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New method: ->iterate_shared(). Same arguments as in ->iterate(),
called with the directory locked only shared. Once all filesystems
switch, the old one will be gone.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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same as read() on regular files has, and for the same reason.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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ta-da!
The main issue is the lack of down_write_killable(), so the places
like readdir.c switched to plain inode_lock(); once killable
variants of rwsem primitives appear, that'll be dealt with.
lockdep side also might need more work
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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If we *do* run into an in-lookup match, we need to wait for it to
cease being in-lookup. Fortunately, we do have unused space in
in-lookup dentries - d_lru is never looked at until it stops being
in-lookup.
So we can stash a pointer to wait_queue_head from stack frame of
the caller of ->lookup(). Some precautions are needed while
waiting, but it's not that hard - we do hold a reference to dentry
we are waiting for, so it can't go away. If it's found to be
in-lookup the wait_queue_head is still alive and will remain so
at least while ->d_lock is held. Moreover, the condition we
are waiting for becomes true at the same point where everything
on that wq gets woken up, so we can just add ourselves to the
queue once.
d_alloc_parallel() gets a pointer to wait_queue_head_t from its
caller; lookup_slow() adjusted, d_add_ci() taught to use
d_alloc_parallel() if the dentry passed to it happens to be
in-lookup one (i.e. if it's been called from the parallel lookup).
That's pretty much it - all that remains is to switch ->i_mutex
to rwsem and have lookup_slow() take it shared.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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We will need to be able to check if there is an in-lookup
dentry with matching parent/name. Right now it's impossible,
but as soon as start locking directories shared such beasts
will appear.
Add a secondary hash for locating those. Hash chains go through
the same space where d_alias will be once it's not in-lookup anymore.
Search is done under the same bitlock we use for modifications -
with the primary hash we can rely on d_rehash() into the wrong
chain being the worst that could happen, but here the pointers are
buggered once it's removed from the chain. On the other hand,
the chains are not going to be long and normally we'll end up
adding to the chain anyway. That allows us to avoid bothering with
->d_lock when doing the comparisons - everything is stable until
removed from chain.
New helper: d_alloc_parallel(). Right now it allocates, verifies
that no hashed and in-lookup matches exist and adds to in-lookup
hash.
Returns ERR_PTR() for error, hashed match (in the unlikely case it's
been found) or new dentry. In-lookup matches trigger BUG() for
now; that will change in the next commit when we introduce waiting
for ongoing lookup to finish. Note that in-lookup matches won't be
possible until we actually go for shared locking.
lookup_slow() switched to use of d_alloc_parallel().
Again, these commits are separated only for making it easier to
review. All this machinery will start doing something useful only
when we go for shared locking; it's just that the combination is
too large for my taste.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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We'll need to verify that there's neither a hashed nor in-lookup
dentry with desired parent/name before adding to in-lookup set.
One possible solution would be to hold the parent's ->d_lock through
both checks, but while the in-lookup set is relatively small at any
time, dcache is not. And holding the parent's ->d_lock through
something like __d_lookup_rcu() would suck too badly.
So we leave the parent's ->d_lock alone, which means that we watch
out for the following scenario:
* we verify that there's no hashed match
* existing in-lookup match gets hashed by another process
* we verify that there's no in-lookup matches and decide
that everything's fine.
Solution: per-directory kinda-sorta seqlock, bumped around the times
we hash something that used to be in-lookup or move (and hash)
something in place of in-lookup. Then the above would turn into
* read the counter
* do dcache lookup
* if no matches found, check for in-lookup matches
* if there had been none of those either, check if the
counter has changed; repeat if it has.
The "kinda-sorta" part is due to the fact that we don't have much spare
space in inode. There is a spare word (shared with i_bdev/i_cdev/i_pipe),
so the counter part is not a problem, but spinlock is a different story.
We could use the parent's ->d_lock, and it would be less painful in
terms of contention, for __d_add() it would be rather inconvenient to
grab; we could do that (using lock_parent()), but...
Fortunately, we can get serialization on the counter itself, and it
might be a good idea in general; we can use cmpxchg() in a loop to
get from even to odd and smp_store_release() from odd to even.
This commit adds the counter and updating logics; the readers will be
added in the next commit.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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marked as such when (would be) parallel lookup is about to pass them
to actual ->lookup(); unmarked when
* __d_add() is about to make it hashed, positive or not.
* __d_move() (from d_splice_alias(), directly or via
__d_unalias()) puts a preexisting dentry in its place
* in caller of ->lookup() if it has escaped all of the
above. Bug (WARN_ON, actually) if it reaches the final dput()
or d_instantiate() while still marked such.
As the result, we are guaranteed that for as long as the flag is
set, dentry will
* remain negative unhashed with positive refcount
* never have its ->d_alias looked at
* never have its ->d_lru looked at
* never have its ->d_parent and ->d_name changed
Right now we have at most one such for any given parent directory.
With parallel lookups that restriction will weaken to
* only exist when parent is locked shared
* at most one with given (parent,name) pair (comparison of
names is according to ->d_compare())
* only exist when there's no hashed dentry with the same
(parent,name)
Transition will take the next several commits; unfortunately, we'll
only be able to switch to rwsem at the end of this series. The
reason for not making it a single patch is to simplify review.
New primitives: d_in_lookup() (a predicate checking if dentry is in
the in-lookup state) and d_lookup_done() (tells the system that
we are done with lookup and if it's still marked as in-lookup, it
should cease to be such).
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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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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will be needed as soon as lookups are not serialized by ->i_mutex
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Right now ext2_get_page() (and its analogues in a bunch of other filesystems)
relies upon the directory being locked - the way it sets and tests Checked and
Error bits would be racy without that. Switch to a slightly different scheme,
_not_ setting Checked in case of failure. That way the logics becomes
if Checked => OK
else if Error => fail
else if !validate => fail
else => OK
with validation setting Checked or Error on success and failure resp. and
returning which one had happened. Equivalent to the current logics, but unlike
the current logics not sensitive to the order of set_bit, test_bit getting
reordered by CPU, etc.
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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... and explain the non-obvious logics in case when lookup yields
a different dentry.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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... and have it use inode_lock()
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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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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grab a reference to dentry we'd got the sucker from, and return
that dentry via *wait, rather than just returning the address of
->i_mutex.
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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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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The rest of work.xattr stuff isn't needed for this branch
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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... and do not assume they are already attached to each other
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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reiserfs_xattr_[sg]et() will fail with -EOPNOTSUPP for V1 inodes anyway,
and all reiserfs instances of ->[sg]et() call it and so does ->set_acl().
Checks for name length in the instances had been bogus; they should've
been "bugger off if it's _exactly_ the prefix" (as generic would
do on its own) and not "bugger off if it's shorter than the prefix" -
that can't happen.
xattr_full_name() is needed to adjust for the fact that generic instances
will skip the prefix in the name passed to ->[gs]et(); reiserfs homegrown
analogues didn't.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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none of that stuff can ever be called for NULL or negative
dentry.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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... and neither can ever be NULL
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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acl_by_type(inode, type) returns a pointer to either inode->i_acl or
inode->i_default_acl depending on type. This is useful in
fs/posix_acl.c, but should never have been visible outside that file.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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When get_acl() is called for an inode whose ACL is not cached yet, the
get_acl inode operation is called to fetch the ACL from the filesystem.
The inode operation is responsible for updating the cached acl with
set_cached_acl(). This is done without locking at the VFS level, so
another task can call set_cached_acl() or forget_cached_acl() before the
get_acl inode operation gets to calling set_cached_acl(), and then
get_acl's call to set_cached_acl() results in caching an outdate ACL.
Prevent this from happening by setting the cached ACL pointer to a
task-specific sentinel value before calling the get_acl inode operation.
Move the responsibility for updating the cached ACL from the get_acl
inode operations to get_acl(). There, only set the cached ACL if the
sentinel value hasn't changed.
The sentinel values are chosen to have odd values. Likewise, the value
of ACL_NOT_CACHED is odd. In contrast, ACL object pointers always have
an even value (ACLs are aligned in memory). This allows to distinguish
uncached ACLs values from ACL objects.
In addition, switch from guarding inode->i_acl and inode->i_default_acl
upates by the inode->i_lock spinlock to using xchg() and cmpxchg().
Filesystems that do not want ACLs returned from their get_acl inode
operations to be cached must call forget_cached_acl() to prevent the VFS
from doing so.
(Patch written by Al Viro and Andreas Gruenbacher.)
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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The get_acl inode operation is called only when no ACL is cached. It
makes no sense to check for a cached ACL as the first thing inside such
inode operations.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.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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Pull ARM fixes from Russell King:
"A couple of small fixes, and wiring up the new syscalls which appeared
during the merge window"
* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
ARM: 8550/1: protect idiv patching against undefined gcc behavior
ARM: wire up preadv2 and pwritev2 syscalls
ARM: SMP enable of cache maintanence broadcast
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It was reported that a kernel with CONFIG_ARM_PATCH_IDIV=y stopped
booting when compiled with the upcoming gcc 6. Turns out that turning
a function address into a writable array is undefined and gcc 6 decided
it was OK to omit the store to the first word of the function while
still preserving the store to the second word.
Even though gcc 6 is now fixed to behave more coherently, it is a
mystery that gcc 4 and gcc 5 actually produce wanted code in the kernel.
And in fact the reduced test case to illustrate the issue does indeed
break with gcc < 6 as well.
In any case, let's guard the kernel against undefined compiler behavior
by hiding the nature of the array location as suggested by gcc
developers.
Reference: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70128
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reported-by: Marcin Juszkiewicz <mjuszkiewicz@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: stable@vger.kernel.org # v4.5
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Wire up the preadv2 and pwritev2 syscalls for ARM.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Masahiro Yamada reports that we can fail to set the FW bit in the
auxiliary control register, which enables broadcasting the cache
maintanence operations. This occurs because we only check that the
SMP/nAMP bit is set, rather than checking whether all the bits we
want to be set are set.
Rearrange the code to ensure that all desired bits are set, and only
update the register if we discover some required bits are not set.
Tested-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Pull MMC fixes from Ulf Hansson:
"Here are a couple of mmc fixes intended for v4.6 rc3:
MMC host:
- sdhci: Fix regression setting power on Trats2 board
- sdhci-pci: Add support and PCI IDs for more Broxton host controllers"
* tag 'mmc-v4.6-rc1' of git://git.linaro.org/people/ulf.hansson/mmc:
mmc: sdhci-pci: Add support and PCI IDs for more Broxton host controllers
mmc: sdhci: Fix regression setting power on Trats2 board
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Add support and PCI IDs for more Broxton host controllers
Other BXT IDs were added in v4.4 so cc'ing stable. This patch
is dependent on commit 163cbe31e516 ("mmc: sdhci-pci: Fix card
detect race for Intel BXT/APL") but that is already in stable
since v4.4.4.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org # v4.4+
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
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Several commits relating to setting power have been introducing
problems by putting driver-specific rules into generic SDHCI code.
Krzysztof Kozlowski reported that after commit 918f4cbd4340 ("mmc:
sdhci: restore behavior when setting VDD via external regulator")
on Trats2 board there are warnings for invalid VDD value (2.8V):
[ 3.119656] ------------[ cut here ]------------
[ 3.119666] WARNING: CPU: 3 PID: 90 at
../drivers/mmc/host/sdhci.c:1234 sdhci_do_set_ios+0x4cc/0x5e0
[ 3.119669] mmc0: Invalid vdd 0x10
[ 3.119673] Modules linked in:
[ 3.119679] CPU: 3 PID: 90 Comm: kworker/3:1 Tainted: G W
4.5.0-next-20160324 #23
[ 3.119681] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[ 3.119690] Workqueue: events_freezable mmc_rescan
[ 3.119708] [<c010e0ac>] (unwind_backtrace) from [<c010ae10>]
(show_stack+0x10/0x14)
[ 3.119719] [<c010ae10>] (show_stack) from [<c0323260>]
(dump_stack+0x88/0x9c)
[ 3.119728] [<c0323260>] (dump_stack) from [<c011b754>] (__warn+0xe8/0x100)
[ 3.119734] [<c011b754>] (__warn) from [<c011b7a4>]
(warn_slowpath_fmt+0x38/0x48)
[ 3.119740] [<c011b7a4>] (warn_slowpath_fmt) from [<c0527d28>]
(sdhci_do_set_ios+0x4cc/0x5e0)
[ 3.119748] [<c0527d28>] (sdhci_do_set_ios) from [<c0528018>]
(sdhci_runtime_resume_host+0x60/0x114)
[ 3.119758] [<c0528018>] (sdhci_runtime_resume_host) from
[<c0402570>] (__rpm_callback+0x2c/0x60)
[ 3.119767] [<c0402570>] (__rpm_callback) from [<c04025c4>]
(rpm_callback+0x20/0x80)
[ 3.119773] [<c04025c4>] (rpm_callback) from [<c04034b8>]
(rpm_resume+0x36c/0x558)
[ 3.119780] [<c04034b8>] (rpm_resume) from [<c04036f0>]
(__pm_runtime_resume+0x4c/0x64)
[ 3.119788] [<c04036f0>] (__pm_runtime_resume) from [<c0512728>]
(__mmc_claim_host+0x170/0x1b0)
[ 3.119795] [<c0512728>] (__mmc_claim_host) from [<c0514e2c>]
(mmc_rescan+0x54/0x348)
[ 3.119807] [<c0514e2c>] (mmc_rescan) from [<c0130dac>]
(process_one_work+0x120/0x3f4)
[ 3.119815] [<c0130dac>] (process_one_work) from [<c01310b8>]
(worker_thread+0x38/0x554)
[ 3.119823] [<c01310b8>] (worker_thread) from [<c01365a4>]
(kthread+0xdc/0xf4)
[ 3.119831] [<c01365a4>] (kthread) from [<c0107878>]
(ret_from_fork+0x14/0x3c)
[ 3.119834] ---[ end trace a22d652aa3276886 ]---
Fix by adding a 'set_power' callback and restoring the default
behaviour prior to commit 918f4cbd4340 ("mmc: sdhci: restore
behavior when setting VDD via external regulator"). The desired
behaviour of that commit is gotten by having sdhci-pxav3 provide
its own set_power callback.
Reported-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Link: http://lkml.kernel.org/r/CAJKOXPcGDnPm-Ykh6wHqV1YxfTaov5E8iVqBoBn4OJc7BnhgEQ@mail.gmail.com
Fixes: 918f4cbd4340 ("mmc: sdhci: restore behavior when setting VDD...)
Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Tested-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org # v4.5+
Reviewed-by: Jisheng Zhang <jszhang@marvell.com>
Tested-by: Jisheng Zhang <jszhang@marvell.com>
Tested-by: Jaehoon Chung <jh80.chung@samsung.com>
Tested-by: Anand Moon <linux.amoon@gmail.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c fixes from Wolfram Sang:
"Some bugfixes from I2C:
- fix a uevent triggered boot problem by removing a useless debug
print
- fix sysfs-attributes of the new i2c-demux-pinctrl driver to follow
standard kernel behaviour
- fix a potential division-by-zero error (needed two takes)"
* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
i2c: jz4780: really prevent potential division by zero
Revert "i2c: jz4780: prevent potential division by zero"
i2c: jz4780: prevent potential division by zero
i2c: mux: demux-pinctrl: Update docs to new sysfs-attributes
i2c: mux: demux-pinctrl: Clean up sysfs attributes
i2c: prevent endless uevent loop with CONFIG_I2C_DEBUG_CORE
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Make sure we avoid a division-by-zero OOPS in case clock-frequency is
set too low in DT. Add missing '\n' while we are here.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Axel Lin <axel.lin@ingics.com>
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This reverts commit 34cf2acdafaa31a13821e45de5ee896adcd307b1. 'ret' is
not set when bailing out. Also, there is a better place to check for 0.
Reported-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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Make sure we don't OOPS in case clock-frequency is set to 0 in a DT. The
variable set here is later used as a divisor.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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Update the docs according to the recent code changes, too.
Fixes: c0c508a418f9da ("i2c: mux: demux-pinctrl: Clean up sysfs attributes")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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sysfs attributes should use the same format for reads and writes,
rather than pretty-printing on read.
* Make the "cur_master" attribute read back as just the name of the
master
* Expose the list of all masters as a read-only "available_masters"
attribute, using space separators as in similar attributes of other
devices
Also, spell out "cur_master" in full as "current_master".
Fixes: 50a5ba876908 ("i2c: mux: demux-pinctrl: add driver")
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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Jan reported this:
===
After enabling CONFIG_I2C_DEBUG_CORE my system was broken
(no network, console login not possible). System log was
flooded with the this message:
...
[ 608.052077] rtc-ds1307 0-0068: uevent
[ 608.052500] rtc-ds1307 0-0068: uevent
[ 608.052925] rtc-ds1307 0-0068: uevent
...
The culprit is the dev_dbg printk in the i2c uevent handler.
If this is activated (for instance by CONFIG_I2C_DEBUG_CORE)
it results in an endless loop with systemd-journald.
This happens if user-space scans the system log and reads the uevent
file to get information about a newly created device, which seems fair
use to me. Unfortunately reading the "uevent" file uses the same
function that runs for creating the uevent for a new device,
generating the next syslog entry.
Ideally user-space would implement a recursion detection and
after reading the same device file for the 1000th time call it a
day, but nevertheless I think we should avoid this problem by
removing the debug print completely or using another print variant.
The same problem seems to be reported here:
https://bugs.freedesktop.org/show_bug.cgi?id=76886
===
His patch converted the message to pr_debug, but I think the debug can
simply go. We have other means to see code paths these days. This
enables us to clean up the function some more while we are here.
Reported-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Tested-by: Jan Glauber <jglauber@cavium.com>
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This reverts commit 1028b55bafb7611dda1d8fed2aeca16a436b7dff.
It's broken: it makes ext4 return an error at an invalid point, causing
the readdir wrappers to write the the position of the last successful
directory entry into the position field, which means that the next
readdir will now return that last successful entry _again_.
You can only return fatal errors (that terminate the readdir directory
walk) from within the filesystem readdir functions, the "normal" errors
(that happen when the readdir buffer fills up, for example) happen in
the iterorator where we know the position of the actual failing entry.
I do have a very different patch that does the "signal_pending()"
handling inside the iterator function where it is allowable, but while
that one passes all the sanity checks, I screwed up something like four
times while emailing it out, so I'm not going to commit it today.
So my track record is not good enough, and the stars will have to align
better before that one gets committed. And it would be good to get some
review too, of course, since celestial alignments are always an iffy
debugging model.
IOW, let's just revert the commit that caused the problem for now.
Reported-by: Greg Thelen <gthelen@google.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux
Pull parisc fixes from Helge Deller:
"Since commit 0de798584bde ("parisc: Use generic extable search and
sort routines") module loading is boken on parisc, because the parisc
module loader wasn't prepared for the new R_PARISC_PCREL32 relocations.
In addition, due to that breakage, Mikulas Patocka noticed that
handling exceptions from modules probably never worked on parisc. It
was just masked by the fact that exceptions from modules don't happen
during normal use.
This patch series fixes those issues and survives the tests of the
lib/test_user_copy kernel module test. Some patches are tagged for
stable"
* 'parisc-4.6-3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
parisc: Update comment regarding relative extable support
parisc: Unbreak handling exceptions from kernel modules
parisc: Fix kernel crash with reversed copy_from_user()
parisc: Avoid function pointers for kernel exception routines
parisc: Handle R_PARISC_PCREL32 relocations in kernel modules
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Update the comment to reflect the changes of commit 0de7985 (parisc: Use
generic extable search and sort routines).
Signed-off-by: Helge Deller <deller@gmx.de>
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Handling exceptions from modules never worked on parisc.
It was just masked by the fact that exceptions from modules
don't happen during normal use.
When a module triggers an exception in get_user() we need to load the
main kernel dp value before accessing the exception_data structure, and
afterwards restore the original dp value of the module on exit.
Noticed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org
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The kernel module testcase (lib/test_user_copy.c) exhibited a kernel
crash on parisc if the parameters for copy_from_user were reversed
("illegal reversed copy_to_user" testcase).
Fix this potential crash by checking the fault handler if the faulting
address is in the exception table.
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>
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We want to avoid the kernel module loader to create function pointers
for the kernel fixup routines of get_user() and put_user(). Changing
the external reference from function type to int type fixes this.
This unbreaks exception handling for get_user() and put_user() when
called from a kernel module.
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org
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