| Age | Commit message (Collapse) | Author | Files | Lines |
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->needs_read_fill is used to implement the following behaviors.
1. Ensure buffer filling on the first read.
2. Force buffer filling after a write.
3. Force buffer filling after a successful poll.
However, #2 and #3 don't really work as sysfs doesn't reset file
position. While the read buffer would be refilled, the next read
would continue from the position after the last read or write,
requiring an explicit seek to the start for it to be useful, which
makes ->needs_read_fill superflous as read buffer is always refilled
if f_pos == 0.
Update sysfs_read_file() to test buffer->page for #1 instead and
remove ->needs_read_fill. While this changes behavior in extreme
corner cases - e.g. re-reading a sysfs file after seeking to non-zero
position after a write or poll, it's highly unlikely to lead to actual
breakage. This change is to prepare for using seq_file in the read
path.
While at it, reformat a comment in fill_write_buffer().
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Given a sysfs_dirent, there is no reason to have multiple versions of
removal functions. A function which removes the specified
sysfs_dirent and its descendants is enough.
This patch intorduces [__}sysfs_remove() which replaces all internal
variations of removal functions. This will be the only removal
function in the planned new sysfs_dirent based interface.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Currently, sysfs directory removal is inconsistent in that it would
remove any files directly under it but wouldn't recurse into
directories. Thanks to group subdirectories, this doesn't even match
with kobject boundaries. sysfs is in the process of being separated
out so that it can be used by multiple subsystems and we want to have
a consistent behavior - either removal of a sysfs_dirent should remove
every descendant entries or none instead of something inbetween.
This patch implements proper recursive removal in
__sysfs_remove_dir(). The function now walks its subtree in a
post-order walk to remove all descendants.
This is a behavior change but kobject / driver layer, which currently
is the only consumer, has already been updated to handle duplicate
removal attempts, so nothing should be broken after this change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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sysfs currently has a rather weird behavior regarding removals. A
directory removal would delete all files directly under it but
wouldn't recurse into subdirectories, which, while a bit inconsistent,
seems to make sense at the first glance as each directory is
supposedly associated with a kobject and each kobject can take care of
the directory deletion; however, this doesn't really hold as we have
groups which can be directories without a kobject associated with it
and require explicit deletions.
We're in the process of separating out sysfs from kboject / driver
core and want a consistent behavior. A removal should delete either
only the specified node or everything under it. I think it is helpful
to support recursive atomic removal and later patches will implement
it.
Such change means that a sysfs_dirent associated with kobject may be
deleted before the kobject itself is removed if one of its ancestor
gets removed before it. As sysfs_remove_dir() puts the base ref, we
may end up with dangling pointer on descendants. This can be solved
by holding an extra reference on the sd from kobject.
Acquire an extra reference on the associated sysfs_dirent on directory
creation and put it after removal.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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sysfs_addrm_start/finish() enclose sysfs_dirent additions and
deletions and sysfs_addrm_cxt is used to record information necessary
to finish the operations. Currently, sysfs_addrm_start() takes
@parent_sd, records it in sysfs_addrm_cxt, and assumes that all
operations in the block are performed under that @parent_sd.
This assumption has been fine until now but we want to make some
operations behave recursively and, while having @parent_sd recorded in
sysfs_addrm_cxt doesn't necessarily prevents that, it becomes
confusing.
This patch removes sysfs_addrm_cxt->parent_sd and makes
sysfs_add_one() take an explicit @parent_sd parameter. Note that
sysfs_remove_one() doesn't need the extra argument as its parent is
always known from the target @sd.
While at it, add __acquires/releases() notations to
sysfs_addrm_start/finish() respectively.
This patch doesn't make any functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Some internal sysfs functions which take explicit namespace argument
are weird in that they place the optional @ns in front of @name which
is contrary to the established convention. This is confusing and
error-prone especially as @ns and @name may be interchanged without
causing compilation warning.
Swap the positions of @name and @ns in the following internal
functions.
sysfs_find_dirent()
sysfs_rename()
sysfs_hash_and_remove()
sysfs_name_hash()
sysfs_name_compare()
create_dir()
This patch doesn't introduce any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The pre-existing sysfs interfaces which take explicit namespace
argument are weird in that they place the optional @ns in front of
@name which is contrary to the established convention. For example,
we end up forcing vast majority of sysfs_get_dirent() users to do
sysfs_get_dirent(parent, NULL, name), which is silly and error-prone
especially as @ns and @name may be interchanged without causing
compilation warning.
This renames sysfs_get_dirent() to sysfs_get_dirent_ns() and swap the
positions of @name and @ns, and sysfs_get_dirent() is now a wrapper
around sysfs_get_dirent_ns(). This makes confusions a lot less
likely.
There are other interfaces which take @ns before @name. They'll be
updated by following patches.
This patch doesn't introduce any functional changes.
v2: EXPORT_SYMBOL_GPL() wasn't updated leading to undefined symbol
error on module builds. Reported by build test robot. Fixed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The way namespace tags are implemented in sysfs is more complicated
than necessary. As each tag is a pointer value and required to be
non-NULL under a namespace enabled parent, there's no need to record
separately what type each tag is or where namespace is enabled.
If multiple namespace types are needed, which currently aren't, we can
simply compare the tag to a set of allowed tags in the superblock
assuming that the tags, being pointers, won't have the same value
across multiple types. Also, whether to filter by namespace tag or
not can be trivially determined by whether the node has any tagged
children or not.
This patch rips out kobj_ns_type handling from sysfs. sysfs no longer
cares whether specific type of namespace is enabled or not. If a
sysfs_dirent has a non-NULL tag, the parent is marked as needing
namespace filtering and the value is tested against the allowed set of
tags for the superblock (currently only one but increasing this number
isn't difficult) and the sysfs_dirent is ignored if it doesn't match.
This removes most kobject namespace knowledge from sysfs proper which
will enable proper separation and layering of sysfs. The namespace
sanity checks in fs/sysfs/dir.c are replaced by the new sanity check
in kobject_namespace(). As this is the only place ktype->namespace()
is called for sysfs, this doesn't weaken the sanity check
significantly. I omitted converting the sanity check in
sysfs_do_create_link_sd(). While the check can be shifted to upper
layer, mistakes there are well contained and should be easily visible
anyway.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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There's no reason for sysfs to be calling ktype->namespace(). It is
backwards, obfuscates what's going on and unnecessarily tangles two
separate layers.
There are two places where symlink code calls ktype->namespace().
* sysfs_do_create_link_sd() calls it to find out the namespace tag of
the target directory. Unless symlinking races with cross-namespace
renaming, this equals @target_sd->s_ns.
* sysfs_rename_link() uses it to find out the new namespace to rename
to and the new namespace can be different from the existing one.
The function is renamed to sysfs_rename_link_ns() with an explicit
@ns argument and the ktype->namespace() invocation is shifted to the
device layer.
While this patch replaces ktype->namespace() invocation with the
recorded result in @target_sd, this shouldn't result in any behvior
difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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For some unrecognizable reason, namespace information is communicated
to sysfs through ktype->namespace() callback when there's *nothing*
which needs the use of a callback. The whole sequence of operations
is completely synchronous and sysfs operations simply end up calling
back into the layer which just invoked it in order to find out the
namespace information, which is completely backwards, obfuscates
what's going on and unnecessarily tangles two separate layers.
This patch doesn't remove ktype->namespace() but shifts its handling
to kobject layer. We probably want to get rid of the callback in the
long term.
This patch adds an explicit param to sysfs_{create|rename|move}_dir()
and renames them to sysfs_{create|rename|move}_dir_ns(), respectively.
ktype->namespace() invocations are moved to the calling sites of the
above functions. A new helper kboject_namespace() is introduced which
directly tests kobj_ns_type_operations->type which should give the
same result as testing sysfs_fs_type(parent_sd) and returns @kobj's
namespace tag as necessary. kobject_namespace() is extern as it will
be used from another file in the following patches.
This patch should be an equivalent conversion without any functional
difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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sysfs ns (namespace) implementation became more convoluted than
necessary while trying to hide ns information from visible interface.
The relatively recent attr ns support is a good example.
* attr ns tag is determined by sysfs_ops->namespace() callback while
dir tag is determined by kobj_type->namespace(). The placement is
arbitrary.
* Instead of performing operations with explicit ns tag, the namespace
callback is routed through sysfs_attr_ns(), sysfs_ops->namespace(),
class_attr_namespace(), class_attr->namespace(). It's not simpler
in any sense. The only thing this convolution does is traversing
the whole stack backwards.
The namespace callbacks are unncessary because the operations involved
are inherently synchronous. The information can be provided in in
straight-forward top-down direction and reversing that direction is
unnecessary and against basic design principles.
This backward interface is unnecessarily convoluted and hinders
properly separating out sysfs from driver model / kobject for proper
layering. This patch updates attr ns support such that
* sysfs_ops->namespace() and class_attr->namespace() are dropped.
* sysfs_{create|remove}_file_ns(), which take explicit @ns param, are
added and sysfs_{create|remove}_file() are now simple wrappers
around the ns aware functions.
* ns handling is dropped from sysfs_chmod_file(). Nobody uses it at
this point. sysfs_chmod_file_ns() can be added later if necessary.
* Explicit @ns is propagated through class_{create|remove}_file_ns()
and netdev_class_{create|remove}_file_ns().
* driver/net/bonding which is currently the only user of attr
namespace is updated to use netdev_class_{create|remove}_file_ns()
with @bh->net as the ns tag instead of using the namespace callback.
This patch should be an equivalent conversion without any functional
difference. It makes the code easier to follow, reduces lines of code
a bit and helps proper separation and layering.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The expansion of to_sysfs_dirent() contains an unncessary trailing
semicolon making it impossible to use in the middle of statements.
Drop it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Pull vfs pile 2 (of many) from Al Viro:
"Mostly Miklos' series this time"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
constify dcache.c inlined helpers where possible
fuse: drop dentry on failed revalidate
fuse: clean up return in fuse_dentry_revalidate()
fuse: use d_materialise_unique()
sysfs: use check_submounts_and_drop()
nfs: use check_submounts_and_drop()
gfs2: use check_submounts_and_drop()
afs: use check_submounts_and_drop()
vfs: check unlinked ancestors before mount
vfs: check submounts and drop atomically
vfs: add d_walk()
vfs: restructure d_genocide()
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Pull namespace changes from Eric Biederman:
"This is an assorted mishmash of small cleanups, enhancements and bug
fixes.
The major theme is user namespace mount restrictions. nsown_capable
is killed as it encourages not thinking about details that need to be
considered. A very hard to hit pid namespace exiting bug was finally
tracked and fixed. A couple of cleanups to the basic namespace
infrastructure.
Finally there is an enhancement that makes per user namespace
capabilities usable as capabilities, and an enhancement that allows
the per userns root to nice other processes in the user namespace"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
userns: Kill nsown_capable it makes the wrong thing easy
capabilities: allow nice if we are privileged
pidns: Don't have unshare(CLONE_NEWPID) imply CLONE_THREAD
userns: Allow PR_CAPBSET_DROP in a user namespace.
namespaces: Simplify copy_namespaces so it is clear what is going on.
pidns: Fix hang in zap_pid_ns_processes by sending a potentially extra wakeup
sysfs: Restrict mounting sysfs
userns: Better restrictions on when proc and sysfs can be mounted
vfs: Don't copy mount bind mounts of /proc/<pid>/ns/mnt between namespaces
kernel/nsproxy.c: Improving a snippet of code.
proc: Restrict mounting the proc filesystem
vfs: Lock in place mounts from more privileged users
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Do have_submounts(), shrink_dcache_parent() and d_drop() atomically.
check_submounts_and_drop() can deal with negative dentries and
non-directories as well.
Non-directories can also be mounted on. And just like directories we don't
want these to disappear with invalidation.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Don't allow mounting sysfs unless the caller has CAP_SYS_ADMIN rights
over the net namespace. The principle here is if you create or have
capabilities over it you can mount it, otherwise you get to live with
what other people have mounted.
Instead of testing this with a straight forward ns_capable call,
perform this check the long and torturous way with kobject helpers,
this keeps direct knowledge of namespaces out of sysfs, and preserves
the existing sysfs abstractions.
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Rely on the fact that another flavor of the filesystem is already
mounted and do not rely on state in the user namespace.
Verify that the mounted filesystem is not covered in any significant
way. I would love to verify that the previously mounted filesystem
has no mounts on top but there are at least the directories
/proc/sys/fs/binfmt_misc and /sys/fs/cgroup/ that exist explicitly
for other filesystems to mount on top of.
Refactor the test into a function named fs_fully_visible and call that
function from the mount routines of proc and sysfs. This makes this
test local to the filesystems involved and the results current of when
the mounts take place, removing a weird threading of the user
namespace, the mount namespace and the filesystems themselves.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Fix up the wording of sysfs_create/remove_groups() a bit.
Reported-by: Anthony Foiani <tkil@scrye.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This fixes up the remaining coding style issues in sysfs.h
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This fixes the coding style warnings in fs/sysfs/file.c for broken
strings across lines.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This fixes up the odd do/while after an if statement warning in dir.c
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This fixes the uaccess.h warnings in the sysfs.c files.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This fixes up the 80 column coding style issues in the sysfs .c files.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This fixes up all of the space-related coding style issues for the sysfs
code.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This removes all trailing whitespace errors in the sysfs code.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The export should happen after the function, not at the bottom of the
file, so fix that up.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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sysfs_remove_group() never had kerneldoc, so add it, and fix up the
kerneldoc for sysfs_remove_groups() which didn't specify the parameters
properly.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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checkpatch complains about the broken string in the file, and it's
correct, so fix it up.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This fixes up the * coding style warnings for the group.c sysfs file.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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There was some trailing spaces in the file, fix that up.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This fixes up the coding style issue of incorrectly placing the
EXPORT_SYMBOL_GPL() macro, it should be right after the function itself,
not at the end of the file.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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These functions are being open-coded in 3 different places in the driver
core, and other driver subsystems will want to start doing this as well,
so move it to the sysfs core to keep it all in one place, where we know
it is written properly.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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When only using bin_attrs instead of attrs the kernel prints a warning
and refuses to create the sysfs entry. This fixes that.
Signed-off-by: Oliver Schinagl <oliver@schinagl.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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groups should be able to support binary attributes, just like it
supports "normal" attributes. This lets us only handle one type of
structure, groups, throughout the driver core and subsystems, making
binary attributes a "full fledged" part of the driver model, and not
something just "tacked on".
Reported-by: Oliver Schinagl <oliver@schinagl.nl>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Pull driver core updates from Greg KH:
"Here's the big driver core merge for 3.11-rc1
Lots of little things, and larger firmware subsystem updates, all
described in the shortlog. Nice thing here is that we finally get rid
of CONFIG_HOTPLUG, after 10+ years, thanks to Stephen Rohtwell (it had
been always on for a number of kernel releases, now it's just
removed)"
* tag 'driver-core-3.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (27 commits)
driver core: device.h: fix doc compilation warnings
firmware loader: fix another compile warning with PM_SLEEP unset
build some drivers only when compile-testing
firmware loader: fix compile warning with PM_SLEEP set
kobject: sanitize argument for format string
sysfs_notify is only possible on file attributes
firmware loader: simplify holding module for request_firmware
firmware loader: don't export cache_firmware and uncache_firmware
drivers/base: Use attribute groups to create sysfs memory files
firmware loader: fix compile warning
firmware loader: fix build failure with !CONFIG_FW_LOADER_USER_HELPER
Documentation: Updated broken link in HOWTO
Finally eradicate CONFIG_HOTPLUG
driver core: firmware loader: kill FW_ACTION_NOHOTPLUG requests before suspend
driver core: firmware loader: don't cache FW_ACTION_NOHOTPLUG firmware
Documentation: Tidy up some drivers/base/core.c kerneldoc content.
platform_device: use a macro instead of platform_driver_register
firmware: move EXPORT_SYMBOL annotations
firmware: Avoid deadlock of usermodehelper lock at shutdown
dell_rbu: Select CONFIG_FW_LOADER_USER_HELPER explicitly
...
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get rid of the kludges in sysfs_readdir()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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If sysfs_notify is called on a binary attribute, bad things can
happen, so prevent it.
Note, no in-kernel usage of this is currently present, but in the
future, it's good to be safe.
Changes in V2:
- Also ignore sysfs_notify on dirs, links
- Use WARN_ON rather than silently failing
- Compiled and tested (huge apologies about first submission)
Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This patch removes sysfs_sb declaration from fs/sysfs/inode.c
(due to 0f4288ec6fcc1a47d1fa0241ec1c6dacd5a09e96,
"Kill unused sysfs_sb variable").
Signed-off-by: Rami Rosen <ramirose@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Fix a typo subling->sibling in the comment of sysfs_link_sibling().
Signed-off-by: Warner Wang <warner.wang@hp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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It might be a kernel disaster if one sysfs entry is freed but
still referenced by sysfs tree.
Recently Dave and Sasha reported one use-after-free problem on
sysfs entry, and the problem has been troubleshooted with help
of debug message added in this patch.
Given sysfs_get_dirent/sysfs_put are exported APIs, even inside
sysfs they are called in many contexts(kobject/attribe add/delete,
inode init/drop, dentry lookup/release, readdir, ...), it is healthful
to check the removed flag before freeing one entry and dump message
if it is freeing without being removed first.
Cc: Dave Jones <davej@redhat.com>
Cc: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The inode->i_mutex isn't hold when updating filp->f_pos
in read()/write(), so the filp->f_pos might be read as
0 or 1 in readdir() when there is concurrent read()/write()
on this same file, then may cause use after free in readdir().
The bug can be reproduced with Li Zefan's test code on the
link:
https://patchwork.kernel.org/patch/2160771/
This patch fixes the use after free under this situation.
Cc: stable <stable@vger.kernel.org>
Reported-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We want the fixes in here.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Pull sysfs fixes from Greg Kroah-Hartman:
"Here are two fixes for sysfs that resolve issues that have been found
by the Trinity fuzz tool, causing oopses in sysfs. They both have
been in linux-next for a while to ensure that they do not cause any
other problems."
* tag 'driver-core-3.9-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
sysfs: handle failure path correctly for readdir()
sysfs: fix race between readdir and lseek
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Only allow unprivileged mounts of proc and sysfs if they are already
mounted when the user namespace is created.
proc and sysfs are interesting because they have content that is
per namespace, and so fresh mounts are needed when new namespaces
are created while at the same time proc and sysfs have content that
is shared between every instance.
Respect the policy of who may see the shared content of proc and sysfs
by only allowing new mounts if there was an existing mount at the time
the user namespace was created.
In practice there are only two interesting cases: proc and sysfs are
mounted at their usual places, proc and sysfs are not mounted at all
(some form of mount namespace jail).
Cc: stable@vger.kernel.org
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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It seems that sysfs has an interesting way of doing the same thing.
This removes the cpu_relax unfortunately, but if it's really needed,
it would be better to add this to include/linux/atomic.h to benefit
all atomic ops users.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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In case of 'if (filp->f_pos == 0 or 1)' of sysfs_readdir(),
the failure from filldir() isn't handled, and the reference counter
of the sysfs_dirent object pointed by filp->private_data will be
released without clearing filp->private_data, so use after free
bug will be triggered later.
This patch returns immeadiately under the situation for fixing the bug,
and it is reasonable to return from readdir() when filldir() fails.
Reported-by: Dave Jones <davej@redhat.com>
Tested-by: Sasha Levin <levinsasha928@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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While readdir() is running, lseek() may set filp->f_pos as zero,
then may leave filp->private_data pointing to one sysfs_dirent
object without holding its reference counter, so the sysfs_dirent
object may be used after free in next readdir().
This patch holds inode->i_mutex to avoid the problem since
the lock is always held in readdir path.
Reported-by: Dave Jones <davej@redhat.com>
Tested-by: Sasha Levin <levinsasha928@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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I'm not sure why, but the hlist for each entry iterators were conceived
list_for_each_entry(pos, head, member)
The hlist ones were greedy and wanted an extra parameter:
hlist_for_each_entry(tpos, pos, head, member)
Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.
Besides the semantic patch, there was some manual work required:
- Fix up the actual hlist iterators in linux/list.h
- Fix up the declaration of other iterators based on the hlist ones.
- A very small amount of places were using the 'node' parameter, this
was modified to use 'obj->member' instead.
- Coccinelle didn't handle the hlist_for_each_entry_safe iterator
properly, so those had to be fixed up manually.
The semantic patch which is mostly the work of Peter Senna Tschudin is here:
@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;
type T;
expression a,c,d,e;
identifier b;
statement S;
@@
-T b;
<+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
|
hlist_for_each_entry_continue(a,
- b,
c) S
|
hlist_for_each_entry_from(a,
- b,
c) S
|
hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
|
hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
|
sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
|
sk_for_each_rcu(a,
- b,
c) S
|
sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
|
sk_for_each_safe(a,
- b,
c, d) S
|
sk_for_each_bound(a,
- b,
c) S
|
hlist_for_each_entry_safe(a,
- b,
c, d, e) S
|
hlist_for_each_entry_continue_rcu(a,
- b,
c) S
|
nr_neigh_for_each(a,
- b,
c) S
|
nr_neigh_for_each_safe(a,
- b,
c, d) S
|
nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
|
- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
|
- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
|
for_each_host(a,
- b,
c) S
|
for_each_host_safe(a,
- b,
c, d) S
|
for_each_mesh_entry(a,
- b,
c, d) S
)
...+>
[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: Peter Senna Tschudin <peter.senna@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Tejun Heo
Linus Torvalds
Miklos Szeredi
Eric W. Biederman
Greg Kroah-Hartman
Oliver Schinagl
Al Viro
Nick Dyer
Rami Rosen
Warner Wang
Ming Lei
Maarten Lankhorst
Sasha Levin