc: fix dentry/inode overinstantiating under /proc/${pid}/net

When a process exits, /proc/${pid}, and /proc/${pid}/net dentries are
flushed. However some leaf dentries like /proc/${pid}/net/arp_cache
aren't. That's because respective PDEs have proc_misc_d_revalidate() hook
which returns 1 and leaves dentries/inodes in the LRU.

Force revalidation/lookup on everything under /proc/${pid}/net by
inheriting proc_net_dentry_ops.

[[email protected]: coding-style cleanups]
Link: https://lkml.kernel.org/r/[email protected]
Fixes: c6c75deda813 ("proc: fix lookup in /proc/net subdirectories after setns(2)")
Signed-off-by: Alexey Dobriyan <[email protected]>
Reported-by: hui li <[email protected]>
Cc: Al Viro <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

fs: proc: store PDE()->data into inode->i_private

PDE_DATA(inode) is introduced to get user private data and hide the
layout of struct proc_dir_entry. The inode->i_private is used to do the
same th

fs: proc: store PDE()->data into inode->i_private

PDE_DATA(inode) is introduced to get user private data and hide the
layout of struct proc_dir_entry. The inode->i_private is used to do the
same thing as well. Save a copy of user private data to inode->
i_private when proc inode is allocated. This means the user also can
get their private data by inode->i_private.

Introduce pde_data() to wrap inode->i_private so that we can remove
PDE_DATA() from fs/proc/generic.c and make PTE_DATE() as a wrapper of
pde_data(). It will be easier if we decide to remove PDE_DATE() in the
future.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Muchun Song <[email protected]>
Acked-by: Christian Brauner <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: Alexey Gladkov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

proc: save LOC in __xlate_proc_name()

Can't look at this verbosity anymore.

Link: https://lkml.kernel.org/r/YFYXAp/[email protected]
Signed-off-by: Alexey Dobriyan <[email protected]

proc: save LOC in __xlate_proc_name()

Can't look at this verbosity anymore.

Link: https://lkml.kernel.org/r/YFYXAp/[email protected]
Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

fs/proc/generic.c: fix incorrect pde_is_permanent check

Currently the pde_is_permanent() check is being run on root multiple times
rather than on the next proc directory entry. This looks like a
co

fs/proc/generic.c: fix incorrect pde_is_permanent check

Currently the pde_is_permanent() check is being run on root multiple times
rather than on the next proc directory entry. This looks like a
copy-paste error. Fix this by replacing root with next.

Addresses-Coverity: ("Copy-paste error")
Link: https://lkml.kernel.org/r/[email protected]
Fixes: d919b33dafb3 ("proc: faster open/read/close with "permanent" files")
Signed-off-by: Colin Ian King <[email protected]>
Acked-by: Christian Brauner <[email protected]>
Reviewed-by: Alexey Dobriyan <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

fs: make helpers idmap mount aware

Extend some inode methods with an additional user namespace argument. A
filesystem that is aware of idmapped mounts will receive the user
namespace the mount has b

fs: make helpers idmap mount aware

Extend some inode methods with an additional user namespace argument. A
filesystem that is aware of idmapped mounts will receive the user
namespace the mount has been marked with. This can be used for
additional permission checking and also to enable filesystems to
translate between uids and gids if they need to. We have implemented all
relevant helpers in earlier patches.

As requested we simply extend the exisiting inode method instead of
introducing new ones. This is a little more code churn but it's mostly
mechanical and doesnt't leave us with additional inode methods.

Link: https://lore.kernel.org/r/[email protected]
Cc: Christoph Hellwig <[email protected]>
Cc: David Howells <[email protected]>
Cc: Al Viro <[email protected]>
Cc: [email protected]
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>

show more ...

stat: handle idmapped mounts

The generic_fillattr() helper fills in the basic attributes associated
with an inode. Enable it to handle idmapped mounts. If the inode is
accessed through an idmapped m

stat: handle idmapped mounts

The generic_fillattr() helper fills in the basic attributes associated
with an inode. Enable it to handle idmapped mounts. If the inode is
accessed through an idmapped mount map it into the mount's user
namespace before we store the uid and gid. If the initial user namespace
is passed nothing changes so non-idmapped mounts will see identical
behavior as before.

Link: https://lore.kernel.org/r/[email protected]
Cc: Christoph Hellwig <[email protected]>
Cc: David Howells <[email protected]>
Cc: Al Viro <[email protected]>
Cc: [email protected]
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: James Morris <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>

show more ...

attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking.

attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/[email protected]
Cc: Christoph Hellwig <[email protected]>
Cc: David Howells <[email protected]>
Cc: Al Viro <[email protected]>
Cc: [email protected]
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>

show more ...

proc: fix lookup in /proc/net subdirectories after setns(2)

Commit 1fde6f21d90f ("proc: fix /proc/net/* after setns(2)") only forced
revalidation of regular files under /proc/net/

However, /proc/ne

proc: fix lookup in /proc/net subdirectories after setns(2)

Commit 1fde6f21d90f ("proc: fix /proc/net/* after setns(2)") only forced
revalidation of regular files under /proc/net/

However, /proc/net/ is unusual in the sense of /proc/net/foo handlers
take netns pointer from parent directory which is old netns.

Steps to reproduce:

(void)open("/proc/net/sctp/snmp", O_RDONLY);
unshare(CLONE_NEWNET);

int fd = open("/proc/net/sctp/snmp", O_RDONLY);
read(fd, &c, 1);

Read will read wrong data from original netns.

Patch forces lookup on every directory under /proc/net .

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 1da4d377f943 ("proc: revalidate misc dentries")
Signed-off-by: Alexey Dobriyan <[email protected]>
Reported-by: "Rantala, Tommi T. (Nokia - FI/Espoo)" <[email protected]>
Cc: Al Viro <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

proc "seq files": switch to ->read_iter

Implement ->read_iter for all proc "seq files" so that splice works on
them.

Suggested-by: Linus Torvalds <[email protected]>
Signed-off-by: Chri

proc "seq files": switch to ->read_iter

Implement ->read_iter for all proc "seq files" so that splice works on
them.

Suggested-by: Linus Torvalds <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

proc "single files": switch to ->read_iter

Implement ->read_iter for all proc "single files" so that more bionic
tests cases can pass when they call splice() on other fun files like
/proc/version

S

proc "single files": switch to ->read_iter

Implement ->read_iter for all proc "single files" so that more bionic
tests cases can pass when they call splice() on other fun files like
/proc/version

Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

proc: add option to mount only a pids subset

This allows to hide all files and directories in the procfs that are not
related to tasks.

Signed-off-by: Alexey Gladkov <[email protected]>
Revi

proc: add option to mount only a pids subset

This allows to hide all files and directories in the procfs that are not
related to tasks.

Signed-off-by: Alexey Gladkov <[email protected]>
Reviewed-by: Alexey Dobriyan <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Signed-off-by: Eric W. Biederman <[email protected]>

show more ...

proc: faster open/read/close with "permanent" files

Now that "struct proc_ops" exist we can start putting there stuff which
could not fly with VFS "struct file_operations"...

Most of fs/proc/inode.

proc: faster open/read/close with "permanent" files

Now that "struct proc_ops" exist we can start putting there stuff which
could not fly with VFS "struct file_operations"...

Most of fs/proc/inode.c file is dedicated to make open/read/.../close
reliable in the event of disappearing /proc entries which usually happens
if module is getting removed. Files like /proc/cpuinfo which never
disappear simply do not need such protection.

Save 2 atomic ops, 1 allocation, 1 free per open/read/close sequence for such
"permanent" files.

Enable "permanent" flag for

/proc/cpuinfo
/proc/kmsg
/proc/modules
/proc/slabinfo
/proc/stat
/proc/sysvipc/*
/proc/swaps

More will come once I figure out foolproof way to prevent out module
authors from marking their stuff "permanent" for performance reasons
when it is not.

This should help with scalability: benchmark is "read /proc/cpuinfo R times
by N threads scattered over the system".

N R t, s (before) t, s (after)
-----------------------------------------------------
64 4096 1.582458 1.530502 -3.2%
256 4096 6.371926 6.125168 -3.9%
1024 4096 25.64888 24.47528 -4.6%

Benchmark source:

#include <chrono>
#include <iostream>
#include <thread>
#include <vector>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

const int NR_CPUS = sysconf(_SC_NPROCESSORS_ONLN);
int N;
const char *filename;
int R;

int xxx = 0;

int glue(int n)
{
cpu_set_t m;
CPU_ZERO(&m);
CPU_SET(n, &m);
return sched_setaffinity(0, sizeof(cpu_set_t), &m);
}

void f(int n)
{
glue(n % NR_CPUS);

while (*(volatile int *)&xxx == 0) {
}

for (int i = 0; i < R; i++) {
int fd = open(filename, O_RDONLY);
char buf[4096];
ssize_t rv = read(fd, buf, sizeof(buf));
asm volatile ("" :: "g" (rv));
close(fd);
}
}

int main(int argc, char *argv[])
{
if (argc < 4) {
std::cerr << "usage: " << argv[0] << ' ' << "N /proc/filename R
";
return 1;
}

N = atoi(argv[1]);
filename = argv[2];
R = atoi(argv[3]);

for (int i = 0; i < NR_CPUS; i++) {
if (glue(i) == 0)
break;
}

std::vector<std::thread> T;
T.reserve(N);
for (int i = 0; i < N; i++) {
T.emplace_back(f, i);
}

auto t0 = std::chrono::system_clock::now();
{
*(volatile int *)&xxx = 1;
for (auto& t: T) {
t.join();
}
}
auto t1 = std::chrono::system_clock::now();
std::chrono::duration<double> dt = t1 - t0;
std::cout << dt.count() << '
';

return 0;
}

P.S.:
Explicit randomization marker is added because adding non-function pointer
will silently disable structure layout randomization.

[[email protected]: coding style fixes]
Reported-by: kbuild test robot <[email protected]>
Reported-by: Dan Carpenter <[email protected]>
Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Joe Perches <[email protected]>
Link: http://lkml.kernel.org/r/20200222201539.GA22576@avx2
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

proc: decouple proc from VFS with "struct proc_ops"

Currently core /proc code uses "struct file_operations" for custom hooks,
however, VFS doesn't directly call them. Every time VFS expands
file_op

proc: decouple proc from VFS with "struct proc_ops"

Currently core /proc code uses "struct file_operations" for custom hooks,
however, VFS doesn't directly call them. Every time VFS expands
file_operations hook set, /proc code bloats for no reason.

Introduce "struct proc_ops" which contains only those hooks which /proc
allows to call into (open, release, read, write, ioctl, mmap, poll). It
doesn't contain module pointer as well.

Save ~184 bytes per usage:

add/remove: 26/26 grow/shrink: 1/4 up/down: 1922/-6674 (-4752)
Function old new delta
sysvipc_proc_ops - 72 +72
...
config_gz_proc_ops - 72 +72
proc_get_inode 289 339 +50
proc_reg_get_unmapped_area 110 107 -3
close_pdeo 227 224 -3
proc_reg_open 289 284 -5
proc_create_data 60 53 -7
rt_cpu_seq_fops 256 - -256
...
default_affinity_proc_fops 256 - -256
Total: Before=5430095, After=5425343, chg -0.09%

Link: http://lkml.kernel.org/r/20191225172228.GA13378@avx2
Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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fs/proc/generic.c: delete useless "len" variable

Pointer to next '/' encodes length of path element and next start
position. Subtraction and increment are redundant.

Link: http://lkml.kernel.org/r

fs/proc/generic.c: delete useless "len" variable

Pointer to next '/' encodes length of path element and next start
position. Subtraction and increment are redundant.

Link: http://lkml.kernel.org/r/20191004234521.GA30246@avx2
Signed-off-by: Alexey Dobriyan <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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proc: change ->nlink under proc_subdir_lock

Currently gluing PDE into global /proc tree is done under lock, but
changing ->nlink is not. Additionally struct proc_dir_entry::nlink is
not atomic so u

proc: change ->nlink under proc_subdir_lock

Currently gluing PDE into global /proc tree is done under lock, but
changing ->nlink is not. Additionally struct proc_dir_entry::nlink is
not atomic so updates can be lost.

Link: http://lkml.kernel.org/r/20190925202436.GA17388@avx2
Signed-off-by: Alexey Dobriyan <[email protected]>
Cc: Al Viro <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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treewide: Add SPDX license identifier for missed files

Add SPDX license identifiers to all files which:

- Have no license information of any form

- Have EXPORT_.*_SYMBOL_GPL inside which was use

treewide: Add SPDX license identifier for missed files

Add SPDX license identifiers to all files which:

- Have no license information of any form

- Have EXPORT_.*_SYMBOL_GPL inside which was used in the
initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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