The format_array_alloc() function is fundamentally racy, in that it
prints the array twice: once to figure out how much space to allocate
for the buffer, and the second time to actually print out the data.
If any of the array contents changes in between, the allocation size may
be wrong, and the end result may be truncated in odd ways.
Just don't do it. Allocate a maximum-sized array up-front, and just
format the array contents once. The only user of the u32_array
interfaces is the Xen spinlock statistics code, and it has 31 entries in
the arrays, so the maximum size really isn't that big, and the end
result is much simpler code without the bug.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
u32_array_open() is racy when multiple threads read from a file with a
seek position of zero, i.e. when two or more simultaneous reads are
occurring after the non-seekable files are created. It is possible that
file->private_data is double-freed because the threads races between
kfree(file->private-data);
and
file->private_data = NULL;
The fix is to only do format_array_alloc() when the file is opened and
free it when it is closed.
Note that because the file has always been non-seekable, you can't open
it and read it multiple times anyway, so the data has always been
generated just once. The difference is that now it is generated at open
time rather than at the time of the first read, and that avoids the
race.
Reported-by: Dave Jones <davej@redhat.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Raghavendra <raghavendra.kt@linux.vnet.ibm.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull driver core changes from Greg Kroah-Hartman:
"Here's the big driver core pull request for 3.6-rc1.
Unlike 3.5, this kernel should be a lot tamer, with the printk changes
now settled down. All we have here is some extcon driver updates, w1
driver updates, a few printk cleanups that weren't needed for 3.5, but
are good to have now, and some other minor fixes/changes in the driver
core.
All of these have been in the linux-next releases for a while now.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>"
* tag 'driver-core-3.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (38 commits)
printk: Export struct log size and member offsets through vmcoreinfo
Drivers: hv: Change the hex constant to a decimal constant
driver core: don't trigger uevent after failure
extcon: MAX77693: Add extcon-max77693 driver to support Maxim MAX77693 MUIC device
sysfs: fail dentry revalidation after namespace change fix
sysfs: fail dentry revalidation after namespace change
extcon: spelling of detach in function doc
extcon: arizona: Stop microphone detection if we give up on it
extcon: arizona: Update cable reporting calls and split headset
PM / Runtime: Do not increment device usage counts before probing
kmsg - do not flush partial lines when the console is busy
kmsg - export "continuation record" flag to /dev/kmsg
kmsg - avoid warning for CONFIG_PRINTK=n compilations
kmsg - properly print over-long continuation lines
driver-core: Use kobj_to_dev instead of re-implementing it
driver-core: Move kobj_to_dev from genhd.h to device.h
driver core: Move deferred devices to the end of dpm_list before probing
driver core: move uevent call to driver_register
driver core: fix shutdown races with probe/remove(v3)
Extcon: Arizona: Add driver for Wolfson Arizona class devices
...
The dentry parameter in debugfs_remove() and debugfs_remove_recursive()
is checked being a NULL pointer. To make cleanup by callers easier this
check is extended using the IS_ERR_OR_NULL macro instead because the
debugfs_create_... functions can return a ERR_PTR() value.
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Many users of debugfs copy the implementation of default_open() when
they want to support a custom read/write function op. This leads to a
proliferation of the default_open() implementation across the entire
tree.
Now that the common implementation has been consolidated into libfs we
can replace all the users of this function with simple_open().
This replacement was done with the following semantic patch:
<smpl>
@ open @
identifier open_f != simple_open;
identifier i, f;
@@
-int open_f(struct inode *i, struct file *f)
-{
(
-if (i->i_private)
-f->private_data = i->i_private;
|
-f->private_data = i->i_private;
)
-return 0;
-}
@ has_open depends on open @
identifier fops;
identifier open.open_f;
@@
struct file_operations fops = {
...
-.open = open_f,
+.open = simple_open,
...
};
</smpl>
[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull vfs pile 1 from Al Viro:
"This is _not_ all; in particular, Miklos' and Jan's stuff is not there
yet."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (64 commits)
ext4: initialization of ext4_li_mtx needs to be done earlier
debugfs-related mode_t whack-a-mole
hfsplus: add an ioctl to bless files
hfsplus: change finder_info to u32
hfsplus: initialise userflags
qnx4: new helper - try_extent()
qnx4: get rid of qnx4_bread/qnx4_getblk
take removal of PF_FORKNOEXEC to flush_old_exec()
trim includes in inode.c
um: uml_dup_mmap() relies on ->mmap_sem being held, but activate_mm() doesn't hold it
um: embed ->stub_pages[] into mmu_context
gadgetfs: list_for_each_safe() misuse
ocfs2: fix leaks on failure exits in module_init
ecryptfs: make register_filesystem() the last potential failure exit
ntfs: forgets to unregister sysctls on register_filesystem() failure
logfs: missing cleanup on register_filesystem() failure
jfs: mising cleanup on register_filesystem() failure
make configfs_pin_fs() return root dentry on success
configfs: configfs_create_dir() has parent dentry in dentry->d_parent
configfs: sanitize configfs_create()
...
This was done to resolve a merge and build problem with the
drivers/acpi/processor_driver.c file.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cautious admins may want to restrict access to debugfs. Currently a
manual chown/chmod e.g. in an init script is needed to achieve that.
Distributions that want to make the mount options configurable need
to add extra config files. By allowing to set the root inode's uid,
gid and mode via mount options no such hacks are needed anymore.
Instead configuration becomes straight forward via fstab.
Signed-off-by: Ludwig Nussel <ludwig.nussel@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Fix new kernel-doc warnings:
Warning(fs/debugfs/file.c:556): No description found for parameter 'nregs'
Warning(fs/debugfs/file.c:556): Excess function parameter 'mregs' description in 'debugfs_print_regs32'
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (165 commits)
reiserfs: Properly display mount options in /proc/mounts
vfs: prevent remount read-only if pending removes
vfs: count unlinked inodes
vfs: protect remounting superblock read-only
vfs: keep list of mounts for each superblock
vfs: switch ->show_options() to struct dentry *
vfs: switch ->show_path() to struct dentry *
vfs: switch ->show_devname() to struct dentry *
vfs: switch ->show_stats to struct dentry *
switch security_path_chmod() to struct path *
vfs: prefer ->dentry->d_sb to ->mnt->mnt_sb
vfs: trim includes a bit
switch mnt_namespace ->root to struct mount
vfs: take /proc/*/mounts and friends to fs/proc_namespace.c
vfs: opencode mntget() mnt_set_mountpoint()
vfs: spread struct mount - remaining argument of next_mnt()
vfs: move fsnotify junk to struct mount
vfs: move mnt_devname
vfs: move mnt_list to struct mount
vfs: switch pnode.h macros to struct mount *
...
"debugfs: add tools to printk 32-bit registers" adds new functions which rely
on IOMEM functionality which is not present on all architectures and therefore
result in compile errors:
fs/debugfs/file.c: In function 'debugfs_print_regs32':
fs/debugfs/file.c:561:7: error: implicit declaration of function 'readl' [-Werror=implicit-function-declaration]
Add an #ifdef CONFIG_HAS_IOMEM to fix this
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Alessandro Rubini <rubini@gnudd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The cast here causes a Sparse warning:
fs/debugfs/file.c:561:42: warning: cast removes address space of expression
fs/debugfs/file.c:561:42: warning: incorrect type in argument 1 (different address spaces)
fs/debugfs/file.c:561:42: expected void const volatile [noderef] <asn:2>*addr
fs/debugfs/file.c:561:42: got void *<noident>
It's redundant to cast it to a (void *) anyway when it is already a
(void __iomem *).
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The regs32 machinery uses readl. I forgot the mandatory include
and the code was not compiling on all archs.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Some debugfs file I deal with are mostly blocks of registers,
i.e. lines of the form "<name> = 0x<value>". Some files are only
registers, some include registers blocks among other material. This
patch introduces data structures and functions to deal with both
cases. I expect more users of this over time.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
Acked-by: Giancarlo Asnaghi <giancarlo.asnaghi@st.com>
Cc: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The file is fs/debugfs/inode.c but the comment says it is file.c.
This patch can fix this little mistake.
Signed-off-by: Harry Wei <harryxiyou@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Enabling DEBUG_STRICT_USER_COPY_CHECKS causes the following
warning:
In file included from arch/x86/include/asm/uaccess.h:573,
from include/linux/uaccess.h:5,
from include/linux/highmem.h:7,
from include/linux/pagemap.h:10,
from fs/debugfs/file.c:18:
In function 'copy_from_user',
inlined from 'write_file_bool' at fs/debugfs/file.c:435:
arch/x86/include/asm/uaccess_64.h:65: warning: call to
'copy_from_user_overflow' declared with attribute warning:
copy_from_user() buffer size is not provably correct
presumably due to buf_size being signed causing GCC to fail to
see that buf_size can't become negative.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
No functional changes requires that we eat errors from strtobool.
If people want to not do this, then it should be fixed at a later date.
V2: Simplification suggested by Rusty Russell removes the need for
additional variable ret.
Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
